notes on a dynamic theory of vision - Visual Edge

NOTES ON A DYNAMIC THEORY OF VISION

Compiled and Published by Optometric Extension Program Foundation, Inc. Copyright 1958. All rights reserved. No part of this book may be reproduced in any form or by any means without permission in writing from the publisher. @

Optometric Extension Program Foundation, Inc. 1921 E. Carnegie Avenue, Suite 3L Santa Ana, CA 92705-5510 (949) 250-8070

NOTES O N A

THEORY OF

O

V

DARELL BOYD HARMON

V O L U M E ONE MOVEMENT, POSTURE AND VISION

THIRD REVISION

1958

--

A

S T U D Y

A N D

D I S C U S S I O N

OUTLI,NE

C o p y r i g h t 1958, b y Dare11 Boyd Harmon A L L RIGHTS RESERVED These Notes, or any part o f them, may not be published i n any form without written permission o f the author. FOR CONFERENCE O R SEMINAR USE O N L Y These Notes are based on, and a revision of: NOTES O N A D Y N A M I C THEORY O F VISION, 1954; REVISED NOTES O N A D Y N A M I C THEORY O F VIS I O N , 1955; and, NOTES O N A D Y N A M I C THEORY O F VISION, Second Revision, 1957. Published b y the Author Austin, Texas

Printed i n the United States of America

FOREWORD "A

DYNAMIC THEORY O F VISION"

A theory is constructed f r o m an evaluation of the existing facts in any given a r e a in o r d e r to bring meaning to that a r e a , provide direction for the acquisition of m o r e facts, and, furnish guidance to those who would apply both f a c t s and accompanying concepts in solving problems. Being conceptional, a theory alone i s n e v e r right o r wrong- -it i s m e r e l y applicable o r inapplicable in solving c e r t a i n p r o b l e m s a t the levelof the solution required.

U p to now the only formally stated theory of vision i s one which i s l a r g e l y optical. An optical theory of vision m a y b e adequate and applicable to p r o b l e m s in the fie1d.s of eye anatomy, eye surgery, physiological opt i c s , o r refraction. That i s beside o u r point h e r e , Advancing r e s e a r c h in human function h a s brought with it the development of present-day concepts of the significance of the total organism in the p r o c e s s e s of growth in development, in theories of learning, in human p e r formance, and, in applications of dynamics to problems of human behavior. An optical theory of vision i s inadequate and inapplicable in studying the function and operations of vision related to these and cornparable a r e a s . An optical theory i s atomistic and, a t t i m e s , static. T h e s e newer a r e a s require a b r o a d e r , holistic, and dynamic theory of vision. These notes a r e a n effort to sketch out s o m e o b s e r v a tions which the author believes m u s t be taken into a c count in constructing such a dynamic theory of vision.

--Dare11 Boyd H a r m o n

M a t e r i a l a n d Sections i n this outline have been used, i n p a r t , i n papers presented a t a number o f professional a n d t e c h n i c a l meetings. Portions have b e e n i n c l u d e d i n presentations m a d e

a t t h e following meetings: Royal C a n a d i a n

Institute

. . . . .

Sixteenth A n n u a l M e e t i n g , A m e r i c a n A c a d e m y o f Pediatrics

.

51st A n n u a l Congress, A m e r i c a n O ~ t o m e t r i c Association

March, 1947

December, 1947

. .

June, 1948

97th A n n u a l Session, Scientific Assembly, A m e r i c a n M e d i c a l Association

June, 1948

. . .

A n n u a l Symposia, Pennsylvania Society oC Archiiecfs, A p r i l , 1950 A m e r i c a n Institute o f A r c h i t e c t s

. . .

N a t i o n a l Technical C o n f e r e n c e , I l l u m i n a t i n g Engineering Society

.

September, 1952

C o n f e r e n c e o n Vision, Bricjhtness, a n d Design, Sept., 1953 Massachusetts I n s t i t u t e o f Technology

.

This outline, i n its first a n d second revised forms, p r o v i d e d t h c basis f o r a d v a n c e d Seminar: o f the O p t o r n e t r i c Extension Program, held i n Chicago, 1955; Pittsburgh, 1955 a n d 1957: Elmira, 1956: Minneapolis, 1956; M o n t r e a l , 1956; Kansas C i t y , 1957; Cincinnati, 1957; a n d N e w Orleans, 1957.

CONTENTS '% D Y N A M I C T H E O R Y O F V I S I O N " Volume One

MOVEMENT, POSTURE, AND VlSlON

...

Foreword .............................................................................................................. 1 1 I Contents ................................................................................................................ v Chapter I , l NTRODUCTION ............................................................................ I

PART ONE VISION: Chapter Chapter Chapter Chapter Chapier Chapter

Is it Perceptual Only?

SOME PRELIMINARY OBSERVATIONS AND CONCLUSIONS SOME FURTHER CONCLUSIONS............................................ "HIGHER" AND "LOWER" FUNCTIONS........... . . ................. SOME BASIC CONSIDERATIONS.. .............................................. 6, IF VISION INCLUDES PERFORMANCE...................................... 7, VISION MUST SERVE TWO FUNCTIONS..... .............................

2, 3, 4, 5,

7 13 27

35 46

56

PART TWO The Role of Posture and Movement in VISION Chapter Chapter Chapter Chapter Chapter Chapter

8, 9, 10, II, 12, 13,

DEVELOPING A DYNAMIC THEORY-OF VISION .................. 60 A LIGHT GRADIENT DETECTOR............. . . ......................... 64 A '"SIGHTING" MECHANISM.............................................. 68 A SPATIAL FRAME OF REFERENCE....................................... 72 A SPACE ANALYZER.................................................. . . 77 THE ROLE OF POSTURE IN VISION .......................................... 88

A General Footnote..............................................................:...............................103 APPENDICES Appendix I , Appendix 11, Appendix I I I, Appendix..lV, ., Appendix V, Appendix VI,

Selected Bibliography .............. .................................................. A- l An Annotated Bibliography................................................... A-5 Evolution of Structure.................................. . . . .................. A-9 Vision, Body Mechanics, and Performance................................ A- 17 Vision, ~ighting,and Learning................................................. A-29 A Brief Glossary.......................................................................... A-37

NOTE: for the reader's convenience the main text has been organized in outline form and printed on right-hand pages only. Left-hand pages have been used for illustrations, tables, explanatory comments, and the like. Space has also been provided on some left-hand pages for the reader t o make his own notes.

"The reorganization of visual habits so that we perceive n o t isolated 'things' in 'space,' b u t structure, order, and, the relatedness o f events i n space-time, i s perhaps the most profound kind o f revolution possible-a t i o n t h a t i s long overdue.

-S.

revoiu-

. . ." I. HAYAKAWA

f r o m the lntjoduciion t o "Language o f Vision" b y G y o r g y Kepes " O n e cannot avoid seeing, beyond every special configura-tion, t h e force, the speed and t h e direction o f movement which created

it.

. . ."

-GYORGY

KEPES

i n "The Language o f Vision"

Chapter 1

INTRODUCTION E v e r y student and p r a c t i t i o n e r working in the v i s u a l s c i e n c e s a g r e e s that the eye i s a complex optical m e c h a n i s m having a n adjustable l e n s s y s t e m which, when accommodated, p r o j e c t s a resolvedlight g r a d i e n t onto a photosensitive l a y e r of r e c e p t o r s . T h e s e r e c e p t o r s , in t u r n , on excitation instigate a signal patt e r n r e p r e s e n t i n g t h a t light gradient i n n e u r a l pathways leading f r o m them to c e r t a i n a r e a s of the brain, .i

Yl. l . 1 0

1.1.1.1.

Equal a g r e e m e n t e x i s t s that the operation of the o c u l a r mechani s m s i s lawful, and t h a t the s t r u c t u r e of the e y e s , t h e i r adnexa, and t h e i r n e u r a l connections m u s t be maintained in a n optimum state of functioning f o r effective vision, The highest type of skilled professional attention i s needed when t h e r e i s i n t e r f e r e n c e with eye s t r u c t u r e o r functioning.

A n extensive l i t e r a t u r e e x i s t s on the anatomy, physiology, and pathology of the eye and o c u l a r l y - r e l a t e d s t r u c t u r e s . T h e r e i s a l s o a voluminous l i t e r a t u r e on physiological and psychological optics, and on p h y s i c a l optics and illumination a s t h e s e two latt e r fields r e l a t e to tfseeing". All of t h i s l i t e r a t u r e and the r e s e a r c h behind i t h a s contributed i m m e a s u r a b l y t o maintaining, promoting, and enhancing human vision in a society s o dependent upon v i s u a l communication.

-

1.1.1.2.

But what is Vision? Page 1

"A

DYNAMIC THEORY OF VISION"

INTRODUCTION

Is vision a s e n s o r y o r a sensorimotor p r o c e s s ? Is it concerned only with resolving a n image of visual space and objects in that space, o r , i s it concerned a l s o with eliciting and directing p e r formance toward that s p a c e and those objects? How i s visual meaning acquired ? What i s the contribution of visual mechanisms in associating visual symbols with t h e concepts for which those symbols s t a n d ? Is f'awarenessllof the visual space world derived solely f r o m the immediate neural input originating a t the central retina, o r , do neural signal patterns f r o m o t h e r o r i gins, past and p r e s e n t , e n t e r into vision? A r e visual mechanisms adaptable? Do only the eyes and immediately related s t r u c t u r e s (including the optic t r a c t and visual a r e a s of the brain) e n t e r into visual proce s s e s , o r , do other organic s t r u c t u r e s and p r o c e s s e s contribute to visual perception, identification, meaning, and p e r f o r m a n c e ? Do optical laws alone govern visual p r o c e s s e s , o r does satisfaction of other physical laws a l s o enter into effective v i s i o n ?

y1.2.1.

Agreement is f a r f r o m unanimous among the professional fields concerned with vision a s t o answers for t h e s e and a multitude of other questions. In f a c t , that p a r t of the l i t e r a t u r e in which ans w e r s to these questions shouldbe found e x p r e s s e s philosophies of vision ra.nging f r o m "vision consists of s e v e r a l distinct p r o c e s s e s .,.(which). ..must a l l be r e l a t e d in some way to the anatomical and chemical s t r u c t u r e of the retina1!, on to "seeing i s m o r e than (ocu l a r ) function., It i s a n activity of the human b e i n g t f .

.

1. 2 . 1 . 1.

Since the days of Helmholtz, preoccupation of both investigators and clinicians with o c u l a r mechanisms and ocularly- related proce s s e s (all s o apparently optical!)--a preoccupation which s e e m s s o justified b y increasing s o c i a l demand for g r e a t e r efficiencies in symbolic visual communication- -has led to a commonly a'cc epted, if not formally stated, optical model of vision.

This preoccupation with efficient resolution of d e t a i l s of symbols has led to a principal c o n c e r n with central visual field functions, and with these functions a l m o s t as i f answers to the p r o b l e m s they p r e s e n t r e s t solely in an optical o r ocular solution.

Page 2

NOT FOR PAGE 3 § 1.3.3.

A n optical model o f vision is one calling f o r (a) an optical projection o f a resolved i m a g e o f the central visual field onto the retina; (b) a point-by-point receptor system in the central retinal area which can b e activated b y t h e proiected image; (c) a neural system leading f r o m those receptors organized so as t o transmit signals equivalent t o the resolved i m a g e t o some appropriate visual recognition center in the brain; (d) a mechanism related t o the visual recognition cent e r which would p e r m i t the individual t o determine voliiionally any desired actions in relation t o the perceived image o f visual space. A n o p t i c a l model o f vision includes sufficient neural connections and m o t o r adnexa t o provide not only f o r accommodation b u t f o r convergence as well, in order t o maintain retinal correspondence so as t o have a single perceived image through a binocular mechanism. Also, through binocularity, the ocular mechanisms, while maintaining retinal correspondence, must provide sufficient disparity and sensing o f triangulation t o obtain perception o f d e p t h and the three-dimensionality o f visual space. The psychology o f an optical model o f vision i s largely sensory. W i t h i n t h a t psychology i s the implication t h a t visual perception i s derived largely f r o m the light stimulus pattern as it incites t h e cent r a l retina, setting u p a neural configuration whose signals g o on t o higher recognition centers-modified only b y past ocular experiences.

"A

DYNAMIC T H E O R Y OF V I S I O N "

INTRODUCTION

g1. 3 . 1 .

Out of t h i s c o n c e r n s e e m s to have come a physiological optics derived l a r g e l y f r o m the g e o m e t r y of static functions d e m o n s t r a b l e on a n optical bench; a physiological optics--to point out only one r e s u l t of t h i s approach-which rationalizes away the "aberrations of human optics i n t e r m s of the equivalence of projected light-point size to central receptor size,

81.3.2.

In addition, t h i s p r i n c i p a l concern h a s given the m e c h a n i s m s of a c commodation ( t h o s e of resolving the details of the t a s k a t the r e t i n a ) p r e c e d e n c e o v e r m e c h a n i s m s , ( a )for locating t h e t a s k , (b)f o r posturing and supporting the ocular mechanisms in a position adequate f o r s u s t a i n e d , efficient optical function (this d o e s not m e a n what i s f a m i l i a r l y known a s "eyet1posturing), and, ( c )f o r effective v i s u a l control o v e r t h e p e r f o r m a n c e of visually-centered tasks. Accompanying t h i s t r e n d h a s been a strong tendency to r e l e g a t e t h e m o t o r a s p e c t s of visually-centered performance t o ''psychologyf', o r , t o a t t r i b u t e the m o t o r a s p e c t s of such p e r f o r m a n c e to s o m e operational s y s t e m o t h e r than visual. Emphasis on v i s u a l function s e e m s to b e placed on acquisition of information only; and, visual p r o b l e m s a r e explained a s p r o b l e m s that a r e innate i n a n individual's l f e y e s f fe, m e r g i n g with growth o r withuse of e y e s i n acquiring information.

rP1.3.3.

1.3.3.1.

While the definition of a n f l o p t i c a l t f m o d eofl vision that is given on the facing Note page probably i s somewhat exaggerated, it does s e e m to b e implied in the interpretation of v i s u a l p r o c e s s e s in m o s t s t a n d a r d r e f e r e n c e s o u r c e s , in m o s t of the w o r k of visual i n v e s t i g a t o r s , and, i n the daily practice of v i s u a l clinicians. T h e r e i s no intention t o i m p l y i n t h e s e NOTES that s i n c e r e investig a t o r s and w r i t e r s on vision completely omit f r o m t h e i r thinking the f a c t that t h e r e could b e other f a c t o r s in vision than t h e purely o c u l a r . That t h e y d o n o t is too well evidenced in existing l i t e r a t u r e . F o r e x a m p l e , Duke-Elder (I: 1 9 ) s a y s : I

"The e x t r a o r d i n a r y r i c h n e s s of t h e s e a s o r y n e r v e supply of the ext r a - o c u l a r muscles, a s w e l l a s t h e i r intimate connection with the p o s t u r a l c e n t e r s of t h e m i d b r a i n , f o r m an index of t h e important p a r t played by t h e m in the perception of directionll (p. 1 0 6 3 ) . He a l s o points out:

NOT FOR P A G E 4 I .4.

"Dr. H a r m o n contends t h a t the response o f the human organism t o patterns o f light involves the whole organism, rather than merely t h e eyes. There i s little d o u b t t h a t there i s no mode o f response o f t h e human organism which i s entirely independent c f any other. Hence, we must agree t h a t l i g h t patterns will influence all modes o f response t o some extent. The question I have concerns t h e extent 30 which patterns o f light influence other modes of response t h a n t h e sensory a n d oculomotor mechanisms of the visual system, I f i n d i h a t Dr. Harmon's account o f the extent o f influence o f patterns o f l i g h t on the postural responses o f the human organism brings t o mind t h e spectacle o f an insect responding t o lighf stimuli with an heliotropic response. I am sure t h a t such a comparison i s n o t intended b y Dr. Harmon. It does seem t o me, however, that Dr. H a r m o n has put his case t o o strongly. H u m a n beings d o n o t respond in t h e gross, undifferentiated manner o f insects t o any stimulus, certainly n o t t o light patterns. A high degree o f differentiation o f response i s t h e special characteristic o f the human. Of course, differentiation d e pends upon maturation a n d experience. Thus, differentiation increases w i t h age. The adult human is very completely differentiaied. In m y opinion, differentiation is relatively complete i n children o f school age. Thus, I believe t h a t the primary effects o f patterns o f the light are u p o n t h e sensory and oculomotor response mechanisms o f t h e visual system. Dr. Harmon refers specifically t o t h e usefulness o f patterns o f light in providing frames o f visual reference t o the organism i h r o u g h postural responses. I believe it i s entirely a p parent t h a t frames o f v i s i ~ a lreference are developed f r o m sensory and kinaesthetic experience. These frames of reference apparently become firmly established a+ an early age. Subsequent organization o f visual space is n o t appreciably dependent upon kinaesthetic cues. Dr. Harmon's contention t h a t patterns o f light elicit b o d i l y orientations and t h a t these in turn provide the cues f o r the organization o f visual space seems t o m e t o deny the human's ability t o develop d i r e c t a n d efficient mechanisms for dealing with the physical world. Let us agree t h a t we can never consider the eyes as functioning entirely in isolation o f all other bodily functions, b u t le) us realize +hat She p r i m a r y effects o f lighf are upon sensory a n d oculomotor mechanisms o f t h e visual sysfem." -Discussion b y W. Richard Blackwell, Visual Research Laboratory, University o f Michigan, o f " A r e 'A'e Coilfusing Eyes W i t h Vision," b y D. B. H a r m o n , I L L d M i N A T l N G E N G I N E E R I N G , Vol. XLVIII, No. 4, (19531, pp. 21 1-212.

"A

D Y N A M I C T H E O R Y O F VISION"

INTRODUCTION

"It i s too often forgotten, owing to the s t r e s s that h a s been laid on the geometric a s p e c t s of the resolving power of the eye, that the m a t t e r (perception of f o r m and contour) i s not and n e v e r c a n be a purely optical one. (Volume 11, p. 1194).

..

1. 3 . 3 . 2 .

11.4, ,

" i

The question in mind is the relative emphasis given ocular over non-ocular f a c t o r s in vision and visual p r o c e s s e s ; whether c e r t a i n non-ocular f a c t o r s (especially mechanisms of body p o s t u r e and of performance in visually-centered t a s k s ) should be considered p a r t of the visual s y s t e m ; and, whether, if the above non-ocular factors a r e a p a r t of that s y s t e m , their purpose i s t r a n s i t o r y and they s e r v e only during childhood, o r whether they contribute t o eff ective seeing throughout a l l life. The statements of one reputable investigator regarding the relative importance of ocular o v e r non-ocular f a c t o r s in vision well illust r a t e s the emphasis on an tfopticalttmodelthat i s being examined h e r e . The p r e s e n t w r i t e r offered a paper before a technical group in which he s t r e s s e d the place he thought posture might play in vision. (This paper w a s based mostly on m a t e r i a l d i s c u s s e d in Chapter 2 and in Appendix IV of these NOTES.) In commenting on the paper, this investigator said* : "....we m u s t a g r e e that light patterns will influence a l l modes of response t o s o m e extent. The question Ihave concerns the extent t o which patterns of light influence other modes of r e s p o n s e than the s e n s o r y and oculomotor mechanisms of the visual s y s t e m A high d e g r e e of differentiation of response i s the special charact e r i s t i c of the human In m y opinion, differentiation i s relatively complete in children of school age. Thus, I believe that the p r i m a r y effects of p a t t e r n s of light a r e upon the s e n s o r y and oculom o t o r mechanisms of the visual system. ,I I

....

...

..

T h e r e i s no question h e r e a s to whether differentiation of response t o a high d e g r e e is o r is not the specia1cha.racteristic of the human. Differentiation of response IS the product of maturation and experience in man. The experienced, sophisticated p e r s o n uses learned symbols and mnemonic t r a c e s of p a s t experiences extensively a s s u r r o g a t e s f o r movement. Humans l e a r n , gain insight, and simplify and specialize behavior--a11 by doing.

*. - F o r

his full discussion,

s e e the Notes on the facing page.

Page 4

NOT

"A

DYNAMIC THEORY O F V I S I O N "

INTRODUCTION

1.4.1.1.

The r e a l questions h e r e a r e : Do mnemonic t r a c e s gained in e a r l y childhood suffice a s f r a m e s of reference of visual s p a c e throughout a l l life ? Do oculomotor-labyrinthine-neck reflex-posturing m u s cle connections become atrophic o r by-passed a s one grows up? Does "learning b y e x p e r i e n c e t fresolve itself principally t o r e o r ganizations of acquired symbols and l%itsti of m e m o r y t r a c e s of motor function in an adult; o r , do p r i m a r y experiences, physical action, posture, and adaptation continue to play a n important p a r t in an adult's visually-centered learnings ? Do "higher l 1 functions replace ltlower" functions in dealing with the world around us a s one m a t u r e s ? Can Ithigher" functions alone support optics in stand a r d reference positions f o r efficient resolution in sustained t a s k s ? Do only "higherIf c e n t e r s , after learning, move m u s c l e s in performing t a s k s when eyes and hands o r eyes and other musc l e s a r e concerned? Can past 'llearning" and n e u r a l t f r e c o r d st ' of past performances alone furnish the I 1 f e e d b a c k t t n e c e s s a r y f o rcont r o l of accuracy, direction, and the amount s t i l l to b e done in t a s k s centered in vision--a process which, on the s e n s o r y side, Sherringtonclassed a t the top of the list of instigators of behavi o r that a r e tlanticipatorytl,and Mc Culloch implied was concerned with actions which take place Itin the light of continuous information about the consequencesff?

3Jl.4.2.

The amount of data on visionand mechanisms of visual p e r f o r m a n c e already in the l i t e r a t u r e ; the growing i n t e r e s t in sensoritonic theories of perception, and the recent advances of knowledge and concepts in neurophysiologyand comparable a r e a s , a l l point t o the fact that the above and many other questions concerning the nature of vision cannot b e lightly brushed aside because they cannot b e fitted to the p r e s e n t tfopticalrfmodel,

1.4.2.1.

The model of vision implied i n m o s t of the existing works needs to be examined critically. If i t i s found to be inadequate to explain existing data o r to put p r o p e r emphasis on some of that data, then, a new conceptual model of vision i s s o r e l y needed.

Y1.4,3.

These NOTES make no p r e t e n s e of constructing s u c h a new model of human vision. They havebeenbrought together m e r e l y to o r ganize and p r e s e n t s o m e data on vision and visual m e c h a n i s m s that should be considered in a n evaluation of existing m o d e l s , and to d i s c u s s some lines of thinking that might prove profitable to those interested in c o n s t r u c t i n g a philosophy of vision. Page 5

PART

O N E

Chapter 2 SOME PRELIMINARY OBSERVATIONS AND CONCLUSIONS . Chapter 3 SOME FURTHER CONCLUSIONS Chaprer 4 "HIGHER" AND "LOWER" FUNCTIONS Chapter 5 SOME BASIC CONSlDERATfONS Chapter 6 IF VISION INCLUDES PERFORMANCE Chapter 7 VISION MUST SERVE TWO FUNCTIONS

NOT FOR PAGE 7 12.1.2.

The following tables are taken from publications mentioned i n this paragraph, a n d are reproduced here t o illustrate some o f t h e findings i n t h e Texas studies: I N C I D E N C E O F O R G A N I C A N D F U N C T I O N A L DIFFICULTIES F O U N D IN NOVEMBER, 1942 E X A M I N A T I O N S Visual Difficulties ..........................................................53.3y0 N u t r i t i o n a l Difficulties .................................................. 7 1.3 Postural Difficulties ...................................................... 30.2 Possible Signs of Chronic Infection .............................. 75.2 Possible Chronic Fatigue .............................................. 20.9 Dental Difficulties ........................................................92.0 -From:

D.

THE

B. Harmon,

C O - O R D I N A T E D C L A S S R O O M ( 1 :4)

A N A L Y S I S OF RELATIONS BETWEEN VISUAL A N D O T H E R PROBLEMS F O U N D IN ABOVE C H I L D R E N ON NOVEMBER, 1942, E X A M I N A T I O N S Entire GRADES (Decimals O m i t t e d ) School I B 2A 2 B 3A 3B 4 A 4B 5 A % t o t a l g r o u p having visual problems 53 35 38 46 58 61 66 72 71 O/, low P.A.'s w i t h visual problems 68 52 40 50 70 87 65 66 68 w i t h visual problems having low P.A.'s 68 60 59 66 85 87 70 50 60 % low E.A.'s w i t h visual problems 62 49 90 46 52 54 80 33 75 with visual problems having low E.A.'s 45 -39 60 66 28 37 60 25 50 % nutrition deficiencies with visual problems 52 22 22 36 46 66 59 62 67 % w i t h visual problems having nutrition deficiencies 62 39 40 66 57 87 70 62 60 % chronic infections with visual problems 67 47 48 58 73 50 64 92 89

%

%

%

w i t h visual problems having chronic infections

71

60

80

66

85

50 60

87

80

-From: D. B. Harmon, Report o f the Executive Director t o the Texas Interprofessional Commission on Child Development, A p r i l 1943.

"A

D Y N A M I C T H E O R Y OF V I S I O N "

Chapter 2

S O M E PRELIMINARY OBSERVATIONS AND C O N C L U S I O N S

The p r o c e s s e s , both purposeful and chance, by which a human infant i s turned into a cultured adult a r e fascinating fields of study. I have t r i e d t o be a diligent student of t h e s e fields, but have often been inept. My p r i m a r y i n t e r e s t h a s been in the physiology and psychophysi c s of adaptation, adjustment, and learning- - m o r e particularly, the dynamic s and mechanic s of bodily operations which e n t e r into building an efficient, well-developed, well-oriented m e m b e r of society. In pursuing t h e s e a r e a s of i n t e r e s t I have found myself m o r e and m o r e involved in problems of vision.

-

Many r e s e a r c h e r s have investigatedor e n u m e r a t e d v a r i o u s types of health and developmental problems in school children and their data h a s consistently shown a l a r g e incidence of visual difficult i e s existing among t h e s e children. Some investigators , studying visual and achievement problems of school children, have c o r r e l a t e d t h e problems they found with various factors of o c u l a r function and school lighting in efforts t o find causes of the difficulties enumerated, o r to develop cont r o l s over the incidence of these difficulties ( e . g . , I: 9,10) These investigations have s e e m e d to show a significant concomitant, i f not c a u s a l , relationship existing between c e r t a i n proc edure s f o r manipulating the optical o r visual environment and alterations in the incidence of visualdifficulties o r in the r e c o r d s of academic achievement.

*.

In e a r l i e r publications I reported findings in Texas studies made of 160,000 school c h i l d r e n (I: 1,2,3,4). In a d d i t i o n t o showing

* . - Numbers

i n p a r e n t h e s e s r e f e r to publications included i n the bibliographies i n APPENDICES I and 11. APPENDIX I, (I: 1 , 2 , 3 ) ; o r , APPENDLX II, (11: 1, 2 , 3 ) #

NOT FOR PAGE 8 52.2.

The following t a b l e illustrates the findings in one o f the studies mentioned: S U M M A R Y O F VISUAL, POSTURAL, A N D D E N T A L PROBLEMS IN A G R O U P O F D A L L A S H I G H S C H O O L C H I L D R E N , C O M PARED WITH THEIR H A B I T U A L NEAR W O R K I N G D I S T A N C E Ratio between normal visual distance f o r task a n d distance a t which the children were habituaiiy f o r c e d t o work:*

{

1 .OO

I

1.22

Percentage o f difficulties in

Percentage

group with this distance ratio:

this g r o u p was o f total group

Visual Postural Dental Visual Postural Dental Visual Postural Dental Visual Postural Dental

i

1.65

{

2.84

15%

0% 32% 70% 15% 85%

70% 28% 87% 79% 49% 89%

10.5%

30.5%

42.0%

17.5%

APPENDIX IV. Lillie M a e Finnegan, RELATION OF C E R T A I N BIOMECHANICAL F A C T O R S OF W R I T I N G A C T I V I T Y TO V I S U A L P E R F O R M A N C E AND OCCLUSION (1: 12). *This is t h e "arm-visual distance" ratio described i n

-From:

12.2. I.

The tables on t h e p a g e facing p a g e 9, which follows, illustrate some o f t h e experimental results obtained in studies referred t o in this paragraph. These tables show changes effected i n educational achievement, a n d in t h e incidences o f visual and certain "non-visual" difficulties when both the lighting and some o f t h e "non-optical" factors were altered i n t h e visual-task environments. W h i l e the t w o experiments were conducted wholly independent o f each other, the experimental changes in classroom lighting, decoration, a n d children's desks were the same i n b o t h studies. ( C o n f i n u e d on page facing Page

"A

9)

D Y N A M I C 'THEORY O F V I S I O N "

SOME PRELIMINARY OBSERVATIONS

SEE Z

PJ Cd

>F

a l a r g e grade-by-grade incidence of visualdifficulties, I reported pathologies found that ranged f r o m postural deviations to nutritional deficiencies, and f r o m behavior problems t a dental defects---all of which w e r e apparently reducing the educational achievement of the children studied. f also described a number of experiments, conducted under my direction, in a n effort to determine the c a u s e s and relationships of these p r o b l e m s of vision, well-being, and learning.

82.1.3.

The high incidence of visual problems among school children found not only in m y own studies, but i n the many studies of o t h e r s , together with the seeming extent and ramification of r e lationships between visual problems and f a c t o r s in environmental design, problems of well-being, and p r o c e s s e s of development and learning, all pointed to a need for a better understanding of visual processes if a b e t t e r understanding of growth, adaptation, adjustment, learning, and human performance was to be achieved.

$2. 2.

In recent y e a r s a number of investigators have conducted studies (e. g. , I: 11,12, 13,14,15)" comparable to some of the experimental work i n which I took part. Both the Texas investigations and some of the se l a t e r studies used experimental and s t a t i s t i c a l procedures to explore o r determine whether, and what, relationships existed: (a)between the visual problems encountered and the optical environment; (b) betwe en visual problems and "nonopticalIt factors in t h e visual-task surround; ( c ) between %onvisualt1pathologies and both optical and non-optical f a c t o r s i n the environment; and, (d)between visual and flnon-visuallldifficulties.

NO;E

92e291e SEE NC'TE

When data f r o m the T e x a s studies, a s well a s that f r o m some of the investigations by o t h e r s , were analyzed statistically, one fact stood out concerning many of the t'non-visualllproblems. A numb e r of these difficulties could be statistically related, and, i n a l a r g e percentage of the incidence of most of them, the common c o r r e l a t e seemed to be visual. Their causal o r precipitating

* .- Some s i m i l a r studies of adults working i n visually-centered occupational tasks have also been reported, with cornparable findings (e. g. , I: 16,17, 18).

Page 8

NOT FOR PAGE 8 CONTINUED

C O M P A R I S O N O F SOME HEALTH PROBLEMS FOUND A T BEGINNING A N D END O F THE SIX-MONTH EXPERIMENTAL PERIOD November, 1942, to May, 1943 Grades I through 5, Becker School, Austin, Texas

% of cases found in PROBLEM November Visual Difficulties 53.3 7 1.3 Nutrition Problems Chronic infection 75.2 Posture Problems 30.2 Chronic Fatigue 20.9

% o f cases

% change dur-

found in May 18.6 37.2 42.6 22.4 9.3

ing 6 month period -65 .O -47.8 -43.3 -25.6 -55.6

ACHIEVEMENT G R O W T H BY MONTHS O F EDUCATIONAL A G E DURING THE SIX-MONTH EXPERIMENTAL PERIOD

Experimental School Control School -From:

Range of Growth Months o f E.A. 0 to +32 -8 t o 18

+

Median Change Months o f E.A. 10.0 6 .O

D. B. Harmon, THE CO-ORDINATED CLASSROOM ( 1 :4).

RESULTS OBTAINED IN T W O EXPERIMENTAL CLASSROOMS AS COMPARED T O T W O CONTROL CLASSROOMS One School Year Grades 4 and 5, Morton School, West Lafayette, Indiana Control Experimen- t-value o f Rooms tal Rooms difference Mean Educational Accomplishment Quotient (Stanford Tests) 85.4 92.1 3.48 Percent o f Postural Deviation 49 .O 27.0 2.18 a t end o f period Differences in Frequency o f Nervous habits between be-.63 -----.95 ginning and end o f period (Olson's Technique) -.---1.52 2.7 1 -From: Kephart and Floyd, CLASSROOM ENVIRONMENT A N D PUPIL WELFARE (1:14).

"A


SOME P R E L I M I N A R Y O B S E R V A T I O N S

f a c t o r s seemed t o l i e i n o r be relatedto the performance of visually-centered t a s k s , the visual problems of the children, o r the visual surroundings in the classroom. 2. 2. 1. 1.

In addition, t h e r e w e r e concomitant, and a t t i m e s , sequential relationships between c e r t a i n 'Inon-visualffand visual problems. F u r t h e r , the l1geometriesM of a number of non-visual problems closely r e sexribled those of the accompanying visual difficulties; a s , f o r example, a geometricA resemblance between a r e f r a c tive e r r o r d i a g r a m e d a s rotations o r skewnesses f r o m a normal binocular relationship with a reading o r writing t a s k , and, body posture defects g r a p h e d a s s t r e s s and strain problems of normal body mechanics. S i m i l a r geometric resemblances w e r e found even between d i a g r a m s of refractive e r r o r , and s t r e s s o r distortion d i a g r a m s of c e r t a i n dental malocclusions.

"

Since m y e a r l i e r publications, I have been concerned with evaluations and rechecks of the data reported; with experimentation; and with examinations of reported visual r e s e a r c h and the visua l l i t e r a t u r e in general- - -searching for visual and visually- related mechanisms which might account for the data r e p o r t e d e a r l i e r , o r f o r the relationships apparent in l a t e r studies (I: 5,6, 7 , 8). 182.3.1.

SEE NOTE

Because the "geometric" resemblances mentioned i n B2.2. 1.1. occurredwith such frequency in the cases of the children studied while a t work in c l a s s r o o m s , this resemblance was taken a s a possible clue f o r a n approach to further investigation.

*. - One of

these sequential relationships often noticed was c e r tain types of functional postural deviations preceding c e r tain types of v i s u a l problems, e. g . , head t i l t s preceding some a s t i g m a t i s m s o r oculomotor difficulties.

A.

-

The t e r m l l g e o r n e t r i c l lhas been used v e r y loosely h e r e - - probably either I ' f ~ r c oe r~ "~s t r e s s - s t r a i n t fwould be a better term.

NOT

FOR P A G E 9

"Ij.3.1.

Measurements (1: 2, 4, 12) show that close visual performance can b e represented schematically as follows (see Appendix IV):

Figure

I

( L e f t ) Vertical relation o f facial plane t o task plane ( R i g h t ) Horizontal relation o f facial plane t o task plane

The circle represents the head. PI i s a plane drawn through t h e eyes and running parallel t o t h e lateral plane o f the head. P , i s t h e plane o f the task. Point "a" i s the inter-pupillary point, and p o i n t "b" is the initial fixation centering. "El" and "E," are t h e points where t h e facial plane intersects t h e foci of the t w o eyes. Visually-dominated reflexes seem t o operate t o maintain these relationships a t as near constants as t h e size o f t h e task and as interfering factors i n t h e environment will permit. Persistent gross deviations f r o m the diagramed relationship, b e yond determinable tolerances, leads t o task-performance distortions, and seems t o lead t o lafer visual, postural, and other difficulties. (Continued on following page)

"A

D Y N A M I C THEORY OF

VISION"

NOT F O R PAGE 9 CONTINUED

C

- --

.'---I--' ,' I

\

I

c Figure 2

Some common deviations f r o m normal eye-head-task relationships, as shown in t h e figure on t h e preceding page, induced b y cjlare, seating, and other unsound classroom features. There are other d e viations, comparable t o these, b u t these are most commonly seen.

a,-Is

seen quite o f t e n in rooms having large, f r o n t areas o f dark chalk board, and when children work on flat table tops t h a t are t o o low.

b.-Occurs frequently when windows give considerabie sky exposure in rooms with desks arranged parallel t o windows. "c" shows another t y p e o f posiure assumed t o p r o t e c i the child f r o m sky glare o f this

+Y pe. c and d.-are common postures o f chiidren working a t f l a t tables and t o l d t o sit square t o the desk while wriiing. These postures are especially conspicuous i n right-eyed children whiie writing on horizontal surfaces. ( C o n t i n u e d o n following page)


NOT

FOR P A G E 9 COE-4TINUED

Figure

2d

Figure

3

Pictured on t h e opposite page i s an actual case record showing a gross deviation f r o m Figure I, induced b y restraining seating 2 n d glare, which persisted f o r one school year. The deviation i s t h e same as Figure 2d, repeated above. The upper l e f t picture, Figure 4, superimposes t h e child's induced posture over what should b e his balanced working posture. The lower l e f t picture, Figure 5, shows his induced posture f o r t h e school year. The l e f t diagram above, Figure Zd, shows his departure f r o m what should b e his head-eye-task relationship. The r i g h t row o f forms above, Figure 3, (produced by him] shows t h e distortion a n d direction o f

his characteristic work, which matches,

geometrically, his typical "optical" approach t o his task. The r i g h t hand pictures o n the opposite page, Figures 6 and 7, show his b o d y distortions a t t h e end o f the school year, distortions he did n o t have a t the beginning o f the year. N o t e how the distortions match his working posture. His visual refraction a t the end of t h e year, when diagramed as spatial distortions, also matched his characteristic p a t tern o f writing o r drawing. For further details o f these tests, see Appendix

"A

IV.


NOT FOR P A G E 9 CONTINUED

Figure b

Figure

5

S O M E PRELIMINARY OBSERVATIONS

Figure 7

NOT

"A



In a l m o s t e v e r y i n s t a n c e of a child working a t a c l o s e visuallycentered t a s k and a p p a r e n t l y restrained f r o m f r e e movement in p e r f o r x i n g that t a s k b y improperly designed d e s k s , seating, o r lighting, it could be observed that his head, o r head and trunk p o s t u r e s and d i s t o r t i o n s in h i s writing o r drawing would both show a strong g e o m e t r i c r e s e m b l a n c e to the pattern of r e s t r a i n i n g f o r c e s o r to the light gradients. In addition, t h e s e p o s t u r a l and work distortions would a l s o show strong r e s e m b l a n c e s to graphic a n a l y s e s of l a t e r e m e r g i n g visual problems and body a s y m m e t r i e s During m y f i r s t acquaintance with fields of visual investigation, I had a l s o been i m p r e s s e d by often repeated s t a t e m e n t s of some investigators to the effect that many visual p r o b l e m s a r e derived f r o m the impact on the o r g a n i s m of sustained visual work a t Itnear I t - - -meaning by "near the traditional reading distance of approximately sixteen inches , but sometimes including occupational t a s k s within a r m ' s length out to occasional v i s u a l c e n t e r ings f r o m one to t h r e e m e t e r s away. With the possible effect of sustained "near" t a s k s i n mind, m y s e a r c h f o r m e c h a n i s m s to account for the Hgeornetric" r e s e m blances and the difficulties I had seen in Texas c h i l d r e n f i r s t cent e r e d in studying o c u l a r needs anddemands on children p e r f o r m ing such t a s k s in school.

B e c a u s e m y own a r e a of specialization was not b a s e d on the visu a l s c i e n c e s , I t u r n e d f o r guidance to standard ophthalmological, physiological, and psychological works on vision (e. g. , I: 19, 20, 21, 2 2 , 2 3 , 24, 25). Starting with the conventional o p t i c a l m o d e l of vision implied i n t h e s e works, m y f i r s t s e a r c h was within the f r a m e of r e f e r e n c e of t h i s model, and by u s e of c u s t o m a r y p r o c e d u r e s in o c u l a r and ocularly-related investigations---i. e. , studies concerned with acuity, accommodation, convergence , resolution, recognition, eye s t r u c t u r e , visual fatigue, etc.

'

*,

Defined in NOTES f o r Page 3 .

Page 1 0

NOT

FOR P A G E I I

$2.5.

There i s no intention here t o deprecate the place o f optics in vision, o r the significance o f d a t a obtained in studies o f central field vision.

It i s only the applicabiliiy o f optically derived theories o f vision t h a t i s being questioned, especially when they are applied i n holistic approaches t o studying human performance.

"A



The inconclusive and incomplete r e sult s obtainable by these methods, plus information related to vision and visually- centered p e r formance in the works of o t h e r s who had exGended the u s u a l a r e a s of visual investigation (e. g. , I: 26, 27, 28, 2 9 , 3 0 , 3 1 ) , o r who had wo rked outside the c u s t o m a r i l y conceptual model of vision (e. g., 1: 32,33,34, 35,36, 37), indicated that the a n s w e r s I was seeking did not lie wholly in the direction I was taking, the methods I was using, o r the optically b a s e d model of vision I was accepting. 2.4. 1.1.

Some of the data and generalizations which led to this d i s s a t i s faction can b e found i n the c h a p t e r s which. follow. Additional data and information can b e found in publications cited in the appended bibliographies. The principal lack i n the methods and concepts being used was inadequate explanations and descriptions of mechanisms o r p r o c e s s e s which would account f o r and p e r m i t control of: (a) the high incidence of deviating visually-centered performance seen i n c h i l d r e n working on learning t a s k s ; (b) the many Ifatypical visual signs1' seen in posture, and the work produced, which could b e geometrically c o r r e l a t e d not only with the f o r c e s entering into t h e visual stimuli, but a l s o with l a t e r e m e r g ing visual and llnon-visuallt difficulties; and, ( c ) the increasing incidence of visual and visually- related problems throughout the school y e a r s which could only be correlated with attendance in school and no tlextra-schooll' factor. The implications in t h e s e observations c a n be summed up in the following c r i t i c i s m s of u s e of a n optical model of vision when applied to studying functional o r operational visual p r o c e s s e s , o r acquired, o r llatypicalll visual problems, and to analyzing the product of visually- cente r e d learning.

$2, 5.

SEE NOTE

T h e o r i e s o r conceptual models of vision which a r e p r i m a r i l y cent e r e d in ( a ) optics; (b) resolution of detail and in c e n t r a l retinal function; ( c ) llvisual i m a g e ' I , o r visual perception derived almost solely f r o m immediate retinal projection; (d) accommodationconvergence relations, o r s i m i l a r retinal- image oculornotor concepts; o r , ( e ) even c o r r e l a t e d optical- retinal-higher corticalvisual perception functions, a r e unsatisfactory because:

-

Page i l

NOT FOR PAGE 1 2 v2.5.2.

That posture i s related t o vision or some o f the visual mechanisms

is n o t a new concept. M a n y standard texts on vision recognize this relationship, and Magnus (1:38) described mechanisms o f this relationship i n d e t a i l in 1924. That posture affects vision, however, is a new concept, having i t s most extensive elaboration with some o f t h e work o f t h e present writer, starting in 1942. "Learning Theory" i s used here in reference t o the c o n c e p t t h a t behavior change i s b r o u g h t about through function-"the

child learns

by doing."

"A



They a r e biologically inconsistent with what is known of s e n s o r i motor functions in o t h e r modalities, in that the a c t i o n s they d e s c r i b e a r e l a r g e l y l i m i t e d to the t r a n s p o r t of the r e c e p t o r s , without description of the m e c h a n i s m s which adjust the t o t a l organi s m to organizations of the e n e r g i e s of stimulus; They do not explain o r d e s c r i b e the visually-related m e c h a n i s m s of postural support f o r sustained visual p e r f o r m a n c e , n o r the v i s ~ a l l yrelated m e c h a n i s m s for manipulative ope r a t i o n s e n t e r ing into visually- c e n t e r e d t a s k s ; They lack description of the mechanisms which s y n t h e s i z e o r int e g r a t e experience i n other modalities into visual o p e r a t i o n s and visual perception-- -a synthesis o r integration which s e e m s to exist; They do not recognize o r d e s c r i b e mechanisms f o r t h e p r o c e s s whereby a change i n output c a u s e s a change in input (feed-back and control), nor do they provide a reason f o r the a b s e n c e of this p r o c e s s , if it i s a b s e n t in vision; They do not explain the acquisition of "meaning " f r o m v i s u a l experience in a m a n n e r consistent with accepted l e a r n i n g theory, nor do they explain why perceptual magnitude s , l o c a l i z a t i o n s , o r other details of p e r c e i v e d v i s u a l events can differ f r o m computed optical equivalents of those f a c t o r s ; They do not recognize the effects of biologic p r o c e s s e s of adap tation on visual m e c h a n i s m s ; nor do they explain why v i s u a l mecha n i s m s a r e not affected by biologic adaptation, i f i t d o e s not apply; They do not d e s c r i b e o r identify the etiological f a c t o r s of experientially acquired v i s u a l difficulties- - -i. e. , difficulties due to s t r e s s - r e l a t e d psychological o r psychophysical f a c t o r s (and not genetic, t r a u m a t i c , o r infectious lesion ), if such difficulties occur.

Page 1 2

NOT

"A

DYNAMfC THEORY OF V I S I O N "

Chapte r 3

S O M E F U R T H E R C O N C L U S I O N S O N L I M I T A T I O N S OF PRESENTLY U S E D C O N C E P T S A N D M E T H O D S

Social e m p h a s i s on communication through v i s u a l s y m b o l s , a s w a s pointed out e a r l i e r ( C h a p t e r 1), h a s led m a n y of t h o s e working with Itseeingl1 t o b e c o n c e r n e d a l m o s t wholly with what m a y be only a v e r y l i m i t e d function of vision: the o c u l a r r e s o l u t i o n of the d e t a i l s of the c e n t r a l v i s u a l field, with i t s a n a t o m i c a l , physiological, and psychological c o r r e l a t e s of a c c o m m o d a t i o n , conv e r g e n c e , and "visual image". P r i m a r y c o n c e r n with accommodation, acuity, a n d efficient opt i c a l r e s o l u t i ~ nof the d e t a i l s of symbols h a s l e d , s e e m i n g l y , to a n u m b e r of a s s u m p t i o n s which dominate m o s t of t h e thinking and r e s e a r c h in the o p e r a t i o n a l field of vision. These assumptions include ( a ) evaluating t h e efficiency o r functioning of the e y e s i n t e r m s of t h e p r i n c i p l e s of g e o m e t r i c optics; ( b ) c o n s i d e r i n g the sole o r m a j o r p u r p o s e of vision to be t h e projection onto t h e r e t ina of a " c a m e r a - l i k e i m a g e " of the details in c e n t r a l - f i e l d v i s u a l s p a c e ; a n d , ( c ) implying that meaningful l l v i s u a l i m a g e H i s a l m o s t wholly a light s t i m u l u s - n e u r a l input configuration d e r i v ative. R e s e r v i n g e l a b o r a t i o n of r e a s o n s until l a t e r , l e t m e p r e s e n t s o m e f u r t h e r tentative c o n c l u s i o n s a s t o the inadequacies of t h e s e a s sumptions and the o p t i c a l m o d e l of vision f r o m which they w e r e d e r i v e d in providing a c c e p t a b l e explanations of the p r o b l e m s m e n tioned in C h a p t e r 2. T h e conclusions s t a t e d w e r e d e r i v e d f r o m a l l o r p o r t i o n s of t h e w o r k s c i t e d and f r o m s i m i l a r s t u d i e s . Howe v e r , the c o n c l u s i o n s s t a t e d a r e not those of t h e a u t h o r s of t h e s e publications but a r e t h o s e of the p r e s e n t w r i t e r .

P a g e 13

NOT

FOR P A G E 1 4

$3.1.

"For the eye has every possible defect t h a t can b e found in an optical instrument, and even some which are peculiar t o itself: b u t they are all so counteracted, that the inexactness o f an eye which results f r o m their presence very litfle exceeds, under ordinary condition o f illumination, the limits which are set t o the delicacy o f sensation b y t h e dimension o f the retinal cones. But as soon as we make our observation under somewhat changed conditions, we b e come aware o f the chromatic aberration, the astigmatism, the blind spot, t h e venous shadows, the imperfect transparency o f t h e media, and all the other defects o f which we have spoken."

-H.

W.

Helmholtz,

PHYSIOLOGICAL OPTICS.

"A


SOME F U R T H E R C O N C L U S I O N S

$3. 1.

SEE ge07$

A m a d e l of vision which s t a r t s with a concept of the "perfect e y e t t derived f r o m bench o r geometric optics and point focus (thereby conceiving the so-called abe r rations and other optical aqomolies and skewnesses of the n o r m a l eye, when compared with the principles of rreametric optics, a s "defects, limitations, o r imper* fections of s t r u c t u r e " r a t h e r thanhaving some p a r t i c u l a r advantageous function f o r the o r g a n i s m ) , i s inadequate either f o r inve stigation o r explanation of total visual performance. (I: 5,13, 1 9 , 2 7 , 2 9 , 3 0 , etc. ). L

W

If I may become philosophical f o r a moment: it is difficult to conceive that evolution h a s produced, in man, a s u p e r i o r intelligence capable of a c c u r a t e l y gathering data of the world around hi& and dealing logically with that data in solving h i s problems of m a s t e r y of that world; and, a t the s a m e t i m e , accept the concept that evolution h a s a l s o produced a n a b e r r a n t , imperfect s e n s e organ f o r the modality through which m a n apparently derives the g r e a t e s t p a r t of the data he uses in problem solving. 3. 1. 1. 1.

When one recognizes that m a n fs problem solving i s through dynamic p r o c e s s e s one can m o r e readily conceive that what might be thought to be a b e r r a t i o n s o r imperfections in a static mechani s m could be determinants of action patterns toward accuracy in a dynamic system.

3 . 1. 1. 2.

Studies o r data in a number of a r e a s of visualfunctioning can be cited in support of t h i s l a t t e r concept in which so-called optical a b e r r a t i o n s o r anomolies of the eye apparently s e r v e a constructive purpose in vision.

83.1. 2.

3 1 2.1.

Fincham (I: 3 0 ) shows that chromatic a b e r r a t i o n s e r v e s a usefulpurpose in human vision. Inthe majority of subjects he studied the vergence of t h e various wave lengths entered into determining the a c c u r a c y and direction of accommodation.

In commenting on s o m e of h i s data Fincham s a y s : Itwithout the information given by the chromaticity of the image, however, Page 14

NOT FOR PAGE I 5

A X I A L C H R O M A T I C ABERRATION T H E HUMAN EYE* Wave Length in Millicrons 3 65 405 43 6 492 546 578 62 1 69 1 750

OF

Average i n Diopters 2.63 1.70 1.19

0.59 0.16 0.00 4 . 1 8 -0.40 4.62

'After Wald and Griffin, "The Change in Refractive Power of the Human Eye in Dim and BrighP Light", Journal of the Optical Society, Table I!, Page 327, Vol. 37, No. 5, May, 1947.

-THE

:13.1.3.1.

C O - O R D I N A T E D C L A S S R O O M ( 1 :4,

p. 40).

"Motions o f t h e retinal image can b e inferred f r o m measurements Involuntary saccadic o f the rotational movements o f the eye. . movements play a major p a r t in correcting the direction of fixation

..

on a test object. W h e n image motion i s artificially eliminated, +he normal dynamic equilibrium o f the receptors becomes a static equilibrium, and vision gradually fades away. Experiments on those matters a t Brown University were conducted through a c o n t r a c t w i t h t h e Office o f Naval Research." -Lorrin

A. Riggs, Brown University, VISUAL EFFECTS O F I N V O L -

U N T A R Y EYE MOVEMENTS. A paper read O c t o b e r 18, 1957 b e fore the O p t i c a l Society o f America. Quotation f r o m t h e A b s t r a c t published in t h e Program o f the meeting.

"A



/T 5"- g

-

%a

C

f"jQTE

t h e r e i s n:, clue t o t h e d i r e c t i o n the a d j u s t m e n t m u s t t a k e , a n d the b r a i n is unable t o give t h e n e c e s s a r y innervation. , The f a c t t h a t , in the a b s e n c e of the effects of c h r o m a t i c a b e r r a t i o n , no r e a c t i o n took p l a c e i n about 34. 5 p e r cent of t h e c a s e s t e s t e d a n d a quite f a l s e r e a c t i o n i n 25. 5 p e r cent m e a n s t h a t i n 60 p e r c e n t the change i n t h e r e t i n a l i m a g e due to the d i f f e r e n t i a l f o c u s ing f o r c o l o u r s a c t s a s a s t i m u l u s to the a c c o m m o d a t i o n r e f l e x , f o r without i t the r e f l e x i s a b s e n t . It m a y a p p e a r r e m a r k a b l e that c h r o m a t i c a b e r r a t i o n , which might be c o n s i d e r e d a fault in t h a s no n o t i c e a b l y h a r m t h e optical s y s t e m of t h e e y e , n ~ anly f u l effect upon the i m a g e which i s perceived, b u t i s i n s t r u m e n t a l in providing the i n f a r m a t i o n which enables the b r a i n t o c a r r y out a n important adjustmentft.

. . .. .

Fincham f u r t h e r points out, in the study r e f e r r e d t o a b 3 v e , that the d i r e c t i o n and a c c u r a c y of accommodation i s a l s o dependent t o v e m e n t s of the eye. 96 A s the eye upon the minute l i s c a n n i n g fm m a k e s t h e s e s m a l l , involuntary l a t e r a l e x c u r s i o n s , l i m i t i n g r a y s of the b l u r c i r c l e s a c q u i r e different d e g r e e s of obliquity a t the retina. The S t i l e s - C r a w f a r d effect then m a k e s i t p o s s i b l e f o r the b r a i n t o d e t e c t , b e c a u s e of the difference in b r i g h t n e s s b e tween the two s i d e s of the a r e a , whether t h e light a t t h e r e t i n a i s convergent o r d i v e r g e n t .

3 . 1. 3. 1.

Some speculation i s n e c e s s a r y a t t h i s point. A n u m b e r of e x p e r i m e n t s have d e m ~ n s t r a t e dthat perception i s r a p i d l y extinguished i f a s t i m u l u s continues with the s a m e a m p l i t u d e and a t t h e s a m e localization on t h e r e c e p t o r s . While the m i n u t e "scanning" m o v e m e n t s of the e y e would offset t h i s , t o s o m e e x t e n t , i t i s possible to v o l u n t a r i l y inhibit t h e s e "scanning " m o v e m e n t s , a s F i n c h a m points out,

3. 1. 3. 1. 1. The p r e s e n c e of s o m e s p h e r i c a l and c h r o m a t i c a b e r r a t i o n i n the eye would tend t o d i s c o u r a g e t h i s inhibition, and a l s o provide

* .-

Movements amounting to probably not m o r e t h a n 6 ' of a n g l e , a c c o r d i n g to F i n c h a m .

Page 15

NOT

FOR PAGE 1 6

13.1.4.

Points raysed in this section (3.1.4. I. through 3.1.4.4.) should n o t b e taken as demonstrated d a t a nor as established conclusions. They are raised in connection with certain "aberrations" o f the eye, t o d e m onstrate what t h e writer believes i s a justifiable method of reasoning when a dynamic p o i n t of view i s taken in analyzing these aberrations.

"A

DYNAMIC THEORY O F VISION"


enough b l u r on t f s c a n n i n g " t o furnish a variable input s i g n a l t o m a i n t a i n accommodation a f t e r i t is once established. 3. 1. 3. 1. 2.

A n u m b e r of o t h e r dynamic and constructive functions c a n b e r e a soned f r o m the l a c k of Irpointtffocus a t the r e t i n a , and f r o m the o t h e r optical Ifanornolies " existing in the eye: e. g. ,

93,1.4, SEE NOTE

3. 4

In addition, the photon s c a t t e r i n g within a r a y bundle, which is random within the l i m i t s of the b l u r of s p h e r i c a l a n d c h r o m a t i c a b e r r a t i o n , would p r o v i d e a second mechanism of modulation t o a s s u r e that accommodation i s maintained.

1

Continued minute a l t e r a t i o n s of accommodation ( Z - a x i s "scanning") within the limits of the various foci r e s u l t i n g f r o m the p r e s e n c e of a b e r r a t i o n s i n a n accommodated eye could be a r e i n f o r c e m e n t device to maintain perception i n keeping with the data r e f e r r e d to i n Y3. 1.3. 1. ;

3. 1.4. 2.

t f P o i n t wf o c u s , e v e n with l a t e r a l tfscanning"m o v e m e n t s t o m a i n t a i n accommodation, could produce a rigid "set" t o w a r d the i m m e d i a t e r e s p o n s e elicited. T h i s rigid s e t would r e s t r a i n o r i m pede any change of r e s p o n s e , and it could m a k e i t difficult t o r e d i n t e g r a t e p a s t e x p e r i e n c e in o r d e r to s e c u r e o p t i m u m m e a n ing f r o m the concepts being dealt with currently. The a c c o m m o dative e x c u r s i o n s , o r Z - a x i s tlscanningtt,mentioned i n lJ3. 1.4.1. would keep the tonus of r e s p o n s e mechanisms i n a I1dynamicequil i b r i u m " , t h e r e b y facilitating needed changes i n t h e s e r e s p o n s e m e c h a n i s m s f o r both r e d i n t e g r a t i o n and for a l t e r a t i o n s in p e r formance;

3.1.4.3.

T h e p r e s e n c e of s o m e c o m a on the p e r i p h e r a l r e t i n a , which does e x i s t , could a i d in p r e s e r v i n g postural balance and c e n t e r i n g with the v i s u a l t a s k ( t h i s will be discussed a t length i n P a r t Two);

3. 1.4.4.

Physiological a s t i g m a t i s m might be the way that r e t i n a l p r o j e c tion of the g e n e r a l f o r m of objects, foreshortened when t h e y a r e approaching the o r g a n i s m l a t e r a l l y o r obliquely, i s brought back t o a contour of s t i m u l u s - n e u r a l configuration which will m o r e r e a d i l y f l s c a n l t f o rrecognition a t higher c e n t e r s and m o r e quickl y r e o r g a n i z e the o r g a n i s m f o r defensive o r o t h e r a d j u s t i v e behavio r e

Page 16

NOT

FOR P A G E 1 7 "Since t o a g r e a t extent the perception o f form and contour i s t h e essence o f all vision, an estimate o f the acuity o f the f o r m sense i s the most practical assessment o f the sensitivity and efficiency o f t h e eye. Therein lies the importance o f visual acuity, which i s a measure o f the smallest retinal image whose form can b e appreciated. W e have already seen t h a t this faculty i s a composite entity composed o f several components, the most important o f which are the l i g h t sense and the resolving power o f the eye on the physiological level, and the power of integrating individual stimuli i n t o a pattern o f t h e psychologicai level . t h e value o f any test i s increased i n so f a r as it eliminates composite patterns which necessitate psychological interpretations, so t h a t t h e ultimate perception (i.e., the minimum cognosible) i s n o t confused by visual judgments, b u t corresponds f o the standard physiological components upon which it i s built. It is t o o o f t e n forgotten, owing t o t h e stress t h a t has been laid on t h e geometric aspects o f t h e resolving power o f the eye, t h a t t h e m a t t e r is n o t and never can be a purely optical one; t o consider it i n this ligh+ is -to inves) a perceptual process o f great complexity w i t h a delusory and ficlitious simplicity."

..

-Duke-Elder, TEXT-BOOK OF OPHTHALMOLOGY, Vol. I I, "Clinical Methods o f Examination, Etc.," Chapter XXIX, "The Subjective Examination o f t h e Eye," p. 1 194.

"A



The function of the "image I t a s p e c t of the c e n t r a l field portion of f t s e e i n g u (whether l a b e l e d resolution, acuity, o r f o r m s e n s e ) i s not t h e sole purpose, n o r n e c e s s a r i l y the f i r s t s t e p i n the visual p r o c e s s . (See a l l r e f e r e n c e s in Appendix 11. )

The human eyes and t h e i r adnexa, being l a r g e l y a comrnunicative mechanism (and o u r dominant one, according to s o m e authori t i e s ) , do give u s c o n c e r n with the a c c u r a c y of the c e n t r a l i n f o r mation they communicate f o r use. However, i n studying visual function we cannot be preoccupied with the c e n t r a l s t r u c t u r e s f o r receiving this information, nor the a p p a r a t u s f o r adjusting the r e c e p t o r s , b e c a u s e , to b o r r o w the terminology of the communications engineer, neglect of other visual f a c t o r s c a n lead to unoisell. w i e n e r * t e l l s u s that "the information c a r r i e d b y a p r e c i s e m e s s a g e in the a b s e n c e of n o i s e A i s infinite. In the p r e s e n c e of noise, this amount of information i s finite, and i t a p p r o a c h e s 0 v e r y rapidly a s t h e n o i s e i n c r e a s e s in intensityt1. 3 . 2 . 1. 1.

Th.e m e c h a n i s m s of vision, like other m e c h a n i s m s having to do with the promotion of r a p p o r t between the o r g a n i s m and i t s environment, i s s t r u c t u r e d to g a t h e r , r e c o r d , p r e s e r v e , o r g a n i z e ,

* .- Norbert

Wiener, C y b e r n e t i c s , John Wiley and Sons, New

Hork, 1948. A.

- 8 t N o i s e H ,in t h i s

s e n s e , c a n be defined a s random agitation of a conductor which l i m i t s ; " b l u r s u ; o r , in a n y m a n n e r int e r f e r e s with t h e i m p u l s e s the conductor should be t r a n s m i t ting;--- ItstaticI t . In this connection, Hnoiseu could be representedbyincompatibility of the visual s e n s a t i o n s of a fact o r i n the s u r r o u n d with sensations of that s a m e f a c t o r through o t h e r modalities ;conflicting use of common pathways o r m u s c u l a t u r e in satisfying both visual and other n e e d s ; p r o p r i o ceptive o r feed-back i m p u l s e s f r o m adjustive a c t i o n s other t h a n v i s u a l t o m o t o r equipment being used i n v i s u a l p r o c e s s e s , etc. Page 17

NOT

"A

DYNAMIC T H E O R Y O F V I S I O N J '

S O M E FURTHER CONCLUSlQNS

unify, transmit, and _ u s e. information. While a p a r t of t h e function of the visual m e c h a n i s m s i s related to the initial organization and communication of information, USE of the information i s also a p a r t of that function. In spite of the diversity of expressions of a function which is possible in the human o r g a n i s m , the complete system of r e c e p t o r s , afferent conductors, a d j u s t o r s , efferent conductors, and effector apparatus (also, supporting s t r u c t u r e , and related s t r u c t u r e and function) m u s t all b e taken into account in evaluating the operation o r efficiency of a n y mechanism. This sensorimotor relationship i s recognized to a limited degree when the efficiency of the extraocular musculature i s consideredwith theefficiencyof the eyeitself. T h e r e f l e x movements of fixations, however, a r e not the only a c t i o n p a t t e r n s r e lated to visual stimulation. Head and body posturing movements, and actions involved in performing the purposeful t a s k a r e also p a r t of the s e n s o r i m o t o r organization of vision.

*

3.2. 1.1.1.

In support of the l a s t statement, Duke-Elder (I: 19, p. 624) says: "Just a s the labyrinth dominates the proprioceptive s y s t e m , s o the eyes tend to dominate the labyrinth.. . t h e r e i s a n intimate association between movements of the eyes and changes of post u r e , a n d a close functionalreflex correlation e x i s t s between the extraocular m u s c l e s and the labyrinths which r e c o r d t h e movements of the head in space, and the muscles of the n e c k which r e g i s t e r movements of the head with respect to the trunk".

3. 2.1.1.2.

Duke-Elder further s a y s (I: 19, p. 250): "(The p o s t e r i o r e x t r e m ity of the optic thalamus) is e specially intimately connected with the angular gyrus, t h e praecuneus, and the o c c i p i t o ~ p a r i e t a land occipito-temporal l o b e s , and therefore, when i t s i n t i m a t e relation with the c e r r e b u l l u m (Horsley and Clarke, 1905) and the r e d

* .- Reflex

movements of fixation primarily function to center the organism on the distribution pattern of light. They can a l s o be directed t o function to center the o r g a n i s m on a socially-compulsive task, many times to the d e t r i m e n t of the organism when both functionings a r e required by t h e s u r round because light-centering and task-centering differ.

Page 18

NOT

"A


S O M E FURTHER CONCLUSIONS

nucleus (Sach, 1909) i s remembered, it s e e m s probable that i t i s largely concerned with the movements of the eyes, the c o r r e la.tion of eyes and hands, and the higher visual functions of s t e r e ognosis". 83.2,2.

3.2.2.1.

F r o m some of the information available in the visual l i t e r a t u r e , a n d f r o m some experimental evidence, it would appear that body postural functions p r e c e d e final central ocular r e solution in satisfying the needs of the o r g a n i s m in any visually-centered task. Duke-Elder can again be cited for supporting neurological evidence: (pp. 247-248) "The f i b r e s from the retina end in two m a s s e s of g r e y m a t t e r : the LATERAL GENICULATE BODY, which i s phylogenetically p a r t of the optic thalamus, and the SUPERIOR COLLICULUS, which i s p a r t of the mid-brain. .The v i s u a l f i b r e s (in m a n ) find a ( r e l a y ) station in the l a t e r a l geniculate body. 80$oftheretinalfibresfindtheirwayhere The ( r e t i n a l ) fibre s which run to (the superior colliculus), however , and in a r e undoubtedly the m o s t primitive phylogenetically.. m a n they a r e a s s o c i a t e d with the primitive photostatic (light and p o s t u r e ) r a t h e r than the higher sensory functions of vision".

..

.. ....

3.2. 2.2.

.... ..

Some experiments conducted by the writer (I: 2 , 4 ) showed that when a subject was allowed to find his most efficient body balance for performing a n e a r , visually-centered task, a t the rnoment he a r r i v e d a t the balance he was already accommodated to the c e n t r a l point of the localization of that task, apparently a s a feed-back function of coming to balance. (This i s d i s c u s s e d m o r e fully in P a r t Two, and in Appendix IV.)

Page 19

NOT

"A

DYNAMIC THEORY O F V I S I O N J '

SOME FURTHER C O N C L U S I O N S

The p r i m a r y function of vision, biological.ly, is r e l a t e d t o the determination of s p a c e r e l a t i o n s and the space m o v e m e n t s of the organism. Only s e c o n d a r i l y , a s a "higher" function of a b s t r a c t ing and symbolizing s p a c e and space movements f o r l a t e r facilitation i s vision a n "image" func- - - - - and r e d i r e c t i o n of movement. tion, biologically. (I: 2, 5, 1 3 , 1 7 , 3 2 , 53, and, 11: 6 , 7, 8, 10. ) V

Lashley (I: 3 3 , 3 4 ) f u r n i s h e s u s o u r most comprehensive evidence i n substantiation of t h i s conclusion. In one of h i s p a p e r s , (I: 33, p. 321) he s a y s : 3.3. 1. 1.

"The visual s y s t e m i s p r i m a r i l y concernedwith s p a t i a l o r i e n t a tion a n d f o r i t s t r a n s i t i o n f r o m a s e n s o r y to a m o t o r p a t t e r n can be m o s t adequately conceived a s a n interplay of p o l a r i z e d s y s t e m s o r of interweaving dynamic patterns in which the spatial p r o p e r t i e s of the v i s u a l s t i m u l u s a r e t r a n s l a t e d b y integration a t a s e r i e s of l e v e l s into modifications of the g e n e r a l p a t t e r n of post u r a l organization. Vernon (I: 25, p. 91) a l s o r e i n f o r c e s this point of view: " F r o m t h i s discussion, i t a p p e a r s that our n o r m a l a c c u r a t e s e n s e of spatial orientation a n d o u r a c c u r a c y of movement a r e dependent upon the maintenance of the habitual relationship of the m a i n coo r d i n a t e s of the visually perceived field with both kinae sthetic and labyrinthine s e n s a t i o n s (the l a t t e r producing together the v e r t i c a l gravitational s e n s e ) . The individual's feeling of stabili t y depends upon the stability of t h i s framework. If s o m e p a r t of the s e n s o r y data which constitute the framework i s i m p a i r e d , o r conflicts with s o m e o t h e r p a r t , stability i s s o f a r affected that t h e individual i s d i s o r i e n t a t e d , that i s to s a y , he l o s e s h i s usual i m p r e s sion of a n exact and enduring position of h i s body i n space

.. .

".

While each of the m e c h a n i s m s of "seeing " i s l a r g e l y the function of the o t h e r s , t h e r e i s growing evidence that accommodation takes precedence only in m o m e n t a r y visual t a s k s , and then p r i m a r i l y when the human o r g a n i s m ' s needs f o r equilibria a r e being s a t i s fied through a c t i v i t i e s initiated other than by i m m e d i a t e visual Page 20

NOT

FOR PAGE 2 1

13.3.3.1.

The human organism strives t o grow, develop, a n d function as an integrated whole. In each o f i t s responses i o the forces o r restraints i n its environment which stimulate it. it performs organically by seeki n g physical balances w i t h those forces and restraints which m e e t certain functions on inherently determined systems o f coordinates. These responses have a large share in determining the organism's later developments, efficiencies, and well-being. The work environment o f the immaiure organism (the child) must b e equally coordinated with the organism itself, if we would have the child arrive a t an optimum maturity, fully capable o f using i i s resources and developmental experiences in meeting i t s needs i n an efficient, acceptable, and satisfying manner.

-THE

CO-ORDINATED CLASSROOM (I: 4), p. I.

"A



stimuli. Such p r e c e d e n c e of accommodation would a p p l y i n c u r , v i s u a l t r t e s t i n g t tsitus o r y visual inspections, l f s h o p p i n g f tmany a t i o n s , s o m e p u r s u i t m o v e m e n t s , and the like. 3.3.3.1.

Y3.3.4.

However, when a c l o s e visually-centered t a s k is s u s t a i n e d , such a s in school t a s k s , i n d r a f t i n g and accounting r o o m s , e t c . , the f i r s t functions of v i s i o n a r e opticokinetic andbody-balancing, loF u l l r e s o l u t i o n follows calization and c e n t e r i n g on the task. not a s a f i r s t function of the details of the t a s k , but a s a these, r e s u l t of the functions of establishing the eye and body b a l a n c e s needed to c e n t e r on t h e t a s k , and establishing the n e c e s s a r y f r a m e s of r e f e r e n c e f o r d i r e c t i o n o f p e r f o r m a n c e . In f a c t , s o m e of these centering a n d balancing functions would s e e m t o have t h e i r s e n s o r y origin, not even in c e n t r a l a r e a s of the r e t i n a , but i n the periphery. The v e r y existence of a three-dimensional o r g a n i s m i n t h r e e - d i mensional space, organizing its actions in t e r m s of d i r e c t i o n of movement within t h r e e - d i m e n s i o n a l f r a m e s of r e f e r e n c e , further supports o u r i n i t i a l conclusion in $ 3 . 3 . The o r g a n i s m o p e r a t e s around a plane, not o n it. The definition of "planeIt t a s k s , such a s reading, w r i t i n g , etc. , without l a n d m a r k s of r e f e r e n c e such a s placement i n t h e individu a l ' s space world, t e x t u r e , and the like, and without p r o v i s i o n f o r full f r e e d o m of p e r f o r m a n c e in relation to the v i s u a l and a l l o t h e r stimuli, is a s o c i a l concept, not a biologic function.

P a g e 21

NOT

"A



In many functions of the v i s u a l p r o c e s s the eye s e r v e s as a gradient detector scanning the light-density pattern of v i s u a l space s o a s t o instigate control and direction of movement, and balancing of movement, on definable three-dimensional f r a m e s of refe r e n c e (both orientation-wise and localization-wise). T h i s scanning a l s o s e t s up signal patterns, through c e n t r a l circuiting, f r o m which can be derived o r abstracted resultants o r r e p r e s e n -

--

ify initial movements, and provide patterns f o r s t o r e d symbols of those resultants o r portions for l a t e r use in redirecting movement (I: 19,20,23,32,35,38,53,56).

This tentative conclusion c a n be derived by logical inference f r o m the one ( 93.3. ) immediately above.

It can a l s o be derivedbyexamining two aspects of r e t i n a l n e u r o l ogy; (a) the receptor-lead r a t i o s in the periphery of the retina, and, (b) the extensiveness of the dendritic p r o c e s s e s of some of the ganglion cells. Polyak (I: 20) describes this extensiveness llPolysynaptic o r Diffuse Varieties of in h i s Chapter XXV, A. The Ganglion Cellsl1. On page 3 11 Polyak says: "The f i r s t (of two groups into which ganglion c e l l s c a n b e c l a s s i fied) c o m p r i s e s the v a r i e t i e s m, n , o, p, r, whose dendritic expansions a r e extensive; they may be called the diffuse ganglion c e l l s , since, of n e c e s s i t y , each cell comes in contact with a g r e a t number of c e n t r i p e t a l bipolars, irrespective of t h e i r variIn addition, because of the partial r e c i p r o c a l overlapety.. ping of t h e i r synaptical t e r r i t o r i e s , the various individuals of the s a m e v a r i e t y and of the other ganglion v a r i e t i e s a r e synaptically related to the s a m e bipolars.

...

Because this conclusion will be discussed a t length i n P a r t Two, no f u r t h e r discussion. i s needed here. Page 22

NOT

FOR PAGE 2 3

73.5.1 -2.

"If

the initial data are funciions of unknown physiological deter-

minants, as ii i s only reasonable t o assume psychological data t o be, then the concepts based on them may be regarded logically as an indication o f the formal properties of the determinants." -Carroll

C. Prati, THE L O G I C OF

MODERN

PSYCHOLOGY,

p. 134.

"A


S O M E FURTHER C O N C L U S I O N S

Within c e r t a i n limits, the g r e a t e r the acuity, a s defined opticswise, the l e s s t h e r e i s f r e e d o m f o r constructive p e r f o r m a n c e (I: 2 7 , 3 2 , 3 5 , 3 6 , 52, 53).

T h i s tentative conclusion is dependent upon the f i n a l d e m o n s t r a tion of the existence of t h r e e functions i n vision: ( a ) s o m e a s pect of p e r f o r m a n c e is a f a c t o r in visual perception; (b) input i s a l t e r e d by output t o s e c u r e a c c u r a t e o r efficient c o n t r o l of d i r e c tion of movement; a n d , ( c ) redintegrative p r o c e s s e s e n t e r into v i s u a l meaning.

3. 5. 1. 1.

T h e existence of a n y of t h e s e functions would n e c e s s i t a t e resolved "visual i m a g e t fbeing a product of a t l s t a t i s t i c a l equilibriumI1 of accommodative input, r a t h e r than the product of a n i n p u t derived f r o m a s h a r p , fixed "point focus",

3 . 5. 1.1. 1. T h i s logically follows f r o m t h e data in the e x p e r i m e n t s mentioned i n 93.1.3.1. and t h e i n f e r e n c e s i n this data mentioned i n 93.1.4.1. a n d 93. 1.4. 2. , i n which i t w a s pointed out that a r i g i d I l ~ e tto'~ w a r d a n i m m e d i a t e r e s p o n s e would r e s t r a i n o r impede r e a d i n e s s t o change r e s p o n s e and f r e e d o m t o redintegrate.

3. 5.1.2. " "

P,, s

s

A

: i-:

Good c a s e s f o r the e x i s t e n c e of one o r m o r e of the t h r e e funct i o n s mentioned i n 93. 5. 1. have been m a d e by a n u m b e r of inv e s t i g a t o r s of vision and p e r c e p t i o n , (e. g . , I: 53, 37,32), b u t t h e complexities of b r a i n s t r u c t u r e s t i l l r e t a r d s the d e m o n s t r a t i o n of exact n e u r a l m e c h a n i s m s f o r these functions, if they exist. However, m a n y i n v e s t i g a t i o n s in experimental psychology have brought f o r t h d a t a indicating t h a t vision o p e r a t e s , i n the investigated a r e a s a t l e a s t , "as if t t physical m e c h a n i s m s f o r t h e s e funct i o n s existed.

93. 5.2,

Without ignoring the i m p o r t a n c e of phonics in teaching reading, o u r conclusion is i m p l i e d i n the many s t u d i e s of r e a d i n g which have d e m o n s t r a t e d t h a t , f r o m a concept building standpoint,

-

P a g e 23

NOT

""AYNAMIC

THEORY

O F VISION"


"word-formt1 and " p h r a s e - f o r m methods of teaching r e a d i n g a r e ~~ in i n c r e a s i n g both s p e e d and s u p e r i o r t o t l l e t t e r - f ~ r mmethods comprehension. F o r c e d t l a c u i t y t tfor l e t t e r - f o r m could r e t a r d the f r e e d o m of p e r f o r m a n c e needed f o r recognizing the l a r g e r units of f o r m . 3. 5. 2.1.

William S . Gray* s t a t e s t h e r e a r e t h r e e f a c t o r s i n b u i l d i n g word perception: (1 ) a c c u r a c y of recognition of meaning a n d pronunciation; (2) wide s p a n ; and, ( 3 ) speed. R e f e r r i n g to f o u r f o r m s of teaching reading: (1) l e t t e r s ; ( 2 ) phonetic; ( 3 ) s y l l a b i c ; a n d , (4) meaningful units ( w o r d s , p h r a s e s , and s e n t e n c e s ) , h e p o i n t s out t h e r e i s a need f o r s k i l l in all of these a r e a s , but h e f e e l s that the fourth method should be emphasized with inclusion of t r a i n ing in the o t h e r t h r e e a r e a s , because of t h e s e t h r e e f a c t o r s in word perception.

jf3. 5.3.

The "book- retinoscopy" techniques derived f r o m the G e s e l l study (I: 32) a l s o i m p l i e s o u r tentative conclusion, i n that i t i s not unreasonable to deduce t h a t the accommodative s h i f t s s e e n through the use of t h e s e techniques a r e related t o " r e d i n t e g r a t i v e r e o r ganization of the o r g a n i s m a s "meaningf1i s d e r i v e d f r o m o r a s If t h i s i s t r u e , f o r c e d sociated with the s y m b o l s being read. Ifacuity1lwould p r e v e n t o r inhibit t h e s e r e d i n t e g r a t i v e a c t i o n s and, hence, s e v e r e l y d e l i m i t the derivation of meaning.

93. 5.4.

An additional implication supporting our tentative conclusion concerning t r a c u i t y t cl a n b e d e r i v e d f r o m the s t u d i e s of Gibson (I: 3 6 ) . Ifdepth i s d e r i v e d f r o m the t e x t u r e of the v i s u a l f i e l d , a s Gibson shows, then the f o r c i n g of fine resolution of c e r t a i n p o r t i o n s of that t e x t u r e would d i s t o r t o r a l t e r the perception of d e p t h , even to disrupting c e n t r a l t a s k o r f i g u r e f r o m i t s ground.

573. 5. 5.

If human o p e r a t i o n s a r e Itdynamic ", then the definition a n d r e s o lution of d e t a i l could b e the " s t a t i c t t portions of the p e r c e p t u a l

* .-

L e c t u r e given b y D r . G r a y at a Conference on Reading, The University of T e x a s , F e b r u a r y , 1957.

Page 2 4

S O M E FURTHER C O N C L U S I O N S

Perceived ltvisual image is derived f rorn some f o r m of integration of: ( a ) the derived o r resultant signals f r o m o t h e r modalit i e s with derivatives of signals representing the light density patt e r n s ; (b) the derivatives of motor actions instigated by a l l the components of the above; ( c ) derivatives of signals indicating the "feeling tonet1a r o u s e d ; and, ( d ) p a s t resultants o r derivatives of all t h e s e and t h e i r resultants o r derivatives (I: 19. 25. 27.32.33,

Page 26

NOT

"A


NOT

FOR PAGE 2 8

74.2.1 .

. . . "No

higher structure alone can move muscles: it can only confrol

the 'central amplification' of the elementary spinal reflex arc" -McCulloch

and Pitts, THE STATISTICAL O R G A N I Z A T I O N

... OF

NERVOUS ACTIVITY, Journal of the American Statistical Association, June 1948, Vol. 4, No. 2, p. 97.

"A


""WIGHER"

A N D '"LOWER"

FUNCTIONS

While the c o r t i c a l o r 'Ihigher" functions, in l a s t a n a l y s i s , a r e probably what s e t m a n a p a r t f r o m other f o r m s of organic life--and no study of human operations would be complete without a thorough exploration and appreciation of "higher " functions insof a r a s data a r e available---nevertheless, the t h r e e field8 mentionedby GeseU DO develop JOINTLY. In a significant r e s p e c t , each i s a function of the others. Full insight into a p r o c e s s cannot b e gained b y confining attention to only a single function in that process. In a n exploration of visual theory it would be well t o examine briefly s o m e a s p e c t s of these t h r e e fields of Ifhigher" and "lowe r t t functions a s they might affect vision.

Vision i s proving t o b e what i s probably the dominant function in a l l the actions of the organism in relation to i t s space world, f r o m the s i m p l e s t to the highest and most complex. In connection with the t h r e e fields enumerated by Gesell which give substance to tfvisualimage ! I , visual p r o c e s s e s enter into localizing the o r ganism in space (I: 31,34); adjusting the organism in efficient relationship with that which it wants o r needs to manipulate (I: 19, 33,38); holding the o r g a n i s m in support (I: 2,38); identifying significant f o r m s , objects, events, o r symbols in the surround (I: 22,24,27); synthesizing and unifying other sensations and experi e n c e s with the immediate visual ones to derive meaning (I: 3 5, 53, 55, 56); directing action (I: 33,34, 55); recording significant a s p e c t s of experience f o r l a t e r use in making p e r f o r m a n c e o r problem solving m o r e efficient (I: 45,46, 57); and, establishing needed and satisfying equilibria (I: 19,38,47). F r o m organic s u r v i v a l t o socialdemand, no one of these visually-relatedproce s s e s can receive emphasis t o the exclusion of o t h e r s if the o r ganism i s to function efficiently.

w.2 , 1. s r,.E; @+

NOTE

The p r e s e n c e of "highert1 functions in man has not excused him from satisfying the tilower ' I functions- - - "higher flfunctions m e r e l y provide m e a n s f o r facilitating ltlowerll functions, thereby inc r e a s i n g t h e i r validity and the range of interpretations that can

Page 28

NOT

"A

D Y N A M I C THEORY OF V I S I O N "

"HIGHER"

AND " L O W E R ' F U N C T I O N S

be m a d e f r o m t h e i r operation. Distortions of the l r l o w e r t procf e s s e s away f r o m t h e i r p r i m a r y biological p u r p o s e s actually t h r e a t e n the validity of the '?ligher I t ones. 4.2.1.1.

The p r o c e s s e s in a l l t h r e e fields---skeletal, v i s c e r a l , and c o r t i c a l - - - a r e equilibrating o n e s , balancing the o r g a n i s m with ext e r n a l and i n t e r n a l d e m a n d s , and each with the o t h e r , i n o r d e r to promote the o r g a n i s m i s integrity and survival. In t h i s balancing the "higher t f f u n c t i o n sa c t a s the summing, synthesizing, delaying, and directing m e c h a n i s m s in reorganizing and r e d i r e c t ing the e x p r e s s i o n of t h e ttlowerll functions in keeping with the total of the p r i r n a r y a s well a s symbolic experiences. The "highe r functions o p e r a t e t o t h i s end efficientlyonly when they do not a l t e r the biological p u r p o s e s of the "lower" functions o r defeat them in meeting the o r g a n i s m ' s biological needs. Constant inhibition and d i r e c t i o n o r redirection of e x p r e s s i o n t a k e s place in o r d e r t h a t a l l t h e needs of the total o r g a n i s m - --biological, psychological, and social-- -can be m e t in a specific environment. Through t h i s redirection of e x p r e s s i o n , a s a r e sult of the Ifhigher" functions, t h e r e can be f u r t h e r and f u r t h e r refinement of e x p r e s s i o n , t h e r e b y continuing t o promote the o r g a n i s m ' s total economy in a l l the surroundings in which i t finds i t s elf.

Skeletal m e c h a n i s m s a r e concerned principally with the organi s m ' s relations with t h e world around it. Motor-wise, these m e c h a n i s m s include t h e m u s c l e s and supporting s t r u c t u r e s f o r p o s t u r e , p o s t u r a l s u p p o r t , and spatial movement. The skeletal nervous s y s t e m includes the r e c e p t o r s and d e t e c t o r s f o r e x t e r n a l s u b s t a n c e s , e n e r g i e s , and f o r c e s of biological significance, and those f o r contact, movement, and direction, In addition, the n e u r a l affector s and e f f e c t o r s f o r adjusting the o r g a n i s m 1s r e l a tions with the environment a r e included i n the skeletal mechani s m s . Other n e u r a l , m o t o r , and supporting s t r u c t u r e s e n t e r the make-up of the s k e l e t a l m e c h a n i s m s , but a l l a r e concerned with the body's actions t o w a r d e x t e r n a l factors.

Page 29

NOT

FOR PAGE 3 0

74.3.2.1.

This concept o f learned reactions does n o t ignore the place t h a t increase o f muscle cross-section through repeated use can occupy in some skills learning. N o d o u b t such muscle adaptations can a d d t o the efficiency o f performing some repetitive types o f tasks. However, this t y p e o f training alone can make f o r a unbalanced organism-especialiy

if

t h e task f o r which this training i s used is

unilateral o r unidirectional. Such imbalances can and d o lead t o inefficiencies i n performing other tasks calling f o r other directions o r t h e use o f t h e developed musculature i n conjunction w i t h lesser developed muscles.

"A D Y N A M I C T H E O R Y O F V I S I O N "

"l-tlGHERt'

914.3.1.

AND "LOWER"

FUNCTIONS

-

Society's preoccupation with communication- -e spec ially symbolic communication---has led some of the fields concerned with vision to be influenced by a few outmoded concepts of learning. Two of these a r e of p a r t i c u l a r i n t e r e s t here. The f i r s t of these concepts h a s assumed that learning was a proce s s of passive absorption--a pouring-inproce ss--with the l e a r n e r sitting like a n empty receptacle waiting to be filled with socially-defined information, h i s behavior changing automatically a s he was presented with these facts in either concrete o r sy-rnbolic form. Little need be said h e r e in refutation of t h i s concept.

4. 3.1.1.

$4.3.2.

4.3.2.1. SEE NOTE

4.3.2.2.

-

Education has long since demonstrated that a child g r o w s , de velops, and l e a r n s through action, both implicit and overt. In fact, a l l ages l e a r n through doing, by means of ( a ) c o n c r e t e a c tions and experiences before symbolization; (b) actions toward the f o r m s of symbols themselves; and, ( c ) actions a f t e r meaningful symbolic experience. Even after learning, the response to stimulation is action o r a surrogate for action. The second outmoded concept of learning which h a s influenced some of those concerned with vision h a s to do with l e a r n e d r e actions and the learning of m o t o r skills. This concept of l e a r n e d reactions and the development of motor skills a s surnes that the s e reactions and skills a r e l e a r n e d through repeated use of a specific group of muscles, with unneeded m u s c l e s dropping out of the group with repetition of the action a s a r e s u l t of the law of economy of effort, until a n acceptable action i s a c q u i r e d o r until the l i m i t of capacity of the individual is reached. This concept, i n effect, a s s u m e s a physiological d u a l i s m in which the s e n s o r y m e c h a n i s m s s e t up a perception of the t a s k to be done a s a model o r standard, and then specific m o t o r equipm e n t i s put into action to reproduce that standard. Thelearnedreactionormotorskillisactuallyshowingitselfto b e , not simplification of operation, through training, of a specific group of m u s c l e s , but s p a t i a l direction of movement i n relation

Page 3 0

NOT

"A


'WIGHER"

AND "LOWER"

FUNCTIONS

*

t o a f r a m e o r f r a m e s of reference. It i s a n adaptive p a t t e r n in w h i c h a c t i o n i s a sequence of statistically d e t e r m i n e d m o v e m e n t s d i r e c t e d ( a ) in relation t o the axes of the body; (b) i n relation to the s p a t i a l coordinates of the organism's orientation t o itself and t o i t s environment, o r , ( c ) i n relation to a l l of these. Direction i s d e t e r m i n e d b y the o r g a n i s m ' s t r a n s l a t i o n o r t r a n s f o r m a t i o n 3 f the s y s t e m s of coordinates of i t s perceptual space world into experientially determined s y s t e m s of coordinates of itself. What i s l e a r n e d i s d i r e c t i o n of movement on the body's p o s t u r a l coordin a t e s toward localizations on the perceived coordinate s of space. Whether the coordinate s used to determine direction of movement a r e " r e a l t f o r not depends upon the adequacy of the o r g a n i s m ' s experiences. 4.3.2.3.

Lashley (11: 7,8), who suggested a s i m i l a r concept of l e a r n e d reaction, s a y s : "The transition from the visual p e r c e p t u a l t o the m o t o r l e v e l thus a p p e a r s to be, primitively, the t r a n s l a t i o n of one s y s t e m of space coordinates into another. Direction i s dominant in v i s u a l m e r n o r y and the reaction reduces t o a sequence of d i r e c t e d movements. Intervening between these i s the s y s t e m which constitutes s p a t i a l and postural orientation.

.. .

"The visual s y s t e m i s p r i m a r i l y concerned with s p a t i a l o r i e n t a tion and f o r i t the t r a n s i t i o n f r o m a s e n s o r y to a m o t o r p a t t e r n c a n be m o s t adequately conceived a s a n interplay of polarized s y s t e m s o r of interweaving dynamic patterns i n which the s p a t i a l p r o p e r t i e s of the visual stimulus a r e t r a n s l a t e d b y integration a t a s e r i e s of l e v e l s into modification of the g e n e r a l p a t t e r n of post u r a l organization. " F r o m the above concept of l e a r n e d reactions i t c a n be readily s e e n that skeletally-related visual p r o c e s s e s of m a j o r significance in l e a r n i n g and development ( o r in any p e r f o r m a n c e ) a r e

* .-

T h e r e i s no intention to imply that economy of effort does not a l s o e n t e r into learning direction of movement. Efficiency of direction of movement also implies the use of the l e a s t m o t o r equipment needed for successful and a c c u r a t e movement and d i r e c t i o n of movement.

Page 31

NOT

FOR PAGE 3 2

74.3.3.1.

Nystagmoid actions brought f o r t h when spatial posturing mecha-

with (especially labyrinthine mechanisms) would of feed-back.

nisms are interfered imply existence

"A


"HIGHER"

AND "'LOWER"

FUNCTIONS

those entering into describing* the f r a m e s of r e f e r e n c e of the space world and the o r g a n i s m ' s orientation to that world, and direction of movement on those f r a m e s of reference. Of necessity, then, the dominant p r o c e s s e s basic to adequate v i s u a l perception a r e the t t d p a m i c l lones derived f r o m t t l o w e r u skeletal functions which e n t e r into determining and describing direction and localization i n t h r e e -dimensional space, and l l m o v e t tthe o r ganism in relation to that direction and localization. 4.3.3.1.

The concomitant optical mechanisms entering into defining the projected light gradient on the retina can then be only a portion of the m e c h a n i s m s of vision, Even these can be affected by the actions brought forth on initial and continued stimulation. In the light of present-day knowledge of mechanisms f o r controlling action, f o r a c c u r a c y of movement and direction of movement--for successful performance--output must affect input. Any action m e c h a n i s m directed toward a spatial goal m u s t feed back and impose a signal on the detecting and directing mechanism, Itreportingt1the s p a t i a l direction and degree of completion of i t s assigned action, and the signals f r o m the detecting and directing m e c h a n i s m m u s t b e modified accordingly, i f the resulting action i s to be efficient and accurate. While many of t h e s e specific feed-back mechanisms a r e still to be identified in visual p r o c e s s e s , the logic of visually-instigated spatial behavior i n human o r g a n i s m s would imply t h e i r existence. V i s c e r a l m e c h a n i s m s a r e concerned with operating the internal economy of the organism. Organs of circulation, digestion, and

*