Ames Perception Experiments

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THE AMESDEMONSTRATIONS

INPERCEPTION

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by WILLIAM H. ITTELSONPRINCETON UNIVERSITY PRESS


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UNIVERSITYOF FLORIDALIBRARIES

COLLEGE LIBRAPV


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THE AMES DEMONSTRATIONS IN PERCEPTION


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THE AMES DEMONSTRATIONSIN PERCEPTION

A GUIDE TO THEIR CONSTRUCTION AND USE

By WILLIAM H. ITTELSONo',^~ , / J

PRINCETON UNIVERSITY PRESS, PRINCETON, NEW JERSEY, 1952


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Copyright 1952, Princeton University Press, Princeton, New JerseyLondon: Geoffrey Cumberlege. Oxford University Press

Reproduction, translation, publication, use, and disposal in whole or in partby or for the United States government

is permitted for all material covered by the above copyright

Printed in the United States of America


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TO MY WIFE


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Digitized by the Internet Archivein 2010 with funding from

Lyrasis IVIembers and Sloan Foundation

http://www.archive.org/details/amesdemonstratioOOitte


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PrefaceIn this volume I have attempted to present some of the more im-demonstrations in perception that have been developed byAmes, Jr., initially with the Dartmouth Eye Institute andwith the Institute for Associated Research at Hanover, New Hamp-Taken together, these demonstrations have over a period of timefor themselves a name, the Ames demonstrations; a name that

emphatically rejected by Ames himself, who insists on the coopera-nature of the endeavor that produced them and generously over-the contributions of his coworkers. Nevertheless, the Ameswould not exist except for the unique combination ofimagination and technical ingenuity of the man from whom theytheir name.Taken as a whole, the demonstrations make it possible to observephenomena ranging from the simplest visual experiences tocomplex situations involving action. It is increasingly be-recognized that they offer a coherent and comprehensive series ofof importance to psychology, psychiatry, philosophy, edu-art and architecture, and related fields.Increased use of the demonstrations in research and educationalhas been accompanied by increased demand for details of theirand operation. Although there are several manuscripts anddescribing one or more of the demonstrations, as yet thereno available source in which all the demonstrations are described orven listed and in which detailed information is presented from whichcan be constructed.The purpose of the present work is to fill this gap. With thisin view, each demonstration is treated separately as a physicalof laboratory equipment, with the following information provided:

1. A brief introductory note;2

.

A photograph or drawing of the apparatus

;

3. A brief description of the apparatus and its operation;4. An outline of typical observations using the apparatus,where possible;5. A construction drawing of the apparatus.Each construction drawing, together with the accompanying photo-and description, provides sufficient information for any reason-competent laboratory technician to duplicate the apparatus. Minordetails have for the most part been omitted both in theof simplicity and in the recognition that each laboratory fav-its own particular type of construction depending on the facilitiesmaterials available.For the sake of brevity, only a very brief account of how to oper-the apparatus and a few typical observations are offered with eachEven the simplest of the demonstrations can be used invariety of ways and can show a wide variety of possible phenomena, alisting of which would be inappropriate and unnecessary. Athought and ingenuity on the part of the interested investiga-can be relied' upon to reveal other potentialities of the demonstra-. The particular methods of operation and the observations thatbeen selected for description represent a distillation of the ex-

of the author and others in viewing the demonstrations forand in studying many hundreds of observers in one or more ofsituations described. However, they are offered only as suggestionsillustrations.vii


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[Readers who are interested in other ways of operating the demon-strations and other phenomena that they show are referred especiallyto manuals written by A. Ames, Jr. (2), Merle Lawrence (23), RossMooney (35,36,37,38), and Hoyt Sherman (32). A comprehensive summaryof experimental and theoretical work utilizing these demonstrations canbe found in Kilpatrick (23). Some of the demonstrations can also beseen in a motion picture, Demonstrations in Perception, produced bythe Naval Photographic Center at the request of the Professional Divi-sion, Bureau of Medicine and Surgery.]

The theoretically minded reader will note that no attempt has beenmade to explain the phenomena that are experienced. This is in keep-ing with the announced aim of this work. However, various interpreta-tions and hypotheses have been formulated by the author and others andcan be found in the references provided in the bibliography appendedat the end of the text. In this connection it is to be hoped that theinclusion of most of the demonstrations in one volume, which necessi-tates their being considered as a whole, will make evident the futilityof piecemeal theorizing and point up the fact that an adequate theoret-ical understanding of any one of the demonstrations should be broadenough to encompass them all.

The conception and construction of the various demonstrations,which took place over a long period of years, followed an evolutionarypattern. Experience with the simpler demonstrations led to the concep-tion of the more complicated ones . The demonstrations are presented inthis volume more or less in the order of their evolutionary development.Each demonstration constitutes a scientific inquiry into a parti-cular controlled concrete visual situation in which (1) certain aspectsare kept constant, (2) certain other aspects are varied, and (3) theeffect of such variations on certain other aspects is qualitatively de-termined. In all cases special care needs to be taken that visual indi-cations of which the investigator may not even be aware are not opera-tive. Many of the details of construction have been empirically workedout to accomplish this purpose.The not inconsiderable financial investment represented by the de-velopment and production of the pieces of apparatus described in thisvolume has been provided largely by support from the Rockefeller Foun-dation, whose officers have offered both funds and enthusiastic en-couragement most generously. Important assistance has also been ob-tained through grants from the Quaker Hill Foundation. In addition,special financing was made available by Mr. and Mrs. E. K. Hall, Jr.for the construction of the full size monocular distorted room and thebinocular distorted rooms. This volume itself is one of several pub-lications in preparation deriving from a larger project initiated bythe Professional Division, Bureau of Medicine and Surgery, and sub-sidized by the Office Of Naval Research, contract N6onr 27014 withPrinceton University and contract Nonr-496(01) with the Institute forAssociated Research, under Navy Medicine's policy of encouraging basicresearch in perceptual phenomena as they relate to personality theory .and social psychiatry. The opinions expressed, however, are those ofthe author and do not represent the opinions or policy of the UnitedStates Navy.With the exception of the binocular distorted rooms, every one ofthe demonstrations was constructed by Kimball Whipple, in charge of theshop of the Institute for Associated Research. The drawings were forthe most part done by Dr. Amos Chang, while I am indebted for the re-maining to John Harrison Rudolph and Rudolph Amann . Special thanks aredue to David E. Scherman, through the courtesy of Scientific American,for the photographs illustrating the effects obtained with the balloon,overlay, and rotating trapezoid demonstrations.viii


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Hadley Cantril, to whom I am permanently indebted for first intro-me to thj Ames demonstrations, has in large measure made thispossible by his continuing support of the work reported here.personal encouragement, as well as his never-failing ability tohelpful suggestions at crucial points, have been invaluable.manuscript has been read in whole or in part by Hadley Cantril,P. Kilpatrick, and Merle Lawrence, all of whom have provided much-criticism. In addition, the entire manuscript has been read bywhose critical comments were most helpful. In all fairness toit should be added that not all his suggestions were incorporatedthe final version.The tedious mechanical tasks involved in preparing the manuscriptbeen most patiently borne by Mrs. Alice Weymouth and Mrs. Grace

. The thousand and one administrative hitches unavoidablyin the production not only of this volume but more especiallythe demonstrations described in it have been systematically over-as they arose by John Pearson, whose neverf ailing good humor hasprovided the otherwise missing essential ingredient. Finally,thanks are due Martha Lane Ittelson for providing the designthe cover of this volume.The Ames demonstrations themselves speak of their creator. It wouldredundant to add further tribute, except to record my personal appre-

of the opportunity of knowing Ames and my thanks to him for thehours we have spent together both at work in his laboratory and atin his office. These are experiences which have become apart of me.

New Jersey W. H. I.1952

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ContentsPreface viiList of illustrations xiii1. The star point demonstration 32. The line demonstration 53. The size-brightness demonstrations 84. The overlay demonstration 135. The parallax demonstration 166. The togetherness and apartness demonstration 187. The thereness-thatness demonstrations 218. The chair demonstration 269. The watch-card-magazine demonstration 30

10. The afterimage demonstration 3211. The artificial retina demonstration 3412. The tilting screen demonstration 3613. The distorted room demonstrations 39

A. Monocular rooms: laboratory size 40B. Monocular room: full size 44C. The architect's room 46D. Binocular rooms 50

14. The aniseikonic glasses demonstration 5315. The radial motion demonstration 5616. The tangential motion demonstration 6317. The circular motion demonstration 6418. The S motion demonstration 6719. The rotating trapezoid demonstration 7220. The surety demonstration 76Bibliography 83

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LIST OF ILLUSTRATIONS

1,1 Apparatus drawing for the star point demonstration 42.1 Apparatus drawing for the line demonstration 62.2 Drawing illustrating typical observations obtained withthe line demonstration 73.1 The balloon demonstration, apparatus photograph 83.2 The square demonstration, apparatus photograph 83.3 The balloon demonstration photographed from theviewing point 93.4 Drawing illustrating typical observations obtained withthe ])alloon demonstration 103.5 Apparatus drawing for the balloon demonstration 113.6 Apparatus drawing for the square demonstration 124.1 The overlay demonstration, apparatus photograph 144.2 The overlay demonstration photographed from theviewing point 144.3 Apparatus drawing for the overlay demonstration 144.4 Construction details for the overlay demonstration 155.1 The parallax demonstration, apparatus photograph 175.2 Apparatus drawing for the parallax demonstration 176.1 The togetherness and apartness demonstration,apparatus photograph 186.2 The togetherness and apartness demonstrationphotographed from the viewing point 196.3 Apparatus drawing for the togetherness andapartness demonstration 207.1 The thereness-thatness demonstration, apparatusphotograph of the projector model 227.2 Drawing illustrating typical observations obtainedwith the thereness-thatness demonstration,projector model 237.3 Drawing illustrating typical observations obtainedwith the thereness-thatness demonstration,

mirror model 23

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7.4 Apparatus drawing for the thereness-thatnessdemonstration, projector model 247.5 Apparatus drawing for the thereness-thatnessdemonstration, mirror model, and the tangentialmotion demonstration 258.1 The chair demonstration, apparatus photograph 268.2 The chair demonstration, photographed from theviewing point and from behind 278.3 Apparatus drawing for the chair demonstration 289.1 The watch-card-magazine demonstration photographedfrom the viewing point 309.2 Apparatus drawing for the watch-card-magazinedemonstration 31

10.1 The afterimage demonstration, apparatus photograph 3210.2 Apparatus drawing for the afterimage demonstration 3311.1 The artificial retina demonstration 3512.1 The tilting screen demonstration, apparatus photograph 3712.2 A typical slide for use with the tilting screendemonstration 3712.3 Apparatus drawing for the tilting screen demonstration 38

Monocular distorted room no. 1 photographed from theviewing point 41Monocular distorted room no. 1 41Monocular distorted room, no . 2 41Drawing illustrating typical observations obtainedwith monocular distorted room no . 1 41Drawing illustrating typical observations obtainedwith monocular distorted room no . 2 41Apparatus drawing for monocular distorted room no . 1 42Exterior photograph of the full size monoculardistorted room 44

3B.2 The full size monocular distorted room photographedfrom the viewing point 44Apparatus drawing for the full size monoculardistorted room 45

. 1 The architect's room photographed from the viewing 46point xiv


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Exterior photograph of the architect's room 47Drawing illustrating: typical ol.>servations obtained withthe architect's room 48Apparatus drawing for the architect's roomdemonstration ^ 49The interior binocular distorted room 50Horizontal cross-sections of the binocular distortedrooms 51Stereoscopic photographs of the binocular distortedrooms taken from the viewing position 52

14.1 Schematic representation of the aniseikonic glasses 5314.2 Aniseikonic glasses 53

14.3 The leaf room 5414.4 Drawing illustrating typical observations obtainedwith the aniseikonic glasses 5515.1 The radial motion demonstration, apparatus photograph 5615.2 The basic settings of the radial motion apparatus 5715.3 Drawing illustrating typical observations obtainedwith the radial motion apparatus, demonstration I 5815.4 Drawing illustrating typical observations obtainedwith the radial motion apparatus, demonstration II 5915.5 Apparatus drawing for the radial motion demonstration 6115.6 Drawing illustrating typical observations obtainedwith the radial motion apparatus, demonstration III 6216.1 The tangential motion demonstration, apparatusphotograph 6317.1 The circular motion demonstration, apparatusphotograph 6417.2 Schematic representation of the circular motiondemonstration 6517.3 Apparatus drawing for the circular motion demonstration 6618.1 The S motion demonstration, apparatus photograph 6818.2 Schematic representation of the S motion demonstration 6818.3 The S motion demonstration photographed from theviewing point 69

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18.4 Typical observations using the S motion demonstration 7018.5 Apparatus drawing for the S motion demonstration 7119.1 The rotating trapezoid demonstration, apparatus photograph 7319.2 The rotating trapezoid demonstration photographed from theviewing point 7319.3 Drawing illustrating typical observations obtained withthe rotating trapezoid demonstration 7419.4 Apparatus drawing for the rotating trapezoid demonstration 7520.1 The surety demonstration, apparatus photograph 7620.2 The surety demonstration photographed from theviewing point 7720.3 Drawing illustrating typical observations obtained with

the surety demonstration, parallax effect. 7820.4 Drawing illustrating typical observations obtained withthe surety demonstration , illumination effect. 7920.5 Apparatus drawing for the surety demonstration 80

XVI


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THE AMES DEMONSTRATIONS IN PERCEPTION


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1. THE STAR POINT DEMONSTRATIONA star point is a minute point of light. When viewed

in an otherwise completely dark room, it represents thesimplest possible visual experience. And yet even in thiselementary situation important depth and direction effectscan be observed. A single star point cannot be accuratelylocalized either in apparent distance or direction, evenusing both eyes. Its apparent distance, for example, islargely determined by such factors as knowledge of the sizeof the room in which it is being viewed. When using one eye,the apparent relative distance of two star points is af-fected by their relative brightness the brighter appearsnearer -- and by their relative positions -- the lower oftwo star points appears nearer or farther when the pointsare respectively in the lower or upper part of the visualfield.Apparatus

The star point apparatus consists of a light-tight boxcontaining three small holes, each illuminated by a separ-ate light placed within the box. The brightness of the twooutside lights can be continuously varied so that as onebecomes brighter the other grows dimmer

.

Viewing conditionsThe star points are viewed in an otherwise completelydark room from a distance of ten or more feet. It is de-sirable to hold the head stationary, but no headrest isneeded. Monocular observation is used except when other-

wise noted.Typical observations

A single star point appears to be localized at a fairlystable distance, which is dependent in both monocular andbinocular observation primarily on knowledge of the viewingconditions. For example, if observers are familiar with thedimensions of the experimental room, they see the star pointat distances limited by those dimensions. If the point ispresented in such a way that it might in fact be a star inthe sky, they will tend to see it off at great distances.The apparent direction of a single star point is veryunstable and continually shifts (autokinetic effect).With two star points visible, both at eye level and thesame distance from the observer, the brighter point appearsnearer. If the relative brightness is continuously varied,the brighter point appears to approach and the dimmer torecede

.

With the two points of equal, constant brightness, onevertically above the other, when the points are near thefloor, the upper appears farther away to a standing observer.When they are near the ceiling, the lower appears fartheraway, provided the ceiling is high enough to give the effect.


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BRIGHTNESS CONTROL'C FOR A a. C )

LIGHT CONTROL FOR B

LIGHT CONTROL FOR AC

OVERALLLIGHT CONTROL

SCALE

NOTESWHITE PAINT FORNTERIOn AND BLACKFOR EXTERIORDRILLED HOLES ONFRONT PANEL SERVEAS STAR POINTS(** 80 DRILL ANDTHIN METAL SHEETJFROSTED BULB FOREACH LIGHT CHAMBERTURNING BRIGHTNESS CONTROLCLOCKWISE CONTINUOUSLYBRIGHTENS A AND D)A\S CAND VICE VERSA

Fig. 1.1. Apparatus for the star point demonstration


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2. THE LINE DEMONSTRATIONThe use of illuminated lines, viewed in an other-wise completely dark room, introduces the simplestvisual conditions under which size can be continu-ously and systematically controlled. In monocularobservation, the relative apparent distance of twolines is dependent on their relative lengths -- thelonger appears nearer and on their relative posi-tions -- the lower may appear nearer even thoughshorter

.

ApparatusThe apparatus for the line demonstration con-sists of a light-tight box on the front of which arefour narrow slits, each illuminated by a separatelight that can be turned on or off independently ofthe others

.

Viewing conditionsThe apparatus is viewed monocularly at eye lev-

el in a completely dark room from a distance of tenfeet or more. The head should not be moved, but noheadrest is needed.Typical observations

When two lines of different lengths are illum-inated, the longer appears nearer.When three lines of different lengths are illum-inated, Ithe depth effect is greater, with the long-est line appearing nearest and the shortest linefarthest

.

When two lines of different lengths are illum-inated with the shorter line lower than the longer,the shorter line appears nearer for most observers.


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SCALEi 1 1 1-

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NOTESWMITE PAINT FORINTERIOR AND BLACKFOR EXTERIORSCRATCHES ON BLACK-PAINTED GLASS FRONTPANEL SERVE AS LINESLOCATION OF LIGHTCONTROLS ARBITRARYSEPARATE LIGHT CONTROLFOR EACH LIGHT CHAMBERDIFFUSION MATERIAL BETWEENEACH SCRATCH AND LIGHT SOURCE

Fig. 2.1. Apparatus for the line demonstration,


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The relativide indicatiodemonstrationstrated both siindication --larger objectthe depth effewith size beinContinuous chaling than statApparatus

lative brightnesses proIn the size-brightnessrightness can be illus-ness provides a depther . Similarly, theindications supplement,ict, it is diminished.for most Observers.cations is more compel-

3. THE SIZE-BRIGHTNESS DEMONSTRATIONSve sizes of objects and their rens of their relative distances.the depth effects of size and bngly and in combination. Brightthe brighter object appears nearappears nearer . When these twoct is enhanced. When they conflg the more important indicationnge of one or both of these indiic difference

.

The two size-brightness dem.onstrations , the balloon demonstrationand the square demonstration, are similar in that each provides twoobjects whose size and brightness can be independently varied. Theydiffer only in the nature of tlie objects used.A. The balloon demonstration makes use of two balloons, each il-luminated from above by a separate light source. The size of the

balloons can be varied continuously by a lever operating a bellows sothat as either balloon grows larger, the other becomes smaller. Simi-larly, the illumination can oe controlled by another level so that asone balloon becomes jrighter, the other grows dimmer. These effectscan be made to supplement each other, i.e., the balloon which is madelarger can also oe made brighter, or to conflict, i.e., the balloonwhicli is made larger can also be made dimmer,

B. The square demonstration consists of a light-tight box on thefront of which are two variable-size square diaphragm openings . Eachopening is covered with a light-diffusing material and is illuminatedfrom behind by a separate light source. The sizes of the square dia-phragm openings can be continuously varied so that as either growslarger, the other becomes smaller. Similarly, the illumination can becontrolled so that as one square grows brighter, the other becomesdimmer. These effects can be made to supplement or to conflict as de-scribed for the balloon demonstration.

Fig. 3.1. The balloondemonstration

.

Fig. 3.2. The squaredemonstration

.

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Size alone Brightness alone

Fig. 3.3. The balloondemonstration from theviewing point

Size and brightness supplementing

conditionsEither apparatus is viewed monocularly, except where otherwisefrom a distance of ten or more feet. The room should be com-dark so that only the two illuminated objects are visible. No

is required.observations

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constant, and size continuouslyrger appears to approach and the, and illumination continuouslyighter appears to approach andnuously varying and supplement-nhanced . This apparent move-oth eyes are used and movemente objects are held fixed at anocular observation and parallax

ightness continuously varying but conflicting,diminished, but for most observers the largerpproach . An occasional observer reports thebrighter object apparently approaching.


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4. THE OVERLAY DEMONSTRATIONOverlay, the fact that a near object partially obscures objectsbehind it, provides one of the most important indications of rela-tive distance. The overlay demonstration illustrates overlay as anisolated indication of relative distance and also compares its ef-fectiveness to that of the indication of relative size.

ApparatusThe overlay demonstration consists of a table on which aremounted three rows of cards. The cards in the left hand row are ofthree different colors and of three different sizes proportioned sothat all three cards subtend the same visual angle at the viewingpoint. The cards in the middle row are also of the same three dif-ferent colors and also subtend the same visual angle at the viewingpoint. In the right hand row two of the cards are normal-size play-ing cards. In the middle and right hand rows the two near cards ineach row are cut out in such a way as to produce a false indicationof overlay. The posts to which the cards are attached have specialmounts permitting lateral and vertical adjustments for alignmentpurposes

.

Viewing conditionsThe overlay demonstration is viewed from a headrest located atthe end of the table in an evenly illuminated room. A shield onthe headrest blocks off the left eye, insuring monocular observa-tion of the cards. Appropriate adjustments are provided on theheadrest so the cards can be viewed from the exact point for whichthe false overlay indications are aligned. The headrest adjust-ments are correct when a small ball on the table top is seen ex-actly in the center of a hole in the shield on the table in front

of the headrest. Also provided on this shield are two flaps. Whenboth flaps are raised, only the left hand row can be seen. When theleft flap is lowered, the middle row is visible. Lowering the rightflap reveals the right hand row. The entire shield can also belowered, permitting the binocular observation of the table top andthe bottom part of the rods holding the cards.Typical observations

The left hand row and the middle row appear identical, the ac-tually far card in the middle row appearing nearer than the middlecard in that row and the actually near card farther than the middlecard

.

In the right hand row the actually near playing card appearsfarther away than the middle card in that row and extremely large.The actually far playing card appears in front of the middle cardand very small.If the entire shield is lowered while viewing the middle row ofcards, the post holding the near card appears to bend backward, withits bottom at the apparent distance of its attachment to the tableand its top at the farther apparent distance of the card mounted onit. Many observers do not experience this effect but instead seethe posts in one apparent order and the cards in the opposite order.

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5. THE PARALLAX DEMONSTRATIONIn everyday observation we are constantly in motion standing up, turning around, walking, sitting down. Veryrarely, if ever, outside of the laboratory does an abso-lutely motionless person look at completely stationary ob-jects for any length of time. As one moves about, therelative positions of objects change in a manner determinedby the actual distances of the objects, thereby providingan indication of the apparent relative distances of theseobjects. In the parallax demonstration this indication ofmovement parallax is controlled by means of a mechanicalarrangement so that it can be demonstrated both as an iso-lated distance indication and in conflict with the indica-tion of size.

ApparatusThe parallax demonstration consists of a table at oneend of which is a headrest that can swing right and leftfor a distance of about six inches. Attached to the head-rest is a mechanical linkage on which are mounted two poststhat swing back and forth as the headrest moves. This link-age is designed so that the far post, when viewed from theheadrest, does not move relative to a stationary referencepost. Similarly, the near post can be adjusted so that itdoes not move relative to a stationary point beyond the end

of the table. Any desired objects, for example the tri-angles shown, can be placed on top of the moving posts.Viewing conditions

The apparatus is viewed from the headrest, in a norm-ally illuminated room. A shield cuts off the view of thetable top from both eyes and of the two movable posts fromthe left eye but allows both eyes to see the referencepost and objects attached to it. In operation, the observerslowly and continually moves his head from side to side,thereby moving the headrest and, through the linkage, theposts and the objects they support.Typical observations

If two objects subtending the same visual angle, suchas the triangles shown in the photograph, are placed on theposts, the far object apparently approaches to approximatelythe distance of the stationary post and becomes smaller,while the near object appears to recede and become larger.This effect can also be observed if familiar objectse.g., match boxes, are placed on the posts. In this case,when the actually far object appears to approach, it is nolonger seen in its familiar size but appears undersize,while the actually near object appears farther away andoversize

.

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SCALE

Fig. 5.1. The parallax demonstration,

TARGETS SUBTEND 5kM[ VI5UHL ANCIE

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Fig. 5.2. Apparatus drawing for the parallax demonstration17


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6. THE TOGETHERNESS AND APARTNESS DEMONSTRATIONAny visual perception can be analyzed into component parts, theelements of which seem to belong together, apart from the other compo-nents of the perception. The impingements from the table across theroom for example seem to belong together quite apart from the wallbehind it or the chair beside it. Among the many familiar indicationsthat things are together or apart in space are brightness, color, lightand shadow, sharpness of outline, and relative movement and binocular

parallax. The togetherness and apartness demonstration illustratesall these as well as another, less frequently mentioned indication,continuity of contour or coincidence of edge. If the edges of two ob-jects coincide, there is a strong indication that the two objects aretogether in space. By this indication alone, an object may appear ata distance quite different from its actual distance and of a size quitedifferent from its true size.Apparatus

The togetherness and apartness demonstration is mounted on a tablealong one edge of which are three posts holding ordinary playing cards.At the same height and distance as the middle or comparison card issuspended a fourth playing card, the test card. Two boards are hingedto the table top so that they can be raised or lowered at will. Inthe illustration both boards are shown raised, although in operationonly one or the other is raised at any one time. A separate lightsource is provided for each of the cards.

Fig. 6.1. The togetherness and apartness demonstration

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Fig. 6.2. The togetherness and apartnessdemonstration from the viewing point.

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s viewed in a dark room against a uniform blackillumination on the cards equated. When the headadrest, a small shield blocks off the view of theleft eye. With this exception, both eyes view theThe headrest is adjustable laterally so that whenised the left edge of the test card can be made toth the right edge of the board. Similarly, whenaised, the right edge of the test card can be madewith the left edge of the board.

observationsWith both boards down, the test card appears athe comparison card and of the same size.When the far board is raised, the test card apand at the same distance as the board, and verycomparison card.When the near board is raised, the test card fto be attached to and at the same distancemuch smaller than the comparison card. (Forthe differences in accommodation at thesecause sufficient difference in the sharpnesscards and the boards to destroy the effect.)If in place of the uniform black background asubstituted and both boards are lowered, the tepart of this background and to appear verycard.The above effects are not experienced if boththe test card, if the head is moved to introdor if the brightness of the test card is madethat of the other cards and the boards

.

t the same distancepears to be attachedmuch larger thanor many observersas the board, andsome observers it isnear distancesof the outlines of

mottled backgroundSt card appears tomuch larger than theeyes are allowed touce movement paral-radically different

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7. THE THERENESS-THATNESS DEMONSTRATIONSThe known size of an object provides an indication of its apparentfrom an observer. In the thereness-thatness demonstration,objects can be unequivocally and correctly localized in dis-on the basis of this indication alone. Discrete changes in the

of such objects are seen as discrete changes in distance, and con-change of size is seen as continuous movement in space. Unfa-objects, or even abstract shapes, are also quite definitely local-in distance. In these cases, however, the apparent distance usu-does not coincide with the actual distance and varies widely fromto observer. Furthermore, if the same observer attributes firstsize and then another size to the same object, he sees this objectat one distance and then at another distance, even though it ac-remains fixed at the same distance.

Both types of apparatus of the thereness-thatness demonstrationof essentially two basic parts, a binocular comparison field

a test field. The test field provides some means for viewing aobject whose apparent distance is to be determined. The binocularfield provides distance indications relative to which thisdistance is judged. The two models differ primarily in theof the test field. In the projector model the test object is anprojected on a screen in front of the observer. The mirror modelreal test objects which are reflected in front of the observer by

of a mirror arrangement

.

A. The projector model is mounted on a long table at one end ofis a headiest. Extending along the left edge of the table is thefield consisting of five illuminated lucite rods. In addi-any desired objects may be added to increase the definiteness of

in this field. To the right, in the test field, is ascreen on which any desired image can be projected. Extendingright angles to the table is the housing for the projector and con-The primary control provides two concurrent adjustments. Turn-the knob clockwise causes the image to grow larger and move acrossscreen to the right. Turning the knob in the opposite directionthe image smaller and moves it across the screen to the left. Aversion of this apparatus can be built in which the lateralof the image is eliminated and only size change provided.adjustments provide for separate control of the illumination ofprojected image and of the objects in the comparison field and forthe distance of the screen.B. In the mirror model of the thereness-thatness demonstrationcomparison field is viewed through a pair of half -silvered mirrorsat approximately 45 to the line of sight. These mirrors enableobserver to see superimposed on the comparison field any desiredobject which can be physically quite removed from this field, suchthe playing card mounted on the tangential motion apparatus as shownthe illustration. The comparison field contains two rows of illum-lucite rods and a movable cart carrying a similar rod. Othermay be used in addition to or in place of these rods. A controlprovides six separate controls for illumination of the objects incomparison field and of the test objects.

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Fig. 7.1. The thereness-thatness demonstration,projector model

.

Viewing conditionsA. The projector model is viewed in a dark room from the headrestprovided. The comparison field on the left is visible to both eyes,but the image projected onto the screen is seen by the right eye only,through an opening in the shield. The distance of the projected imagemay simply be estimated relative to the posts, or the size of the imagemay be changed until it appears at the same distance as one of theposts

.

B. The mirror model is also viewed in a dark room, the illuminatedcomparison posts being visible to both eyes through the half -silveredmirrors. Two adjustments are provided on the mirror mount, a lateraladjustment which allows the test object to be seen with one eye or withboth, and an angular adjustment which controls the apparent angular di-rection of the test object with respect to the comparison field. Appro-priate drapes and shields must be added to mask out all undesired partsof the apparatus. In making distance judgments the cart in the compari-son field is moved until it appears to be at the same distance as thetest object.Typical observations

Any object in the test field is localized defvocally at some apparent distance.A familiar object, such as a playing card, isdistance. If an oversized playing card is used,than its true distance. For example, a double-sizseen at one-half its actual distance. Similarly,seen farther than their true distances. For exampcard is seen at twice its actual distance.If an ambiguous object is used, its apparentthe particular interpretation the observer makes,rectangle is seen at one distance following the su

a calling card and at another distance if it is suenvelope

.

The mirror model can also be used in conjunctother demonstrations in order to obtain a quantitaeffect observed with those demonstrations. It iswith the tangential motion demonstration.

initely and unequi-seen at its true

it is seen closere playing card isundersized cards arele , a half -sizedistance depends onFor example, a whiteggestion that it isggested to be anion with many of thefive measure of theillustrated in use

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fIRST-SURFACE-AMRROR 5H1FT5 FOOMa TO d &IVIWG THE SHIFT OFPLAYIN&-CAHD-1AG FROM A TO DON THE 5CBEEM

THERENE5S-THATNE5S' DEMONSTRATION( PHOJECTOH MODEL )

ACTUALITYPLAYING-CARD-IMAGE SHIFTS LATERALLYFROM LEFT TU RIGHT WHILE SIZE ISINCREA51WG AND FROM RIGHT TO LEFTWHILE 5IZE IS REDUCiflG

PERCEPTIONPLAYING CAflD OF CONSTANT 5IZESHIFTS LOWGITUDINALLY IN SPACE

ACTUALITY AND PERCEPTION CORRES-POND AT C WHERE PLAYING CARDIS Judged as normal size: seen atACTUAL DISTANCE

Fig. 7.2. Typical observations using the projector modelof the thereness-thatness demonstration.

THERENESS-THATNESS DE/rtOMSTRATIOMWITH MIRROR A\ODEL OP SIZE DISTANCE TABLE

PERCEPTION5IZE NORMALDISTANCE 2 LSPEED 2D/5EC-

BELTACTUALITY

SIZE OF OBJECT >JALF-5/ZE PLAYING-CARDDISTANCE FQCM EYE LSPEED OF /HOTIOM D/SEC

Fig. 7.3. Typical observations using the mirror model ofthe thereness-thatness demonstration in conjunctionwith the tangential motion demonstration.

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19. THE ROTATING TRAPEZOID DEMONSTRATIONThe rotating trapezoid demonstration combines many of thevisual indications illustrated by the other demonstrations inconstantly changing patterns of agreement and conflict. What isexperienced in viewing this demonstration eludes verbal descrip-tion. As the trapezoid rotates it appears to oscillate andchange size, while objects attached to it appear to become de-

tached or else strangely contorted in ways that are never quitethe same for any two observers, or for the same person from onemoment to the nextApparatus

A trapezoid of sheet metal, with holes cut out to resemblewindow panes and shadows painted to give the appearance of thick-ness, is mounted on a vertical shaft that rotates at approximatelytwo revolutions per minute, driven by a small electric motor.Various objects are provided to be mounted on the trapezoid androtate with it. For example, a tube can be suspended through oneof the openings, or a cube can be attached to one edge of thetrapezoidViewing conditions

The rotating trapezoid, with or without objects attached, isviewed from a distance of ten feet or more monocularly, or binocu-larly from twenty-five feet or more. The center of the trapezoidpreferably should be at eye-level height. Equal illumination isprovided from the right and the left of the line of sight of theobserver. (The portable model that is illustrated is completelyself-contained in a small carrying case and can be used for demon-strations before large groups in which considerable departure fromthese ideal viewing conditions can safely be tolerated.)Typical observations

When the trapezoid alone is viewed, it appears to be a rec-tangle of varying size and thickness oscillating at varying speedthrough an arc of approximately 100 .When a cube is attached to the small end of the trapezoid,it is seen as traveling in a circular path about the apparentlyoscillating rectangle, so that during part of its movement thecube breaks away and seems to float freely through space.When a tube is suspended through one of the openings, part ofthe time the tube and the apparent rectangular window are per-ceived as moving in opposite directions. When they meet, severaldifferent effects can be seen. The most commonly reported are thatthe tube either bends around or else cuts through the apparentrectangle.Observers tend to see the tube bend around if it has pre-viously been suggested to them that the tube is actually made offlexible material. On the other hand, if it is suggested thatthe tube is actually rigid, observers tend to see it cut through.

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Fig. 19.1. The rotating trapezoid demonstration

Fig. 19.2. The rotating trapezoid demonstrationfrom the viewing position.73


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EVE LEVEL 46 TO GROUND

SWAYING HEAD -REST

RHEOSTAT FOR B, &. 6^^O d OLIGHT CONTROL FOR B, & B2~^^\CTHICKNJESS ILLUAMNATION) WLIGHT CONTROL FOR A, i A2(FRONT SURFACE ILLUAMNATION)

APPROXI/AATELY 72 TO SCREEN WALL

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BIBLIOGRAPHYof

Books and Articles Referring to theAmes Demonstrations in Perception

Works dealing exclusively orprimarily with the Ames demonstrationsare listed as primary references.Those dealing only secondarily ortangentially with the demonstrationsare arranged according to areas ofinterest


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PRIMARY REFERENCESAmes, A., Jr. Binocular vision as affected by relations betweenuijiocular stimulus patterns in commonplace environments. Amer. J.Psychol . , 1946, 59: 333-357.Ames, A., Jr. Nature and origin of perception: Preliminarylaboratory manual for use with demonstrations disclosing phenomenawhich increase our understanding of the nature of perception .Mimeographed . Hanover : Insti tute~f or AssociateH Research, 1946-1947.Ames, A., Jr. Nature and origin of perception : Literature deal -ing with the significance oT the pEenomena disclosed by thedemonstrations. Mimeographed. Hanover: Institute for AssociatedResearchAmes, A., Jr. Transaction of living. Chart I : Analysis of sub-phenomena involved in and involving perception . MimeograpTTedHanover : InstituteHTor Associated Research, 1949Ames, A., Jr. Sensations, their nature and origin. trans/forma-tion , 1950, 1: 11-12.Ames, A., Jr. Visual perception and the rotating trapezoidalwindow. Psychological Monograph, 1951 (Sept.), 65 (7): WholeNo. 324.Ames, A., Jr. & Cantril, H. Further Notes Toward an Understandingof Human Behavior: Values, Choice, and Action. (Inter-OfficeCommunication) October, 1951.Cantril, Hadley . Understanding man 's social behavior. Prelimin-ary notes. Princeton : Office of FKiblic Opinion Research,TMl . LTthoprinted. Pp. 75.Cantril, Hadley. The nature of social perception. Trans. N. Y.Acad . Science , 1948, 10: 142-153. ~ ~Cantril, Hadley. Toward a scientific morality. J. Psychol., 1949,27: 363-376. ~Cantril, Hadley. An inquiry concerning the characteristics of man.J. abnorm . soc . Psychol., 1950, 45: 490-503.Cantril, Hadley. The why of man's experience. New York:Macmillan, 1950. PpT I^E~.Cantril, H., Ames, A., Jr., Hastorf, A. H. & Ittelson, W. H.Psychology and scientific research. Science, 1949, 110: 461-464;491-497; 517-522.Hastorf, A. H. The influence of suggestion on the relationshipbetween stimulus size and perceived distance. J. Psychol., 1950,29: 195-217. ~Hastorf, A. H. & Knutson, A. L. Motivation, perception and atti-tude change. Psychol . Rev . , 1949, 56: 88-94.

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16. Ittelson, W. H. Size as a cue to distance. Amer. J. Psychol .,

1951, 64: 54-67, 188-202.17. Ittelson, W. H. The constancies in perceptual theory. Psychol .Rev. , 1951, 58: 285-294.18. Ittelson, W. H. & Ames, A., Jr. Accommodation, convergence, andtheir relation to apparent distance. J. Psychol . , 1950, 30: 43-

62.19. Ittelson, W. H. & Ames, A., Jr. Accommodation, convergence, andtheir relation to apparent distance. Optical Developments, 1950,Vol. XX, No. VIII.20. Ittelson, 'W. H. & Kilpatrick, F. P. Experiments in perception.Scientific American , 1951, 185: 50-55.21. Kelley, Earl C. Education for what is real . New York: Harper,1947. Pp. 114.22. Kilpatrick, F. P. Some aspects of the role of assumptions in per-

ception. Ph. D. Thesis , Princeton University, 1950.23. Kilpatrick, F. P. (Ed.) Human behavior from the transactionalpoint of view. Hanover: Institute for Associated Research, r95224. Kilpatrick, F. P. & Ittelson, W. H. Three demonstrations involvingvisual perception of movement. J. Exp. Psychol . , 1951, 42: 394-402.25. Lawrence, Merle. Studies in human behavior . Princeton: UniversityPress, 1949.26. Lawrence, Merle. An inquiry into the nature of perception. Han-over: Institute for Associated Research, T54WT27. Luneburg, Rudolf K. Mathematical analysis of binocular vision .Princeton: University I>ress , 1947 Pp . TOlT Lithoprinted28. Smith, William M. Past experience and perception: a study of theinfluence of past experience on apparent size and distance . ^n^^published PE. D. Thesis , I>rinceton University, 195D^

OTHER REFERENCES ARRANGED ACCORDING TO AREAS OF INTERESTArt and Architecture29. Ames, A., Jr. Statement about paintings of Alexander James. Han-over Gazette , July 19, 1951.30. Creighton, Thomas H. (Ed.) Building for modern man. PrincetonUniversity Press, 1949. Pp. 21931. Gropius, Walter. Design topics. Magazine of Art, 1947, 40: 299-304.32. Notes on the Ames demonstrations: Art and Perception. trans/form-ation, 1950, 1: 8-10.

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Progress Report: Form still follows function. ProgressiveArchitecture , 1947 (Dec), p. 20.Sherman, Hoyt L. The Visual Demonstration Center at the OhioState University: A manual oT~~operation with ari~emphasis on thearts . University Book Store7~Columbus 10, Ohio. Pp. 129.Looseleaf . Lithoprinted.

Bode, Boyd H., & Morse, William C. Manual to accompany Educationfor what is real. Minneapolis: Professional Books , TncT^ 1948

.

PpT TE~.Bristow, William H. Curriculum: Foundations (Chap. 1). Rev .Educ. Research , 1948, 18: 221-230.Mooney , Ross L. Teacher's manual on the distorted room demonstra-tion. Columbus: Bureau of EducatTonal Research, Ohio State Uni-versity , 1950. Pp. ii & 21. Lithoprinted.Mooney, Ross L. Student's manual on the distorted room demonstra-tion. Columbus: Bureau of EducatTonal Research, Ohio State Uni-versity , 1950. Pp. ii & 7. Lithoprinted.Mooney, Ross L, Lecture-demonstrations on perception as a trans-action. Columbusi Bureau of EducationaT^Research , OhiTo StateUniversity , 1951. Pp. iv & 15. Lithoprinted.Mooney, Ross L, Perception, language, and the part-whole problem.Columbus: Bureau of Educational Research, Ohio State University,1951. Pp. iv & 21. Lithoprinted.Price, Mary Alice. Teaching mental hygiene with visual demonstra-tions . Columbus: Bureau of Educational Research' Ohio StateUniversity, 1950. Pp. ii & 45. Lithoprinted.Price, Mary Alice. Notes on the presentation of the demonstrationsto groups of widely differeTTt interests and backgrounds. ColumbusBureau of Educational Research, Ohio StaTe~Universi ty , 1950, Pp.ii & 11. Mimeographed.

Luneburg, R. K. Chapter entitled: Metric methods in binocularvisual perception, in Courant Anniversary Volume (New York Univer-sity), 1948.Luneburg, R. K. The metric of binocular space. J. Opt. SocAmerica , 1950, 40: 627-642. Stein, Anna. A certain class of binocular ly equivalent configura-tions. J. Opt . Soc . America , 1947, 37: 944-962.

Bentley, Arthur F. Kennetic inquiry. Science , 1950, 112: 775-783.-

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47. Freeman, Eugene. Veridical perception. Amer . J. Optom . & Arch ... Amer . Acad . Optom., 1951, 28: 213-220.

48 ** Fries, Horace S. Five suggestions for research and action.trans/formation , 1951, 1, No. 2, 107-109.49. Fries, Horace S. To sail beyond the sunset. Educational Theory1951, 1, 23-24.

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