Eye and hand: Differential memory and its effect on matching

Neuropsychologia,

1971, Vol.

9. pp. 89 to 95.

Pcrgamon

Press.

Primed

in England

EYE AND HAND: DIFFERENTIAL MEMORY AND ITS EFFECT ON MATCHING JACQUELINEJ. GOODNOW The George Washington

University, Washington, (Received

D.C., 20006, U.S.A.

27 July 1970)

Abstract-An analysis of matching tasks in terms of memory demands has two advantages: it accounts for some variations in the difficulty of matching by eye and by hand, and it suggests an analysis of “visual” and “tactual” tasks in terms that may cut across modalities. Memory for information gathered by hand appears to be less stable than for information gathered by eye, more likely to show loss when the number of comparison objects is large. As memory demands increase, accuracy declines first on any matching that starts with inspection by hand.

INTRODUCTION feels an object, usually called a standard, and them compares it with other objects he sees or feels. Such matching tasks have a long history of use as diagnostic tools and as evidence for the role of modalities in brain function. The tasks vary a great deal in their format : the match may be intramodal or crossmodal; the stimuli may be familiar or novel, simple or complex; the comparison may be simultaneous or successive; the individual may face one or several comparison objects. The tasks also vary a great deal in their level of difficulty, even with normal Ss, and the questions arise: What task features are related to what type of result? And how does the link take place? The present article is concerned with the relative difficulty of tasks that vary in the modality of presentation: V-V (standard and comparison objects seen), T-T (all objects felt), V-T (standard seen, comparisons felt) and T-V. The relative difficulty of such tasks, the hypothesis runs, depends on an interaction of two task features: the presenting modality of the standard object, and the number of comparison objects. More specifically, the difference between matches starting from visual vs. tactual standards (V-V vs. T-T, V-T vs. T-V) will be least when only one comparison object is involved, and will increase as the number of comparison objects increases. The expected effect is based on the general hypothesis that memory for objects inspected by hand is less stable than for objects inspected by eye, more vulnerable to the increased load created by a greater number of comparison objects. The hypothesis has three main antecedents: 1. A general argument offered by RUDEL and TEUBER [I]. In most matching studies, the hope has been that the presenting modalities would be the major factor determining behavior; the relative difficulty of various matches (e.g. V-V in relation to T-T or V-T) would then be expected to remain fairly constant across experiments. In contrast, RUDEL and TEUBER [l] argued that no single factor-the presenting modality, for examplecould account for behavior, and that results should not be expected to remain invariant. In their own study with preschool children, they found V-V to be easiest, T-T hardest, with V-T and T-V intermediate in difficulty. These results, they suspected, might not AN INDIVIDUAL sees or

89

JACQUIZLINE J. GOODNOW

90

hold if the stimuli were changed (the difficulty of T-T, for example, might change considerably if Ss made judgments of texture rather than shape), and they urged in general a fuller analysis of stimuli and procedures as a way of pinning down critical conditions that would interact with the presenting modality or cut across modalities. 2. A specific experiment by POSNER [2]. His Ss moved a lever to reproduce a distance initially experienced by eye or by hand-and-arm movement. The difference in relative accuracy between the two conditions was small when reproduction was immediate, but became larger when reproduction was delayed. The effect, POSNER considered, reflected a differential coding of visual and kinesthetic stimuli. 3. The appearance of order in the literature on matching tasks when we sort by initial modality and by the number of comparison objects. (This sort assumes that the number of comparison objects should function like POSNER’Sdelay in time between standard and reproduction, i.e. should first affect matches starting from a tactual standard). In the series of studies that have compared all four conditions (V-V, T-T, V-T, and T-V), the conditions V-V and T-T are closest together when there is one comparison object [3, 51, and furthest apart when there are five comparison objects [l, 61. And the strongest evidence for a difference between V-T and T-V (with T-V poorer) comes from a study with five comparison objects [ 11. The hypothesis is tested in two steps. study I repeats an experiment by HERMELIN and Memory demands were at their peak (five O’CONNOR [7] that does not fit the hypothesis. standard objects, five comparison objects), but no significant differences occurred among any of the four matching tasks. study II deliberately varies the number of comparison objects, remedying the lack of an experiment that varies the number of comparison objects while holding constant the type of stimulus and the type of S. STUDY

I:

A TASK

WITH

HEAVY

MEMORY

DEMANDS

In an early and provocative study of intermodal relationships, HERMELINand O’CONNOR [7] reported two results: (a) Amon, 0 a group of children with normal intelligence, aged 5-7 years, no significant differences in accuracy appeared among the four forms of matching (V-V, V-T, T-V, and T-T); and (b) Among a group of severely retarded children (I.Q. 30-55), recognition was more accurate by hand than by eye. The present study is concerned only with the first result, and in style is a replication of part of the original experiment, with an expanded sampling of Ss. Subjects Ss were 92 children,

52 drawn from kindergarten grade class in a public school.

classes in a private school, and 4@ from a fourth

Material

Stimuli were identical to those used in the original study:

IO Greek and Russian letters, cut from

Masonite and approximately four inches high. Procedure

“I am going to give you some shapes to look at (or Children were given the following instructions: feel) for a little while. I want you to get to know them, because later I’ll mix them in with some new ones and ask you to tell me which ones are new ones and which ones you met before.” Ss were then shown 5 letters, one at a time, to see or feel, followed by the recognition series of 10 letters. The time allowed for inspection was longer and more varied than the 5 set per figure allowed in the original study. Children were allowed to inspect a shape until they were ready to set it down, wrth an outside limit of 15secfora visual inspection, and 30 set for inspection by hand. Most children were willing to set the figures aside before this time, or accepted the limit as reasonable.

EYE

AND HAND:

DIFFERENTIAL

MEMORY

AND ITS EFFECT

91

ON MATCHING

Results Results are shown in Table 1. Matching by hand (T-T) turns out to be consistently poorer than matching by eye (V-V), the difference being very large at the youngest age level (5 :0-5 :5) and then decreasing but remaining significant at later age levels. In addition, crossmodal matching that starts from a tactual standard (T-V) is more difficult than matching that starts from a visual standard (V-T). In sum, the renlication yields results in line with a stress on memory demands. Table 1. Number of correct recognitions with stimuli and procedure from Hermelin and O’Connor (5 Greek or Russian letters presented first; recognition series of 10 letters). Maximum score is 10 Ss and Conditions

Frequency of Correct Responses

Matching

No. Ss

Mean correct

K-S :Oto 5 :5

v-v T-T

10 10

9.0

5.5

-

K-5 : 6 to 6:8

v-v T-T

12 20

9.8 7.6

10 2

4-9:oto 10 :o

v-v T-T V-T T-V

10 10 16 16

9.9 8.2 8.8 7.1

9 34 1

Grade and Age

10 4 -

Distribution 7 6 5

9

8

3

2 l_---3--

5

2------7.3

3

4---

l_--_--_ 4 6 4 3 1

2 1 6

l---l__-2 3---

4 l-

3

2 1 1

Statements about statistical significance are based on chi-squares, with Ss divided throughout into two groups: those correct on 9 or 10 trials vs. those correct on 8 or less. This division yields, for the three age groups respectively, differences between V-V and T-T significant at the 0.01, 0.02 and 0.01 levels. The same basis of division yields a significance level of 0.05 for the difference between V-T and T-V. The replication suggests some reasons why differences among various forms of matching may fail to reach statistical significance. One reason lies in the maiked inter-subject variability around ages 5-6. Under these task conditions, a sharp division appears, somewhere around 5 : 6 in the present sample. between chaos and relative accuracy in matching complex shapes by hand. The degree of variability was unexpected, and the double kindergarten sample was a response to the age difference becoming apparent as a large sample of children within one grade were tested. (In the original”study, the age difference was less likely to appear since normal Ss were selected primarily as controls for the retarded Ss and covered a wider range of ages and grades.) Grouping by year, or by grade, even in a school where children are fairly homogeneous, is apparently too gross a control at the early age levels, and could easily result in some unintended differences among the groups assigned to different forms of matching. To such inter-subject variability may be added a restricted range of scores that reflect performance over and above chance (with a recognition series of ten trials, and a yes or no answer on each trial, any set of answers yields a chance score of five correct). In short, significant differences among different forms of matching may be hard to achieve with young Ss and this type of design and, at the younger age levels, small variations in the sampling of Ss and the range of scores may produce results that vary from study to study.

STUDY

II.

VARYING

THE

NUMBER

OF COMPARISON

OBJECTS

At this point of investigation, memory demands appeared to be a promising way of accounting for some aspects of performance on matching tasks. The evidence, however, was circumstantial, and, in some respects, not to be leaned on heavily. There were, and still are, relatively few studies with data on all four conditions of matching: V-V, V-T, T-V, and T-T. And to compare these with one another for an effect from the number of comparison objects, one has to close one’s eyes to differences in stimuli and sometimes to a difference in the age of Ss. (Of the studies cited, two are with young children [l, 71, the remainder with adults.)

JACQUELINE J. GOODNOW

92

To obtain more definitive data, Study I1 started from an experiment by CAVINESS [3], an experiment using GIBSON’S [S] solids as stimuli, adults as Ss, and one comparison object. In the original study, the mean number of errors, out of a possible 20, was 3.4 (V-V), 4.6 (T-T), 6.7 (V-T), and 6.4 (T-V), results marked by the small differences between comparisons starting from a visual as against a tactual standard [3, p. 641. Study II uses the same stimuli as the earlier study [3]. It explores the differential efrect of 1, 3, and 5 comparison objects on the conditions V-V and T-T, and the differential effect of 1 and 3 comparison objects on the conditions V-T and T-V. In both cases, the major question is the same, namely the interaction of memory demands with the provision of a visual or a tactual standard as a point of origin. Ss were 156 college students. Each S was given 20 trials, under one of 10 conditions: V-V or T-T with 1, 3, or 5 comparison objects; V-T or T-V with 1 or 3 comparison objects. The group for each condition contained 12 Ss, giving a base sample of 120 Ss, with an additional 36 for a replication of T-T with 1, 3, and 5 objects. Procedure

Stimuli were GIBSON’S free-form solids, 10 in number. For all groups, the standard was presented first, for four seconds. Comparison objects were then presented one at a time, each for four seconds. When only one comparison object was presented, Ss said either “same” or “different”. When more than one was presented, Ss waited until the end of the series to say which one was the same as the standard. In all, Ss made 20 judgments, 2 with each standard. Objects were placed in the cupped palm of the nonpreferred hand, and explored with the other hand, with Ss warned not to change the orientation of the figure. Results Results are shown in Fig. I and Table 2. To determine the effect of a visual or tactual standard, we may compare V-V with T-T, and V-T with T-V. In both cases, an increase in the number of comparison objects has its major effect on performance starting from a tactual standard. We can, in effect, alter the relative difficulty of V-V in relation to T-T, and V-T in relation to T-V by altering the number of comparison objects and the demand on memory.

Y

/I T-V

/

1’

/I

0

I_

I

I

5

3

Crossmodol

InframOdal

motch,ng

matching

Number

FIG.

I

3

of

Comparison

ObJeCtS

1. Variations in mean errors on a matching task, as a function of modality of standard (Visual or Tactual), type of match (intramodal or crossmodal), and number of comparison objects.

EYE AND

HAND : DIFFERENTIAL

Table2. Number and distribution

MEMORY

AND ITS EFFECT

of errors in matching across and within modalities

Number and distribution Condition

Mean

V-IV

I.5 1.2

v-3v v-5v T-IT”’ T-3T”:

O&I

T-ST”

4.2 4.5 6.8

V-IT VP3T

4.1 3.8

T-IV T-3V

4.2 7.8

28~3

4&5

7

1

of errors 8 &9

7 5 I

2 7

5 3

4 2

3 3

-

3

5 3

3

-

-

3 1 1

6&l

10ormore

2 I 1

9 6

1.6

93

ON MATCHING

-

2 1 2

7 1 -

5

3

* Mean values on replication are 4.7, 3.8, and 6.1. If we look first at intramodal comparisons (V-V and T-T), the number of comparison objects clearly makes no difference to the number of V-V errors (mean errors are 1.5, 1.2, and 1.6 out of a possible 20). Matching by hand (T-T), however, is affected, the effect appearing with a shift from 3 to 5 comparison objects (mean errors are 4.2, 4.5, and 6.8). On an analysis of differences [9, p. 411, the shift in T-T errors is significant at the 0.02 level. More important, the effect is replicable: an additional 36 Ss yield, for T-T, mean errors of 4.7, 3.8, and 6.1 for 1, 3, and 5 comparison objects. With cross-modal comparisons, the effect of increasing the number of comparison objects seems to appear at an earlier breaking point. If the original standard is visual, it does not matter if 1 or 3 felt objects are presented for comparison (4.1 and 3.8). But if the original standard is tactual, an increase from 1 to 3 seen objects pushes up errors considerably (from 4._7 to 7.8). Significance levels were determined by chisquare, with Ss divided at 7 errors (7 or less vs. 8 or more). The difference between T-IV and T-3V is significant at the 0.001 level; the difference between V-IT and V-3T is not significant. A change in the number of comparison objects appears to have an additional interaction effect, this time on the relative difficulty of intramodal and crossmodal matching. The conditions V-V and V-T are different from one another with only one comparison object, and they maintain the same degree of difference (1.5 and 4.2 for 1 object, 1.2 and 3.8 for 3 objects). In contrast, the conditions T-T and T-V are the same as one another with only one comparison object, but become different as the number of comparison objects increases (4.2 and 4.2 for 1 object, 4.5 and 7.8 for 3 objects). If we maintain the same basis of division for chi-square as before (a division at 7 errors), only the last of these differences (4.5 for T-3T and 7.8 for T-3V) is statistically significant (0.01 level).

DISCUSSION Accuracy in matching is clearly affected by demands on memory. The question now is how the effect takes place. The following suggestions are based on concepts drawn from information theory, particularly as articulated by POSNER [cf. 2, lo]. In general, results point to an interaction between the form of the initial information (gathered by eye or by hand), and the type of demand on memory. One kind of demand occurs primarily as a function of time, or time plus interference from encountering objects similar to the first object. Intramodal matching can be viewed as making this kind of demand. The demand appears to have little effect on information gathered visually, but does disturb information gathered by hand [2; Study II in the present article]. At the least, an effect on information gathered by eye will appear later than for information gathered by hand, and does not appear at all within the time and interference limits studied so far.

94

JACQUELINE J. GOODNOW

A second kind of demand comes from the need to transform the original information, to reduce or change it in some way so that it can be matched against later information. Transformation is not in itself a direct memory demand but it can have a strong effect on the amount remembered, the size of the effect varying with the difficulty of the transform [lo]. In a sense, the S’s grasp on the original information is weakened by the need to switch attention to the task of transforming. POSNER and ROSSMAN[lo] have offered this kind of analysis for information gathered by ear (numbers to be coded as odd or even, above or below 50, or into both categories). An extension seems feasible to crossmodal matching, i.e. one can regard the task as calling for some kind of transformation (abstraction, reduction, or changed terms) without committing oneself to a transformation into visual images or words. Transformations appear to bring some memory loss to information gathered by eye or by hand. In contrast, memory demands imposed by time or interference appear as limited to information gathered by hand, An emphasis on memory, however, will not answer all our questions about matching tasks. We do not know, for example, why information gathered by hand is less stable than information gathered by eye. The effect may stem, as POSNER [2] suggests, from the way tactile-kinesthetic information is coded or from our inexperience in coding such information. Inexperience is suggested as the major factor by SHAGAN’S[13] replication, with blind Ss, of POSNER’Slever-moving task. Her blind Ss gave results like POSNER’Snormally sighted Ss working with vision, and not like his Ss working temporarily without vision. Nor do we know what happens when the S’s grasp on the original information begins to fail, or how a memory effect interacts with any differences in the way an object was first perceived, interacts, for example, with any differential sampling of stimulus properties [12]. GIBSON has pointed out that distinctions between “perception” and “memory” are often artificial, and can generate pseudo-problems of interaction or opposition [8, pp. 275-2771. It is possible, however, to avoid pseudo-problems by regarding conditions at the time of first exploring an object, and conditions between then and the making of a comparison, as having a common type of effect on judgment. In any matching situation, we may argue, the likelihood of an S accurately judging two stimuli as “the same” will depend on the points of similarity or overlap in the properties he attributes to the two stimuli, at the moment of comparison. Differences in the original perception, and memory loss, may both serve to cut down on the degree of overlap, the one by presenting S with two pictures that are clear but taken from different positions, the other by washing out the original event, evenly or unevenly, and perhaps distorting it. Despite these limitations, an emphasis on memory helps to round out our picture of the processes involved in matching tasks. By and large, we tend to attribute the effect of variations in Ss or procedures to a change in the discrimination or original perception of a stimulus. This approach has been helpful in accounting for results given by both normal and brain-damaged Ss [cf. 12-151. Attention to demands on memory, and the way in which individuals meet these demands, may be equally helpful [cf. 16, 171 in moving us towards the goal of effective links between the behavior displayed by an individual and his internal state.

Acknowledgements-1

wish to acknowledge

the generous

help of JAMES GIBSON, NEIL O’CONNOR and as well several fruitful discussions on the matching problem. My debt is also large to BARBARABAUMand ELLENMCGRAW for a major role in testing Ss. The research was supported by grants from the National Institute for Child Health and Human Development (lK03 HD36791, lROl-HD03105, and 1 TOI-HDO0203).

BEATEHERMELIN, who made it possible to reproduce their original stimuli and contributed

EYEAND HAND: DIFFERENTIAL MEMORY ANDITS EFFECTON MATCHING

95

REFERENCES 1. RUDEL, R. and TEUBER, H. L. Crossmodal transfer of shape discrimination

by children. Ne~lropsychologiu 2, 1-8, 1964. 2. POSNER,M. I. Characteristics of visual and kinesthetic memory codes. J. exp. Psychol. 75, 103-107, 1967. 3. CAVINESS,J. A. Visual and tactual perception of solid shapes. Unpublished Dissertation, Cornell University, Ithaca, New York, 1964. 4. BJBRKMAN.M. Relations between intra-modal and cross-modal matching. Scand. J. Pswhol. 8. 65-76, 1967. ’ 5. GARVILL,J. and MOLANDER,B. Intra-modal Univ. of Utned Psychol. Reps 11, 1969.

and cross-modal

accuracy in a form discrimination

6. CASHDAN,S. Visual and haptic form discrimination under conditions of successive stimulation. Psyckol. 76, 215-218, 1968. 7. HERMELIN,B. and O’CONNOR,N. Recognition of shape by normal and subnormal children.

task. J. exp. Bit.

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Psychol. 52,281-284, 1961. 8. GIBSON, J. J. The Senses Considered as Perceptual Systems. Houghton Mifflin, New York, 1966. 9. WINER, B. J. Statistical Principles in Experimental Design. McGraw-Hill, New York, 1962. 10. POSNER, M. I. and ROSSMAN,E. The effect of size and location of informational transforms upon short-term retention. J. exp. Psychol. 70, 496-505, 1965. 11. SHAGAN,J. Kinesthetic memory, comparing blind and sighted subjects. Unpublished Dissertation, George Washington University, 1970. 12. GOODNOW,J. J. Eye and hand: differential sampling of form and orientation properties. Neuvopsychologia 7, 365-373, 1969. 13. PICK, H. L., PICK, A. D. and KLEIN, R. E. Perceptual integration in children. In Advances in Child Development and Behavior, Vol. 3, LIPSITT, L. P. and SPIKER, C. C. (Editors), pp. 192-220. Academic

Press, New York, 1967. 14. TYLER, H. R. Defective stimulus exploration in aphasic patients. Neurology 19, 105-112, 1969. 15. LURIA, A. R., KARPOV,B. A. and YARBUSS,A. L. Disturbances of active visual perception with lesions of the frontal lobes. Cortex 2,202-212, 1966. 16. GOULD, J. D. Pattern recognition and eye-movement parameters. Perception & Psychophysics 2, 399-407, 1967. 17. BUTTERS,N., BARTON,M. and BRODY,B. A. Role of the right parietal lobe in the mediation modal associations and reversible operations in space. Cortex, in press, 1971.

of cross-

R&sum&En faisant appel aux facteurs mntsiques, l’analyse des Cpreuves d’appariement prtsente deux avantages: rendre compte des variations dans les difficult& d’appariement visuel et manuel, et suggkrer une analyse des Cpreuves “visuelles” et “tactiles” en termes de propriCtCs intermodales. Les souvenirs de l’information obtenus par la main apparaissent moins stables que ceux obtenus par voie visuelle et semblent moins diminuer avec I’augmentation du nombre des objets g comparer. Lorsque la charge mnCsique augmente, l’exactitude d&line en premier lieu dans les appariements qui dCbutent par inspection manuelle. Zusammenfassung-Vergleichende Testuntersuchungen von Gedichtnisleistungen bieten zweierlei Vorteile; bei Gegentiberstellung von Auge und Hand kiinnen sie einige Unterschiede der Schwierigkeitsgrade demonstrieren und fordern eine modalitatsgerechte Analyse visueller und taktiler Aufgaben. Dnrch die Hand erworbene Informationen scheinen weniger stabil zu sein als solche, die optisch aufgenommen wurden. Noch stsrker ist die Differenz bei einer grijBeren Anzahl verglichener Objekte. Im gleichen Umfange wie die Gedgchtnisanforderungen steigen, sinkt die Genauigkeit, und zwar vor allem bei jenen Untersuchungen, die auf rein taktiler Grundlage beruhen.