Reprinted from: the Journal of General Psychology, 107, 31-40, 1982
NonLinguistic Knowledge, Hemispheric Laterality, and the Conservation of Inequality in NonConserving Children.
R. E. Gallagher & Rhawn Joseph
Journal of General Psychology, 107, 31-40, 1982
UHS/The Chicago Medical School
Nonconserving children may fail to conserve because of difficulties in verbally expressing nonlinguistic knowledge of equivalence relationships. This may be partly due to an inability of the right hemisphere, which mediates the performance of internal reversals and conservation, to communicate with the speaking left hemisphere because of the immaturity of the corpus callosum. This relationship presumably results in the asymmetrical activation of the left hemisphere when verbal responses are required. To assess the possibility that nonconservers have an awareness of the reversibility of these operations, three groups of nonconserving children (N=42) were either asked which of two containers (one of which appeared to contain more liquid, but had previously been shown to contain less) had more in it, or which (pretending they were very thirsty and it was their favorite drink) they would prefer. To assess whether nonconservers respond primarily with left hemisphere activation, patterns of lateral eye movement in response to verbal-analytic or spatial-emotional stimuli were obtained in a fourth group (N=37). Both hypotheses were supported.
Piaget demonstrated that if you show a child two beakers of water, one of which isshort and fat, the other tall and thin, and ask the child which beaker contains more water, children under the age of 7 will generaly choose or say 'the tall one', even though both contain the same amount of water.
Piaget argued that children fail to "conserve" and are fooled by the differences in the size of the container, because children younger than 7 have not developed the cognitive and symbolic ability to conserve volume.
Conservation of volume is the ability to realise that two different containers may have the same volume, even though the containers are of a different shape.
Conservation in young children appears to require the ability to perform spatial analysis, internal reversals, and the temporal integration of an object’s identity in separate and changing contexts (16, 21, 25) so that relational constancies may be ascertained. The nonconserver supposedly lacks this sensitivity and is unable to match his image of a substance with a changing series of appearances (2, 37). However, crucial to the verbal expression of conservation is the ability of the right hemisphere, which mediates spatial and nonlinguistic operations (19, 27) and the performance of internal reversals (4), to successfully communicate with the left (25).
As Kraft (25) has shown with nonconservers and others have demonstrated with young children (9, 10, 23, 32), the ability of the right hemisphere to transfer information to the analytical, linguistic left hemisphere, is severely limited in young children, presumably because of the immaturity of the major interhemispheric fiber bundle, the corpus callosum. In fact, information transfer is so limited that when visual stimuli are tachistoscopically presented directly to the right hemisphere, young children will respond when questioned concerning the stimulus, with fictitious accounts and large gaps in the information reported. These findings suggest that the failure of young children to demonstrate conservation is not a function of some inability to perform spatial and relational operations, but rather is due to the left hemisphere and the language areas of the brain not being fully linked to all functional knowledge sources (19, 21, 23, 26); operations normally performed by the right hemisphere are not fully available for linguistic coding.
It is noteworthy that in paradigms requiring nonverbal demonstration of conservation, or in tasks presented in the context of a reinforcer (30, 42), a significant number of “nonconserving” children successfully demonstrate comprehension of the operations involved. This raises the possibility that young children retain a tacit knowledge (8, 18) of equivalence relationships, but are forced to rely on and predominantly activate the speaking left hemisphere so as to process verbal-analytical spatial problems alike when the response requirements involve verbal mediation.
In several recent studies, individual differences in predominant mode of asymmetrical hemispheric activation have been inferred by observation of lateral eye movements in response to stimuli requiring reflective thought (1, 14, 15, 21, 24, 29, 34, 43). Although Kinsbourne (24) found that Ss responded to spatial questions with predominantly left lateral eye movements and to verbal questions with right movements, the majority of right-handed adults demonstrated a stable tendency to respond to emotional-spatial and analytical-verbal material predominantly with left lateral eye movement, and thus with asymmetrical activation of the right hemisphere (1, 15, 21, 34, 43). Not surprisingly, due in part to these later findings, the efficacy of using lateral eye movements as a truly scientific research tool has been cast into doubt (7). Nevertheless, it is important to realize that most of our eye movements are reflexive and nonvoluntary (3, 6). Moreover, there is firm neuroanatomical and electrophysiological evidence that the majority of these movements reflect, at the cortical level, hemispheric activation (3, 6, 35, 39). For example, situated in the anterior portions of the frontal lobes is a large cortical field (area 8) which when stimulated results in activation of the extrinsic eye muscles and contralateral eye movements (6, 35). This is important in that the frontal lobes are recipients of converging somatosensory, auditory, and visual input (17, 33), and act in concert with the reticular activating system to modulate or inhibit ongoing activity throughout the telencephalon (5, 20, 22, 28, 41).
Hence, it is not surprising that heightened activity in this region ipsilaterally would result in conjugate lateral movement of the eyes. It should also be noted that within the inferior parietal lobule is a similar neuronal field that when activated can influence direction of gaze (31). Indeed, although it is questionable whether predominant left- or right-looking is a function of “cognitive style” as many authors claim, one must meet with skepticism the notion that nonvoluntary lateral eye movements do not indicate asymmetrical activity. Moreover, it is important to note that the measurement and occurrence of lateral eye movements is highly reliable both across sessions and between raters [see Ehrlichman & Weinberger (7, p. 1093)]. One might expect, therefore, that an individual who responds primarily with nonvoluntary right lateral eye movements is processing most stimuli in the left hemisphere, an orientation which could confer an advantage when dealing with verbal-analytic material, and a disadvantage in efficient processing of spatial or emotional stimuli. Preliminary results with adults and children tend to bear out these predictions (14, 21).
The purpose of the present study was twofold; in part, it was designed to investigate the possibility that children may be responding predominantly with asymmetrical use of the left hemisphere during problem solving or in response to questions requiring reflective thought. In addition, the presence of nonlinguistic or tacit knowledge concerning equivalence relationships was examined, as well as the influence of reinforcers in the demonstration of conservation.
All Ss were four or give years of age and enrolled in day care centers or nursery schools in Roanoke, Virgina (conditions 1-3, N=47), or Waukegan, Illinois (condition 4, N=37). All Ss in condition 4 were right-handed. Five children in conditions 1 through 3 were eliminated, two because they were conservers and three because of unruly behavior.
The testing room contained two chairs and a table short enough to accommodate the child comfortable. At the center of the table was a cardboard screen (30cm x 50cm) with a small red arrow on both the right and left sides of the surface facing the child (conditions 1-3 only). To one side of the screen were a small flask containing colored water, four (short) 6.5 cm x 5 cm diameter cylindrical glasses, and one (tall) 19cm x 2.5 cm diameter glass cylinder. The walls facing the S were uniform; doors and other distracting stimuli were behind the S.
Immediately prior to the experiment all participants were given a preliminary test to determine whether they were conservers or nonconservers. Each child was brought individually to the testing room and was seated at the table facing the E. The child was asked to pick out two of the short glasses, and to place them before himself. Next, the child was asked to take the flask and to pour some of the colored water into each of these two glasses so that they would both contain the same amount. If necessary, the E would always make equalizing adjustments. The E then asked the child to take one of the short glasses and to pour its contents into the tall glass. The child was then asked, “Do these glasses have the same amount of liquid in them, or does one have more?” If the child responded correctly, he was classified as a conserver and was excused from further testing. Those who indicated that the taller glass contained more was classified as nonconservers and were then tested according to one of the four conditions described below. Conditions 1-3 contained 14 children per group, with all groups balanced for sex.
a. Condition 1. The E asked the child to pour the liquid from the tall glass back into the short glass used during the pretest. The child was asked whether the two short glasses now held the same amount, or if one had more. When the child confirmed that the two quantities were the same, he was asked to pour a little from one short glass into the other. The E then asked, “Which glass has more?” Each S received a score of correct or incorrect according to his response to the final question.
b. Condition 2. Procedures and scoring were exactly the same as in condition 1, with these exceptions: When the two short glasses held unequal amounts, the E said, “Let’s pretend that you are very thirsty, and this is your favorite drink. If I were going to pour one of these into a glass for you to drink, which one would you rather have?” When the liquid in the short glass that contained less was transferred to the tall glass, the E asked, “If you were very thirsty and this was your favorite drink, which one would you rather have me pour for you?”
c. Condition 3. To control for the possibility that those children who responded correctly in condition 2 may have made simple transfer or external reversal from the tall glass back to the short one, a third condition was employed, which was similar to condition 2 with one exception. After the child poured the contents of the short glass containing less liquid into the tall glass, the E said, “I’m going to put these two glasses (the remaining empty short glasses) back here behind this screen. One glass is here (pointing to one of the arrows), and one glass is here (pointing to the other arrow). OK, now I’m going to pour this (tall) glass into the glass behind here, and this other (short) glass into the one behind here.” The E then asked the same final question as in condition 2.
d. Condition 4. After initial testing for conservation ability, the stimulus materials were removed and the child was assessed for dominant handedness by demonstrating the use of a pencil in drawing or writing. The E then asked the child a series of 10 questions which were designed to elicit five numerical and unemotional responses, and five emotional replies. The questions were derived from Woods, Beecher, and Ris (43), but were modified so that the content would be appropriate for young children. The E recorded the direction of gaze exhibited by the child while answering each question. If the child did not look to either side, or looked up and down or equally in both directions, the response was scored as mixed or ambiguous.
1. Conditions 1-3
The results were unambiguous. Only three of the children in condition 1 were able to conserve correctly when asked which of two nonequivalent substances had more volume. In contrast, when asked about preference, only four children in condition 2 made an incorrect response. Correspondingly, asking this same question in condition 3, which required the performance of an internal reversal, yielded only five correct responses. A chi square test performed across conditions indicated that these differences in frequency of correct responding were significant (X2= 7.58, p< .025). Since no significant differences were found between condition 1 and 3 (x2= .175, n.s.), the correct response scores for these groups were combined for comparison to the scores of Ss in condition 2. It was found that Ss in condition 2 (preference) made significantly more correct responses than did those in conditions 1 and 3 (x2= 12.23, p< .005).
2. Condition 4
To be designated a right- or left-looker, Ss had to make at least six responses in one direction and no more than three in either of the others. A chi square analysis showed no significant sex differences in eye movement. As predicted, there were significantly more right-lookers than left (x2= 8.82, p< .005); however, the right-lookers did not significantly exceed in number those classified as mixed responders (x2= 3.457, n.s.). Overall, it was found that right lateral eye movements exceeded left (x2= 48.4, p< .001) and ambiguous/mixed (x2= 217.56, p< .0001). In addition, there were significantly more left lateral eye movements than ambiguous/mixed (x2= 87.2, p< .005).
The results suggest that children who are not yet capable of generating accurate verbal statements about equivalence relationships may nevertheless possess an awareness (18) of them, and realize that the operations involved are reversible rather than absolute. This is consistent with previous findings (30, 42). It appears, however, that because of the immaturity of interhemispheric fiber connections in children (19, 26, 32, 44) or the left hemisphere’s dominant activity, nonlinguistic knowledge of spatial relations (25), as well as other cognitive-perceptual capacities (9, 10, 19, 23, 32), are at best only incompletely transferred to the language portions of the brain.
Under certain conditions, though, this failure to transfer may be circumvented. For example, in that the right hemisphere mediates affectively endowed, arousing information (19, 20, 38), the use of a reinforcer (30, 42) or the phrasing of questions in a rewarding context may sufficiently engage the right hemisphere so as to allow information to be transferred to the speech centers of the left hemisphere via intact callosal fibers, the limbic system, or other subcortical pathways such as the anterior commissure (11, 12, 19).
On the other hand, it may simply be that relational concepts are not adequately understood by children in this age group (13), regardless of functional asymmetries, and that questions directly related to the child’s experience are more effective elicitors of information than are those that require him to specify relationships among external objects. Since it is characteristic of preoperational individuals to be decidedly egocentric in perspective (19, 36), and to describe their experiences in absolute rather than relational language (40), questioning them in terms of preference may accommodate the egocentric point of view and eliminate certain linguistic referents which they do not yet have at their command.
Nevertheless, even correct knowledge of these operations appeared to be related to immediate or previous perceptual contexts, for when the E poured the liquids into the glasses behind the screen and then posed the preference question, only 1/3 of the children responded correctly. Whether it is a function of lack of experience in observing physical relationships, limited acquisition of the language skills required to express such operations, left hemispheric predominance, right hemispheric inhibition, incomplete information transfer, or a combination of these variables, cannot be determined from these data. However, these findings, coupled with the eye movement data, are consistent with the proposition that children at this stage of development are processing stimuli in general with the left hemisphere when verbal reports are required. It may be this linguistic orientation which limits children to concrete modes of thinking and static imagery, an imagery that defies projection and transformation to subsequent perceptual contexts (36) unless specifically provided by the E.
As compared to the findings of Bakan (1), Gur, Gur, and Harris (15), Paradowski, Brucker, and Zaretsky (34), Wood et al. (43), and others who have shown that the majority of adult males respond predominantly with left lateral eye movements, our findings of a dominant right-looking tendency among nonconservers leads to the possibility that as children age and the brain and cognitive functioning develop, asymmetrical functioning would shift, manifesting itself in left-looking and a corresponding enhancement of spatial processing. It contrast, it might be expected that individuals who continue to respond primarily with right-looking may perform poorly on spatial tasks. We are currently investigating this hypothesis, and our preliminary results (21) partially support these speculations.
On the whole, the construct of conservation is supported by the results of the present study, since the recognition of equivalence relationships as demonstrated in condition 2 was disrupted by the condition requiring completely internalized transformation. However, the differences in correct responses between children who were questioned about preference and those who were asked to respond to the same relationship in modifying terminology indicates that the traditional conservation tests may lack sensitivity to a form of mental imagery and tacit knowing that prevails in the thinking of the young child. By requiring the child to ascribe relational characteristic to external objects and express these relationships in terms that may cause confusion, Es may fail to assess a form of knowing which is essentially imaginal rather than linguistic, and thus misrepresent what the child actually knows.
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