Developmental differences in shape processing

Considerable evidence indicates that shape similarity plays a major role in object recognition, identification and categorization. However, little is known about shape processing and its development. Across four experiments, we addressed two related questions. First, what makes objects similar in shape? Second, how does the processing of shape similarity develop? We specifically asked whether children and adults determine shape similarity by using categories (e.g., straight vs. curved), as proposed by Biederman (1987), or whether they treat all shape variability uniformly, as proposed by Ullman (1998). Findings from Experiments 1 and 2 suggest that adults and 7-year-olds generally engage in a process in which they impose categories on shape variation and judge objects that fall within those categories as being similar in shape. Four-year-olds are far less likely to engage in such a process. Experiments 3 and 4 address whether 4-year-olds are more likely to treat shape similarity categorically (as older children and adults do) when the objects are given familiar names, functions, and internal properties. Naming did lead to more advanced treatment of shape similarity in some cases. Overall, these findings provide evidence of developmental differences in shape processing and suggest that knowledge of abstract properties of objects may affect the calculation of shape similarity.     

Developmental differences in the allocation of processing capacity

Recently psychologists have formulated a comprehensive view of attention involving allocation of processing capacity. Although developmental changes in processing capacity have been proposed as one source of age differences in certain cognitive skills, there has been little systematic investigation of this hypothesis. In the present study, second and sixth graders and adults (8, 12, and 20 years of age, respectively) performed a letter-matching task (primary task) concurrently with an auditory detection task (secondary task). Changes in reaction time in the secondary task as a function of manipulations of the primary task were used to estimate capacity allocation to the primary task. Primary task variables included stage of processing (alerting, encoding, rehearsing, responding) and matching condition (physical-identity vs name-identity matching). Age differences in secondary task performance were found to be related to stage of processing but not to matching condition. Earlier stages of the letter match task (alerting, encoding) required somewhat more capacity allocation in younger subjects. Later stages (rehearsing, responding) made substantially higher demands on capacity in children. Capacity allocation may be an important cognitive variable mediating developmental differences in basic information processing skills, and may underlie age trends found in performance of certain complex cognitive tasks.     

Developmental differences in visual processing: strategy versus structure

The present study was an examination of two contrasting explanations for the finding that young children tend to classify objects according to similarity relations whereas adults emphasize dimensional structure. Subjects from three different age groups were given tasks that tapped different aspects of the visual process: Feature search, Conjunction search, and Restricted Classification tasks. In addition, three different stimulus objects (a highly separable, a highly integral, and an intermediate dimensional combination) were studied to explore the contribution of stimulus structure in dictating the nature of the processing mode. The results provided evidence against the view that children perceive objects according to a more primitive holistic structure. Rather, the results can be taken with past research to suggest that less efficient visual processing may lead the younger subjects to adopt a classification strategy that emphasizes similarity relations. In addition, the current research supported Garner's (1974, The processing of information and structure, Potomac, MD: Erlbaum) suggestion that the nature of the processing mode is stimulus-driven.     

Developmental differences in remembering sentences after integrative or selective semantic processing

Fifth graders (age: 10 years) and college undergraduates performed one of four different semantic orienting activities on a series of agent-action-object sentences. Afterwards all subjects received a memory test combining recognition for whole sentences with cued recall for component agents, actions, and objects. Overall levels of both recall and recognition varied with the orienting activities. Relative recallability of agents, actions, and objects varied with orienting activity as well. Recognition performance improved with grade level but recall did not. The interaction between type of memory test and grade level was taken to indicate that organization of material in memory increases during adolescence even when the total amount of material stored does not.     

Developmental differences in the neural correlates supporting semantics and syntax during sentence processing

School‐aged and adolescent children continue to demonstrate improvements in how they integrate and comprehend real‐time, auditory language over this developmental time period, which can have important implications for academic and social success. To better understand developmental changes in the neural processes engaged during language comprehension in this age group, we use electroencephalography to investigate how 8–9 year old, 12–13 year olds, and adults process semantics and syntax in naturally paced, auditory sentences. Participants listened to semantically and syntactically correct and incorrect sentences and were asked to complete an acceptability judgment task. When processing a semantic error, developmental differences were observed in theta, but not the N400, suggesting that the N400 may be too gross a measure to identify more subtle aspects of semantic development that occur in the school years. For the syntactic task, errors resulted in a larger P600 and greater beta decrease than correct sentences, but the amplitude and location of the P600 and amplitude of beta decreases differed as a function of age, suggesting specialization of syntactic skills is ongoing through adolescence. The current findings shed new light on the development of the neural oscillations supporting language comprehension and suggest that the neural substrates underlying semantic processing reach adult‐like levels at a younger age than those underlying syntactic processing.     

Developmental differences in mental rotation.

A reaction time paradigm was used to investigate developmental differences in ability to rotate and compare imaginal representations. Third grade, fifth grade, and college students (ages 9, 11, and 20 years, respectively) were required to determine whether a letter of the alphabet was presented in its backward or normal position. Letters were presented at 0, 60, 120, 180, 240, or 300° orientations from upright. Subjects were given no advance information about a test letter, or they were given identity and orientation information. In the no information condition, reaction time increased for all age groups as a function of the departure in orientation of the test letter from an upright position. In the advance information condition, reaction time remained uniform across orientation for only the college subjects. The developmental implications of these findings are discussed.     

Developmental changes in face processing skills

Expertise in processing differences among faces in the spacing among facial features (second-order relations) is slower to develop than expertise in processing the shape of individual features or the shape of the external contour. To determine the impact of the slow development of sensitivity to second-order relations on various face-processing skills, we developed five computerized tasks that require matching faces on the basis of identity (with changed facial expression or head orientation), facial expression, gaze direction, and sound being spoken. In Experiment 1, we evaluated the influence of second-order relations on performance on each task by presenting them to adults (N=48) who viewed the faces either upright or inverted. Previous studies have shown that inversion has a larger effect on tasks that require processing the spacing among features than it does on tasks that can be solved by processing the shape of individual features. Adults showed an inversion effect for only one task: matching facial identity when there was a change in head orientation. In Experiment 2, we administered the same tasks to children aged 6, 8, and 10 years (N=72). Compared to adults, 6-year-olds made more errors on every task and 8-year-olds made more errors on three of the five tasks: matching direction of gaze and the two facial identity tasks. Ten-year-olds made more errors than adults on only one task: matching facial identity when there was a change in head orientation (e.g., from frontal to tilted up). Together, the results indicate that the slow development of sensitivity to second-order relations causes children to be especially poor at recognizing the identity of a face when it is seen in a new orientation.     

Gender differences in phonetic processing

In research on dyslexia, inadequate or inappropriate comparisons have often been made with control subjects, frequently overlooking important gender differences. More information is needed regarding the performance of control subjects, and adults, on measures purportedly assessing phonological and orthographic processing. Using tests similar to those used in dyslexic research, 20 female and 20 male college-age students were tested to examine gender differences in phonetic processing skills. The findings suggest that in equally competent readers, gender and other factors do play a significant role in determining the time it takes for phoneme manipulation and word identification. Females, especially those with poorer academic records, are significantly slower than males on measures typically used in dyslexic research. These findings show a need for a reexamination of control group equivalence (especially regarding gender), and further exploration of variables that might influence performance on these tasks.     

Gender differences in phonetic processing

In research on dyslexia, inadequate or inappropriate comparisons have often been made with control subjects, frequently overlooking important gender differences. More information is needed regarding the performance of control subjects, and adults, on measures purportedly assessing phonological and orthographic processing. Using tests similar to those used in dyslexic research, 20 female and 20 male college-age students were tested to examine gender differences in phonetic processing skills. The findings suggest that in equally competent readers, gender and other factors do play a significant role in determining the time it takes for phoneme manipulation and word identification. Females, especially those with poorer academic records, are significantly slower than males on measures typically used in dyslexic research. These findings show a need for a reexamination of control group equivalence (especially regarding gender), and further exploration of variables that might influence performance on these tasks.     

Sex differences in information processing

Sex differences in cognitive activity were investigated. Using a list containing words with masculine, feminine, and neutral connotations, Experiment 1 revealed that masculine words were better recalled by male college students (n=16) while feminine words were better recalled by female college students (n=16). This difference was reduced on a recognition test. Experiment 2 demonstrated that the phenomenon was not due to a difference in the way males (n=20) and females (n=20) interpreted the meaning of the words. Finally, in Experiment 3, the memorial selectivity was shown to exist in the same manner for White middle-class elementary school (n=32) and high school (n=32) students. Learning and repression interpretations of the effect were proposed. Some practical implications of the data were suggested.These investigations were supported by a seed grant to the first author. This grant was jointly funded by Southern Methodist University and the National Science Foundation's Institutional Grants for Science Program (GU-3752). The authors would like to express their appreciation to the pupils and teachers on Fain Elementary School and Rider High School, both in Wichita Falls, Texas.     

Hemispheric differences in case processing

Morphosyntactic capacities of normal brain hemispheres were compared in lexical decision studies involving centrally and laterally presented Serbo-Croatian nouns in different cases. Cases are distinguished by different suffixes and syntactic roles. Experiment 1 confirmed and extended previous findings of the nominative superiority effect: words in the nominative case were processed faster and more accurately than words in other three cases, and nonwords in the nominative case led to more false positive reactions than nonwords in other cases. In Experiment 2 this effect was replicated for right visual field stimuli: nominatives had faster reaction times and smaller error rates than accusatives, and the reversed pattern was found for nonwords. For left visual field stimuli, only the word error analysis found the nominative superior, while the other three analyses (word reaction times, nonword reaction times, and nonword error rates) showed no significant case effect. Word familiarity had an equally strong effect in both hemispheres. The results suggest that centrally presented stimuli are processed by the left hemisphere, that laterally presented stimuli are processed by the initially receiving hemisphere, and that the right hemisphere has a frequency-sensitive lexicon. Reduced right-hemisphere sensitivity for case differences may be due to different lexicon structure or the absence of appropriate morphological or syntactic mechanisms.     

Developmental differences in children's context-dependent word learning

In this study, 2.5-, 3-, and 4-year-olds (N = 108) participated in a novel noun generalization task in which background context was manipulated. During the learning phase of each trial, children were presented with exemplars in one or multiple background contexts. At the test, children were asked to generalize to a novel exemplar in either the same or a different context. The 2.5-year-olds’ performance was supported by matching contexts; otherwise, children in this age group demonstrated context dependent generalization. The 3-year-olds’ performance was also supported by matching contexts; however, children in this age group were aided by training in multiple contexts as well. Finally, the 4-year-olds demonstrated high performance in all conditions. The results are discussed in terms of the relationship between word learning and memory processes; both general memory development and memory developments specific to word learning (e.g., retention of linguistic labels) are likely to support word learning and generalization.     

Developmental differences in children's labeling of movement

Children's encoding of information, specifically, the correct use and application of labels, is one factor frequently used to account for developmental differences in verbal learning. Labels may also be used in connection with remembering positional movements. The purpose of this study was to evaluate developmental differences in the effects of labels upon remembering movements. In addition, the study evaluated whether better or poorer labeling strategies would increase or decrease performance in the age groups studied. Subjects consisted of kindergarten children (N=27), fifth grade children (N=27), and adults (N=27) randomly assigned within each age level to one of three groups: subjective label, irrelevant label, and relevant label. Subjects were tested on a two-dimensional positioning task allowing estimates of radial, location, and distance errors. Results indicated that relevant labels (clock face) improved performance for remembering positions within all age conditions. Of major interest was the finding that relevant labels increased performance of the kindergarten children to the approximate level of the irrelevant label (animals) group for fifth graders. The same finding was evident for the fifth graders with the relevant label group approximating performance of adults forced to use a less sophisticated strategy (irrelevant label, i.e., animals). This finding suggests that a significant portion of the differences between younger and older children and adult performance is due to the processing deficit of poor encoding strategies used by children.     

Developmental differences in rehearsal and free recall

The purpose of this experiment was to analyze developmental differences in rehearsal strategies which may mediate the commonly found age effect on free recall. As expected, significant age differences in recall were found; analysis of rehearsal strategies showed that fifth and eighth graders tended to repeat stimulus words immediately after presentation, and not enter items into subsequent rehearsal sets. Adults, in contrast, tended to reenter items for additional rehearsal, and had larger rehearsal buffers. Immediate repetition may have served as additional massed presentation trials, which are less consequential for learning than later reentry of items (spaced trials). It was inferred that children engaged primarily in maintenance rehearsal, and adults in both maintenance and elaborative rehearsal.     

Social value related response latencies: Unobtrusive evidence for individual differences in information processing

While much research concerning decision-making in interdependency situations concentrates on the influence of social values or different preferences for certain distributions of outcomes for self and other (McClintock, 1978), little attention has been paid to the cognitive processes underlying the expression of these different social values. The present research focuses on the cognitive processes by examining the influence of the dominant social values on decision-makers' response latencies (RLs) in interdependency situations. Using the Ring Measure of Social Values (Liebrand 1984), three experiments were conducted to assess these RLs. Experiment 1 examines the reliability of the social value construct and the RL effect. Experiments 2 and 3 investigate the generality of the RL effect across presentation of combinations of own and other's outcomes (all positive versus all negative). As predicted, RLs were shorter for individualists than for cooperators and competitors. Further, regardless of values, shorter RLs occurred across experiments when own outcomes are positive rather than negative. More important, the predicted interaction between social value and outcome distribution was observed, reflecting increasing RLs for cooperators as their joint outcomes decreased, longer RLs for individualists when own outcomes were negative rather than positive, and longer RLs for competitors when they were outcome disadvantaged rather than advantaged relative to other. These findings are consistent with the expectation that (I) the transformations associated with different social values require different cognitive processes, and (2) subsequent to the value transformations of outcomes, RLs increase when the utility of the transformed outcome distributions decreases.     

Developmental levels of processing in metaphor interpretation

We outline a theory of metaphor interpretation. The theory posits varying levels of semantic processing and formalizes them in terms of kinds of semantic-mapping operators that transform properties of the metaphoric vehicle (i.e., predicate) into properties of the metaphoric topic (i.e., subject). We used cognitive-developmental theory to estimate the mental-processing complexity of the various mapping operators, and thereby to predict the timing of their emergence in childhood, and to construct a measure of the metaphoric-processing levels. Metaphor interpretations collected from children (aged 6-12 years) and adults were coded and scored according to the processing levels. In two separate developmental studies, processing score increased with age in a predictable way. Growth in a mental-attentional resource accounted for much of the developmental variance in metaphor interpretation. Possible moderating effects of knowledge and context are discussed.     

Hemispheric differences in processing handwritten cursive

Hemispheric asymmetry was examined for native English speakers identifying consonant-vowel-consonant (CVC) non-words presented in standard printed form, in standard handwritten cursive form or in handwritten cursive with the letters separated by small gaps. For all three conditions, fewer errors occurred when stimuli were presented to the right visual field/left hemisphere (RVF/LH) than to the left visual field/right hemisphere (LVF/RH) and qualitative error patterns indicated that the last letter was missed more often than the first letter on LVF/RH trials but not on RVF/LH trials. Despite this overall similarity, the RVF/LH advantage was smaller for both types of cursive stimuli than for printed stimuli. In addition, the difference between first-letter and last-letter errors was smaller for handwritten cursive than for printed text, especially on LVF/RH trials. These results suggest a greater contribution of the right hemisphere to the identification of handwritten cursive, which is likely related visual complexity and to qualitative differences in the processing of cursive versus print.     

Developmental changes in units of processing in reading

A visual search task was used to investigate the development of word processing skills used in reading meaningful prose. Children from the second and fourth grades and college students were asked to locate a prespecified letter, syllable, word, or category exemplar as they read through sentences. Target detection time, sentence reading time, and sentence comprehension were measured. The results provide converging evidence that whole words were the preferred units of processing during reading for all three grade levels. Reading rates for sentences in the word search condition were comparable to normal reading rates. The search for smaller units required additional processing time, but word and category search times differed only for the youngest subjects.