Age-related changes in discrimination of unfamiliar odors

If odor perception involves mnemonic processes, differences in olfactory experience should affect discriminative ability. This was examined here by comparing discriminative performance in children and adults. Using an oddity test of discrimination, in Experiment 1 we tested 6-year-olds (G1), 11-year-olds (G6), and adults (A) on their ability to discriminate unfamiliar odors that varied either in quality (Q) or in quality and intensity (QI). G1 participants were poorer at discriminating the QI set, relative to G6 and A. In Experiment 2, we used an analogous visual procedure and confirmed that this age-related difference was olfactory specific. In Experiment 3, we repeated Experiment 1 but used an articulatory suppression task. G1 participants were poorer than G6 and A participants for both the Q and the QI sets. The implications of these findings for experiential accounts of odor perception and olfactory working memory are discussed.     

Perceptual learning of a non-focal color discrimination between ages three and six

A match-to-sample task and a preference-ranking procedure were used to provide predifferentiation experiences on a color discrimination of 3-, 4-, 5-, and 6-year-old children. Chronological age was the best predictor of task success. Six-year-olds averaged twice as many correct matches as 3-year-olds. Gender and predifferentiation experience were not significant as main effects or in interactions affecting test performance. There was no difference between scores of untrained and trained children. The predifferentiation experiences had no effect. The data suggest that the years between 3 and 6 may be an important period in the development of the perceptual abilities needed to discriminate among subtle differences in one hue. Boys' and girls' abilities seem to develop at the same rate during this age span.     

Development of the Correspondence Between Real and Imagined Fine and Gross Motor Actions

The development of the correspondence between real and imagined motor actions was investigated in 2 experiments. Experiment 1 evaluated whether children imagine body position judgments of fine motor actions in the same way as they perform them. Thirty-two 8-year-old children completed a task in which an object was presented in different orientations, and children were asked to indicate the position of their hand as they grasped and imagined grasping the object. Children’s hand position was almost identical for the imagined- and real-grasping trials. Experiment 2 replicated this result with 8-year-olds as well as 6-year-olds and also assessed the development of the correspondence of the chronometry of real and imagined gross motor actions. Sixteen 6-year-old children and seventeen 8-year-old children participated in the fine motor grasping task from Experiment 1 and a gross motor task that measured the time it took for children to walk and imagine walking different distances. Six-year-olds showed more of a difference between real and imagined walking than did 8-year-olds. However, there were strong correlations between real and imagined grasping and walking for both 6- and 8-year-old children, suggesting that by at least 6 years of age, motor imagery and real action may involve common internal representations and that motor imagery is important for motor control and planning.     

Enhanced recognition and recall of new words in 7- and 12-year-olds following a period of offline consolidation

Recent studies of adults have found evidence for consolidation effects in the acquisition of novel words, but little is known about whether such effects are found developmentally. In two experiments, we familiarized children with novel nonwords (e.g., biscal) and tested their recognition and recall of these items. In Experiment 1, 7-year-olds were then retested on either the same day or the following day to examine changes in performance after a short delay compared with a longer delay that included sleep. Experiment 2 used two age groups (7- and 12-year-olds), with all participants being retested 24h later. The 12-year-olds accurately recognized the novel nonwords immediately after exposure, as did the 7-year-olds in Experiment 2 (but not in Experiment 1), suggesting generally good initial rates of learning. Experiment 1 revealed improved recognition of the novel nonwords after both short (3- to 4-h) and longer (24-h) delays. In contrast, recall was initially poor but showed improvements only when children were retested 24h later, not after a 3- to 4-h delay. Similar improvements were observed in both age groups despite better overall performance in 12-year-olds. We argue that children, like adults, exhibit offline consolidation effects on the formation of novel phonological representations.     

Age-related changes in children's hedonic response to male body odor

Male sweat smells disgusting to many adults, but it is unclear whether children find it so. In Experiment 1A, children (mean age = 8.7 years) and adolescents (M=16.6 years) smelled male sweat and other odors, rated each for liking, and attempted their identification. Only female adolescents disliked male sweat and could identify it. Experiment 1B, using the same procedure, obtained this gender difference in adults (M=26.7 years). In Experiment 2, children (M=8.1 years) and adolescents (M=16.6 years) were cued about the identity of the same odors. Irrespective of gender, adolescents disliked male sweat more than did children. In sum, dislike for the odor of male sweat may be an acquired social response that is based on odor identification.     

The development of category-based induction: reexamining conclusions from the induction then recognition (ITR) paradigm

Three studies examined the development of category-based induction using an induction then recognition (ITR) procedure in which participants make category-based predictions about study items and are then given a surprise recognition test that requires discrimination between old and new category members. Exposure duration for study items was either self-paced (Experiment 1) or fixed for 5-year-olds and adults (Experiments 2a-b). Adults always showed a decrement in recognition performance following induction. Children showed the same decrement when exposure duration was equated across age groups. These results show that both young children and adults spontaneously access category-level information during induction. When study exposure time is self-paced, however, children may process additional, noncategorical aspects of study stimuli. (PsycINFO Database Record (c) 2008 APA, all rights reserved).     

Young children's (Homo sapiens) understanding of knowledge formation in themselves and others.

Three- and 4-year-old children (Homo sapiens) were tested for comprehension of knowledge formation. In Experiment 1, 34 subjects watched as a surprise was hidden under 1 of 4 obscured cups. The experimenter then pointed to the cup. All children searched under the correct cup, but no 3-year-olds (in contrast to most 4-year-olds) could explain how they knew where to look. Subjects then discriminated between simultaneous pointing by 2 adults, one who had hidden a surprise and one who had left the room before the surprise was hidden. Most 4-year-olds (but no 3-year-olds) showed clear discrimination between the adults. In Experiment 2, 16 subjects were tested with procedures designed to make the source of their own knowledge more obvious, but this had no effect on performance. We conclude that studies using very similar procedures with chimpanzees and rhesus macaques were measuring an ability (or inability) to understand how knowledge states form.     

Developmental continuity in the processes that underlie spatial recall

This study investigated whether children's spatial recall performance shows three separable characteristics: (1) biases away from symmetry axes (geometric effects); (2) systematic drift over delays; and (3) biases toward the exemplar distribution experienced in the task (experience-dependent effects). In Experiment 1, the location of one target within each geometric category was varied. Children's responses showed biases away from a midline axis that increased over delays. In Experiment 2, multiple targets were placed within each category at the same locations used in Experiment 1. After removing geometric effects, 6-year-olds'--but not 11-year-olds'--responses were biased toward the average remembered location over learning. In Experiment 3, children responded to one target more frequently than the others. Both 6- and 11-year-olds showed biases toward the most frequent target over learning. These results provide a bridge between the performance of younger children and adults, demonstrating continuity in the processes that underlie spatial memory abilities across development.     

Cross-cultural perspectives on pitch memory

We examined effects of age and culture on children's memory for the pitch level of familiar music. Canadian 9- and 10-year-olds distinguished the original pitch level of familiar television theme songs from foils that were pitch-shifted by one semitone, whereas 5- to 8-year-olds failed to do so (Experiment 1). In contrast, Japanese 5- and 6-year-olds distinguished the pitch-shifted foils from the originals, performing significantly better than same-age Canadian children (Experiment 2). Moreover, Japanese 6-year-olds were more accurate than their 5-year-old counterparts. These findings challenge the prevailing view of enhanced pitch memory during early life. We consider factors that may account for Japanese children's superior performance such as their use of a pitch accent language (Japanese) rather than a stress accent language (English) and their experience with musical pitch labels.     

Age differences in facial trustworthiness judgement based on multiple facial cues

Multiple facial cues such as facial expression and face gender simultaneously influence facial trustworthiness judgement in adults. The current work was to examine the effect of multiple facial cues on trustworthiness judgement across age groups. Eight-, 10-year-olds, and adults detect trustworthiness from happy and neutral adult faces (female and male faces) in Experiment 1. Experiment 2 included both adult and child faces wearing happy, angry, and neutral expressions. Nine-, 11-, 13-year-olds, and adults had to rate facial trustworthiness with a 7-point Likert scale. The results of Experiments 1 and 2 revealed that facial expression and face gender independently affected facial trustworthiness judgement in children aged 10 and below but simultaneously affected judgement in children aged 11 and above, adolescents, and adults. There was no own-age bias in children and adults. The results showed that children younger than 10 could not process multiple facial cues in the same manner as in older children and adults when judging trustworthiness. The current findings provide evidence for the stable-feature account, but not for the own-age bias account or the expertise account.     

Paired associate learning in Chinese children with dyslexia

A total of 82 Chinese 11- and 12-year-olds with and without dyslexia were tested on four paired associate learning (PAL) tasks, phonological awareness, morphological awareness, rapid naming, and verbal short-term memory in three different experiments. Experiment 1 demonstrated that children with dyslexia were significantly poorer in visual-verbal PAL than nondyslexic children but that these groups did not differ in visual-visual PAL performance. In Experiment 2, children with dyslexia had more difficulties in transferring rules to new stimuli in a rule-based visual-verbal PAL task as compared with children without dyslexia. Long-term retention of PAL was not impaired in dyslexic children across either experiment. In Experiment 3, rates of visual-verbal PAL deficits among children with dyslexia were all at or above 39%, the highest among all cognitive deficits tested. Moreover, rule-based visual-verbal PAL, in addition to morphological awareness and rapid naming ability, uniquely distinguished children with and without dyslexia even with other metalinguistic skills statistically controlled. Results underscore the importance of visual-verbal PAL for understanding reading impairment in Chinese children.     

A further analysis of time bisection behavior in children with and without reference memory: the similarity and the partition task

Experiment 1 compared the temporal performance of 5-year-olds, 8-year-olds and adults in a bisection task with and without referent durations (similarity vs. partition). The results showed that temporal sensitivity was lower in the partition than in the similarity condition in children, whereas it was similar in these two conditions in the adults. In addition, the 5-year-olds produced a higher bisection point value in the partition than in the similarity task. Experiment 2, which examined changes in bisection performance over the trial blocks in the partition task, revealed that the 5-year-olds' bisection performance improved over the trial blocks, whereas the performance of the older participants did not. Further analyses revealed a greater variability in the establishment of the duration criterion in young children.     

The width of the auditory filter in children

Because young children have poorer auditory temporal resolution than older children, they ought to have, according to the inverse relation between temporal and frequency resolution, narrower auditory filters than older children. Therefore, the auditory filters of two 6-year-olds, two 10-year-olds, and two adults were measured by having them detect a 400-ms sinusoid (500, 1000, or 3000 Hz) centered in a spectral notch in a band of noise. The signal power for 71% correct was determined as a function of notch width with the two-alternative, forced-choice procedure. The principal results showed a significant decrease in signal power with age and a significant interaction between age and notch width. The best-fitting parameters of a model of the auditory filter showed that the filter was significantly wider for the 6-year-olds than for the 10-year-olds or the adults.     

The development of idiom comprehension: an investigation of semantic and contextual processing skills

Two experiments compared 7- and 8-year-olds' and 9- and 10-year-olds' ability to use semantic analysis and inference from context to understand idioms. We used a multiple-choice task and manipulated whether the idioms were transparent or opaque, familiar or novel, and presented with or without a supportive story context. Performance was compared with that of adults (Experiment 1) and 11- and 12-year-olds (Experiment 2). The results broadly support Cacciari and Levorato's global elaboration model of figurative competence with a notable exception: Even the youngest children were able to use semantic analysis to derive the meanings of transparent idioms as well as being sensitive to meaning in context. The findings show that young children process language at both the small-grain phrase level and the discourse level to establish figurative meaning, and they demonstrate that the language processing skills that aid idiom comprehension, as well as idiom knowledge itself, are still not fully developed in 11- and 12-year-olds.     

Naming solids and nonsolids: Children's default construals

Four experiments used a free-naming task to examine children's and adults' default construals of solids and nonsolids. In Experiment 1,4-year-old children viewed entities presented in familiar geometric shapes (e.g., square, triangle), without touching them. One half saw solids (e.g., a square made of wood); the other half saw nonsol ids matched carefully in shape (e.g., a square with the same dimensions but made of peanut butter). To tap their default construals, children were simply asked, “What is that?” Answers varied sharply with the type of stimulus. If the entity was solid, children tended to provide an individual-related word (e.g., “a square”), even if they also knew a substance-related word (e.g., “wood”). But if the stimulus was nonsolid, children tended to give a substance-related word (e.g., “peanut butter”), even if they also knew an individual-related word (e.g., “a square”). These words were usually common nouns produced in appropriate sentential contexts, suggesting that 4-year-olds represented the words as naming kinds. The same pattern of results obtained in Experiments 2 and 3, which were modified replications of Experiment 1. The results of Experiment 4 replicated the main findings of Experiment 1 using adults as participants. The studies suggest that, as a default, 4-year-olds conceptualize solids and nonsolids in (a) fundamentally distinct, (b) kind-based (rather than perceptual property-based), and (c) adult-like ways.     

Integration of Category Induction and Hierarchical Classification: One Paradigm at Two Levels of Complexity

Hierarchical classification (HC) and category induction (CI) were tested by a common property inference procedure to facilitate comparison and enable relative complexities to be assessed. Relational complexity theory predicts that HC is more complex because it entails a ternary relation between categories B, A, and A' such that A and A' are included in B, whereas CI entails a simpler binary relation between a category and its complement. Experiment 1 tested inferences about familiar categories with plausible but unfamiliar attributes, and Experiment 2 assessed inferences about fictitious categories with familiar attributes. As predicted, HC was more difficult than CI. Children over 5 years succeeded on both, but 3-year-olds succeeded on CI only. Tasks of the same level of complexity predicted 68% (Experiment 1) and 80% (Experiment 2) of age-related variance. The results suggest that HC and CI may be regarded as 1 paradigm with 2 levels of structural complexity.     

Modeling face identification processing in children and adults

Two face identification experiments were carried out to study whether and how children (5-year-olds) and adults integrate single facial features to identify faces. Using the paradigm of the Fuzzy Logical Model of Perception each experiment used the same expanded factorial design, with three levels of eyes variations crossed with three levels of mouth variations as well as their corresponding half-face conditions. In Experiment 1, an integration of facial features was observed in adults only. But, in adjusting the salience of the features varied, the results of Experiment 2 indicate that children and adults evaluated and integrated information from both features to identify a face. A weighted Fuzzy Logical Model of Perception fit the judgments significantly better than a Single Channel Model and questions previous claims of holistic face processing. Although no developmental differences in the stage of the integration of facial information were observable, differences between children and adults appeared in the information used for face identification.     

Psychophysical design influences frequency discrimination performance in young children

We investigated how different psychophysical procedures affect frequency discrimination performance in children. Four studies used a design in which listeners heard two tone pairs and had to identify whether the first or second pair contained a higher frequency target tone. Thresholds for 6- and 7-year-olds were higher than those for 8- and 9-year-olds and adults. Two manipulations led to lower (better) thresholds in young children: (a) moving the standard comparison tone before the target tone and (b) using three target comparison tone pairs. It is suggested that young children benefit from designs that help cue them to when they need to attend to a target tone. The two-interval, forced-choice procedure that is widely used in studies of developmental disorders led to variable performance even in adults and did not give a realistic picture of the perceptual capabilities of children under 8 years of age.     

Children's understandings of the attributes of life

Previous investigations of children's understandings of the life concept have focused on their classifications of the life status of familiar objects. In this study, we attempted to examine more directly the processes by which children infer life status by examining their reasoning about unfamiliar objects. In Experiment 1, 4- to 11-year-olds and adults were asked to name attributes of living things to establish which attributes they associated most closely with life. Children age 7 and younger most often named attributes true only of animals but not of plants; older children more often named attributes true of both animals and plants. However, movement was the single attribute cited most frequently by children of all ages tested. In Experiment 2, 4- to 11-year-olds and adults were presented information about attributes of imaginary objects on a distant planet and were asked to infer if those objects were alive. Again, young children relied relatively heavily on qualities true only of animals but not of plants, whereas older children relied more on attributes true of both plants and animals. Also as before, movement was viewed as indicative of life at all ages tested. In Experiment 3, we examined the hypothesis that children discriminate among different types of motion and that the types of motion they associate with life are in fact typical of living things. Children ranging from age 5 through 11 were found to discriminate among different types of motion and to infer that objects were alive only when they showed the types of motion typical of living beings. The results of Experiment 3 allowed interpretation of seemingly conflicting results that have arisen in previous studies, as well as in Experiments 1 and 2 of the present study.     

What counts as by? Young children's use of relative distance to judge nearbyness

The authors investigated how 3- and 4-year-old children and adults use relative distance to judge nearbyness. Participants judged whether several blocks were by a landmark. The absolute and relative distance of the blocks from the landmark varied. In Experiment 1, judgments of nearbyness decreased as the distance from the landmark increased, particularly for 4-year-olds and adults. In Experiment 2, 4-year-olds and adults were more likely to judge objects at an intermediate distance as by the landmark when intervening objects were absent than when intervening objects were present. In Experiment 3, participants of all ages were more likely to judge objects at a short distance as by the landmark when intervening objects were absent. Reliance on relative distance to judge nearbyness becomes more systematic and applicable to larger spatial extents across development.