Ensemble perception of size in 4–5‐year‐old children

Groups of objects are nearly everywhere we look. Adults can perceive and understand the ‘gist’ of multiple objects at once, engaging ensemble‐coding mechanisms that summarize a group's overall appearance. Are these group‐perception mechanisms in place early in childhood? Here, we provide the first evidence that 4–5‐year‐old children use ensemble coding to perceive the average size of a group of objects. Children viewed a pair of trees, with each containing a group of differently sized oranges. We found that, in order to determine which tree had the larger oranges overall, children integrated the sizes of multiple oranges into ensemble representations. This pooling occurred rapidly, and it occurred despite conflicting information from numerosity, continuous extent, density, and contrast. An ideal observer analysis showed that although children's integration mechanisms are sensitive, they are not yet as efficient as adults’. Overall, our results provide a new insight into the way children see and understand the environment, and they illustrate the fundamental nature of ensemble coding in visual perception.     

Performance on Stroop‐like assessments of inhibitory control by 4‐ and 5‐year‐old children

The rapid development of an aspect of executive functioning (EF), inhibitory control (IC), between the ages of 3‐ and 5‐years, leads to an increase in a child's capacity to suppress inappropriate responding and therefore activate the necessary resources to carry‐out goal‐directed activity (Psychological Bulletin, 1997, 121 , 65–94). To measure EF in children, tasks administered clinically to adults are adapted. The Day–Night Stroop (DNS) is a pictorial modification of the Stroop Test (Journal of Experimental Psychology, 1935, 18 , 642–662), developed for pre‐literate children. Although suitable as a measure of IC in 3‐ to 4‐year‐old children, ceiling effects have been reported on the DNS in slightly older preschoolers. The present study attempted to overcome this limitation by examining the suitability of two modified versions of the DNS in 4‐ to 5‐year‐old preschoolers. To investigate the executive demands made by both Stroop‐like tasks, their associations with another measure of IC (stop‐signal task) and a measure of working memory were examined. Counter to expectations, no significant association was found in performance between the two Stroop‐like tasks; however, the modified DNS developed in this study showed significant relationships with the other executive tasks. The results are discussed in relation to the different methodologies used by these Stroop measures. Implications of this study suggest that researchers should consider more test‐specific factors when assessing EF in young children. Copyright © 2010 John Wiley & Sons, Ltd.     

A 2‐year‐old child's memory of hospitalization during early infancy

A child who had had surgery at 5 months of age, and who had been treated at the time for post‐traumatic symptoms (reported in a previous paper by the author), was interviewed 2 years later and almost 3 years later to test for possible verbal recall of his hospitalization. He appeared to have some memories of the experience at 29 months of age, and he was able to superimpose verbal labels onto the preverbal memories. At 40 months of age, however, the memories were no longer verbally accessible. The results are discussed in the context of different theories of encoding, storage, retrieval, and loss of early memories. The findings from this study support other findings indicating that there appears to be some form of long‐term memory in place early in life, at least for highly salient, traumatic events. There may be one memory system for traumatic memories, fully functional at birth, and a later developing, different system for neutral memories. It is further hypothesized that there may be a sensitive period around 2–3 years of age for the recall of early traumatic memories, and that verbal recall is more likely to be present in verbally precocious children during that period. Copyright © 2008 John Wiley & Sons, Ltd.     

Processing of facial and non‐facial visual stimuli in 2–5‐year‐old children

The present experiments examined the degree to which analytic and holistic modes of processing play a role in the way 2–5‐year‐old children process facial and non‐facial visual stimuli. Children between 2 and 5 years of age were instructed to categorize faces (in Experiment 1) and non‐facial visual stimuli, such as birds and planes (in Experiment 2), into two categories. The categories were so constructed as to allow the children to categorize the facial and non‐facial stimuli either analytically (by focusing on a single attribute) or holistically (in terms of overall similarity). The results demonstrated that the previous conclusions concerning older children's (from 6 years onwards) holistic mode of facial processing could not be generalized to younger children because most of the 2–5‐year olds processed the faces by taking single facial attributes into account. A similar pattern of results emerged for the processing of objects, showing that the majority of the children focused on single attributes. Thus, for both visual domains, holistic processing was the exception rather than the rule. Copyright © 2002 John Wiley & Sons, Ltd.     

Facial identity and facial expression matching in 5–12‐year‐old children and adults

Facial identity and facial expression matching tasks were completed by 5–12‐year‐old children and adults using stimuli extracted from the same set of normalized faces. Configural and feature processing were examined using speed and accuracy of responding and facial feature selection, respectively. Facial identity matching was slower than face expression matching for all age groups. Large age effects were found on both speed and accuracy of responding and feature use in both identity and expression matching tasks. Eye region preference was found on the facial identity task and mouth region preference on the facial expression task. Use of mouth region information for facial expression matching increased with age, whereas use of eye region information for facial identity matching peaked early. The feature use information suggests that the specific use of primary facial features to arrive at identity and emotion matching judgments matures across middle childhood. Copyright © 2009 John Wiley & Sons, Ltd.     

Children’s coding of human action: cognitive factors influencing imitaation in 3‐year‐old

We used imitation as a tool for investigating how young children code action. The study was designed to examine the errors children make in re‐enacting manual gestures they see. Thirty‐two 3‐year‐old children served as subjects. Each child was shown 24 gestures, generated by systematically crossing four factors: visual monitoring, spatial endpoint, movement path, and number of hands. The results showed no difference as a function of whether the children could visually monitor their own responses. Interestingly, children made significantly more errors when the adult's action terminated on a body part than they did when the same movement terminated near the body part. There were also significantly more errors when the demonstrated act involved crossing midline than when it did not, and more errors when it involved one hand rather than two hands. Our hypothesis is that human acts are coded in terms of goals. The goals are hierarchically organized, and because young children have difficulty simultaneously integrating multiple goals into one act they often re‐enact the goals that are ranked higher, which leads to the errors observed. We argue that imitation is an active reconstruction of perceived events and taps cognitive processing. We suggest that the goal‐based imitation in 3‐year‐olds is a natural developmental outgrowth of the perceptual–motor mapping and goal‐directed coding of human acts found in infancy.     

The relationships between quantity‐number competencies,working memory,and phonological awareness in 5‐ and 6‐year‐olds

In this study, the interdependencies among phonological awareness, verbal working memory components, and early numerical skills in children 1 year before school entry are addressed. Early numerical skills were conceptualized as quantity‐number competencies (QNC) at both basic (QNC Level 1) and advanced (QNC Level 2) levels. In a sample of 1,343 children aged 5 and 6, structural equation modelling provided support for the isolated number words hypothesis (Krajewski & Schneider, 2009, J. Exp. Child Psychol., 103, 516–531). This hypothesis claims that phonological awareness contributes to the acquisition of QNC Level 1, such as learning the number word sequence, but not of QNC Level 2, which requires the linkage of number words to quantities. In addition, phonological awareness relied on verbal working memory, especially with regard to the phonological loop, central executive, and episodic buffer. The results were congruent with the idea that phonological awareness mediates the impact of verbal working memory on QNCs. The relationships between verbal working memory, phonological awareness, and QNCs were comparable in monolingual and bilingual children.     

Spontaneous analog number representations in 3‐year‐old children

When enumerating small sets of elements nonverbally, human infants often show a set‐size limitation whereby they are unable to represent sets larger than three elements. This finding has been interpreted as evidence that infants spontaneously represent small numbers with an object‐file system instead of an analog magnitude system ( Feigenson, Dehaene & Spelke, 2004 ). In contrast, non‐human animals and adult humans have been shown to rely on analog magnitudes for representing both small and large numbers ( Brannon & Terrace, 1998 ; Cantlon & Brannon, 2007 ; Cordes, Gelman, Gallistel & Whalen, 2001). Here we demonstrate that, like adults and non‐human animals, children as young as 3 years of age spontaneously employ analog magnitude representations to enumerate both small and large sets. Moreover, we show that children spontaneously attend to numerical value in lieu of cumulative surface area. These findings provide evidence of young children’s greater sensitivity to number relative to other quantities and demonstrate continuity in the process they spontaneously recruit to judge small and large values.     

Comprehension and production of body part labels in 2‐ to 3‐year‐old children

This study examined which body part labels children could (i) produce when the experimenter touched different locations on her own body, asking each time ‘What's this?’ and (ii) comprehend by touching the correct locations on their own bodies in response to the experimenter asking ‘Where's the [body‐part label]?’. Seventeen children aged between 26 and 41 months, tested in a repeated measures procedure, were presented with 50 different body part stimuli in 200 test trials per child. Overall, the children produced fewer body part labels than they could comprehend. The accuracy of children's responses depended on (i) the location or extent of each body part (facial and broad body features were better known; joints and features in or attached to broad body parts the least well known); (ii) the amount of sensory (but not motor) representation each body part has in the human cortex; and (iii) whether a body part was commonly named by caregivers. These results present a precise mapping of the body parts that young children are able to name and locate on their own bodies in response to body part names; they suggest several possible determinants of lexical‐semantic body knowledge and add to the understanding of how it develops in childhood.     

The role of associative strength and conceptual relations in matching tasks in 4‐ and 6‐year‐old children

T he associative strength between target and associates, a factor assumed to be critical but generally not controlled, and the type of conceptual relation (thematic and taxonomic) were manipulated independently in a matching to sample task to determine their respective effects on the matching behaviour of 4‐ and 6‐year‐old children. Perceptual similarity between target and associates was controlled and maintained at a low level. A preliminary task was designed to assess the associative strength between targets and several associated pictures. These judgments served to construct for each child the sets of stimuli used in the matching task. Exp. 1 opposed a strong and a weak associate with the target in different configurations: the sets included a target and two thematic associates, two taxonomic associates, or one associate of each type. Children were asked to choose the picture that “went well” with the target. Data revealed the role of associative strength on matching choices. This factor interacted sometimes with the greater availability of thematic relations in 4‐ and 6‐year‐old children. In Exp. 2, two other configurations were tested. Thematic and taxonomic associates were both either strongly or weakly related with the target. Results replicated those of Exp. 1 and extended them. They showed that younger children were biased towards thematic relations only when these relations corresponded to strong associations. Thus, increasing experience with objects appears to reinforce both associative strength and thematic orientation. Finally, in Exp. 3, instructions orienting toward taxonomic choices modified responses in 6‐year‐olds only. Altogether, these results show the influence of specific instances and suggest that preschoolers' matching decisions are partly stimulus driven.     

Development of navigational working memory: Evidence from 6‐ to 10‐year‐old children

The ability to learn complex environments may require the contribution of different types of working memory. Therefore, we investigated the development of different types of working memory (navigational, reaching, and verbal) in 129 typically developing children. We aimed to determine whether navigational working memory develops at the same rate as other types of working memory and whether the gender differences reported in adults are already present during development. We found that navigational working memory is less developed than both verbal and reaching working memory and that gender predicts performance only for navigational working memory. Our results are in line with reports that children made significantly more errors in far space than adults, showing that near space representation develops before far space representation.     

A measure of inspection time in 4‐year‐old children: The Benny Bee IT task

Inspection time (IT) measures speed of information processing without the confounding influence of motor speed. While IT has been found to relate to cognitive abilities in adults and older children, no measure of IT has been validated for use with children younger than 6 years. This study examined the validity of a new measure of IT for preschool children. N=71 4‐year‐old children completed the new IT task and standardized measures of fluid ability, visuospatial ability, and speed of processing. N=50 adults completed the same tasks and, additionally, a standard IT task. Results showed that the new IT task is a stable, reliable measure of IT in 4‐year‐old children. The new task had reasonable concurrent validity with the standard IT task in adults and the relationships between cognitive abilities, particularly general cognitive ability, and IT are sufficiently similar in young children and adults to suggest that the new IT task may be a useful tool for research in populations where IT was previously not measurable.     

Can 2‐ and 3‐year‐old children be trained to perform visual perception tasks?

Children aged 2 and 3 years were exposed to a novel paradigm designed to train visual perception skills. The results indicate that children of this age could be trained to perform both percept deprivation and percept diagnosis tasks. Results are discussed with reference to engagement, a precursor to an adult‐like understanding of perception.     

Cognitive components of a mathematical processing network in 9‐year‐old children

We determined how various cognitive abilities, including several measures of a proposed domain‐specific number sense, relate to mathematical competence in nearly 100 9‐year‐old children with normal reading skill. Results are consistent with an extended number processing network and suggest that important processing nodes of this network are phonological processing, verbal knowledge, visuo‐spatial short‐term and working memory, spatial ability and general executive functioning. The model was highly specific to predicting arithmetic performance. There were no strong relations between mathematical achievement and verbal short‐term and working memory, sustained attention, response inhibition, finger knowledge and symbolic number comparison performance. Non‐verbal intelligence measures were also non‐significant predictors when added to our model. Number sense variables were non‐significant predictors in the model and they were also non‐significant predictors when entered into regression analysis with only a single visuo‐spatial WM measure. Number sense variables were predicted by sustained attention. Results support a network theory of mathematical competence in primary school children and falsify the importance of a proposed modular ‘number sense’. We suggest an ‘executive memory function centric’ model of mathematical processing. Mapping a complex processing network requires that studies consider the complex predictor space of mathematics rather than just focusing on a single or a few explanatory factors.     

Cognitive control moderates early childhood temperament in predicting social behavior in 7‐year‐old children: an ERP study

Behavioral inhibition (BI) is a temperament associated with heightened vigilance and fear of novelty in early childhood, and social reticence and increased risk for anxiety problems later in development. However, not all behaviorally inhibited children develop signs of anxiety. One mechanism that might contribute to the variability in developmental trajectories is the recruitment of cognitive‐control resources. The current study measured N2 activation, an ERP (event‐related potential) associated with cognitive control, and modeled source‐space activation (LORETA; Low Resolution Brain Electromagnetic Tomography) at 7 years of age while children performed a go/no‐go task. Activation was estimated for the entire cortex and then exported for four regions of interest: ventromedial prefrontal cortex (VMPFC), ventrolateral prefrontal cortex (VLPFC), dorsal anterior cingulate cortex (dorsal ACC), and dorsal lateral prefrontal cortex (DLPFC). BI was measured in early childhood (ages 2 and 3 years). Anxiety problems and social reticence were measured at 7 years of age to ascertain stability of temperamental style. Results revealed that BI was associated with increased performance accuracy, longer reaction times, greater (more negative) N2 activation, and higher estimated dorsal ACC and DLPFC activation. Furthermore, early BI was only associated with social reticence at age 7 at higher (more negative) levels of N2 activation or higher estimated dorsal ACC or DLPFC activation. Results are discussed in the context of overcontrolled behavior contributing to social reticence and signs of anxiety in middle childhood.