More than a matter of getting ‘unstuck’: flexible thinkers use more abstract representations than perseverators

Why do people perseverate, repeating prior behaviours that are no longer appropriate? Many accounts point to isolated deficits in processes such as inhibition or attention. We instead posit a fundamental difference in rule representations: flexible switchers use active representations that rely on later‐developing prefrontal cortical areas and are more abstract, whereas perseverators use latent representations that rely on earlier‐developing posterior cortical and subcortical areas and are more stimulus‐specific. Thus, although switchers and perseverators should apply the rules they use to familiar stimuli equally reliably, perseverators should show unique limitations in generalizing their rules to novel stimuli, a process that requires abstract representations. Two behavioural experiments confirmed this counterintuitive prediction early in development. Three‐year‐old children sorted cards by one rule, were asked to switch to another rule, and then were asked simply to continue their behaviour, with novel cards. Perseverators applied the rule they were using (the first rule) just as reliably as switchers applied the rule they were using (the second rule) with familiar cards; however, only switchers generalized their rule to novel cards. This finding supports an early link between active representations that support switching and abstract representations that support generalization. We interpret this synergy in terms of prefrontal cortical development.     

Tool use as a way to assess cognition: how do captive chimpanzees handle the weight of the hammer when cracking a nut?

Tool use in apes has been considered a landmark in cognition. However, while most studies concentrate on mental operations, there are very few studies of apes’ cognition as expressed in manual skills. This paper proposes theoretical and methodological considerations on movement analysis as a way of assessing primate cognition. We argue that a privileged way of appraising the characteristics of the cognitive abilities involved in tool use lies at the functional level. This implies that we focus on how the action proceeds, and more precisely, on how the functional characteristics of the task are generated. To support our view, we present the results of an experiment with five captive chimpanzees investigating the way how chimpanzees adapt to hammers of various weights while cracking nuts. The movement performed in the hammering task is analyzed in terms of energy production. Results show that chimpanzees mobilise passive as well as active forces to perform the compliant movement, that is, they modulate the dynamics of the arm/tool system. A comparison between chimpanzees suggests that experience contributes to this skill. The results suggest that in tool use, movements are not key per se, but only in as much as they express underlying cognitive processes. Electronic supplementary material  The online version of this article (doi:) contains supplementary material, which is available to authorized users.

Early development of subcortical regions involved in non-cued attention switching

This study examined the cognitive and neural development of attention switching using a simple forced-choice attention task and functional magnetic resonance imaging Fourteen children and adults made discriminations among stimuli based on either shape or color. Performance on these trials was compared to performance during blocked trials requiring all color or all shape discriminations. Magnetic resonance echo planar images were acquired during performance of the task. Both children and adults showed robust bilateral activity of the caudate nucleus when switching attention between color and shape discriminations that correlated negatively with mean response latency on these trials. However, neither switching costs nor caudate activity correlated with age, suggesting early development of the underlying neural circuitry involved in switching between salient stimulus sets. Overall, children and adults differed in performance and patterns of brain activity on the task, with adults responding more accurately and faster than children, and recruiting more prefrontal and parietal regions. These results suggest an important role of subcortical regions (i.e. caudate nucleus) in non-cued attention switching, with increasing recruitment of cortical regions with age.     

Development of eating behavior by Japanese toddlers in a nursery school: relation to independent walking

The eating behavior of 32 toddlers in a nursery school at 10, 12, and 14 months old was observed in relation to the age at onset of independent walking. With increasing age, the frequency at which the toddlers ate food given by a teacher decreased, and the frequency at which the toddlers ate by themselves increased. The toddlers who started walking earlier also advanced faster in the development of eating behavior. The time when the frequency of eating by oneself surpassed the frequency of passive eating coincided with the time when the toddlers started walking.     

When actions speak louder than words: improving children's flexibility in a card-sorting task

People often perseverate, or repeat habitual behaviors when they are no longer appropriate. For example, after sorting cards by one rule, children will reliably perseverate with this rule even when they are clearly and repeatedly instructed to switch to a new rule. Such perseveration may result from limitations in working memory abilities for holding instructions actively in mind. If so, children may switch more readily to a new rule following experiences that are less demanding on working memory, such as guided practice with the new rule. In a study testing this prediction, 3-year-old children received direct instructions to switch to a new rule, guided practice with the new rule, or both. Providing children with guided practice was much more effective than telling them what to do. These findings support theories of perseveration based on competing memory systems, challenge alternative theories, and suggest effective methods for countering prepotent behaviors.     

Global interference: the effect of exposure duration that is substituted for spatial frequency

In this study, participants were required to identify hierarchically structured patterns that appeared at either global or local level. Paquet and Merikle (1984 Canadian Journal of Psychology 381 45-53) showed that global interference is affected by exposure duration in the processing of a hierarchical structure. They showed that only global-to-local interference occurred at short exposure durations. In contrast, global-to-local as well as local-to-global interference was observed at long exposure durations. They suggested that the effect of exposure duration with global interference depends on the high-spatial-frequency versus low-spatial-frequency channel. In the present study, exposure duration (short or long) was varied randomly from trial to trial (experiment 1), or held constant (experiment 2). In experiment 1, global-to-local interference occurred at both short and long exposure durations, even though the same physical properties existed as in experiment 2. In experiment 2, both global-to-local and local-to-global interference occurred at only long exposure durations, in line with the results reported by Paquet and Merikle. This suggests that the effect of exposure duration on global interference is explained not only by spatial-frequency channels, but also by attentional shift.     

Trust matters: Seeing how an adult treats another person influences preschoolers' willingness to delay gratification

Holding out for a delayed reward in the face of temptation is notoriously difficult, and the ability to do so in childhood predicts diverse indices of life success. Prominent explanations focus on the importance of cognitive control. However, delaying gratification may also require trust in people delivering future rewards as promised. Only limited experimental work has tested this idea, and such studies with children were focused on general reward expectations, so evidence was ambiguous as to whether social trust played a role. The present study provides the first targeted test of a role for social trust in children's willingness to delay gratification. Children observed an adult behave in either a trustworthy or untrustworthy manner toward another adult, then were tested in the classic delay of gratification task by that adult. Children were less likely to wait the full delay period, and waited less time overall, for a reward promised by an untrustworthy adult, relative to children tested by a trustworthy adult. These findings demonstrate that manipulations of social trust influence delaying gratification, and highlight intriguing alternative reasons to test for individual differences in delaying gratification and associated life outcomes.     

Sociability modifies dogs’ sensitivity to biological motion of different social relevance

Preferential attention to living creatures is believed to be an intrinsic capacity of the visual system of several species, with perception of biological motion often studied and, in humans, it correlates with social cognitive performance. Although domestic dogs are exceptionally attentive to human social cues, it is unknown whether their sociability is associated with sensitivity to conspecific and heterospecific biological motion cues of different social relevance. We recorded video clips of point-light displays depicting a human or dog walking in either frontal or lateral view. In a preferential looking paradigm, dogs spontaneously viewed 16 paired point-light displays showing combinations of normal/inverted (control condition), human/dog and frontal/lateral views. Overall, dogs looked significantly longer at frontal human point-light display versus the inverted control, probably due to its clearer social/biological relevance. Dogs’ sociability, assessed through owner-completed questionnaires, further revealed that low-sociability dogs preferred the lateral point-light display view, whereas high-sociability dogs preferred the frontal view. Clearly, dogs can recognize biological motion, but their preference is influenced by their sociability and the stimulus salience, implying biological motion perception may reflect aspects of dogs’ social cognition.