Executive Function in Young Children and Chimpanzees (Pan troglodytes): Evidence From a Nonverbal Dimensional Change Card Sort Task

In this article the authors compared chimpanzees’ executive function with that of children. They developed a nonverbal dimensional change card sorting task, which indexed the development of executive function. Three pairs of mother and offspring chimpanzees and 30 typically developed 5-year-old children were presented with 2 target stimuli and a test stimulus comprising 2 dimensions (size and shape) on a display; they were required to sort the test stimulus according to 1 dimension (e.g., shape). After 5 consecutive correct trials, the participants had to sort the test stimulus according to the other dimension (e.g., size). The results showed that the chimpanzees often failed to sort the test stimuli according to the first and reversed dimensions. On the other hand, the children were correctly able to use both dimensions. These results indicate that chimpanzees may have less developed executive skills than children.     

Positive affect facilitates task switching in the dimensional change card sort task: Implications for the shifting aspect of executive function

Using the modified Dimensional Change Card Sort task, we examined the influence of positive affect on task switching by inspecting various markers for the costs, including restart cost, switch cost and mixing cost. Given that the executive-control processes that underlie switching performance—i.e., inhibition or shifting—are distinct from the component processes that underlie non-switching performance—i.e., stimulus evaluation, resource allocation or response execution—we hypothesised that if positive affect facilitates task switching via executive-control processes, rather than via component processes, positive affect would reduce both switch and restart costs, but not mixing cost, because both switch and restart costs rely on executive processes, while mixing cost imposes only minimal demands on executive processes. We found beneficial effects of positive affect on both restart and switch costs, but not on mixing costs. These results suggest that positive affect improves switching abilities via executive processes rather than via component processes.     

The facilitative effect of positive stimuli on 3-year-olds’ flexible rule use

This study examined the effect of emotional stimuli on 3- to 4-year old children's flexible rule use, as measured by the Dimensional Change Card Sort (DCCS). In Experiment 1, children in two countries (Canada and China) were given 2 versions of the DCCS. The Standard version required children to sort red and blue boats and rabbits first by shape and then by color (or vice versa); the Emotional Faces version required children to sort happy and sad male and female faces first by emotion and then by gender (or vice versa). Children performed significantly better on the Emotional Faces version, and performance on the 2 versions was related. Order in which dimensions were presented had no effect. Experiment 2 examined which aspects of the emotional faces were responsible for the facilitation of children's performance. Performance on the Standard version was compared to performance on three contextual faces versions, in which children were shown happy, sad, or neutral faces and required to sort them by age (child versus adult) and then by gender (or vice versa). Facilitation was only seen in the context of happy faces. Results are consistent with the suggestion that positive stimuli promote cognitive flexibility, perhaps by increasing dopamine levels in prefrontal cortex.     

Two types of perseveration in the Dimension Change Card Sort task

In the Dimension Change Card Sort (DCCS) task, 3-year-olds can sort cards well by one dimension but have difficulty in switching to sort the same cards by another dimension when asked; that is, they perseverate on the first relevant information. What is the information that children perseverate on? Using a new version of the DCCS, the experiments in this article reveal that there are two types of perseverators: those who perseverate at the level of dimensions and those who perseverate at the level of values (stimulus features). This novel finding has implications for theories of perseveration.     

Performance Effects of Reward-Related Feedback on the Dimensional Change Card Sort Task

The Dimensional Change Card Sort (DCCS) is one of the most widely used measures of preschool executive function, yet relatively little is known about how altering emotional demands of the task affects DCCS performance. This study examined the effects of emotionally evocative reward-related feedback on preschool children's performance on the DCCS in a sample of 105 children aged 3.5–4.5 years. In a within-subjects design, children completed the standard DCCS and a modified version of the DCCS in which sticker rewards were gained or lost after each trial. With a reward at stake, children were more accurate but had slower reaction time on the post-switch DCCS. Another sample (N = 20) of 3.5- to 4.5-year-olds who completed the standard DCCS twice without reward showed no change in performance, indicating results are not due to practice effects. Findings demonstrate preschool children's ability to adjust their approach to the DCCS in the presence of emotionally evocative reward-related feedback by prioritizing accuracy over speed. Trial-by-trial reward-related feedback may facilitate cognitive control in early childhood.     

Perspective taking and cognitive flexibility in the Dimensional Change Card Sorting (DCCS) task

In a study with 79 3-year-olds, we confirm earlier findings that separating the sorting dimensions improve children's performance on the Dimensional Change Card Sorting (DCCS) task. We also demonstrate that the central reason for this facilitation is that the two sorting dimensions are not integral features of a single object. Spatial separation of the sorting dimensions has no additional significant influence. This finding highlights the important role of objects with respect to children's attentional flexibility. Implications for current theories on the DCCS task and for the development of perspective taking and cognitive flexibility are discussed.     

3～4岁幼儿认知灵活性实验研究

采用维度变化卡片分类测验,对3~4岁儿童进行认知灵活性测试。根据测验结果发现在标准版本与全部变化版本间存在十分显著差异,在部分变化版与全部变化版本间同样存在十分显著差异,而在标准版本与部分变化版本间差异不显著。性别之间在后转换阶段成绩存在显著差异。年龄之间在前转换阶段成绩存在显著差异,这就表明3岁幼儿当需要在两套不相容的规则之间进行灵活的转换时遇到了困难,即前转换阶段激活了的规则保持在后转换阶段中。超过3岁到4岁间的幼儿比低于3岁或刚3岁的幼儿分类成绩要好。