执行功能和尺寸变化卡排序任务

Developing executive function is one of the key challenges faced by children as they age.

For example, a child must use several executive processes to stop playing with toys and start cleaning their room. Such processes include: inhibition—stopping what they’re doing, planning—the actions needed to clean the room, and attentional control—staying on task until the cleaning is done.

A breakdown of executive function during any of these steps would lead to the room remaining messy.

Importantly, decision-making processes improve across normal development, as associated brain regions—like the prefrontal cortex—mature slowly, well into an individual’s twenties.

This video demonstrates how to assess executive function in children—ages 3 to 5 years—by discussing the steps required to set-up and run an experiment involving the Dimensional Change Card Sort Task, as well as how to analyze the data and interpret the results.

In the Dimensional Change Card Sort Task, children switch from sorting cards by one feature to another. In this case, two target cards consist of a red boat and a blue rabbit and the 16 test cards are split evenly between pictures of red rabbits and blue boats.

This task consists of three phases. During the demonstration phase, each child is introduced to the target cards and the rules of the game. For example, in the color game, all cards of the same color go in the tray with the same color of target card.

Following the demonstration phase, children are exposed to the pre-switch phase—where patterns of thinking and attention are developed by learning to pay special attention to one feature, such as color, and to ignore the other, shape.

Once six test cards are sorted, children move on to the post-switch phase, where the game is changed from color- to shape-sorting.

This phase requires children to shift their attention to a new dimension, which they had been actively ignoring, and to overcome their tendency to perform the same physical actions. The number of correct responses during the post-switch phase trials is the dependent variable.

Three-year-olds typically have a very difficult time transitioning from the first game to a new game because they fail to inhibit their recently learned patterns of thinking and acting.

In contrast, most 5-year-olds do not have a problem transitioning to the new game, which suggests their emerging development of executive function.

Prior to the arrival of participants, make sure a chair and table are set-up with two trays and the target and test cards. Ensure the test cards are pseudo-randomized so that two cards of the same type are not in a row and that the first two cards contain a red rabbit and a blue boat.

After greeting the child, instruct him to sit within view of the trays and target cards. Next, describe the two target cards: Here is a blue rabbit and here is a red boat.

Introduce the pre-switch rules for the color game: Now, we’re going to play a card game. In the color game, all the blue ones go here, and all the red ones go here.

Draw a test card to demonstrate the rules to the child, label its color aloud, and then place it face down into the appropriate tray.

After repeating the rules, pick another card and label it. Then hand the card to the child and encourage him to place it face down in the appropriate tray, and help if necessary.

Following the demonstration phase, introduce the pre-switch rules: select a card, label it for the child, and then ask him to sort it.

Once the child completes six trials, transition to the post-switch phase. Explain the rules now based on shape: Now we’re going to play a new game. We’re going to play the shape game. In the shape game, all the rabbits go here, and all the boats go here.

For the remaining six cards, select one, label it by shape, and hand it to the child for placement.

After the last card has been placed, thank the child for their participation.

To analyze the results, determine the number of correct responses during the post-switch trials for each child in the study and graph the mean results by age group.

A child that scores 80% or more on post-switch trials is said to have passed the Dimensional Change Card Sort Task assessment of executive function. As predicted, on average, the 5-year-olds passed, while the younger 3-year-olds did not, which highlights a critical age for the progression of executive function.

Now that you are familiar with the Dimensional Change Card Sort Task to evaluate children’s executive function, let’s look at other ways that experimental psychologists use it.

Researchers use permutations of this task diagnostically to identify children with particularly poor executive function, which can be indicative of developmental delay or a clinical disorder, such as ADHD or Autism Spectrum Disorder.

In addition, researchers examine decision-making in early adulthood because the prefrontal brain regions are still developing. This lag partly explains how even smart individuals make poor decisions—like choosing the short-term benefits of going to a party over the long-term benefits of studying for a test.

Other researchers have combined the Dimensional Change Card Sort Task and functional magnetic resonance imaging in order to investigate the role of various brain regions in executive function. Findings that suggest age-related differences in connectivity within areas, especially the lateral prefrontal and anterior cingulate cortices, provide insights into the neural mechanisms involved in card sorting performance.

You’ve just watched JoVE’s introduction to the development of executive function using the Dimensional Change Card Sort Task. Now you should have a good understanding of how to setup and perform the experiment, as well as analyze and assess the results.

Thanks for watching!