Windows to Research: Differences in the Minds of Children
Adapted from Carlson, S. M. & Moses, L. J. (2001). Individual Differences in Inhibitory Control and Children’s Theory of Mind. Child Development, 72(4), 1032-1053.
Although you may not realize it, when you trick someone into thinking something that isn’t true, you are performing a complex task that assumes the existence of that person’s mind. For the past two decades researchers have been trying to unpack the mystery of how children develop the understanding that other people have minds of their own. This understanding is often referred to as Theory of Mind (ToM). Children’s understanding of the mind is a foundational domain of cognitive development. It appears that for the first few years of life, children believe that the world parallels what they experience. In essence, the child's world is the only one that exists. A typically developing 3-year old will often perform poorly on experimental tasks that assess the ability to recognize that individuals may perceive the same scene in different ways or that one’s own beliefs may be false. Children at this age often assume that the way something appears or what someone believes is always representative of reality. However, by the age of 5, most children are somehow able to comprehend these situations and tasks in a much more complex and adult-like way.
One potential factor that may play a critical role in the development of ToM is executive functioning. Executive functioning refers to the processes that serve to monitor and control one's thoughts and actions. It allows one to maintain a cognitive distance from the immediate surrounding activities and reflect on the past or look to the future to make decisions. Examples include planning, self-regulation, response inhibition, and error detection and correction. How executive functioning may relate to the development and expression of ToM seems to follow easily. That is, without capacity to distance oneself from current stimuli (in particular, one’s own mind), children would never be able to reflect on representations of others’ minds. Many ToM experimental tasks require children to override their habitual or dominant tendency to refer to reality for an answer and instead choose a conflicting response. If executive functioning does play a critical role in the development of ToM, then individual differences in children’s executive functioning should account for substantial variation in young children’s ToM task performance.
In the present study, the researchers explored individual differences in executive functioning for clues to ToM development. In particular, they identified inhibitory control (IC) as a prime candidate for an executive ability that might relate to ToM development.
Inhibitory control is the ability to restrain responses to stimuli that are unrelated to a mentally represented goal. For example, suppose you are at a restaurant as the dessert tray goes by. You watch as a decadent piece of chocolate cake appears to be calling to you. If you are on a diet, it is necessary to inhibit your desire to order the cake to achieve your greater goal of losing weight. This example is an instance of how you have exercised inhibitory control. There are two general types of tasks that have been used to assess the inhibitory control abilities of preschool children (children between the ages of 3 and 5). First, researchers use tasks that require children to delay an immediate gratification. An example of this task (gift delay) asks children to close their eyes and not peek while the researcher noisily wraps a gift for them. As children age, their ability to withstand longer gift delays without peeking grows. A second task category that is often used for IC assessment requires children to respond a certain way when they are faced with a conflicting more habitual response option. For example, children might be told to answer "night" when they are shown a picture of a sunny day. Similar to the gift-delay tasks, a child's performance on tasks like the day/night task tends to improve with age.
The goal of the research reported here was to take a more in-depth look at how IC might be related to ToM Development. Specifically, researchers tested whether children who had lower inhibitory control ability also had lower ToM scores (and vice versa).
The Study
Participants for this study were 107 preschool age children who were recruited by telephoning parents included in a database of birth announcements. Sixty-two of the children were 3-year-olds (34 boys and 28 girls) and forty-five were 4-year-olds (17 boys and 28 girls). Each child was individually tested and videotaped on ToM tasks and IC tasks.
To test ToM, the researchers used
four measures, two of which were a false-belief task and an appearance-reality
task. The four measures together composed a "Theory-of-Mind
Figure1. Child participating in the false belief task.
In the appearance-reality task, each child was shown two objects that had misleading appearances; the first was a piece of sponge painted to look like a rock and the other a picture of a castle that looked black when held behind a green filter. For each object, children were shown how it appeared as well as its true identity or color. The experimenter repeated to the child that the object appeared one way, but was really another way. Children were then asked the appearance question, "when you look at this right now, does it look (like a sponge/red) or does it look (like a rock/black)?" Children passed the task if they answered both questions correctly.
Figure 2. Child participating in the Appearance/Reality task.
To test IC, the researchers used 10 measures, two of which were a day/night task and a bear/dragon command task. The 10 tasks together composed an "Inhibitory Control Battery." In the day/night task, children were instructed to say "day" when shown a black card with the moon and stars on it, and to say "night" when shown a white card with a yellow sun. Two practice trials (one with each card) were conducted before the test trials. If the child answered incorrectly during the practice trial, the experimenter repeated both instructions to the child and repeated the practice trial. Each child received 16 test trials without feedback in the same random order.
In the bear/dragon command task, children were shown two puppets, a bear and a dragon. After the experimenter verified that the child was able to follow directions for 10 simple tasks (e.g., touch your nose, stick out your tongue, clap your hands), the child was told that the bear was a "nice bear"- "so when he talks to us, we will do what he tells us to do." The dragon was described as a "naughty dragon"-"so when he talks to us we won’t listen to him. If he tells us to do something, we won’t do it." The experimenter then conducted practice trials moving the bear’s mouth and saying in a high pitched voice, "touch your nose" and then move the dragon’s mouth and saying in a low, gruff voice, "touch your tummy." After children demonstrated that they were able to follow/ignore the directions of the bear/dragon (some children required the help of an additional experimenter to follow directions), they were tested on 10 trials (5 bear and 5 dragon) where they were unassisted. Children were scored (from 0 to 3) on each dragon trial where 0 was a full commanded movement, a 1 represented a partial commanded movement, a 2 for a wrong movement, and a 3 for the correct response of no movement.
Figure 3. Child Participating in the Bear/Dragon task.
Results for Theory of
Mind Tasks
The results from this study
confirmed conclusions of previous studies showing that 4-year-olds tend to
outperform 3-year-olds on ToM tasks. Table 1 shows a
comparison of the two age groups. The researchers used a Pearson chi-square
test to determine whether the age cohorts differed from each other. As is clear
from the table, there was a significant age difference for each of the ToM tasks (false belief: p<.001, appearance-reality
(identity): p<.05, and appearance-reality (color): p<.001).
|
Theory of Mind Tasks |
3-Year-Olds (n=62) |
4-Year-Olds (n=45) |
Overall Average (n= 107) |
|
|
|
False Belief |
10% |
49% |
26% |
20.8*** |
|
|
Appearance-Reality |
Identity |
47% |
69% |
56% |
5.2* |
|
Color |
55% |
87% |
68% |
12.2*** |
|
Table 1. Percentage of Children Who Passed Theory-of-Mind Items as a Function of Age. *p<.05, ***p<.001
Results for Inhibitory
Control Tasks
Similarly, 4-year-olds tended to
outperform 3-year-olds on IC tasks. Table 2 shows another comparison of the two
age groups, but representing IC tasks. The researchers used t-tests to test for
age differences. As is evident from Table 2, the three and four-year-olds did
not differ significantly on the day/night test, but did differ significantly
(p<.05) on the bear/dragon command task.
|
Inhibitory Control Tasks |
3-Year-Olds |
4-Year-Olds |
Overall Average |
Age Differences |
|
59.9% |
65.7% |
62.4% |
Not significant |
|
Bear/Dragon Score |
12.1 |
13.9 |
12.9 |
t(105)= 2.0* |
Table 2. Mean Performance on the Inhibitory Control Measures as a Function of Age. *p<.05.
The Theory of
Mind/Inhibitory Control Relationship
The most important finding from this study confirmed the researchers' hypothesis that there is a positive relationship between inhibitory control and theory of mind. As Table 3 shows, there were strong correlations between each of the ToM measures and each of the IC measures. Additionally, even after the researchers controlled for possible confounding variables, partial correlations were significant for all but one comparison. The partial correlation procedure computes correlation coefficients that describe the linear relationship between two variables while controlling for the effects of one or more additional variables. In this study, the partial correlations were calculated while controlling for potentially confounding factors such as age, gender, number of siblings, and verbal ability. As can be seen, the overall IC battery (measure that incorporated all IC tasks) and the ToM battery (measure that incorporated all ToM tasks) were highly correlated (r=.66, p<.001).
|
Inhibitory Control Tasks |
Theory of Mind Tasks |
||
|
False Belief |
Appearance-Reality |
ToM |
|
|
Day/Night |
.33**(.22*) |
.24*(.08) |
.36**(.23*) |
|
Bear/Dragon |
.38***(.17*) |
.49***(.31**) |
.57***(.42***) |
|
IC |
.50**(.20*) |
.57***(.31**) |
.66***(.41***) |
Table 3. Raw (and Partial Correlations) between Inhibitory Control and Theory of Mind Measures. *p<.05, **p<.01, ***p<.001.
From these results the researchers concluded that there is an apparent link between inhibitory control and theory of mind in preschool age children. As a child develops inhibitory control abilities, s/he also develops theory of mind.
Inhibitory control may well be necessary for theory of mind development. However, IC is not sufficient for this advancement. After all, even with a fully mature executive system, children would still have to learn much about mental states for a fully developed ToM. Other aspects of executive functioning, such as planning ability and self-regulation may also be important factors. Nevertheless, these findings support the notion that IC may play a crucial enabling role in both the development and expression of children’s ToM.
Questions
1. What type of study did the researchers conduct?
2. The researchers made a point of distinguishing between 3-year-olds and 4-year-olds in this study. Why?
3. Why is it logical to assume that children need inhibitory control to succeed on theory of mind tasks? Give an example.
4. The researchers found a significant positive correlation between inhibitory control and theory of mind. How should the reader interpret a correlation of .66 between these two measures?
5. What could the researchers conclude if the raw correlations came out statistically significant but not the partial correlations?