What is the relationship between theory of mind and executive function? My research focuses on this question by examining cognitive development in normal preschoolers. Theory of mind (ToM) is the ability to attribute independent mental states to self and others in order to predict and explain actions. Executive function (EF) is defined as the decision making processes that are necessary to enact goal-directed behavior. These processes may involve planning a flexible action sequence, and inhibiting pre-potent inappropriate responses to salient stimuli (Goldman-Rakic, 1987).

The archetypal task used to evaluate ToM is the false belief task (Wimmer & Perner, 1983). In this task, the subject is asked to predict the action of another, based on the other person's understanding of a situation. The other person's belief is false in that it no longer corresponds to the current state of reality, which is known to the subject. Thus, in order to pass this task, the subject must infer the other person's mental state, which of course does not correspond to the subject's own knowledge. Children usually acquire this ability between the ages of 3 and 4.

Two tasks typically used to measure EF in adults are the Wisconsin Card Sorting Test (WCST) (Heaton, 1981) and the Tower of Hanoi (TOH) (Borys, Spitz & Dorans, 1982). The WCST is a task which measures the ability to flexibly modify incorrect strategies by inhibiting pre-potent, but incorrect, responses. In this task, the subject must sort cards by color, shape, or number. Successful performance requires flexibility in shifting from one problem solving set to another. The TOH is a task measuring planning ability. It consists of three posts, and rings of varying size that must be placed in a particular order on a particular post. Successful performance requires deducing a sequence of moves in advance of action. These tests are administered to adults and adolescents. Using simplified versions of these tests of EF, abilities of pre-potent inhibition and planning skills can be shown as early as preschool.

Why should there be a relationship between ToM and EF, and why is it important? The answer to the first part of the question may not be intuitive upon initial examination of the disparate tasks used to measure ToM and EF. However, if one looks closely at the false belief task, one can show that inhibition and planning are actually important skills that can be used to pass ToM. Thus, one can ask if EF is necessary for successful ToM performance, or is the knowledge of mental states somehow "special?" Why is the hypothetical relationship between ToM and EF important? Elucidating this relationship is important because it may lead to a better understanding of autism. Autism is a developmental disorder characterized by impairments in social interaction and communication, with restrictive and stereotyped patterns of behavior, interests and activities. Along with these behavioral symptoms, recent research has shown that deficits in ToM and EF are also prevalent.

In my research, I have used variants of the false belief task, as well as age-appropriate executive tasks on a sample of normal preschoolers. Preliminary data analyses have shown a relationship between specific components of ToM and EF. In order to find out which components come "on-line" when in normal cognitive development, I am also following some of these children longitudinally. Future work may involve using my experimental paradigm in the autistic population.

References:

Borys, S. V., Spitz, H. H. & Dorans, B. A. (1982). Tower of Hanoi performance of retarded young adults and nonretarded children as a function of solution length and goal state. Journal of Experimental Psychology, 33, 7-110.