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theses

Our social world is complex and often includes multiple individuals with distinct thoughts or beliefs. Can preschoolers use their theory of mind to track the mental states and predict the actions of multiple individuals taking part in the same scenario? Theory of mind ability is traditionally tested in preschoolers using a single-agent false-belief task. In the main task, the Sally-and-Anne task, four-year-olds typically “pass” by predicting that an agent will search in accordance with her false belief, while three-year-olds typically “fail” by predicting that an agent will search in accordance to the child’s own belief. Some argue that three-year-olds’ failures are due to a conceptual deficit while others reason that failures are due to processing (e.g., executive function) demands such as working memory (WM) and inhibition. This suggestion of WM limitations in preschool theory of mind has never been directly tested, so we do not know what the WM limit for theory of mind may be nor whether it plays a role in limiting three-year-olds’ performance. The dissertation summarizes a series of seven studies designed to test preschoolers’ multiple-agent theory of mind on four WM levels: two, three, four, and five agents each with distinct false beliefs combined with two levels of inhibition: low and high. The traditional single agent false belief task is tested with a binary response, pass/fail. This all but precludes the study of error patterns. Multiple agent false belief tasks, on the other hand, can for the first time provide data on how children fail when they fail, that is, provide for error analysis. We calculate the number of possible responses in a false belief task by raising the number of beliefs to the power of the number of agents, BA. For example, with two agents, there are three possible beliefs (two false and one true) to the power of two agents (Sally and Anne), BA=32. Of these nine responses, only one is ever fully correct and the remaining are errors of varying sorts. Although the number of responses differs across seven experiments, the two most common responses for both age groups were attributing the correct false belief to all of the agents and attributing the child’s own (true) belief to all of the agents. Inhibitory demand played the largest role in determining preschoolers’ performance across age groups: three-year-olds’ performed poorly in all of the high-demand tasks. In the low demand tasks, by contrast, differences between threes and fours were diminished or were absent. WM appeared to have an independent and incremental effect: three-year-olds’ performance appeared to drop off only when they were required to track four agents with distinct false beliefs while four-year-olds’ performance suffered with five agents. In both cases, evidence for a drop off appeared only in shifting error patterns rather than in their fully correct responding. These results strongly establish that WM capacity does not limit three-year-olds’ performance in the single-agent false-belief task. In sum, preschoolers are capable of tracking from three to five agents each with distinct false beliefs and acting within the same scenario. For every additional agent, the cognitive load increases only slightly in comparison to the inhibitory demand of the standard Sally and Anne task. Theory of mind may have evolved to permit young children to track individuals in a small family-sized group.

ETD_8593

Ph.D.

Includes bibliographical references

by Michelle Cheng

doi:10.7282/T3FX7DNK

ETD doctoral

The author owns the copyright to this work.