Dopaminergic functioning and preschoolers' theory of mind

Representational theory of mind (RTM) development follows a universal developmental timetable whereby major advances in reasoning about mental representations occur between the ages of 3 and 5 years old. This progression appears to be only absent in the case of specific neurodevelopmental impairments, such as autism. Taken together, this suggests that neuromaturational factors may play a role in RTM development. Recent EEG work has shown that one neuromaturational factor pacing this universal developmental timetable is the functional maturation of medial prefrontal cortex. The neurotransmitter dopamine (DA) is thought to play a crucial role in typical frontal lobe development. Therefore, the goal of the present study was to investigate the role that DA may play in RIM development. Ninety-one 48-62-month olds were given a battery of RIM tasks along with EEG measurement. EEG recordings were analyzed for eyeblinks, a reliable indicator of DA functioning, and we calculated their average eyeblinks per minute (EBR). Regression analyses showed that EBR was associated with RIM after controlling for children's performance on a Stroop-like measure, language ability, gender, and age. These findings provide evidence that DA functioning is associated with RTM in the preschool years, and are discussed with respect to how DA might provide a mechanism that helps to account for both neurobiological and experiential factors that are known to affect the timetable of preschoolers' RIM development. (C) 2010 Elsevier Ltd. All rights reserved.