To date, there is compelling evidence to show that theory-of-mind development is influenced by different environmental and cognitive factors. However, despite our understanding of the different individual processes that facilitate theory-of-mind acquisition, what remains relatively unclear is how these processes operate together during development. The goal of the present dissertation is to examine mediation (examines the relationship between two different factors and address the question of “why” or “how” one variable predicts or causes an outcome variable) and moderation (examines “when” or “for whom” a variable most strongly predicts or causes an outcome variable) processes that can help explain why and under what conditions environmental and cognitive factors are important for theory-of-mind development. The investigation began by examining the influence of environmental factors on theory-of-mind development. Mediation analyses were used to examine “why” environmental factors such as family (i.e., family risk) and socio-linguistic factors (i.e., parental cognitive talk), may be important for theory-of-mind development. Preliminary results demonstrated possible mediated effects of both family risk and parental cognitive talk on theory of mind. That is, family risk may delay children’s theory-of-mind development by impeding the rate of language acquisition, whereas parental cognitive talk may facilitate more advanced theory-of-mind understanding by encouraging more parent-child reciprocity during conversations. Next, the effects of cognitive factors on theory-of-mind development were explored. Moderation analysis was used to examine under what conditions children’s language abilities and conflict inhibition skills (children’s ability to inhibit a prepotent response while responding with a less salient response) are important for theory-of-mind acquisition. Although there may be limited effects of child language and conflict inhibition on early theory of mind, advanced theory-of-mind understanding such as false belief requires both. However, optimal effects of child language on false-belief understanding occurred when children also had high levels of conflict inhibition ability. These findings suggest that effects of child language on false belief are contingent on children’s conflict inhibition skills. Finally, to investigate how environmental and cognitive factors operate together during theory-of-mind development, moderation analysis was conducted to examine whether delays in language and/or conflict inhibition can be compensated for by more exposure to parental cognitive talk (and vice versa) during theory-of-mind acquisition. Although there was no evidence to suggest compensatory effects, results demonstrated that child language and parental cognitive talk both independently contributed to theory of mind. These findings suggest that environmental (e.g., parental cognitive talk) and cognitive factors (e.g., child language) play distinct roles during theory-of-mind development. Overall, these results demonstrate the value of understanding theory-of-mind development from a bioecological perspective where children are both directly and indirectly influenced by multiple mechanisms during theory-of-mind development.

To date, there is compelling evidence to show that theory-of-mind development is influenced by different environmental and cognitive factors. However, despite our understanding of the different individual processes that facilitate theory-of-mind acquisition, what remains relatively unclear is how these processes operate together during development. The goal of the present dissertation is to examine mediation (examines the relationship between two different factors and address the question of “why” or “how” one variable predicts or causes an outcome variable) and moderation (examines “when” or “for whom” a variable most strongly predicts or causes an outcome variable) processes that can help explain why and under what conditions environmental and cognitive factors are important for theory-of-mind development. The investigation began by examining the influence of environmental factors on theory-of-mind development. Mediation analyses were used to examine “why” environmental factors such as family (i.e., family risk) and socio-linguistic factors (i.e., parental cognitive talk), may be important for theory-of-mind development. Preliminary results demonstrated possible mediated effects of both family risk and parental cognitive talk on theory of mind. That is, family risk may delay children’s theory-of-mind development by impeding the rate of language acquisition, whereas parental cognitive talk may facilitate more advanced theory-of-mind understanding by encouraging more parent-child reciprocity during conversations. Next, the effects of cognitive factors on theory-of-mind development were explored. Moderation analysis was used to examine under what conditions children’s language abilities and conflict inhibition skills (children’s ability to inhibit a prepotent response while responding with a less salient response) are important for theory-of-mind acquisition. Although there may be limited effects of child language and conflict inhibition on early theory of mind, advanced theory-of-mind understanding such as false belief requires both. However, optimal effects of child language on false-belief understanding occurred when children also had high levels of conflict inhibition ability. These findings suggest that effects of child language on false belief are contingent on children’s conflict inhibition skills. Finally, to investigate how environmental and cognitive factors operate together during theory-of-mind development, moderation analysis was conducted to examine whether delays in language and/or conflict inhibition can be compensated for by more exposure to parental cognitive talk (and vice versa) during theory-of-mind acquisition. Although there was no evidence to suggest compensatory effects, results demonstrated that child language and parental cognitive talk both independently contributed to theory of mind. These findings suggest that environmental (e.g., parental cognitive talk) and cognitive factors (e.g., child language) play distinct roles during theory-of-mind development. Overall, these results demonstrate the value of understanding theory-of-mind development from a bioecological perspective where children are both directly and indirectly influenced by multiple mechanisms during theory-of-mind development.