Explaining individual and cross-cultural differences in mirror self-recognition

Mirror self-recognition (MSR) is considered the benchmark of the capacity to think about oneself. Around 18 months of age, infants across cultures vary systematically in their MSR abilities. Understanding the developmental processes that underlie these differences is critical to understanding the ontogeny of human self-awareness. The overarching goal of my dissertation was to identify the early experiences that are linked to infants’ ability to self-recognize, with three independent but linked studies. In study 1, I recruited 18- to 22 months-old infants and their mothers from two distinct sociocultural environments: urban Canada and rural Vanuatu, a small-scale island society located in the South Pacific. Consistent with previous cross-cultural research, ni-Vanuatu infants passed the MSR test at significantly lower rates (7%) compared to Canadian infants (68%). Among a suite of social-interactional variables, mothers’ imitation of their infants during a short free play session with toys best predicted infants’ performance on the MSR test. In addition, low passing rates among ni-Vanuatu infants could not be attributed to reasons non-related to self-development (i.e., motivation to show mark-directed behavior, understanding mirror-correspondence, representational thinking). In study 2, I aimed to replicate my previous results on imitation, this time in a culturally diverse urban Canadian sample of 15- to 21-month-old infants and their parents, in order to bypass potential confounding factors related to the cross-cultural validity of the test. In this study, mothers’ imitation of their infants observed during a short free play session predicted infants’ MSR, while controlling for infants’ temperament. In study 3, I examined whether the referential content of mothers’ child-directed speech systematically differed between ni-Vanuatu and Canadian cultures. When interacting with their 18- to 28-month-olds during a dyadic free play session, Canadian mothers referred significantly more to their toddlers’ mind-minded internal states (e.g., desire), linked toddlers’ internal states to their acts and perceptions, and produced more references to past events. These results bring attention to the role that language interactions may be playing in the emergence of a self-concept. Together, these 3 studies provide evidence that will help us better understand the social-interactional processes underlying the development of self-awareness in infancy.