Effects of a mirror on young children's transgression in a gift-delay task.

While the development of self-recognition in a mirror by toddlers is well documented, less is known about how the presence of a mirror affects young children's behaviour. Here, we explored how the presence of a mirror affected 2.5- to 3.5-year-olds' behaviour in a gift-delay task. Behaviour was assessed for a five-minute test period during which children sat in front of a gift bag that was not to be touched until an experimenter returned. Transgressive behaviour by adults is reduced in the presence of a mirror, so we hypothesized that children faced with a mirror would be less likely to touch the gift than children tested without a mirror. We found that the mirror reduced transgressions in children starting from around 3 years of age. We conclude that the presence of a mirror facilitated self-monitoring in 3-year-old children, such that deviations from a behavioural standard are noticed and corrected immediately. Statement of contribution What is already known on the subject? Children's self-recognition in a mirror has been well documented. Adults' behaviour can be affected by the presence of a mirror. There is a lack of research investigating how the presence of a mirror affects young children's behaviour. What does this study add? We show that the presence of a mirror decreases young children's likelihood to transgress in a gift-delay task. This effect appears to emerge at around three years of age. These findings raise interesting questions regarding the development of self-awareness and how it relates to other mechanisms.