Young Infants´ Sensitivity to Social Contingency from Mother and Stranger: Developmental Changes

We investigated whether 1- and 4-month-old infants are sensitive to social contingency from mother and stranger via DV live-replay paradigm. The result indicated that 1-month-old infants could detect mother´s non-contingency. Four-month-olds infants might be able to use smile as a social tool to make a stranger´s response contingent again. We defined that there are two subdivision components in sensitivity to social contingency such as detection and expectancy. Detection is a basic ability, and expectancy is an ability what infants form to partner´s contingency. Development of detection may be earlier than that of expectancy. Those two components are necessary for development of sensitivity to social contingency. Using smile as a social tool is one of applied abilities, and it develops later. We also found that infants´ interest in mother and stranger differed in two age groups. One-month-old can only detect mother´s unusual responses but not stranger´s. By age of 4 months, infants became more sensitive to contingency from strangers because they are interested in strangers more