How some infant smiles get made

Developmental change is the cumulative product of individual events taking place in brief moments in time. This study identifies factors that play a role in moment-to-moment smile production at 8 months of age, and that might contribute to the development of 'anticipatory' smiling-smiling then turning the smiling face towards another-which appears in the second half of the first year. In Experiment 1 (N = 20), mothers' attention promotes infants' smiling during looks to mother from a distance. In Experiment 2 (N = 16), we identify infant and maternal behaviors that positively predict these smiles. An account is proposed whereby three factors-infants' looking to mother, infants' active toy play, and mothers' social responses during infant looks-come together to produce infant smiles at 8 months and to promote the development of 'anticipatory' smiles thereafter.