In this paper we apply a dynamic systems perspective to infant emotional development. We propose that emotions are not states but self‐organizing dynamic processes intimately tied to the flow of an individual's activity in a context. We review data on the relationship between emotional actions and the social context, in particular the development of smiling and laughter. These data are more adequately explained by our perspective than by other theories of emotional development. We provide a model for how emotional processes in early infancy become embedded into sociocultural systems, and suggest new avenues of research on emotional development.

Disagreement as to whether all smiling or specific types of smiling index positive emotion early in life was addressed by examining when infants produced different types of smiling and other facial expressions. Thirteen infants were observed weekly from 1 to 6 months of age. Smiling alone-without cheek raising or mouth opening-was relatively more likely than periods without smiling both when mothers were smiling and when infants were gazing at their mothers' faces. Cheek-raise (Duchenne) smiling was relatively more likely than smiling alone only when mothers were smiling. Open-mouth (play) smiling was relatively more likely than smiling alone only when infants were gazing directly at mothers' faces. Smiling involving both cheek raising and mouth opening was relatively likely both when mothers were smiling and when infants were gazing at mothers' faces and became increasingly likely with age when both conditions co-occurred. The cheek-raise and open-mouth dimensions of smiling appear to be associated with, respectively, the amplification of processes of sharing positive affect and of visual engagement that are present to a lesser degree in smiling alone.

In positive social contexts, both adults and older infants show more Duchenne smiling (which involves high cheek raising) than non-Duchenne smiling (which does not). This study compared Duchenne and non-Duchenne smiles in early infancy for clues to their emotional significance. Infants (N = 13) from 1 to 6 months of age were videotaped weekly for 5 min in 208 face-to-face interactions with their mothers. Levels of Duchenne and non-Duchenne smiling were correlated within interactive sessions, and the 2 smiles had similar developmental trajectories. Duchenne smiles were typically preceded by non-Duchenne smiles. The results suggest these frequently contrasted types of smiles occur in similar situations and are often different temporal phases of a continuous emotional process. In contrast to adults, infant Duchenne smiles had longer durations than non-Duchenne smiles, suggesting infant smiling does not fit adult models of emotional functioning.

Weekly laboratory observations of free play for 13 middle-income mother±infant dyads, from 1 to 6 months of age, were used to study the synchronization of developmental trajectories between infant postural position and gaze direction. Mothers sat in a straight-backed chair while holding infants on their laps and were free to adjust the infant's posture. Postural position was coded as upright (supported sitting or standing on the mother's lap) or other (lying, cradling, or being held close to mother). Gaze was coded as either at mother's face or away. The age of onset of visually guided reaching was also assessed. Results show that there were longer durations of gazing away when the infant was in an upright position. Over the 5 month period of observation, the dyads began with a pattern of non-upright positions accompanied by gaze at mother. Contrary to previous predictions, the developmental shift in the first 6 months from exclusive gazing at mother's face to gazing away from mother was not synchronized with the development of reaching, but rather with changes in the infant's posture to more upright positions. The possible role of postural position in fostering positive emotional communication is discussed.Adult ± infant face-to-face play consists of mutual gazing and smiling to achieve a unique form of positive emotional communication in early life (Brazelton,

This study examined the relationship between smile type and play type during parent-infant interactions in the home. Thirty-six mother-infant and father-infant dyads were videotaped playing for 10 min. Smile type (basic, Duchenne, and duplay smiles) and play type (object, physical, vocal, and book reading) were coded. Results of loglinear analysis indicated that different types of smiles occur during different types of play more often than expected if distributed equally. In addition, different smile-type and play-type patterns occurred for father-infant dyads compared with mother-infant dyads. Qualitative analyses were used to generate hypotheses about the reasons why different types of smiles occurred during various play activities.