Four- and 7-month-old infants' sensitivities to contingency during face -to -face social interactions

Although infants' abilities to perceive contingencies within perceptual-cognitive contexts have been established, their sensitivities to contingency during social interactions are less well delineated. The present research consisted of three experimental and two control studies. Studies 1 and 2 confirmed that 7- and 4-month-olds could perceive and learn a contingent relationship during social adult-infant interactions. Infants in the contingent condition were reinforced through standardized tactile stimulation for gazing at an experimenter's neutral face. Yoked infants in the noncontingent condition received the same tactile stimulation regardless of their behaviours. Infants in the contingent condition learned the contingency; their level of gazing at the face was higher, and gazing away was lower, relative to infants in the noncontingent condition. Study 3 extended these results into more natural touch-alone interactions with 4- and 7-month-olds and their mothers. Mothers in the contingent condition played naturally with their infants using only touch. Mothers in the noncontingent condition imitated the touching of mothers in the contingent condition. Reliability measures and control studies confirmed that mothers in the noncontingent condition successfully imitated mothers in the contingent condition. Results revealed that 4- and 7-month-olds in the noncontingent condition displayed higher and more variable amounts of gazing away than infants in the contingent condition who exhibited lower, more stable, gazing away. Infants in the noncontingent condition displayed a linear increase in their fretting whereas infants in the contingent condition displayed low, stable amounts of fretting. During the normal period following the contingent or noncontingent interaction period, infants in the noncontingent condition spent more tune fretting than infants in the contingent condition, and they exhibited a decrease in their fretting, indicating slower re-engagement with their mothers. In contrast, infants in the contingent condition displayed low, stable amounts of fretting. These results indicate that by 4 months of age infants are capable of perceiving, and respond differently to, the presence or lack of contingency during social interactions. Further, infants' motivations to engage in subsequent interactions after participating in noncontingent interactions may be compromised. Implications for infants' social awareness and the optimal contexts for their normal socio-emotional development are discussed.