Early sensitivity to interpersonal timing Anne Henning Max-Planck-Institute for Evolutionary Anthropology Cultural Ontogeny Department Deutscher Platz, 6 04103 Leipzig henning@eva.mpg.de Tricia Striano Max-Planck-Institute for Evolutionary Anthropology Cultural Ontogeny Department Deutscher Platz, 6 04103 Leipzig Abstract Sensitivity to timing in interaction was assessed in mother-infant interaction. In Study 1, three-month- old infants were presented with an image of their mother interacting with them on television, which was either live or temporally delayed by 1 second. Infants detected the temporal delay and were more attentive when the mother was presented live compared to delayed by 1 second. In Study 2, mothers interacted with an image of their three- month-old infant, which was either live or temporally delayed by 1 second. Mothers did not respond to a 1- second delay in their infants' behavior. In Study 3 and 4, the results were replicated with six-month-old infants. 1. Introduction Interpersonal timing is a crucial aspect of human communication and intersubjectivity. Temporal coordination of behavior, i.e., changes in the timing of one individual's behavior in relation to timing of another’s behavior, has been called the "bedrock of all social interaction" (Crown, Feldstein, Jasnow, Beebe, & Jaffe, 2002). In early caregiver-infant interactions interpersonal timing is likely essential for mutual attunement (Rochat & Striano, 1999). Parental responses generally occur within 1-2 seconds after the infants' behavior (e.g., Keller, Lohaus, Völker, Cappenberg, & Chasiotis, 1999). Interestingly, this timing falls within the 3-second time interval that infants require to detect a contingent relation between their own actions and an outcome (Watson, 1967). Temporal contingency is likely an independent component of parenting behavior, i.e., promptness of maternal behavior is not associated with warmth and affection (Keller et al., 1999). However, in prior research on infant sensitivity to social contingencies in interaction, timing of responses has never been assessed alone (e.g., Murray & Trevarthen, 1985; Nadel, Carchon, Kervella, Marcelli, & Réserbat- Plantey, 1999). In the present series of studies, therefore, we assessed three- and six-month-old infants' and caregivers' sensitivity to interpersonal timing by using a new paradigm, in which only the timing of responses was manipulated 1 . 2. Method A double closed-circuit color monitor system was built similar to that used by Murray and Trevarthen (1985). Mothers and infants interacted over a double video system in real time and temporal delays of 1 second were implemented within the on-going interaction. The caregiver’s image was transmitted to the infants’ monitor and vice versa. A steel frame supported a TV monitor facing down. The image was reflected onto a one-way mirror, positioned diagonally in the steel frame and reflecting the partner's video image at eye level. Digital video cameras filming the interaction were positioned at eye level behind the mirrors so as to enable eye contact. The 4- minute interaction was separated into two 2-minute seamless segments. For 2 minutes the dyad interacted in real time (Live condition), and for 2 minutes the image and voice of one partner was temporally delayed (Delay condition). Conditions were counterbalanced. The audio delay was consistent with the image in the delay condition. In Study 1 and 3, three- and six-month-old infants interacted with an image of their caregiver, which was live or delayed by 1 second (Ns = 34 and 29 respectively). In Study 2 and 4, caregivers interacted with an image of their 3- or 6- month-old infant, which was live or delayed by 1 second (Ns = 33 and 26 respectively). 3. Results and Discussion The amount of time the partners gazed, smiled and vocalized to each other was coded. General Linear Mixed 1 The presented data is currently submitted for publication (Striano, Henning, & Stahl). 145 In Berthouze, L., Kozima, H., Prince, C. G., Sandini, G., Stojanov, G., Metta, G., and Balkenius, C. (Eds.) Proceedings of the Fourth International Workshop on Epigenetic Robotics Lund University Cognitive Studies, 117, ISBN 91-974741-3-4