Infant Behavior & Development 28 (2005) 418–425 Two-month-old infants of depressed mothers show mild, delayed and persistent change in emotional state after non-contingent interaction Jacqueline Nadel ∗ , Robert Soussignan, Pierre Canet, Guillaume Libert, Priscille G´ erardin La Salpˆ etri` ere Hospital, Unit 7593 CNRS–University Paris 6, Group Psychopathology and Development, 47 Bd de l’H ˆ opital, F-75013, Paris Received 27 September 2004; received in revised form 17 February 2005; accepted 24 March 2005 Abstract The aim of this study was to explore how early infants show different responses to non-contingent maternal behavior according to their past history of relations with their mother. Two groups of 2-month-olds interacted with their mother who was assessed as depressed (group 1) or non-depressed (group 2). Although they received a continuous image and voice of their mothers, the infants were presented either a 30-s contingent maternal communication (live episode 1) or a thirty second non-contingent episode (replay of prior maternal communication), or again a 30-s contingent live episode (live2). The lower percentage of negative facial expressions displayed during replay by infants of depressed mothers suggests on one hand that they are less sensitive to a non-contingent maternal behavior than infants of non-depressed mothers. However, within group comparisons demonstrate a notable difference: while infants of non-depressed mothers show a U curve of smile, infants of depressed mothers show decreasing smile throughout the three episodes. Taken together, these results plead in favour of an other profile of sensitivity displayed by infants of depressed mothers. Instead of the strong but short-term reaction of infants of non-depressed mothers, the response of infants of depressed mothers appeared to be a mild, delayed and more persistent change in emotional state. These findings are discussed in the light of possible cognitive and social incidence of passive avoidance of stressful events in infants of depressed mothers. © 2005 Elsevier Inc. All rights reserved. Keywords: Infant; Emotion; Contingency; Post-partum depression A key parameter of social communication is the capacity to detect and expect partner’s contingency. Numerous studies have been devoted to explore the effect of non-contingent behaviour upon the early socio-cognitive development of infants. Pioneer studies of clinical cases have reported unstable contingency of depressed mothers (Tronick, Als, Adamson, Wise, & Brazelton, 1978). In parallel, other studies have shown that infants of depressed mothers are at risk in their socio-cognitive and emotional development (Hay, 1997; Murray & Cooper, 1997; Tronick & Weinberg, 1997). Put together, these elements have led to postulate the importance of establishing stable contingent relationships for an optimal development of infants’ cognitive capacities to expect events (Nadel & Tremblay-Leveau, 1999). Previous experimental procedures have mostly consisted in simulating all-or-none contingency. Non-depressed ∗ Corresponding author. E-mail address: jnadel@ext.jussieu.fr (J. Nadel). 0163-6383/$ – see front matter © 2005 Elsevier Inc. All rights reserved. doi:10.1016/j.infbeh.2005.03.005