Right–left approach and reaching arm movements of 4-month infants in free and constrained conditions

Recent theories on the evolution of language (e.g. Corballis, 2009) emphazise the interest of early manifestations of manual laterality and manual specialization in human infants. In the present study, left- and right-hand movements towards a midline object were observed in 24 infants aged 4 months in a constrained condition, in which the hands were maintained closed, and in a free condition. A left-hand dominance for approach movements without contact with the object, and a right-hand dominance for reaching movements with object contact was observed in the free condition. In the constrained condition reaching movements of the right hand decreased dramatically. These results are interpreted as strong evidence of manual specialization in 4-month olds, with approach movements having a localization role and reaching movements announcing future right-hand dominance for prehension and object manipulation.     

Emergence of amae crying in early infancy as a possible social communication tool between infants and mothers

Amae is defined as “wishing to be loved (Scheidlinger (1999). The Journal of the American Academy of Psychoanalysis, 27(1), p. 91)”. Amae crying is known as crying of infants when seeking intimate emotional communication with caregivers. The objective of this study was to delineate when and how amae crying emerges in early infancy. Crying episodes of four infants were observed bimonthly, in the natural context of their homes, from birth to 6 months of age, for approximately 60 min per session. Crying episodes (total = 275) as determined by two coders were analyzed with respect to several behavioral measures. Results indicated that amae crying emerged at the age of 2 months, and consistently accounted for 30–40% of the total crying episodes after the ages of 3 months. Amae crying could be accurately identified when infants were not in acute discomfort and had already got the attention of their mothers. At such times, infants did not shed tears, cried with a fussy voice, and frequently looked at their mothers. Mothers responded to amae crying more promptly than they did to other types of crying behaviors. It is concluded that 3 months of age, when infants probably begin to use crying as a social communication tool is a major turning point for crying behavior from the perspective of its biological and social roles. It is suggested that amae crying might play an important role in strengthening and encouraging mother–infant interactions.     

The impact of prenatal serotonin reuptake inhibitor (SRI) antidepressant exposure and maternal mood on mother–infant interactions at 3 months of age

Exposure to maternal depression increases risks for altered mother–infant interactions. Serotonin reuptake inhibitor (SRI) antidepressants are increasingly prescribed to manage antenatal maternal illness. The impact of SRIs on early mother–infant interactions was unknown. Three-month-old infants of 32 depressed mothers treated with SRI medications during pregnancy and 43 non-medicated mothers were studied. Using an established face-to-face mother–infant interaction paradigm, dyad interactions were studied with and without a toy. Videotaped sessions yielded 4 measures: maternal sensitivity, dyadic organization, infant readiness to interact, and maternal interruptive behaviors. Even with prenatal SRI treatment, depressed mothers interrupted their infants more during toy play. In the absence of prenatal SRI treatment, maternal postnatal depression adversely influenced infant behavior. Higher levels of maternal depression symptoms at 3 months predicted poorer infant readiness to interact during the toy session. Conversely, in the SRI-exposed group, higher prenatal depression scores predicted greater infant readiness to interact at 3 months. Increased infant readiness with SRI exposure suggests a “fetal programming effect” whereby prenatal maternal mood disturbances shaped a future response to a postnatal depressed maternal environment.     

Social referencing in infants of mothers with symptoms of depression

The present study examined the acquisition of social referencing skills in infants of mothers with symptoms of depression (n = 44). We aimed to determine if a short discrimination training could facilitate infants’ social referencing. Mothers were instructed to pose either joyful or fearful facial expressions to cue infants’ approach/avoidance responses toward an ambiguous object. Maternal expressions were correlated with pleasant or unpleasant events occurring after the infant's response. The results showed that after the intervention, infants looked at their mothers more frequently and reached or avoided the ambiguous object based on the preceding maternal expression. The results suggest that discrimination training procedures can establish social referencing in infants of mothers with symptoms of depression.     

Temperamental precursors of infant attachment with mothers and fathers

The degree to which parent sensitivity and infant temperament distinguish attachment classification was examined. Multilevel modeling was used to assess the effect of parent sensitivity and infant temperament on infant–mother and infant–father attachment. Data were collected from mothers, fathers, and their infants (N = 135) when the infant was 3-, 5-, 7-, 12-, and 14-months old. Temperament was measured using the Infant Behavior Questionnaire-Revised ( Gartstein & Rothbart, 2003); parent sensitivity was coded during the Still Face Paradigm ( Tronick, Als, Adamson, Wise, & Brazelton, 1978); attachment was coded using the Strange Situation ( Ainsworth, Blehar, Waters, & Wall, 1978). Results indicate that mothers and fathers were less sensitive with insecure-avoidant infants. Whereas only one difference was found for infant–mother attachment groups and temperament, five significant differences emerged for infant–father attachment groups, with the majority involving insecure-ambivalent attachment. Infants classified as ambivalent with fathers were higher in perceptual sensitivity and cuddliness and these infants also showed a greater increase in low-intensity pleasure over time compared with other infants. Results indicate the importance of both parent sensitivity and infant temperament, though operating in somewhat different ways, in the development of the infant–mother and infant–father attachment relationship.     

Feature or location? Infants and adults adopt different strategies to search for a hidden toy in an ambiguous task

Evidence suggests that infants and adults attribute different importance to certain object properties when performing object-directed actions. Namely, infants tend to rely on information about an object's location, whereas adults are more likely to base their actions on its features. In this study, we tested whether the strategic choices of infants (aged 13 months) and adults would be modified by the context of the demonstration. Participants watched as an experimenter hid a ball under one of two different coloured containers, using either a communicative or a non-communicative manner. Then, the locations of the two containers were changed out of sight of the participant. During the test, participants were encouraged to look for the ball under one of the containers. We found that adults were more likely to follow a feature-based strategy than infants. However, there was no effect of the context of the demonstration, suggesting that communication may play different roles in encoding object properties and directing overt behaviour.     

Physical activity in infants with Down syndrome receiving a treadmill intervention

Despite the recognized relevance of physical activity in the development and health of children, assessment of physical activity levels (PA-level) in infancy is limited, especially in infants with Down syndrome (DS). Increasing PA-level using a treadmill training (TMT) intervention may benefit infants with motor delays. The purpose of this study was to investigate whether a higher intensity, individualized TMT protocol (HI) would elicit immediate and short-term higher PA-level in infants with DS than a lower intensity, generalized training protocol (LG).Thirty infants with DS were randomly assigned to the LG or the HI group. Training was terminated when the infants could walk three steps independently. Activity monitors were placed on infants’ trunks and legs for a 24-h period every other month during the intervention phase, and at set intervals 1-year post-independent walking onset. Data were analyzed to separate sedentary-to-light activity (Lowact) and moderate-to-vigorous activity (Highact).Overall our results demonstrate that infants receiving the HI TMT had higher levels of Highact than infants in the LG group, factoring out the activity produced by the intervention itself. Infants in the LG group spent more time in Lowact than the HI group. In addition, these results seemed to be retained during the post-intervention follow-up. Despite these exciting results, more work is needed to understand the relationship of the intensity of TMT on PA-level in infants with DS, and whether PA-level and TMT are related to motor milestone achievement and/or health benefits.     

Newborn right-holding is related to depressive symptoms in bottle-feeding mothers but not in breastfeeding mothers

This study examines the relationships between infant holding preferences and maternal depression according to the newborn feeding mode. Links between depression and infant holding biases have been observed in mothers [Vauclair, J., Scola, C. (in press). Dépression, alexithymie et latéralisation dans la fa?on de porter un nouveau-né [Infant holding biases in relation to depression, alexithymia and laterality]. Annales Médico-psychologiques; Weatherill, R. P., Almerigi, J. B., Levendosky, A. A., Bogat, G. A., von Eye, A., & Harris, L. J. (2004). Is maternal depression related to side of infant holding? International Journal of Behavioral Development, 28, 421-427] but the fact that breastfeeding has never been studied in relation to these two factors is surprising as breastfeeding has some influence on depression (e.g., [Mezzacappa, E. S., Guethlein, W., Vaz, N., & Bagiella, E. (2000). A preliminary study of breast-feeding and maternal symptomatology. Annals of Behavioral Medicine, 22, 71-79]) and must also affect holding biases. Mothers who just gave birth (N=100) were tested few days after delivery. Measures of handedness, infant holding-side preferences, and level of depressive symptoms expressed by mothers (assessed with the CES-D scale) were collected via questionnaires. Asymmetries in emotional perception were assessed via a Chimeric Figure Task and a Dichotic Listening Task. Results showed that breastfeeding (1) reduced left-side bias for holding newborns and (2) was associated with lowest levels of depressive symptoms. Moreover, holding biases were related to maternal depression in bottle-feeding but not in breastfeeding mothers, namely that holding on the right-side while bottle-feeding was associated with higher levels of depressive symptoms. These results were not due to hemispheric specialization as auditory and visual asymmetries were similar between breastfeeding and bottle-feeding mothers. The discussion emphasizes the striking role of the early mother/child relationship's establishment on infant holding biases.