The dynamics of intermodal matching: Seven- and 12-month-olds' intermodal matching of affect

The purpose of this experiment was to examine whether and how a common methodological difference frequently employed within the intermodal matching procedure affects infants' intermodal matching. Specifically we examined the effects of incorporating or excluding silent control trials on seven- and 12-month-olds' intermodal matching of affect. Results revealed that seven-month-olds showed reliable matching when presented all in-sound trials whereas 12-month-olds showed reliable matching when half of the trials were presented silently and half of the trials were presented in-sound. Results are discussed in terms of the dynamics of infant attention and those conditions where the inclusion of silent trials may be appropriate.     

Attention to lexical stress and early vocabulary growth in 5-month-olds at risk for autism spectrum disorder

Typically developing infants differentiate strong–weak (trochaic) and weak–strong (iambic) stress patterns by 2 months of age. The ability to discriminate rhythmical patterns, such as lexical stress, has been argued to facilitate language development, suggesting that a difficulty in discriminating stress might affect early word learning as reflected in vocabulary size. Children with autism spectrum disorder (ASD) often have difficulty in correctly producing lexical stress, yet little is known about how they perceive it. The current study tested 5-month-old infants with typically developing older siblings (SIBS-TD) and infants with an older sibling diagnosed with ASD (SIBS-A) on their ability to differentiate the trochaic and iambic stress patterns of the word form gaba. SIBS-TD infants showed an increased interest in attention to the trochaic stress pattern, which was also positively correlated with vocabulary comprehension at 12 months of age. In contrast, SIBS-A infants attended equally to these stress patterns, although this was unrelated to later vocabulary size.     

Beyond the information given: Infants’ transfer of actions learned through imitation

Five experiments were conducted to investigate infants’ ability to transfer actions learned via imitation to new objects and to examine what components of the original context are critical to such transfer. Infants of 15 months observed an experimenter perform an action with one or two toys and then were offered a novel toy that was not demonstrated for them. In all experiments, infants performed target actions with the novel toy more frequently than infants who were offered the same toy but had seen no prior demonstrations. Infants exhibited transfer even when the specific part to be manipulated looked different across the toys, even when they had not performed the actions with the demonstration toys themselves, even when the actions produced no effects on the demonstrations, and even when the actions were demonstrated with only a single exemplar toy. Transfer was especially robust when infants not only observed but also practiced the target actions on the demonstration trials. Learning action affordances (“means”) seems to be a central aspect of human imitation, and the propensity to apply these learned action affordances in new object contexts may be an important basis for technological innovation and invention.     

Sing that tune: Infants’ perception of melody and lyrics and the facilitation of phonetic recognition in songs

To better understand how infants process complex auditory input, this study investigated whether 11-month-old infants perceive the pitch (melodic) or the phonetic (lyric) components within songs as more salient, and whether melody facilitates phonetic recognition. Using a preferential looking paradigm, uni-dimensional and multi-dimensional songs were tested; either the pitch or syllable order of the stimuli varied. As a group, infants detected a change in pitch order in a 4-note sequence when the syllables were redundant (experiment 1), but did not detect the identical pitch change with variegated syllables (experiment 2). Infants were better able to detect a change in syllable order in a sung sequence (experiment 2) than the identical syllable change in a spoken sequence (experiment 1). These results suggest that by 11 months, infants cannot “ignore” phonetic information in the context of perceptually salient pitch variation. Moreover, the increased phonetic recognition in song contexts mirrors findings that demonstrate advantages of infant-directed speech. Findings are discussed in terms of how stimulus complexity interacts with the perception of sung speech in infancy.     

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.