Search

This study investigated the role of joint attention in infants' word learning. Infants aged 18–21 months were taught new words in two social contexts, joint attention (eye contact, positive tone of voice) or non-joint attention (no eye contact, neutral tone of voice). Event-related potentials were measured as the infants saw objects either congruent or incongruent with the taught words. For both social contexts, an early negativity was observed for the congruent condition, reflecting a phonological-lexical priming effect between objects and the taught words. In addition, for the joint attention, the incongruent condition elicited a late, widely distributed negativity, attributed to semantic integration difficulties. Thus, social cues have an impact on how words are learned and represented in a child's mental lexicon.

This study investigates infants' processing of emotional expressions in combination with referential eye gaze cues. In experiment 1, 7-month-old infants' neural responses to fearful and neutral faces, which were looking at a novel object, were assessed. Infants' attention, as indexed by the negative central component of the event-related potential, was enhanced when the adult gazed at the object with a fearful expression compared with a neutral expression. In experiment 2, no effect of emotion on amplitude of the negative central was found when the face directed eye gaze at the infant and away from the object. We conclude that by 7 months, infants use emotional expressions in triadic person-object-person contexts to detect threat in the environment.

In the current study, we examined 7-month-old infants' processing of emotional prosody using event-related brain potentials. Infants heard semantically neutral words that were spoken with either a happy, angry, or neutral voice. The event-related brain potential data revealed that angry prosody elicited a more negative response in infants' event-related potentials than did happy or neutral prosody, suggesting greater allocation of attention to angry prosody. A positive slow wave was elicited by angry and happy prosody over temporal electrode sites. This indicates an enhanced sensory processing of the emotionally loaded stimuli (happy and angry). The current findings demonstrate that very early in development, the human brain detects emotionally loaded words and shows differential attentional responses depending on their emotional valence.

Emotional tone of voice indicates the significance of a spoken utterance. We asked whether listeners recognize this significance even when attending to something else and whether men and women differ in this regard. To answer these questions, we presented emotionally or neutrally spoken syllables as standards and deviants in a mismatch negativity paradigm. Independent of the listeners' sex, deviants elicited a mismatch negativity in the scalp-recorded event-related potential as an indicator of preattentive acoustic change detection. Only women, however, showed a larger mismatch negativity to emotional than to neutral deviants. Thus, even though both sexes detect change in voice preattentively, only women recruit additional processing resources when the change in voice is one of emotional valence.

A major issue in developmental science is how infants use the direction of other's eye gaze to facilitate the processing of information. Four-month-old infants passively viewed images of an adult face gazing toward or away from objects. When presented with the objects a second time, infants showed differences in a slow wave event-related potential, indicating that uncued objects were perceived as less familiar than objects previously cued by the direction of gaze of another person. This result shows that the direction of eye gaze of another cannot only bias infant attention, but also lead to enhanced information processing of the objects concerned.