Franziska Kopp

Neural dynamics of audiovisual synchrony and asynchrony perception in 6-month-old infants

Young infants are sensitive to multisensory temporal synchrony relations, but the neural dynamics of temporal interactions between vision and audition in infancy are not well understood. We investigated audiovisual synchrony and asynchrony perception in 6-month-old infants using event-related brain potentials (ERP). In a prior behavioral experiment (n = 45), infants were habituated to an audiovisual synchronous stimulus and tested for recovery of interest by presenting an asynchronous test stimulus in which the visual stream was delayed with respect to the auditory stream by 400 ms. Infants who behaviorally discriminated the change in temporal alignment were included in further analyses. In the EEG experiment (final sample: n = 15), synchronous and asynchronous stimuli (visual delay of 400 ms) were presented in random order. Results show latency shifts in the auditory ERP components N1 and P2 as well as the infant ERP component Nc. Latencies in the asynchronous condition were significantly longer than in the synchronous condition. After video onset but preceding the auditory onset, amplitude modulations propagating from posterior to anterior sites and related to the Pb component of infants’ ERP were observed. Results suggest temporal interactions between the two modalities. Specifically, they point to the significance of anticipatory visual motion for auditory processing, and indicate young infants’ predictive capacities for audiovisual temporal synchrony relations.

Audiovisual temporal fusion in 6-month-old infants

Highlights • Neural activity differentiates between synchronous and perceptually fused stimuli.• Auditory latency shifts are present in asynchrony but not fused perception.• Infants predictively adjust neural activity depending on AV synchrony relations.• ERP differences are confined to anterior locations in 6-month-olds.

10-Month-Old Infants Are Sensitive to the Time Course of Perceived Actions: Eye-Tracking and EEG Evidence

Research has shown that infants are able to track a moving target efficiently – even if it is transiently occluded from sight. This basic ability allows prediction of when and where events happen in everyday life. Yet, it is unclear whether, and how, infants internally represent the time course of ongoing movements to derive predictions. In this study, 10-month-old crawlers observed the video of a same-aged crawling baby that was transiently occluded and reappeared in either a temporally continuous or non-continuous manner (i.e., delayed by 500 ms vs. forwarded by 500 ms relative to the real-time movement). Eye movement and rhythmic neural brain activity (EEG) were measured simultaneously. Eye movement analyses showed that infants were sensitive to slight temporal shifts in movement continuation after occlusion. Furthermore, brain activity associated with sensorimotor processing differed between observation of continuous and non-continuous movements. Early sensitivity to an action’s timing may hence be explained within the internal real-time simulation account of action observation. Overall, the results support the hypothesis that 10-month-old infants are well prepared for internal representation of the time course of observed movements that are within the infants’ current motor repertoire.

Maternal Affect Attunement: Refinement and Internal Validation of a Coding Scheme

The concept of maternal affect attunement has evoked considerable theoretical interest, but attempts at empirical validation have been scarce. The aim of this study was to refine the coding scheme for assessment of maternal affect attunement and to establish the internal validity of the measure. Forty dyads with seven-month-old infants and their mothers were recorded in two face-to-face play situations. Mother-child interactions were coded by four raters on the dimensions of Maintaining Attention and Warm Sensitivity, the latter comprising the subscales of Positive Affect, Social Responsiveness, and Warm Concern. Inter-rater agreements for all scales and subscales were high. Scale reliabilities and construct stabilities as estimated by test-retest correlations were satisfactory. We conclude that the Maternal Affect Attunement Scale (MAAS) reliably captures individual differences in Maintaining Attention and Warm Sensitivity.

Visual context modulates action perception in 10-month-old infants

Research on early action perception has documented infants’ astounding abilities in tracking, predicting, and understanding other people’s actions. Common interpretations of previous findings tend to generalize across a wide range of action stimuli and contexts. In this study, ten-month-old infants repeatedly watched a video of a same-aged crawling baby that was transiently occluded. The video was presented in alternation with videos displaying visually either dissimilar movements (i.e., distorted human, continuous object, and distorted object movements) or similar movements (i.e., delayed or forwarded versions of the crawling video). Eye-tracking behavior and rhythmic neural activity, reflecting attention (posterior alpha), memory (frontal theta), and sensorimotor simulation (central alpha), were concurrently assessed. Results indicate that, when the very same movement was presented in a dissimilar context, it was tracked at more rear parts of the target and posterior alpha activity was elevated, suggesting higher demands on attention-controlled information processing. We conclude that early action perception is not immutable but shaped by the immediate visual context in which it appears, presumably reflecting infants’ ability to flexibly adjust stimulus processing to situational affordances.