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A View of Their Own: Capturing the Egocentric View of Infants and Toddlers with Head-Mounted Cameras

Infants and toddlers view the world, at a basic sensory level, in a fundamentally different way from their parents. This is largely due to biological ...

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Gaze in Action: Head-mounted Eye Tracking of Children's Dynamic Visual Attention During Naturalistic Behavior

Young children's visual environments are dynamic, changing moment-by-moment as children physically and visually explore spaces and objects and interact ...

Indiana University

Previous studies have shown that people's grasps of objects are tuned to the objects' inertial properties. In most of those studies, information obtained about the attunement of the grasps to the objects' inertial properties was limited to first-order grasp planning (i.e., planning of grasps based on immediate task demands). We investigated attunement of grasps to an object's inertial properties in the context of second-order grasp planning (i.e., planning of grasps based on subsequent task demands). In Experiment 1, participants grasped a horizontal rod whose right or left end would be brought down onto a target. Consistent with previous findings, participants grasped the rod so as to complete the movement with a thumb-up posture, using an overhand grasp when the right end of the rod was to be brought to the target and an underhand grasp when the left end was to be brought to the target. They also grasped the rod to the right of center, but more so when doing this with an underhand than when with an overhand grasp. In Experiment 2, participants performed the same task with an asymmetrically weighted rod. Changes in subjects' grasps in Experiment 2 compared to Experiment 1 suggested that participants grasped the rod based on the inertial properties of the rod in a way that took advantage of the pendular properties of the hand-plus-object.

Second-order grasp planning reflects sensitivity to inertial factors.

The study of vocal coordination between infants and adults has led to important insights into the development of social, cognitive, emotional and linguistic abilities. We used an automatic system to identify vocalizations produced by infants and adults over the course of the day for fifteen infants studied longitudinally during the first two years of life. We measured three different types of vocal coordination: coincidence-based, rate-based, and cluster-based. Coincidence-based and rate-based coordination are established measures in the developmental literature. Cluster-based coordination is new and measures the strength of matching in the degree to which vocalization events occur in hierarchically nested clusters. We investigated whether various coordination patterns differ as a function of vocalization type, whether different coordination patterns provide unique information about the dynamics of vocal interaction, and how the various coordination patterns each relate to infant age. All vocal coordination patterns displayed greater coordination for infant speech-related vocalizations, adults adapted the hierarchical clustering of their vocalizations to match that of infants, and each of the three coordination patterns had unique associations with infant age. Altogether, our results indicate that vocal coordination between infants and adults is multifaceted, suggesting a complex relationship between vocal coordination and the development of vocal communication.

Multiple Coordination Patterns in Infant and Adult Vocalizations.

Recent studies of naturalistic face-to-face communication have demonstrated coordination patterns such as the temporal matching of verbal and non-verbal behavior, which provides evidence for the proposal that verbal and non-verbal communicative control derives from one system. In this study, we argue that the observed relationship between verbal and non-verbal behaviors depends on the level of analysis. In a reanalysis of a corpus of naturalistic multimodal communication (Louwerse, Dale, Bard, & Jeuniaux, ), we focus on measuring the temporal patterns of specific communicative behaviors in terms of their burstiness. We examined burstiness estimates across different roles of the speaker and different communicative modalities. We observed more burstiness for verbal versus non-verbal channels, and for more versus less informative language subchannels. Using this new method for analyzing temporal patterns in communicative behaviors, we show that there is a complex relationship between verbal and non-verbal channels. We propose a "temporal heterogeneity" hypothesis to explain how the language system adapts to the demands of dialog.

Drew H. Abney

Department of Psychological and Brain Sciences

Indiana University

A View of Their Own: Capturing the Egocentric View of Infants and Toddlers with Head-Mounted Cameras

Gaze in Action: Head-mounted Eye Tracking of Children's Dynamic Visual Attention During Naturalistic Behavior