Because both heard language and observed action consist of continuous streams of to-be-processed information, they provide similar challenges to the listener/observer with respect to identifying and discriminating meaningful segments (e.g., phrases / actions). In the language domain, prosodic boundary cues (e.g., preboundary pitch-change, lengthening, pause) help to segment the incoming speech stream into prosodic phrases of different strengths. They guide the hearer’s syntactic analysis, and they also help to chunk the information into appropriate sub-chunks that can be processed incrementally. Young infants have been shown to be highly sensitive to prosodic cues.
In the action domain, different types of cues help to identify boundaries that segregate single actions within a behaviour stream. First, the attainment of action goals is an important conceptual cue, reflecting top-down processing that integrates an observer’s representation of the current event with previously stored knowledge. By 11 months, infants are sensitive to action units marked by intention boundaries. Second, kinematic movement features (e.g., changes in acceleration or velocity) provide perceptual cues for bottom-up processing of action segments, which is determined by the perceptual input. In infants, the processing of kinematic cues other than pauses has not been studied so far, and neither have infant EEG correlates of action segmentation.
This project aims to understand whether segmentation or chunking processes in speech perception and action observation are based on similar domain-general mechanisms, whether they can be found in both domains in adults and in infants, and whether they share a common neurocognitive basis. In EEG and eyetracking studies, the processing of different boundary cues in the language and action domain will be compared in various conditions. By this, the project will give important insight into the domain-specificity or –generality, potential age effects, and brain-behaviour relations for segmentation processes in speech and action.