Jeff Loucks

Sources of information for discriminating dynamic human actions

Despite the importance of action identification and discrimination in action perception and social cognition more broadly, little research has investigated how these processes are achieved. To this end, we sought to identify the extent to which adults capitalize on featural versus configural sources of information when discriminating small-scale human actions such as grasp and place. Results across two experiments indicate adults are sensitive to both sources of information in action discrimination, but selectively attend to featural over configural action information. The findings also parallel what is known regarding face processing: processing of configural information is especially disrupted by inversion, whereas processing of featural information is specifically affected by low-pass filtering.

Children's Representation and Imitation of Events: How Goal Organization Influences 3‐Year‐Old Children's Memory for Action Sequences

Childrens imitation of adults plays a prominent role in human cognitive development. However, few studies have investigated how children represent the complex structure of observed actions which underlies their imitation. We integrate theories of action segmentation, memory, and imitation to investigate whether childrens event representation is organized according to veridical serial order or a higher level goal structure. Children were randomly assigned to learn novel event sequences either through interactive hands-on experience (Study 1) or via storybook (Study 2). Results demonstrate that childrens representation of observed actions is organized according to higher level goals, even at the cost of representing the veridical temporal ordering of the sequence. We argue that prioritizing goal structure enhances event memory, and that this mental organization is a key mechanism of social-cognitive development in real-world, dynamic environments. It supports cultural learning and imitation in ecologically valid settings when social agents are multitasking and not demonstrating one isolated goal at a time.

Human Action Perception is Consistent, Flexible, and Orientation Dependent

Previous research has found that observers of object-directed human action pay more attention to information regarding hand contact over information regarding spatial trajectories in action, and that processing of trajectory information is disrupted by inversion. However, observers can also flexibly modulate their attention to spatial trajectory depending on the goal or context of the actor. In Experiments 1(a) and 1b of the current research, we directly compared attention with hand and trajectory information across placing and dropping actions in order to determine whether the hand bias is always present or whether flexibility in action perception can attenuate this bias. Results demonstrated that observers attend more to hand information for placing, but attend equally to hand and trajectory information for dropping. Experiment 2 explored the role of the actor’s goal in processing spatial trajectory for mimed dropping actions and non-human control stimuli, and the role of goals in the inversion effect. Results indicated that goal relevance increases processing of trajectory information, and that processing of all spatial trajectories in human action is disrupted by inversion, regardless of the actor’s goal. The present findings highlight the role of prediction in action perception, and suggest that human action is processed with expertise.

Temporal perception is enhanced for goal-directed biological actions

ABSTRACT Research into the visual perception of goal-directed human action indicates that human action perception makes use of specialized processing systems, similar to those that operate in visual expertise. Against this background, the current research investigated whether perception of temporal information in goal-directed human action is enhanced relative to similar motion stimuli. Experiment 1 compared observers’ sensitivity to speed changes in upright human action to a kinematic control (an animation yoked to the motion of the human hand), and also to inverted human action. Experiment 2 compared human action to a non-human motion control (a tool moved the object). In both experiments observers’ sensitivity to detecting the speed changes was higher for the human stimuli relative to the control stimuli, and inversion in Experiment 1 did not alter observers’ sensitivity. Experiment 3 compared observers’ sensitivity to speed changes in goal-directed human and dog actions, in order to determine if enhanced temporal perception is unique to human actions. Results revealed no difference between human and dog stimuli, indicating that enhanced speed perception may exist for any biological motion. Results are discussed with reference to theories of biological motion perception and perception in visual expertise.