The HED Task Catalog is under development. IDs are not stable until formal release. Comments are welcome at github.com/hed-standard/hed-task/issues.

Biological Motion Perception Task

HED task ID: hedtsk_biological_motion_perception

Family: Perceptual judgment and psychophysics tasks

Also known as: Point-Light Displays, Point-Light Walker Task, PLW

Judgment of human action or identity from sparse point-light displays attached to major joints; indexes recognition of biological motion from kinematic cues alone.

Description

Participants view point-light display stimuli, animations created by placing markers on the joints of a person performing actions and capturing only the light points. The resulting stimuli (12-15 dots representing joints) convey complex human actions (walking, running, dancing) from minimal motion cues. Participants may recognize actions, judge coherence (upright vs. inverted), or discriminate biological from scrambled motion. The task measures perception of complex human movement and activates the posterior superior temporal sulcus, a region specialized for biological motion processing.

Inclusion test

An experiment is an instance of this task when its procedure matches, it manipulates at least one of the listed variables, and it records at least one of the listed measures.

Procedure

Participants view point-light displays (dots at major joints) and identify actions, discriminate facing direction, or detect biological motion embedded in noise dots.

Manipulation

Display type (intact vs. scrambled vs. inverted); noise dot density; action category; viewpoint angle.

Measurement

Accuracy and RT for action identification, direction discrimination, or detection; noise-dot threshold for biological motion detection.

Variations

Named versions that change what the participant experiences or does. The identifier of a variation is hedvar_<task>__<variation>.

Variation

Description

Justification

Intact Biological Motion

hedvar_biological_motion_perception__intact_biological_motion

Standard point-light walkers with coherent body structure.

Standard point-light walker; canonical biological motion stimulus

Scrambled Displays

hedvar_biological_motion_perception__scrambled_displays

Dot positions randomized; preserves local motion, disrupts configural structure.

Spatially scrambled dots preserve local motion but destroy global form; control condition with different percept

Inverted Displays

hedvar_biological_motion_perception__inverted_displays

Upside-down presentation; impairs perception, revealing orientation specificity.

Walker inverted; disrupts configural processing while preserving motion signals

Reversed (Backward) Motion

hedvar_biological_motion_perception__reversed_backward_motion

Normal actions played in reverse.

Temporal reversal disrupts action identity while preserving form

Action Recognition

hedvar_biological_motion_perception__action_recognition

Classify depicted actions (walk, run, jump, throw, kick).

Participant identifies specific action (running, kicking); classification task beyond detection

Detection in Noise

hedvar_biological_motion_perception__detection_in_noise

Biological motion figures embedded in scrambled dot noise masks.

Walker embedded in noise dots; detection task with varying signal-to-noise

Gender/Identity Discrimination

hedvar_biological_motion_perception__gender_identity_discrimination

Judge walker’s gender or identity from motion cues alone.

Discrimination of walker gender or identity; different judgment dimension

Emotion from Body Motion

hedvar_biological_motion_perception__emotion_from_body_motion

Recognize emotional states from body/gait dynamics.

Emotional state judged from body kinematics; different recognition task

Partial/Occluded Displays

hedvar_biological_motion_perception__partial_occluded_displays

Subsets of body points visible.

Subset of dots visible; tests perceptual completion of biological motion

Comparison with Mechanical Motion

hedvar_biological_motion_perception__comparison_with_mechanical_motion

Biological vs. rigid/mechanical motion; tests specificity.

Mechanical motion control alongside biological; category discrimination task

Facing Direction Discrimination

hedvar_biological_motion_perception__facing_direction_discrimination

Determine whether the walker faces left or right; sensitive to viewpoint processing.

Ambiguous facing direction judgment; different perceptual task

Cognitive processes

This task is designed to engage the following processes:

Key references

  • Johansson, G. (1973). Visual perception of biological motion and a model for its analysis. Perception & Psychophysics, 14(2), 201-211. (DOI)

  • Grossman, E. D., & Blake, R. (2002). Brain areas active during visual perception of biological motion. Neuron, 35(6), 1167-1175. (DOI, PubMed)

  • Blake, R., & Shiffrar, M. (2007). Perception of human motion. Annual Review of Psychology, 58, 47-73. (DOI, PubMed)

Further references

  • Pavlova, M. A. (2012). Biological motion processing as a hallmark of social cognition. Cerebral Cortex, 22(5), 981–995. (DOI)

  • Thompson, J. C., & Baccus, W. (2012). Form and motion make independent contributions to the response to biological motion in occipitotemporal cortex. NeuroImage, 59(1), 625–634. (DOI, PubMed)

  • Federici, A., et al. (2020). Biological motion perception in autism: A meta-analysis. Research in Autism Spectrum Disorders, 77, 101610. (DOI)

  • Gilaie-Dotan, S., Kanai, R., Bahrami, B., Rees, G., & Saygin, A. P. (2013). Neuroanatomical correlates of biological motion detection. Neuropsychologia, 51(3), 457–463. (DOI, PubMed)

  • Thurman, S. M., & Lu, H. (2016). Revisiting the importance of common body dynamics in human action perception. Attention, Perception, & Psychophysics, 78, 2187–2199.

  • van Boxtel, J. J. A., & Lu, H. (2013). A biological motion toolbox for reading, displaying, and manipulating motion capture data in research settings. Journal of Vision, 13(12), 7. (DOI, PubMed)

  • Miller, L. E., & Saygin, A. P. (2013). Individual differences in the perception of biological motion: Links to social cognition and motor imagery. Cognition, 128(2), 140–148. (DOI, PubMed)