Disentangling five dimensions of animacy in human brain and behaviour

Area of Science:

• Cognitive Neuroscience
• Perception Psychology
• Computational Neuroscience

Background:

• Distinguishing animate from inanimate objects is crucial for behavior.
• Distinct neural and behavioral responses exist for animate vs. inanimate stimuli.
• The specific object properties driving these animacy responses remain unclear.

Purpose of the Study:

• To investigate the role of five key animacy dimensions in brain and behavior.
• To determine which object properties (e.g., agency, mobility) best explain neural and behavioral responses.

Main Methods:

• Used functional magnetic resonance imaging (fMRI) and electroencephalography (EEG) to measure brain activity.
• Collected behavioral data through property and similarity judgments from 19 participants.
• Employed a stimulus set of 128 images optimized by a genetic algorithm to disentangle five animacy dimensions.

Main Results:

• The five investigated dimensions significantly explained variance in behavioral similarity judgments.
• Each dimension, except 'being alive', explained significant variance in brain representations, though less than in behavior.
• Brain regions sensitive to animacy may process distinct dimensions, aiding in alive detection or reflecting inherent behavioral importance.

Conclusions:

• Object properties like agency and mobility are strong drivers of animacy perception in both behavior and brain.
• Neural representations of animacy are influenced by multiple object dimensions, with varying degrees of behavioral relevance.
• Specific brain regions may specialize in processing distinct animacy-related features, contributing to survival-relevant object categorization.