Disentangling five dimensions of animacy in human brain and behaviour

Abstract

The perception of animate things is of great behavioural importance to humans. Despite the prominence of the distinct brain and behavioural responses to animate and inanimate things, however, it remains unclear which of several commonly entangled properties underlie these observations. Here, we investigate the importance of five dimensions of animacy: being alive, looking like an animal, having agency, having mobility, and being unpredictable in brain (fMRI, EEG) and behaviour (property and similarity judgments) of 19 subjects using a stimulus set of 128 images that disentangles the five dimensions (optimized by a genetic algorithm). Our results reveal a differential pattern across brain and behaviour. The living/non-living distinction (being alive) was prominent in judgments, but despite its prominence in neuroscience literature, did not explain variance in brain representations. The other dimensions of animacy explained variance in both brain and behaviour. The having agency dimension explained more variance in higher-level visual areas, consistent with higher cognitive contributions. The being unpredictable dimension instead captured representations in both lower and higher-level visual cortex, possibly because unpredictable things require attention. Animacy is multidimensional and our results show that distinct dimensions are differentially represented in human brain and behaviour.

The influence of movement on perceptions of aliveness: a replication and extension of Goldberg & Thompson-Schill (2009)

“…Neuroimaging studies have shown that models of animacy (including humans/ animals, excluding plants) capture neural activity better than models of aliveness (including plants) (Contini et al, 2020;Jozwik et al, 2022). Our movement results suggest that this could be because plants move on a different global scale and frequency, the same explanation as others have provided for plant blindness (Wandersee & Schussler, 1999).…”