PhD Kamila Jozwik | Disentangling and modelling face perception and animacy representation

In this talk, I will present two studies about face perception and animacy representation. In the first part of my talk, I will discuss a study about face perception. Discerning the subtle differences between individuals faces is crucial for social functioning. It requires us not only to solve general challenges of object recognition (e.g., invariant recognition over changes in view or lighting) but also to be attuned to the specific ways in which face structure varies. Three-dimensional morphable models based on principal component analyses of real faces provide descriptions of statistical differences between faces, as well as tools to generate novel faces. We rendered large sets of realistic face pairs from such a model and collected similarity and same/different identity judgments. The statistical model predicted human perception as well as state-of-the-art image-computable neural networks. Results underscore the statistical tuning of face encoding. In the second part of my talk, I will discuss a study about animacy representation. Distinguishing animate from inanimate things is of great behavioural importance. Despite distinct brain and behavioural responses to animate and inanimate things, it remains unclear which object properties drive these responses. We investigated the importance of five object dimensions related to animacy (being alive, looking like an animal, having agency, having mobility, and being unpredictable) in brain (fMRI, EEG) and behaviour (property and similarity judgements) of 19 participants. We used a stimulus set of 128 images, optimized by a genetic algorithm to disentangle these five dimensions. The five dimensions explained much variance in the similarity judgments. Each dimension explained significant variance in the brain representations (except, surprisingly, being alive), however, to a lesser extent than in behaviour. Different brain regions sensitive to animacy may represent distinct dimensions, either as accessible perceptual stepping stones toward detecting whether something is alive or because they are of behavioural importance in their own right.

https://www.pnas.org/doi/10.1073/pnas.2115047119

https://www.nature.com/articles/s42003-022-04194-y

Zoom link:

https://zoom.us/j/95920087550