Ensemble representation of animacy could be based on mid-level visual features

Studies suggest that mid-level features could underlie object animacy perception. In the current research, we tested whether ensemble animacy perception is based on high- or mid-level features. We used five types of images of animals and inanimate objects: color, grayscale, silhouettes, texforms – unrecognizable images that preserve mid-level texture and shape information – and scrambled images. In the series of Experiments 1, we asked participants to evaluate the animacy of single images and sets of eight images using a 10-point scale. In the series of Experiments 2, participants were shown two sets of eight images and had to choose a more animate one in the two-alternative forced-choice (2AFC) task. We found that in both paradigms, observers could report the mean animacy of the set of texform images without direct access to information about high-level features. Thus, ensemble animacy could be extracted only based on mid-level features such as shape and texture without access to more high-level information.