Faces are special for newly hatched chicks: evidence for inborn domain-specific mechanisms underlying spontaneous preferences for face-like stimuli.

It is currently being debated whether human newborns' preference for faces is due to an unlearned, domain-specific and configural representation of the appearance of a face, or to general mechanisms, such as an up-down bias (favouring top-heavy stimuli, which have more elements in their upper part). Here we show that 2-day-old domestic chicks, visually naïve for the arrangement of inner facial features, spontaneously prefer face-like, schematic, stimuli. This preference is maintained when the up-down bias is controlled for (Experiment1) or when put in direct conflict with facedness (Experiment 4). In contrast, we found no evidence for the presence of an up-down bias in chicks (Experiment 2). Moreover, our results indicate that the eye region of stimuli is crucial in determining the expression of spontaneous preferences for faces (Experiments 3 and 4).