The visual encoding of graspable unfamiliar objects

Abstract We explored by eye-tracking the visual encoding modalities of participants (N = 20) involved in a free-observation task in which three repetitions of ten unfamiliar graspable objects were administered. Then, we analysed the temporal allocation (t = 1500ms) of visual-spatial attention to objects’ manipulation (i.e., the part aimed at grasping the object) and functional (i.e., the part aimed at recognizing the function and identity of the object) areas. We found a reversed quadratic trend in the way participants visually explored the objects. Within the first 750ms, participants tended to shift their gaze on the functional areas while decreasing their attention on the manipulation areas. Then, participants reversed this trend, decreasing their visual-spatial attention to the functional areas while relatively increasing fixations to the manipulation areas. Crucially, the global amount of visual-spatial attention for objects’ functional areas significantly decreased as an effect of stimuli repetition while remaining stable for the manipulation areas, thus indicating stimulus familiarity effects. These findings support the action reappraisal theoretical approach, which considers object processing and tool use as abilities emerging from the integration among semantic, technical/mechanical, and sensorimotor knowledge.