| It is an open question how our visual system integrates information from different spatial frequencies to form a coherent percept as we move through the world. Here we investigate such perceptual grouping in scale space using hybrid faces, which contain different images at low and high spatial frequency. Observers judged how similar a hybrid was to each of its component images while walking towards or away from it or having the stimulus moved towards or away from the observer. When the stimulus is approaching, observers independently integrate spatial frequency at each moment. However, when the stimulus is receding, observers show a perceptual hysteresis effect, holding on to details that are imperceptible in a static stimulus condition. These results demonstrate that different perceptual grouping rules operate during online processing: observers stick with their previous interpretation when losing information, but constantly reinterpret their input when gaining information. |