Mert Can¹ (), Thérèse Collins¹; ¹Integrative Neuroscience and Cognition Center, Université Paris Cité & CNRS, France

Perceptual reports can be attracted towards or repulsed from previously seen stimuli. We investigated the conditions in which attraction and repulsion occur with oriented Gabors by manipulating response type (continuous or categorical), response frequency (to every stimulus or every other stimulus), and stimulus duration (50 or 500 ms). When participants gave a continuous response by adjusting a response cue to match the orientation of the stimulus, repulsion from the previous stimulus occurred when the stimulus was presented for 50 ms and attraction to the previous stimulus when the stimulus was presented for 500 ms. These effects occurred whether participants responded to every stimulus or every other stimulus. When participants gave a categorical response by indicating whether the orientation was clockwise or counter-clockwise from a reference, there was attraction to the previous response and repulsion from the previous stimulus. Attraction to the previous response was weaker when participants responded to every other stimulus, suggesting a decay of response representation over time, and stronger when the stimulus was ambiguous (i.e., oriented close to the reference stimulus). Our results provide evidence of temporal differences between repulsion and attraction, which may relate to the involvement of feedforward and feedback processes in facilitating these effects. They also show that the processes resulting in repulsion or attraction were defined by response type. We suggest that attraction is both a decisional effect associated with categorical responses and a perceptual effect associated with continuous responses.