Attractive and repulsive history effects in categorical and continuous estimates of orientation perception

Perceptual reports can be attracted towards or repulsed from previous stimuli and responses. We investigated the conditions in which attractive and repulsive history effects occur with oriented Gabors by manipulating response type and frequency, and stimulus duration. When subjects adjusted a continuous response cue to match orientation, we observed repulsion from the previous stimulus when the stimulus was presented for 50 ms and attraction from the previous stimulus and response when it was presented for 500 ms, regardless of whether responses were given to every stimulus or every other stimulus. With a categorical clockwise/counter-clockwise response, there was attraction to the previous response and repulsion from the previous stimulus. Attraction to the previous response was stronger with sequential responses and short relative orientations. Repulsion was constant across all stimulus durations and response frequencies, and increased with relative orientation. The overall history effect of the previous response and stimulus was repulsive with alternating categorical responses and attractive with sequential categorical responses. Our results replicate and synthesize seminal findings of the serial dependence and adaptation literature, and show independent history effects working with and against each other determined by whether the response is categorical or continuous.