Adaptation can have an immediate effect on the subsequently viewed stimuli; discrimination thresholds decrease at the adapted stimulus orientation and increase for orientations away from the adapted stimulus (Regan & Beverley, 1985; Clifford et al., 2001). Here we investigated the effects that perceptual adaptation could have for orientation discrimination for trained and untrained orientations. Participants were initially trained in an orientation discrimination task at the adapted orientation. On each trial a Gabor pattern was presented at fixation and the adaptor was followed by the test stimulus. Participants compared the test stimulus orientation to a standard that had the same orientation as the adapting stimulus. Participants completed a total of 10 sessions that were administered in separate days. Thresholds across sessions for the adaptation condition were lower compared to a control condition at a different orientation with no adapting stimulus. In the second part of the study, we examined participants' orientation discrimination at an orientation 10 degree away from the adapted orientation. Two conditions were compared: orientation discrimination at the previously trained orientation and at an untrained orientation. Participants completed 4 sessions for the two conditions. In both cases, adapting to an orientation 10 degree away from the test orientation increased thresholds. However, the threshold increase was larger for the previously trained orientation than for the untrained orientation. Our results are consistent with the idea that training orientation discrimination increases the weights of the neighboring orientation mechanisms relative to the mechanism most sensitive to the test orientation (Blaser et al., 2004).
Scilipoti, Erika,
"The Role of adaptation in perceptual learning"
(2010).
Cognitive Sciences Theses and Dissertations.
Brown Digital Repository. Brown University Library.
https://doi.org/10.7301/Z0PK0DDG
