The Short-term Temporal Dynamics of the Face Identity After-effect: an Adaptation-Interference Study
26.526, Saturday, May 11, 2:45 - 6:45 pm, Vista Ballroom
Ghazal Kiani1, Jodie Davies-Thompson1, Jason J.S. Barton1; 1Departments of Medicine (Neurology), Ophthalmology and Visual Sciences, University of British Columbia, Vancouver, Canada
BACKGROUND: The duration of aftereffects depends on the adaptation duration, the time lag between adapting and test stimuli, and the duration of the test stimuli. However, while there is data suggesting that face aftereffects may last days, not much is known about the short-term temporal decay of aftereffects and the influence of intervening stimuli. OBJECTIVE: Our goal was to investigate the magnitude of face identity aftereffects across variable delay periods and to determine the effects of other faces during these intervals. METHODS: In Experiment 1, subjects performed a face adaptation task, in which an adaptor period was followed by a 150ms interference interval, and then the ambiguous probe image. There were three conditions: 1) faces in the adaptor period, blank in the interference interval, 2) adapting face in the adaptor period, opposing face in the interference interval, and 3) a face in the interference interval, no stimulus in the adapting period. In Experiment 2, subjects performed a similar task, but with interference intervals of 300ms, 1500ms, and 3000ms, and unrelated faces as interfering stimuli. RESULTS: Experiment 1 showed that a brief 150ms presentation of a face caused a slight attractive aftereffect of about 13%, while the adaptor stimulus alone caused a repulsive aftereffect of 27%. Having the interference face follow the adaptor did not decrease the aftereffect, though variance was substantially increased. Experiment 2 showed that the aftereffect of adaptors alone showed a trend to decrease by about half over 3000ms, from 23% to 12%. A face in the interference interval caused aftereffects to decline by about half, to 11%, for the 300ms interval, but had no effect in longer intervals. CONCLUSION: These results show there is a modest but rapid short-term decline in the magnitude of the face identity aftereffect, and that a following face may accelerate this decline.