Abstract
We examined the recently-discovered phenomenon of Adaptation-Induced Blindness (AIB) in which exposure to a rapidly flickering grating causes a gradually on-ramped static grating to remain invisible even as it reaches high contrast. We compared this approach to a more traditional paradigm measuring threshold elevation for low contrast stimuli after adaptation. Using very similar stimuli to those inthe original experiment, we found post-adaptation threshold elevations were equivalent for both gradual and abruptly onset test stimuli, and both displayed orientation-tuned adaptation, with partial interocular transfer. Then, using full-contrast test stimuli with either abrupt or gradual onsets, we tested the “disappearance” of these stimuli in a paradigm similar to that of the original AIB experiment. If, as the original authors suggested, AIB were a high-level (perhaps parietal) effectresulting from the “gating” of awareness, we would not expect the effects of AIB to be tuned to the adapting orientation, and the effect should transfer between the eyes. Instead, we found that AIB (which was present only for the gradual onset test stimuli) was very tightly orientation-tuned and showed absolutely no interocular transfer. Our results therefore suggest a very early cortical locus for this effect.
