Abstract
Background: Differences in perceptual learning transfer may be related to the cerebral sites of modification due to experience: hard-condition tasks are seen as requiring low-level (specific) representations while easy-condition tasks are performed using high cortical level mechanisms alone (Ahissar & Hochstein, Nature, 1997). As an example, we recently found that inter-hemispheric transfer also depends on task difficulty. Subjects practiced a color and an orientation feature search task, each within one hemifield. Following training, we switched the sides of the two tasks. We found nearly complete transfer for easy conditions, and considerably less with difficult conditions (Pavlovskaya & Hochstein, VSS, 2003). Methods & Results: We now ask whether learning effects may transfer also from one visual dimension to another in such rapid odd-element detection tasks, and if this transfer depends similarly on task difficulty. We trained subjects on one of the following search tasks: a color pop-out task, an orientation pop-out task, or a line-gap detection task. In each case, we used either easy or hard conditions and either central or lateral presentation. Following training, and experience-based performance improvement, we tested (and then further trained) the subjects on the other tasks. We found that for the difficult spatial conditions, there was little or no transfer to the new conditions. On the other hand, for easy conditions, there was at least partial transfer to new search dimensions. Conclusions: These results suggest a very high cortical level for performance and perceptual learning of rapid search, where the same mechanisms might be responsible for finding odd elements of various features.
Support: Charles E. Smith Laboratory for Collaborative Research in Psychobiology, Jerusalem; Israel Science Foundation “Center of Excellence” grant; US-Israel Binational Science Foundation.