Abstract
Visual attention can bias the competition between different visual stimuli — resulting in a simultaneous facilitation of attended, and suppression of unattended, input. This study addressed whether there is attentional learning, i.e. can one learn to more strongly bias the competition between different visual stimuli?
Using transparent, bivectorial motion adaptors, we studied the plasticity of attentional modulation of the motion aftereffect (MAE). During adaptation, 70% of the dots, the MAE of which was measured, were colored red and moved along 0°. The rest of the dots were green and alternated direction every 4 s between +90° and −90°. Before and after learning, observers performed two test sessions. The test contained adaptation periods during which observers attended to the luminance of one or the other dot field in order to detect occasional brief luminance increases. The difference in the MAE duration between these two conditions was used as the index of the strength of attentional modulation. During the learning phase (seven one-hour sessions), observers always performed the luminance detection task over the dots with alternating motion directions.
We found a strong direction specific learning effect on the attentional modulation of motion processing. When the same bivectorial motion display was used during learning and test, the magnitude of attentional effects increased significantly with learning. However, learning had an opposite, suppressive effect on attentional modulation when the surface that was unattended during learning was made to move in the opposite direction during test.
Our results provide strong evidence for attentional learning, a phenomenon that allows one to bias sensory competition more strongly as a result of practice. The fact that attentional learning effects are specific for the properties of the unattended stimuli implies that the plasticity of the mechanisms of attentional suppression plays an important role in attentional learning.