Abstract
Our sensory system adjusts its function driven by both shorter-term (e.g. adaptation) and longer-term (e.g. learning) experiences. Most past adaptation literature focuses on short-term adaptation. Only recently researchers have begun to investigate how adaptation changes over a span of days but reported mixed findings. However, this question is important, since in real life many environmental changes stretch over multiple days or longer. Here we addressed this issue by tracking perceptual bias (also known as aftereffect) induced by motion or contrast adaptation across multiple daily adaptation sessions when attention was focused on the adapters by a task or on the fixation. In the experiments of motion adaptation, dynamic motion aftereffect (dMAE), which was evaluated using nulling percentage (Blake, R. et al., 1993, Vision Res), was measured during top-up adaptation; static motion aftereffect (sMAE), which was evaluated using MAE duration, was measured after adaptation. In the experiments of contrast adaptation, the contrast thresholds before and after continuous adaptation were tracked using ramp detection method (Dong, X. et al., 2014, Perception). Aftereffects were measured every day which corresponded to the degree of adaptation on each day. Though the sMAE remained constant, which is consistent with previous study, dMAE and contrast adaptation effect showed similar general reduction after several days of repeated adaptation sessions. For passively viewed adapters, repeated adaptation attenuated aftereffects. Once adapters were presented with an attentional task, aftereffects could either reduce for easy tasks, or initially show an increase followed by a later decrease for demanding tasks. Quantitative analysis of the time for decay in contrast adaptation showed that repeated exposure of the adapter appeared to be equivalent to adaptation to a weaker stimulus. These results suggest that both attention and a non-attentional habituation-like mechanism jointly determine how adaptation develops across multiple daily sessions.
Meeting abstract presented at VSS 2016