The role of the blobs in determining the perception of drifting plaids and their motion aftereffects

Motion aftereffects (MAEs) can be induced by adaptations to a pair of differently oriented drifting gratings whether the gratings are presented simultaneously, as a coherent plaid, or in alternation. The fact that the former MAEs were generally larger than the latter led to the suggestion that simultaneous adaptatian involved higher-level extrastriate processes not involved in the alternating effects. In the past few years evidence has accumulated that the difference is in fact due to a low-level monocular precast which may be termed the 'blob-teaching mechanism'. A review is presented of the evidence an MAEs induced by simultaneous and alternating adaptation, the evidence for the monocularity of the blob-teaching mechanism, the data which implicate the blob monocularity in the determinatian of MAE magnitude, perceived plaid drift direction, and in perceived plaid coherence.