||Attention-based motion perception.
Two "attentive" tracking tasks reveal the existence of an attention-based motion process. In the 1st task, oppositely rotating luminance and color gratings were superimposed. Because of masking from the color grating, the bars of the luminance grating were not visible; nevertheless, their motion was visible and it determined the perceived direction of the stimulus rotation. In a 2nd task, the perceived velocity of a color grating, typically slow at equiluminance, speeded up when individual bars were attentively tracked. Findings demonstrate 2 independent motion processes: one that is low level or automatic in that it signals motion even in the absence of attention to the stimulus and one that is mediated by attention to visible features and provides accurate velocity judgments independently of the features being tracked. (PsycINFO Database Record (c) 2007 APA, all rights reserved)