Cue contrast modulates the effects of exogenous attention on appearance.

摘要: Exogenous spatial attention can be automatically engaged by a cue presented in the visual periphery. To investigate effects of exogenous attention, previous studies have generally used highly salient cues that reliably trigger attention. However, cueing threshold has been unexamined. We investigated whether attentional effect varies with salience. examined magnitude on apparent contrast [Carrasco, M., Ling, S., & Read, S. (2004). Attention alters appearance. Nature Neuroscience, 7(3), 308–313.] elicited negative Weber between 6% and 100%. Cue modulated effect, even at contrasts above level which observers perfectly localize cue; hence, result is not due to an increase visibility. No observed when 100% after stimuli, ruling out bias or sensory interaction stimuli as alternative explanations. A second experiment, using same paradigm high motion gave similar results, providing further evidence against explanation, task were defined dimension independent from contrast. Although triggered involuntarily, gradual.