Carrasco Marisa, Fuller Stuart, Ling Sam
Department of Psychology, New York University, New York, NY 10003, USA.
Percept Psychophys. 2008 Oct;70(7):1151-64. doi: 10.3758/pp.70.7.1151.
Carrasco, Ling, and Read (2004) showed that transient attention increases perceived contrast. However, Prinzmetal, Long, and Leonhardt (2008) suggest that for targets of low visibility, observers may bias their response toward the cued location, and they propose a cue-bias explanation for our previous results. Our response is threefold. First, we outline several key methodological differences between the studies that could account for the different results. We conclude that the cue-bias hypothesis is a plausible explanation for Prinzmetal et al.'s (2008) results, given the characteristics of their stimuli, but not for the studies by Carrasco and colleagues, in which the stimuli were suprathreshold (Carrasco, Ling, & Read, 2004; Fuller, Rodriguez, & Carrasco, 2008; Ling & Carrasco, 2007). Second, we conduct a study to show that the stimuli used in our previous studies are not near-threshold, but suprathreshold (Experiment 1, Phase 1). Furthermore, we found an increase in apparent contrast for a high-contrast stimulus when it was precued, but not when it was postcued, providing more evidence against a cue-bias hypothesis (Experiment 1, Phase 2). We also show that the visibility of the stimuli in Prinzmetal et al. (2008) was much lower than that of Carrasco, Ling, and Read, rendering their stimuli susceptible to their cue-bias explanation (Experiment 2). Third, we present a comprehensive summary of all the control conditions used in different labs that have ruled out a cue bias explanation of the appearance studies. We conclude that a cue-bias explanation may operate with near-threshold and low-visibility stimuli, as was the case in Prinzmetal et al. (2008), but that such an explanation has no bearing on studies with suprathreshold stimuli. Consistent with our previous studies, the present data support the claim that attention does alter the contrast appearance of suprathreshold stimuli.
卡拉斯科、凌和里德（2004年）表明，短暂的注意力会提高感知对比度。然而，普林兹梅尔、朗和莱昂哈特（2008年）认为，对于低可见度的目标，观察者可能会将他们的反应偏向于提示的位置，并且他们为我们之前的结果提出了一种提示偏差的解释。我们的回应有三点。首先，我们概述了这些研究之间几个关键的方法学差异，这些差异可能解释了不同的结果。我们得出结论，鉴于普林兹梅尔等人（2008年）研究中刺激的特征，提示偏差假设对他们的结果是一个合理的解释，但对卡拉斯科及其同事的研究则不然，在那些研究中刺激是阈上的（卡拉斯科、凌和里德，2004年；富勒、罗德里格斯和卡拉斯科，2008年；凌和卡拉斯科，2007年）。其次，我们进行了一项研究，以表明我们之前研究中使用的刺激不是接近阈限的，而是阈上的（实验1，第一阶段）。此外，我们发现当高对比度刺激被预提示时，其明显对比度增加，但当它被后提示时则不然，这为反对提示偏差假设提供了更多证据（实验1，第二阶段）。我们还表明，普林兹梅尔等人（2008年）研究中刺激的可见度远低于卡拉斯科、凌和里德研究中的刺激，这使得他们的刺激容易受到他们的提示偏差解释的影响（实验2）。第三，我们全面总结了不同实验室使用的所有控制条件，这些条件排除了对外观研究的提示偏差解释。我们得出结论，提示偏差解释可能适用于接近阈限和低可见度的刺激，就像普林兹梅尔等人（2008年）的情况一样，但这种解释与阈上刺激的研究无关。与我们之前的研究一致，目前的数据支持注意力确实会改变阈上刺激的对比度外观这一说法。
