Francis G
Department of Psychological Sciences, Purdue University, West Lafayette, Indiana 47907-1364, USA.
Psychol Rev. 2000 Oct;107(4):768-85. doi: 10.1037/0033-295x.107.4.768.
In metacontrast masking, the effect of a visual mask stimulus on the perceptual strength of a target stimulus varies with the stimulus-onset asynchrony (SOA) between them. As SOA increases, the target percept first becomes weaker, bottoms out at an intermediate SOA, and then increases for still larger SOAs. As a result, a plot of target percept strength against SOA produces a U-shaped masking curve. Theories have proposed special mechanisms to account for this curve, but new mathematical analyses indicate that it is a robust characteristic of a large class of neurally plausible systems. The author describes 3 quantitative methods of accounting for the U-shaped masking effect and analyzes 4 previously published mathematical models of masking. The models produce the masking curve through mask blocking, whereby a strong internal representation of the target blocks the mask's effects.
在元对比掩蔽中，视觉掩蔽刺激对目标刺激感知强度的影响会随着它们之间的刺激呈现间隔（SOA）而变化。随着SOA增加，目标感知首先变弱，在中间的SOA时达到最低点，然后对于更大的SOA又会增加。结果，将目标感知强度与SOA作图会产生一条U形掩蔽曲线。已有理论提出了特殊机制来解释这条曲线，但新的数学分析表明，它是一大类具有神经合理性的系统的一个稳健特征。作者描述了3种解释U形掩蔽效应的定量方法，并分析了4个先前发表的掩蔽数学模型。这些模型通过掩蔽阻断产生掩蔽曲线，即目标的强内部表征会阻断掩蔽的效应。
