Higher order mechanisms in color discrimination

对人类颜色视觉的研究表明，许多关于颜色刺激检测和辨别的数据可以用三个独立的基本机制来解释，它们在颜色空间中调整到不同的方向，以及一个求和规则，如概率求和。最近的研究表明，在某些条件下，调谐到颜色空间中许多不同方向的高阶颜色机制可能会影响颜色刺激的检测和识别。观察者适应状态的变化最清楚地揭示了高阶颜色机制的作用。这些更高阶的颜色机制可能结合了来自三种基本机制的信号，这三种机制被认为是在视觉系统的初始阶段形成的。这项工作的两个目的是确定基数机制在颜色搜索任务中是否独立发挥作用，以及在颜色空间中调谐到许多不同方向的高阶颜色机制是否有助于在颜色搜索任务中检测目标刺激。对视觉搜索任务的研究表明，注意控制下的某种不同的、更灵活的高阶机制可能有助于在不同的分心刺激中检测到目标刺激。这些研究的结果表明，不同感觉编码机制中的信号可能在注意控制下的机制中组合，以促进对目标的检测。要组合的感觉信号可以由观察者选择，并且可能因任务而异。这项工作的第三个目的是研究不同颜色机制中的信号如何在注意控制下的机制中组合，以促进在颜色不同的分心刺激中检测目标刺激。

Studies of human color vision suggest that much of the data on detection and discrimination of color stimuli can be explained with only three independent cardinal mechanisms, tuned to different directions in color space, and a summation rule such as probability summation. Recent studies suggest that higher order color mechanisms, tuned to many different directions in color space, may influence detection and discrimination of color stimuli under some conditions. The action of higher order color mechanisms has been revealed most clearly by changes in the adaptive state of the observer. These higher order color mechanisms presumably combine signals from the three cardinal mechanisms which are believed to be formed in the initial stages of the visual system. Two aims of the proposed work are to determine whether cardinal mechanisms function independently in chromatic search tasks and whether higher order color mechanisms, tuned to many different directions in color space, contribute to the detection of a target stimulus in chromatic search tasks. Studies of visual search tasks have suggested that a somewhat different, more flexible, type of higher order mechanism under attentional control may contribute to the detection of a target stimulus among heterogeneous distractor stimuli. Results from these studies suggest that signals in different sensory coding mechanisms may be combined in mechanisms under attentional control to facilitate detection of the target. The sensory signals to be combined can be selected by the observer and may vary from task to task. The third aim of the proposed work is to investigate how signals in different color mechanisms are combined in mechanisms under attentional control to facilitate the detection of a target stimulus among distractor stimuli that are heterogeneous in color.