Zenger B, Braun J, Koch C
Caltech 139-74, Computation and Neural Systems, 91125, Pasadena CA, USA.
Vision Res. 2000;40(27):3717-24. doi: 10.1016/s0042-6989(00)00218-2.
We studied how attention affects contrast detection performance when the target is surrounded by mask elements. In each display quadrant we presented a hexagon of six vertical Gabor patches (the 'surround'). Only one of the hexagons contained a central Gabor patch (the 'target') and the task was to report that quadrant (spatial four-alternative-forced choice). Attention was manipulated by means of a double-task paradigm: in one condition observers had to perform concurrently a central letter-discrimination task, and the contrast-detection task was then only poorly attended, while attention was fully available in the other condition. We find that under poorly attended conditions targets can be detected only when the target contrast exceeds the surround contrast (contrast popout) or when the target orientation differs from the surround orientation by more than 10-15 degrees (orientation popout). When the target orientation is similar to the surround orientation, attention can reduce the contrast detection thresholds in some cases more than four-fold, demonstrating a very strong attentional effect.
我们研究了当目标被掩蔽元素包围时，注意力如何影响对比度检测性能。在每个显示象限中，我们呈现了一个由六个垂直的伽柏补丁组成的六边形（“周边”）。只有一个六边形包含一个中央伽柏补丁（“目标”），任务是报告那个象限（空间四选一强制选择）。通过双任务范式来操纵注意力：在一种条件下，观察者必须同时执行中央字母辨别任务，此时对比度检测任务的关注度很低，而在另一种条件下注意力则完全可用。我们发现，在关注度低的条件下，只有当目标对比度超过周边对比度（对比度突显）或目标方向与周边方向相差超过10 - 15度（方向突显）时，才能检测到目标。当目标方向与周边方向相似时，在某些情况下注意力可以将对比度检测阈值降低四倍以上，显示出非常强的注意力效应。
