De Vries Jelmer P, Hooge Ignace T C, Wertheim Alexander H, Verstraten Frans A J
Helmholtz Institute, Utrecht Neuroscience & Cognition, Department of Experimental Psychology, Utrecht University, Netherlands.
Vision Res. 2013 Jun 28;86:128-38. doi: 10.1016/j.visres.2013.04.010. Epub 2013 Apr 25.
The ability to detect an object depends on the contrast between the object and its background. Despite this, many models of visual search rely solely on the properties of target and distractors, and do not take the background into account. Yet, both target and distractors have their individual contrasts with the background. These contrasts generally differ, because the target and distractors are different in at least one feature. Therefore, background is likely to play an important role in visual search. In three experiments we manipulated the properties of the background (luminance, orientation and spatial frequency, respectively) while keeping the target and distractors constant. In the first experiment, in which target and distractors had a different luminance, changing the background luminance had an extensive effect on search times. When background luminance was in between that of the target and distractors, search times were always short. Interestingly, when the background was darker than both the target and the distractors, search times were much longer than when the background was lighter. Manipulating orientation and spatial frequency of the background, on the other hand, resulted in search times that were longest for small target-background differences. Thus, background plays an important role in search. This role depends on the individual contrast of both target and distractors with the background and the type of feature contrast (luminance, orientation or spatial frequency).
检测物体的能力取决于物体与其背景之间的对比度。尽管如此，许多视觉搜索模型仅依赖于目标和干扰项的属性，而没有考虑背景。然而，目标和干扰项与背景都有各自的对比度。这些对比度通常不同，因为目标和干扰项至少在一个特征上存在差异。因此，背景很可能在视觉搜索中发挥重要作用。在三个实验中，我们在保持目标和干扰项不变的同时，分别操纵了背景的属性（亮度、方向和空间频率）。在第一个实验中，目标和干扰项的亮度不同，改变背景亮度对搜索时间有广泛影响。当背景亮度介于目标和干扰项之间时，搜索时间总是很短。有趣的是，当背景比目标和干扰项都暗时，搜索时间比背景亮时长得多。另一方面，操纵背景的方向和空间频率，会导致目标与背景差异较小时搜索时间最长。因此，背景在搜索中起着重要作用。这个作用取决于目标和干扰项与背景的各自对比度以及特征对比度的类型（亮度、方向或空间频率）。
