Solomon Joshua A, May Keith A, Tyler Christopher W
J Vis. 2016;16(1):13. doi: 10.1167/16.1.13.
Intuition suggests that increased viewing time should allow for the accumulation of more visual information, but scant support for this idea has been found in studies of voluntary averaging, where observers are asked to make decisions based on perceived average size. In this paper we examine the dynamics of information accrual in an orientation-averaging task. With orientation (unlike intensive dimensions such as size), it is relatively safe to use an item's physical value as an approximation for its average perceived value. We displayed arrays containing eight iso-eccentric Gabor patterns, and asked six trained psychophysical observers to compare their average orientation with that of probe stimuli that were visible before, during, or only after the presentation of the Gabor array. From the relationship between orientation variance and human performance, we obtained estimates of effective set size, i.e., the number of items that an ideal observer would need to assess in order to estimate average orientation as well as our human observers did. We found that display duration had only a modest influence on effective set size. It rose from an average of ∼2 for 0.1-s displays to an average of ∼3 for 3.3-s displays. These results suggest that the visual computation is neither purely serial nor purely parallel. Computations of this nature can be made with a hybrid process that takes a series of subsamples of a few elements at a time.
直觉表明，增加观看时间应该能够积累更多的视觉信息，但在自愿平均的研究中，很少能找到对这一观点的支持。在这些研究中，观察者被要求根据感知到的平均大小做出决策。在本文中，我们研究了方向平均任务中信息积累的动态过程。对于方向（与大小等强度维度不同），将项目的物理值用作其平均感知值的近似值相对安全。我们展示了包含八个等偏心Gabor图案的阵列，并要求六名经过训练的心理物理学观察者将其平均方向与在Gabor阵列呈现之前、期间或仅在呈现之后可见的探测刺激的平均方向进行比较。从方向方差与人类表现之间的关系，我们获得了有效集合大小的估计值，即理想观察者为了像我们的人类观察者一样准确估计平均方向而需要评估的项目数量。我们发现显示持续时间对有效集合大小的影响不大。它从0.1秒显示时的平均约2增加到3.3秒显示时的平均约3。这些结果表明，视觉计算既不是纯粹串行的，也不是纯粹并行的。这种性质的计算可以通过一种混合过程来进行，该过程一次对几个元素进行一系列子采样。
