ELSC Edmond & Lily Safra Center for Brain Research & Life Sciences Institute, Hebrew University, Jerusalem, Israel.
ELSC Edmond & Lily Safra Center for Brain Research & Psychology Department, Hebrew University, Jerusalem, Israel.
J Vis. 2023 Mar 1;23(3):7. doi: 10.1167/jov.23.3.7.
Ensemble perception refers to the visual system's ability to efficiently represent groups of similar objects as a unified percept using their summary statistical information. Most studies focused on extraction of current trial averages, giving little attention to prior experience effects, although a few recent studies found that ensemble mean estimations contract toward previously presented stimuli, with most of these focusing on explicit perceptual averaging of simultaneously presented item ensembles. Yet, the time element is crucial in real dynamic environments, where we encounter ensemble items over time, aggregating information until reaching summary representations. Moreover, statistical information of objects and scenes is learned over time and often implicitly and then used for predictions that shape perception, promoting environmental stability. Therefore, we now focus on temporal aspects of ensemble statistics and test whether prior information, beyond the current trial, biases implicit perceptual decisions. We designed methods to separate current trial biases from those of previously seen trial ensembles. In each trial, six circles of different sizes were presented serially, followed by two test items. Participants were asked to choose which was present in the sequence. Participants unconsciously rely on ensemble statistics, choosing stimuli closer to the ensemble mean. To isolate the influence of earlier trials, the two test items were sometimes equidistant from the current trial mean. Results showed membership judgment biases toward current trial mean, when informative (largest effect). On equidistant trials, judgments were biased toward previously experienced stimulus statistics. Comparison of similar conditions with a shifted stimulus distribution ruled out a bias toward an earlier, presession, prototypical diameter. We conclude that ensemble perception, even for temporally experienced ensembles, is influenced not only by current trial mean but also by means of recently seen ensembles and that these influences are somewhat correlated on a participant-by-participant basis.
整体感知是指视觉系统利用其汇总的统计信息，有效地将相似物体的群组表示为一个统一的感知。大多数研究都集中在提取当前试验的平均值上，很少关注先前的经验效应，尽管最近有几项研究发现，整体均值估计会向先前呈现的刺激收缩，其中大多数研究都集中在同时呈现的项目集合的显式感知平均上。然而，时间元素在真实的动态环境中至关重要，在这些环境中，我们随着时间的推移遇到集合项目，汇总信息直到达到总结代表。此外，物体和场景的统计信息是随着时间学习的，通常是隐式的，然后用于预测，这些预测塑造了感知，促进了环境的稳定性。因此，我们现在关注集合统计的时间方面，并测试先前的信息是否会影响隐含的感知决策，而不仅仅是当前的试验。我们设计了方法来分离当前试验的偏差和先前看到的试验集合的偏差。在每次试验中，都会连续呈现六个不同大小的圆圈，然后呈现两个测试项目。要求参与者选择序列中存在的那个。参与者无意识地依赖于集合统计信息，选择更接近集合均值的刺激。为了隔离早期试验的影响，两个测试项目有时与当前试验均值等距。结果表明，当信息丰富时（最大效应），成员判断会偏向当前试验均值。在等距试验中，判断会偏向先前经验刺激的统计数据。对具有移位刺激分布的类似条件进行比较排除了对先前、预会话、原型直径的偏向。我们得出结论，即使是对时间上经历过的集合，集合感知也不仅受到当前试验均值的影响，还受到最近看到的集合的影响，而且这些影响在参与者之间有一定的相关性。
