The accurate perception of human crowds is integral to social understanding and interaction. Previous studies have shown that observers are sensitive to several crowd characteristics such as average facial expression, gender, identity, joint attention, and heading direction. In two experiments, we examined ensemble perception of crowd speed using standard point-light walkers (PLW). Participants were asked to estimate the average speed of a crowd consisting of 12 figures moving at different speeds. In Experiment 1, trials of intact PLWs alternated with trials of scrambled PLWs with a viewing duration of 3 seconds. We found that ensemble processing of crowd speed could rely on local motion alone, although a globally intact configuration enhanced performance. In Experiment 2, observers estimated the average speed of intact-PLW crowds that were displayed at reduced viewing durations across five blocks of trials (between 2500 ms and 500 ms). Estimation of fast crowds was precise and accurate regardless of viewing duration, and we estimated that three to four walkers could still be integrated at 500 ms. For slow crowds, we found a systematic deterioration in performance as viewing time reduced, and performance at 500 ms could not be distinguished from a single-walker response strategy. Overall, our results suggest that rapid and accurate ensemble perception of crowd speed is possible, although sensitive to the precise speed range examined.

对人群的准确感知是社会理解和互动所不可或缺的。先前的研究表明，观察者对人群的一些特征敏感，例如平均面部表情，性别，身份，共同注意力和方向。在两个实验中，我们使用标准的点光助行器（PLW）检查了人群速度的整体感知。要求参与者估计由12个人以不同速度移动的人群的平均速度。在实验1中，完整PLW的试验与加扰的PLW的试验交替进行，观看时间为3秒。我们发现，尽管全局上完整的配置增强了性能，但对人群速度的整体处理可能仅依赖于局部运动。在实验2中，观察者估计，在五个试验阶段（2500毫秒至500毫秒）中，观看时间持续缩短的完整PLW人群的平均速度。无论观看时间长短，对快速人群的估计都是精确而准确的，并且我们估计在500毫秒内仍可以集成三到四个步行者。对于慢速人群，我们发现随着观看时间的减少，系统性能会有所下降，并且无法将500 ms的性能与单行人的响应策略区分开。总体而言，我们的结果表明，尽管对所检查的精确速度范围敏感，但可以快速而准确地对人群速度进行整体感知。并且我们估计在500毫秒内仍可以集成3到4个助行器。对于慢速人群，我们发现随着观看时间的减少，性能会出现系统性下降，并且无法将500 ms的性能与单步行者的响应策略区分开。总体而言，我们的结果表明，尽管对所检查的精确速度范围敏感，但可以快速而准确地对人群速度进行整体感知。并且我们估计在500毫秒内仍可以集成3到4个助行器。对于慢速人群，我们发现随着观看时间的减少，系统性能会有所下降，并且无法将500 ms的性能与单行人的响应策略区分开。总体而言，我们的结果表明，尽管对所检查的精确速度范围敏感，但可以快速而准确地对人群速度进行整体感知。