Previous research has demonstrated that individuals exhibit a tendency to overestimate the variability of both low-level features (e.g., color, orientation) and mid-level features (e.g., size) when items are presented dynamically in a sequential order, a finding we will refer to as the variability overestimation effect. Because previous research on this bias used sequential displays, an open question is whether the effect is due to a memory-related bias or a vision-related bias. To assess whether the bias would also be apparent with static, simultaneous displays, and to examine whether the bias generalizes to spatial properties, we tested participants’ perception of the variability of a cluster of dots. Results showed a consistent overestimation bias: Participants judged the dots as being more spread than they actually were. The variability overestimation effect was observed when there were 10 or 20 dots but not when there were 50 dots. Taken together, the results of the current study contribute to the ensemble perception literature by providing evidence that simultaneously presented stimuli are also susceptible to the variability overestimation effect. The use of static displays further demonstrates that this bias is present in both dynamic and static contexts, suggesting an inherent bias existent in the human visual system. A potential theoretical account—boundary effect—is discussed as a potential underlying mechanism. Moreover, the present study has implications for common visual tasks carried out in real-world scenarios, such as a radiologist making judgments about distribution of calcification in breast cancer diagnoses.

先前的研究表明，当项目按顺序动态呈现时，个人倾向于高估低级特征（例如颜色、方向）和中级特征（例如大小）的可变性，我们将发现这一发现称为变异性高估效应。因为之前关于这种偏差的研究使用了顺序显示，所以一个悬而未决的问题是这种影响是由于记忆相关的偏差还是视觉相关的偏差。为了评估静态、同步显示的偏差是否也很明显，并检查偏差是否推广到空间属性，我们测试了参与者对一组点的可变性的感知。结果显示出一致的高估偏差：参与者认为这些点比实际分布得更广。当有 10 或 20 个点时观察到变异性高估效应，但在有 50 个点时没有。综上所述，当前研究的结果通过提供证据表明同时呈现的刺激也容易受到变异性高估效应的影响，从而为整体感知文献做出了贡献。静态显示的使用进一步表明这种偏见存在于动态和静态环境中，表明人类视觉系统中存在固有的偏见。一个潜在的理论解释——边界效应——被讨论为一种潜在的潜在机制。此外，本研究对在现实世界场景中执行的常见视觉任务有影响，例如放射科医生对乳腺癌诊断中钙化分布的判断。