Visual confidence is the observers’ estimate of their precision in one single perceptual decision. Ultimately, however, observers often need to judge their confidence over a task in general rather than merely on one single decision. Here, we measured the global confidence acquired across multiple perceptual decisions. Participants performed a dual task on two series of oriented stimuli. The perceptual task was an orientation-discrimination judgment. The metacognitive task was a global confidence judgment: observers chose the series for which they felt they had performed better in the perceptual task. We found that choice accuracy in global confidence judgments improved as the number of items in the series increased, regardless of whether the global confidence judgment was made before (prospective) or after (retrospective) the perceptual decisions. This result is evidence that global confidence judgment was based on an integration of confidence information across multiple perceptual decisions rather than on a single one. Furthermore, we found a tendency for global confidence choices to be influenced by response times, and more so for recent perceptual decisions than earlier ones in the series of stimuli. Using model comparison, we found that global confidence is well described as a combination of noisy estimates of sensory evidence and position-weighted response-time evidence. In summary, humans can integrate information across multiple decisions to estimate global confidence, but this integration is not optimal, in particular because of biases in the use of response-time information.

视觉置信度是观察者对其在单个感知决策中的精确度的估计。然而，归根结底，观察者通常需要判断他们对一般任务的信心，而不是仅仅根据一个单一的决定。在这里，我们测量了通过多个感知决策获得的全局信心。参与者对两个系列的定向刺激执行双重任务。知觉任务是方向辨别判断。元认知任务是一个整体的信心判断：观察者选择了他们认为在感知任务中表现更好的系列。我们发现，无论全局置信度判断是在感知决策之前（前瞻性）还是之后（回顾性）做出，随着系列中项目数量的增加，全局置信度判断中的选择准确性会提高。这一结果证明，全局置信度判断是基于跨多个感知决策的置信度信息的整合，而不是基于单个决策。此外，我们发现全局信心选择受响应时间影响的趋势，最近的感知决策比一系列刺激中的早期感知决策更受影响。使用模型比较，我们发现全局置信度被很好地描述为感官证据和位置加权响应时间证据的噪声估计的组合。总之，人类可以整合多个决策的信息来估计全局置信度，但这种整合并不是最佳的，特别是因为响应时间信息的使用存在偏差。