Uncertainty and Confidence in Visual Perception

Visual perception is often seen as an inference problem where uncertainty comes from ambiguities in the world (eg, the two 3D interpretations of the Necker cube), noise in the world (eg, identifying a scene behind falling snowflakes), or noise in the visual system (eg, synaptic noise). Uncertainty not only influences our performance in visual perception tasks (eg, how well can we discriminate between two orientations) but also our confidence in being able to perform these tasks (how well can we predict our performance). We present here the results of three psychophysical experiments that illustrate how uncertainty weakens our perception and how it can determine our confidence in our perceptual decisions. In the first experiment on stereopsis, we show that the same level of uncertainty can lead to very different levels of performance depending on the context. In the next two experiments on orientation discrimination, we show that objective confidence judgments are correlated with discrimination performance and that these confidence judgments are not just based on some visibility cues in the stimulus. Overall, these results open the door for a thorough investigation of the processing of uncertainty by the visual system