Perceptual decisions are derived from the combination of priors and sensorial input. While priors are broadly understood to reflect experience/expertise developed over one’s lifetime, the role of perceptual expertise at the individual level has seldom been directly explored. Here, we manipulate probabilistic information associated with a high and low expertise category (faces and cars respectively), while assessing individual level of expertise with each category. 67 participants learned the probabilistic association between a color cue and each target category (face/car) in a behavioural categorization task. Neural activity (EEG) was then recorded in a similar paradigm in the same participants featuring the previously learned contingencies without the explicit task. Behaviourally, perception of the higher expertise category (faces) was modulated by expectation. Specifically, we observed facilitatory and interference effects when targets were correctly or incorrectly expected, which were also associated with independently measured individual levels of face expertise. Multivariate pattern analysis of the EEG signal revealed clear effects of expectation from 100 ms post stimulus, with significant decoding of the neural response to expected vs. not stimuli, when viewing identical images. Latency of peak decoding when participants saw faces was directly associated with individual level facilitation effects in the behavioural task. The current results not only provide time sensitive evidence of expectation effects on early perception but highlight the role of higher-level expertise on forming priors.

感知决策源自先验和感官输入的结合。虽然先验被广泛理解为反映一个人一生中积累的经验/专业知识，但感知专业知识在个人层面的作用很少被直接探讨。在这里，我们操纵与高和低专业知识类别（分别是面孔和汽车）相关的概率信息，同时评估每个类别的个人专业知识水平。 67 名参与者在行为分类任务中学习了颜色提示与每个目标类别（面部/汽车）之间的概率关联。然后，以类似的范式记录相同参与者的神经活动（EEG），这些参与者具有先前学到的意外事件，但没有明确的任务。在行为上，对更高专业类别（面孔）的看法是由期望来调节的。具体来说，我们观察到当目标被正确或错误预期时的促进和干扰效应，这也与独立测量的个人面部专业知识水平相关。 EEG 信号的多变量模式分析揭示了刺激后 100 毫秒的预期效果，在观看相同图像时，对预期刺激与非刺激的神经反应进行了显着解码。参与者看到面孔时的峰值解码延迟与行为任务中的个体水平促进效应直接相关。目前的结果不仅提供了预期对早期感知影响的时间敏感证据，而且强调了更高水平的专业知识在形成先验方面的作用。