In the scope of the research project 129/20 - Investigating the role of expertise in the predictive coding framework combining time resolved neural and behavioural evidence, supported by the BIAL Foundation, Marie Smith and colleagues, through a behavioural categorization task in which 67 participants learned the probabilistic association between a colour cue and a high and low expertise category (faces and cars respectively), they assessed the individual level of expertise in each category. They found that the perception of the high expertise category (faces) was modulated by expectation. That is, there was a faster response when the faces were expected. Furthermore, in the analysis of neural activity (EEG), there were effects of expectation, with significant decoding of the neural response to expected stimuli. These results support the influence of expectation on face perception, highlight the role of expertise and draw attention to individual variability, which is often neglected. More information is available in the article Effects of expectation on face perception and its association with expertise published in the scientific journal Scientific Reports.
ABSTRACT
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 colour 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.
