Research master thesis | Psychology (research) (MSc)
open access
Identical sensory input may be perceived differently, based on expectations and goals. For example, object recognition is facilitated for expected or task-relevant objects. At the same time,...Show moreIdentical sensory input may be perceived differently, based on expectations and goals. For example, object recognition is facilitated for expected or task-relevant objects. At the same time, unexpected objects are found to elicit a stronger neural response. These effects can be explained by predictive coding accounts of visual processing, presenting perception as a process of minimizing the difference between predicted and observed sensory input. However, as expectation and task-relevance are often conflated, it is insufficiently clear how these factors influence sensory processing in conscious perception. The current study aimed to investigate the relative influence of expectation and task-relevance on behavioral and neural measures of perception. During two EEG sessions, participants performed a task in which they discriminated between masked face and house images while we independently manipulated expectation and task-relevance. We find that images were more often correctly recognized when they were expected or task-relevant. In addition, we used multivariate pattern analysis to show that a classifier trained on sensory representations of face and house stimuli is better able to distinguish between expected or task-relevant face and house images than between unexpected or task-irrelevant images. These results suggest that expectation and task-relevance have independent effects on sensory processing. Finally, our results show that cue-based manipulations may activate sensory templates even before stimulus onset. We therefore recommend that future studies manipulate expectation and task-relevance without the use of explicit cues.Show less
