Prior expectation powerfully shapes perception, yet its effects have been notoriously difficult to characterize due to the confounding influence of attention. In this study, we systematically investigated expectation's influence on conscious visual object recognition while carefully disentangling it from attentional effects. Across three experiments, we observed that expectation's effect varied markedly depending on the experimental context. When expectation was manipulated in isolation, it enhanced recognition sensitivity, mirroring the effects of attention. However, when expectation and attention were orthogonally manipulated, a surprising interaction effect emerged whereby observers were less likely to report recognition of an expected stimulus in the unattended condition-an effect attributed to swap errors. Finally, a stronger expectation cue in both space and time reduced swap errors and increased the likelihood of observers reporting seeing the expected stimuli. These findings reveal a remarkable degree of flexibility and context dependence in expectation's influence on perception and shed new light on how attention and expectation jointly shape conscious object recognition.
Wu et al. (Mon,) studied this question.