Visual imagery and external perception rely on similar representations. However, whether the same processes underpin the subjective appraisal of both percepts and mental images is not yet known. One well-known effect in perceptual detection tasks is that people take longer to report perceptions of absence compared to presence. Vividness reports are detection-like in that participants report the presence or absence of a mental image. We therefore asked whether reports of low vividness share commonalities with reports of target absence. Across five pre-existing datasets, we report a robust negative relationship between imagery vividness ratings and reaction times: participants take longer to report the vividness of mental images when they are weak. In addition, we tentatively find that individual differences in detection asymmetries and trait imagery can predict the strength of this vividness-response time relationship. Our results may be suggestive of a shared mechanism employed across both perception and imagery that evaluates the strength of visual experience. Future research is necessary to fully characterise the mechanisms driving this effect.
Barnett et al. (2025) studied this question.