Inter-individual variations in internal noise correlate with visual attention but not with post-perceptual processes

Internal noise is an intrinsic component of the perceptual system that is linked to behavioral variability. Recently, we showed that individual levels of internal noise can predict the effects of different types of visual attention such as spatial attention and temporal attention. Here, we sought to extend the examination of the link between visual attention and internal noise by probing the correlations between internal noise and the effects of object-based attention. Post-perceptual factors, in particular working memory, are the most often considered factors in the study of individual differences in attention. Therefore, we also investigated the role of post-perceptual processes such as working memory capacity, meta-perception, and mind wandering. To that end, we estimated observers’ internal noise based on behavioral variability in the double-pass procedure combined with an external noise paradigm, and computational modelling. We also measured the effects of object- and space-based attention in the two-rectangle paradigm which is commonly used in the examination of object-based attention. Post-perceptual factors were assessed in a battery of tasks. We found reliable negative correlations between individual levels of internal noise and the effects of both types of visual attention (space- and object-based); participants with higher levels of internal noise demonstrated smaller effects of attention. Interestingly, we found no correlations between internal noise and any of the post-perceptual factors measured in this study. Taken together these findings demonstrate that internal noise – a fundamental characteristic of visual perception – can predict individual differences in the effects of various types of visual attention. Furthermore, this correlation is unlikely to reflect the involvement of post-perceptual factors that are often considered when investigating individual differences in attentional processes.