We discuss the results from the perspective of a cognitive-relevance theory of attentional guidance. The results strongly suggest that meaning guides attention in real-world scenes. This pattern was observed in early as well as late fixations, fixations including and excluding the centers of the scenes, and fixations following short as well as long saccades. The results showed that both meaning and image salience predicted the duration-weighted distribution of attention, but that when the correlation between meaning and salience was statistically controlled, meaning accounted for unique variance in attention whereas salience did not. Extending previous work, here the distribution of attention was operationalized as duration-weighted fixation density. We investigated the degree to which meaning versus image salience predicted human viewers' spatiotemporal distribution of attention over scenes. Meaning maps were coded in a format that could be directly compared to maps of image salience generated from image features. Meaning was captured by “meaning maps” representing the spatial distribution of semantic information in scenes. Together, this awareness-dependent mapping of saliency reconciles several previous, seemingly contradictory findings regarding the nature of the saliency map.We compared the influence of meaning and of salience on attentional guidance in scene images. Crucially, we further revealed that the graded distribution was contingent upon feedback from the posterior intraparietal sulcus (pIPS, especially from the right pIPS), whereas the non-graded distribution was innate to V1. By combining psychophysics, fMRI, and effective connectivity analysis, we found a graded distribution of salience with awareness, changing to a non-graded distribution without awareness.

The invisible and visible displays were empirically validated by a two-alternative forced choice test (detecting the quadrant of the target) demonstrating subjects’ performance at or above chance level, respectively. Interference, or not, by the distractor with the effective salience of the target served to index a graded or non-graded nature of salience mapping, respectively. These questions were addressed here using either visible or invisible displays presenting two foreground stimuli (whose bars were oriented differently from the bars in the otherwise uniform background): a high salience target and a distractor of varied, lesser salience. Yet, how salience is mapped when multiple salient stimuli are present simultaneously, and how this mapping interacts with awareness remains unclear.

The allocation of exogenously cued spatial attention is governed by a saliency map.

Attention map vs. saliency map