what we see

Source:

University College London

"Typically when we see something, we have insight not only into what it is that we've seen, but also how clearly we've seen it," 

To explain this ability, research has previously suggested that the brain acts a bit like a scientist or statistician, evaluating the quality of our experiences to inform how confident we feel. Our study challenges this view, instead finding that confidence is closely related to unconscious states of physiological arousal."

Unbeknownst to the volunteers, on some trials a startling image of a disgusted face appeared too briefly to be consciously perceived, causing their heart rate and pupil dilation to increase. Although the volunteers' confidence was reduced when the dots were noisier and more difficult to detect, this effect was counteracted by the increased arousal.

"Our results suggest that subtle, unconscious changes in the physiological state of our bodies impact how we perceive uncertainty. Interestingly, we found that not only did confidence correlate with how fast a participant's heart beat on each trial, but that artificially increasing arousal actually caused participants to act as if they were blind to the quality of their visual experiences. This suggests that our capacity for conscious introspection is much more embodied than previously thought," said lead author Micah Allen (UCL Institute of Neurology).

Co-author Professor Geraint Rees (Dean, UCL Faculty of Life Sciences) added: "As disorders such as depression and anxiety can be linked to altered states of arousal, our findings raise the possibility that patients suffering from these conditions might perceive an unrealistically certain or uncertain world."