Abstract
There is a compelling subjective impression that peripheral vision is colorful and vivid. However, peripheral visual processes carry less information than foveal vision: it is associated with low spatial resolution, low color sensitivity and in general receives little attention compared to the foveal location. How does this low information capacity account for the subjective vividness in peripheral perception We have previously shown that at identical eccentricity, the lack of covert spatial attention can inflate subjective perception, making detection criterion liberal (Rahnev et al 2011 Nature Neuroscience). Our computational model suggests that this is because under the lack of attention, the internal perceptual response may be more variable. Under a somewhat inflexible detection criterion set commonly for both the attended and unattended locations, high variability may mean that the internal response can exceed the criterion more frequently, leading to a liberal detection bias. We hypothesized that the same mechanism of subjective perceptual inflation may be at work in peripheral vision. We investigated this possibility in psychophysical experiments in which subjects detected the presence of Gabor patches in either the fovea or the periphery. Confirming our hypothesis, we found that subjects tended to use a more liberal detection criterion in the periphery than in the center (that is, subjects reported seeing the target more frequently in the periphery). In trying to understand the neurobiological mechanism behind this phenomena, we developed a neuronal model which takes into account the fact that peripheral vision involves a relatively fewer number of neurons with large spatial uncertainty (receptive fields). Assuming the overall sensory response is reflected by pooling information over many neurons, the model gives a plausible explanation as to why peripheral vision produces sensory responses with larger variability, and thereby inflated subjective perception.
Meeting abstract presented at VSS 2013