Capacity Limits in Visual Processing Revealed by Spatial Biases

Our early visual system extracts fine grained information about our rapidly changing world, yet in certain laboratory conditions, participants fail to report some items that are clearly presented within their field of vision. These failures are likely to occur because later stages of the visual system do not have capacity to process all of the information extracted at the retina. In this thesis, I investigate a particular failure of awareness that occurs when two target letters are briefly presented at the same time in different spatial locations. A clue to the cause of these failures may lie in the spatial pattern of errors that participants make. A recent theory suggests that the consistency in spatial errors across participants may reflect a functional strategy used by the brain to prioritise information at a key processing bottleneck. I investigate this claim, and conduct research to investigate other aspects of the limitation, such as the processing stage at which it occurs, and its implications for visual processing tasks such as reading