Getting ahead with the flash-lag illusion
We found that for a flash in the middle of the front of a moving visual stimulus the flash-lag illusion was substantially reduced compared with when the flash was displayed in the more usual position to the side of the moving stimulus. Various stimulus arrangements were then used to test for a number of processes which might contribute to this result, and to the flash-lag illusion itself. With two flashes, one at each location, it was determined that the difference in illusions was not due to the relative positions of the two flashes being perceptually distorted by the presence of the moving stimulus. Similarly, temporal order judgements did not reveal a temporal asynchrony between the flashes. Finally, the hypothesis that masking of the 'in-front' flash by the moving object was causing the reduced flash-lag illusion there was tested by similarly masking the lower flash. Again, results did not support this account. Current investigations are pursuing the possibility that inhibitory (Chappell, 2007) or attentional (e.g., Chappell, et al., 2006; 2007) processes around the moving stimulus are differentially affecting flashes in the two locations.
Australian Journal of Psychology