Abstract
Previous research has shown that the shape of a backward masking function depends upon a number of factors, including the structural properties of the mask, and the relative contrast between target and mask. In our study, we compared backward masking functions between a full face mask and a head outline mask. In both cases, the target was a full face. In the full face mask condition, the target was half the contrast of the mask, and in the head outline mask condition the target and mask contrasts were equal. We found that the full face mask produced peak masking at a lower SOA (stimulus onset asynchrony) compared to the head outline mask, a finding that can be readily explained with several models of masking. We then compared the effect of these two masks in a common onset trailing masking paradigm. Notably, while the full face mask showed a steady increase in masking as a function of trail duration, and saturated at 100 ms, the head outline mask showed a markedly lower amount of masking compared to the full face mask, with some observers showing recovery from masking at longer trail durations. A three way repeated measures ANOVA revealed an interaction between mask type (full face, head outline) and masking paradigm (backwards, trailing) (p = 0.023). We explain these findings by integrating the idea of parvocellular and magnocellular pathways with object updating models.
Meeting abstract presented at VSS 2015