Spatial frequency thresholds for face recognition when comparison faces are filtered and unfiltered

Previous work has shown an advantage of middle spatial frequencies (SFs) in face recognition. However, a few recent studies have suggested that this advantage is reduced when comparison and test stimuli are spatially filtered in a similar way. In the present study, we used standard psychophysical methods, in combination with a match-to-sample task, to determine the SF thresholds for face matching under conditions in which: (1) comparison stimuli were unfiltered and (2) comparison stimuli were spatially filtered in the same way as test stimuli. In two experiments, we show that SFs closer to the middle band are sought out more in the former case than in the latter. These results are compatible with the idea that a middle band of SFs will be most useful for any visual task and that the breadth of this optimal middle band will vary depending on task characteristics.