|Faces Equally Special in Different Spatial Formats|
Faces are thought to be special. But some research argues that a line drawing of your cousin Ginny is much less special than, say, an out-of-focus picture of your uncle Bob. That is, we may recognize a very blurry image (containing low spatial frequencies) of a face just like we do a normal photo, but line drawings (containing high spatial frequencies) appear not to engage the same holistic strategy typical of face recognition. Holistic processing generally helps us recognize faces, but it also makes it hard to perceive one half of a face while ignoring another half, as the two parts seem to fuse into a whole (see Figure). NSF-funded researchers from the Temporal Dynamics Learning Center, Olivia Cheung, Jennifer Richler, Thomas Palmeri and Isabel Gauthier from Vanderbilt University published a new study in which they re-investigate this question. They find that observers used the same holistic strategy to process faces with either high or low spatial frequencies. The difference found in prior work appeared instead to be due to our high propensity to say that two line drawings are the same, regardless of whether they are or not. While it is still unclear why we have developed this response bias, the researchers suggest that the longer perceived persistence of higher-spatial frequencies, after the image is no longer present, may lead an observer to misinterpret how much time he or she has been looking at a face without having yet recognized it. In essence, this differential visual persistence is misinterpreted by our brains as a signal of differential recognition. An intriguing implication is that simple factors influencing low-level vision, such as the temporal dynamics of different spatial frequencies, can influence higher level processes that translate in a response bias.
Cheung, O.S., Richler, J.J., Palmeri, T.J. & Gauthier, I. (in press). Revisiting the role of spatial frequencies in the holistic processing of faces. Journal of Experimental Psychology: Human Perception and Performance.