Face Familiarity, Distinctiveness, and Categorical Perception

Abstract

Four experiments with faces support the original interpretation of categorical perception (CP) as only present for familiar categories. Unlike in the results of Levin and Beale (2000), no evidence is found for face identity CP with unfamiliar faces. Novel face identities were shown to be capable of encoding for immediate sorting purposes but the representations utilized do not have the format of perceptual categories. One possibility explored was that a choice of a distinctive face as an end-point in a morphed continuum can spuriously produce effects that resemble CP. Such morphed continua provided unequal psychological responses to equal physical steps though much more so in a better likeness paradigm than for forced-choice recognition. Thus, researchers doing almost the same experiments may produce very different results and come to radically different conclusions.

What’s in the name? Categorical perception for unfamiliar faces can occur through labeling

“…We found this result both with two highly typical and with two highly distinctive faces and in spite of a larger z-score difference in distinctiveness between the pair of faces than for the familiar pair (for which CP was found). This result supports the conclusion of Angeli et al (2008) that previous reports of CP for unfamiliar faces without preexposure (Campanella et al, 2003) may have resulted from unequal distinctiveness of the endpoint faces.…”

“…However, Angeli et al (2008) did not find CP for unfamiliar faces in a better-likeness task, despite the fact that participants studied the endpoint faces with names before the experiment. This difference might be the result of differential task demands, because the better-likeness task requires participants to explicitly relate each presented pair of stimuli back to the studied endpoints ("Which one looks most like Jamie?…”

“…However, Campanella et al did not control the distinctiveness of the faces. Angeli, Davidoff, and Valentine (2008) suggested that Campanella et al's CP effect may have arisen as an artifact because, when the distinctiveness of the faces varies, the perceptual space is larger between morphs that are close to the distinctive face. Thus, the physical difference may have been greater in the between-category discrimination trials than in the within-category trials.…”

A unified account of categorical effects in phonetic perception

“…This ability to streamline processing applies to various types of input, both linguistic and nonlinguistic in nature (Harnad, 1987). Evidence that these categories affect listeners' treatment of perceptual stimuli has been found in diverse areas such as color perception (Davidoff et al, 1999), facial expressions (Angeli et al, 2008;Calder et al, 1996), familiar faces (Beale & Keil, 1995), artificial categories of objects (Goldstone et al, 2001), speech perception (Liberman et al, 1957;Kuhl, 1991), and even emotions (Hess et al, 2009;Sauter et al, 2011). Two core tendencies are found across these domains: a sharp shift in the identification function between category centers, and higher rates of discrimination for stimuli from different categories than for stimuli from a single category.…”

Face-Space: A Unifying Concept in Face Recognition Research

“…Gobet & Simon, 1996a, b) and is based upon the ability to form category boundaries. Category boundaries are associated with face expertise (Angeli, Davidoff & Valentine, 2008;Balas, 2012). Therefore, it is possible that experience narrows the number of dimensions used to recognize faces ensuring that only the most appropriate dimensions remain for frequently encountered faces.…”