Covert recognition relies on affective valence in developmental prosopagnosia: evidence from the skin conductance response.

OBJECTIVE: It has traditionally been thought that covert face recognition cannot be observed in developmental cases of prosopagnosia, because the phenomenon is thought to rely on the activation of face representations created during a period of normal processing. Yet, recent studies have provided evidence of covert recognition in some developmental cases, and critically the findings of one study suggest that these individuals might be processing faces on an affective dimension rather than a familiarity dimension. The current study aimed to examine this possibility using a physiological measure of covert recognition, the skin conductance response (SCR).
METHOD: One 61-year-old male with developmental prosopagnosia and 10 age-matched (M = 59.80 years, SD = 4.02) controls (5 men) took part in this study. Participants viewed a set of 15 famous faces intermixed with 30 novel faces, and the SCR was recorded throughout.
RESULTS: Although control participants demonstrated an increased SCR for famous faces in comparison with novel faces, t(9) = 2.112, p = .032, d = .382, the same finding was not observed in Patient WS. However, when WS' increase in SCR was correlated with his affective ratings of the celebrities from name cues, a strong negative correlation was observed (r = -.614, n = 34, p = .020).
CONCLUSION: This pattern of findings was interpreted as evidence that WS is covertly processing faces on an affective dimension rather than a familiarity dimension, and fits well with recent neurophysiological findings that support hypotheses for independent processing of cognitive and affective information.