Models of Face Recognition and Delusional Misidentification: A Critical Review

Abstract

The "two-route model of face recognition" proposed by Bauer (1984) and adopted by Ellis and Young (1990), has become a widely accepted model in studies of face processing disorders, including both prosopagnosia and the delusional misidentification syndromes. We review the origin and application of the two-route model of face recognition in examining both the neuroanatomical pathways and the cognitive pathways to face recognition. With respect to the neuroanatomy, we conclude that face recognition is subserved by a single pathway, the ventral visual pathway, as there is no evidence to suggest that the dorsal visual pathway is capable of visual recognition or of providing an affective response to familiar stimuli. We demonstrate how operation of the ventral visual pathway and its connections to the amygdala can parsimoniously account for the findings in the literature on prosopagnosia and delusional misidentification syndromes. In addition, we propose a cognitive model of face processing stemming from the work of Bruce and Young (1986). Our model involves two pathways subsequent to the system responsible for face recognition: one pathway to a system containing semantic and biographical information about the seen face, and a second pathway to a system responsible for the generation of an affective response to faces that are familiar. We demonstrate how this cognitive model can explain the dissociations between overt and covert recognition observed in prosopagnosia and the Capgras delusion.

Brain potentials reflect residual face processing in a case of prosopagnosia

“…We propose that the frontal-P3 (in contrast to P3b) is downstream from the same affective evaluation system that leads to the SCR (see Figure 4 in Breen et al, 2000). This would be consistent with the evidence discussed above on preserved early face processing and short latencies for the P300 related to familiar faces.…”

“…The fact that both responses are correlated with the same variable opens the possibility that the neural pathways generating SCR and P300 share some common stages, and that both reflect the processing of affective or social cues. Among the neural structures involved in the processing of this type of information are the STS, the amygdala, and ventromedial frontal cortex (Breen et al, 2000).…”

“…This hypothesis can be made more precise in relation to the update of the Bruce and Young (1986) model of face processing presented recently by Breen et al (2000;see also Ellis & Lewis, 2001). In the model there are two routes that follow from the FRUs.…”

“…Prosopagnosia is simulated in this model by weakening the connections between FRUs and PINs (Young & Burton, 1999). Normal latencies of the frontal-P3 would be expected for this simulation if this ERP component arises subsequent to activation of the FRUs (therefore explaining the covert recognition), but generated within a route parallel to the PINs, as proposed in the model of Breen et al (2000).…”

“…More recently, Breen, Caine, and Coltheart (2000) have modified the Bruce and Young (1986) model of face recognition, including an independent pathway from the face recognition unit to an affective system, which could contribute to covert processing. In this model, the operation of the parallel pathway and its connections with the amygdala can explain covert recognition in prosopagnosia, as well as abnormal emotional processing in Capgras' syndrome (see also Breen & Coltheart, 2001;.…”