The role of scanpaths in facial recognition and learning

Abstract

We carried out a comprehensive assessment of eye movements in 2 subjects with impaired facial learning and recognition to determine if the defect might be associated with abnormal scanning of faces. Standard electroculogram showed that fixation, pursuit, saccades, and scanning of salient features of scenes and faces were normal, indicating that the defect was not due to abnormal scanning. However, study of the transitional properties of scanning revealed that the scanpaths of personally meaningful familiar faces, whether or not they were consciously recognized, were less predictable than those of other faces. This result indicates the existence of an internal and relatively specific schema for familiar faces sufficient to alter the "predictable" scanpath used for nonfamiliar faces. This internal schema is accessed even when conscious recognition fails, i.e., when other pertinent memories related to the possessor of the face are not evoked. The meaning of this finding is comparable to that obtained with autonomic studies of covert recognition in prosopagnosia and suggests that properties of scanning can be used as an index of higher neural processing.

Brain potentials reflect residual face processing in a case of prosopagnosia

“…Covert recognition effects have also been revealed by eye-movement scan paths (Rizzo, Hurtig, & Damasio, 1987) and by skin conductance responses (SCR; Bauer, 1984;Tranel & Damasio, 1985). However, covert recognition is not found in all cases of prosopagnosia, and not all forms of covert processing may be present in those cases where it is found (Bauer, 1984;Etcoff, Freeman, & Cave, 1991;McNeil & Warrington, 1991;Newcombe, Young, & De Haan, 1989), which is consistent with the heterogeneous nature of the disorder.…”

Honeybee (Apis mellifera) vision can discriminate between and recognise images of human faces

“…Future experiments may be able to reveal the visual mechanism used by bees to facilitate face recognition by using a wider range of face stimuli and by considering the variety of approaches previously used to reveal feature extraction and configural mechanisms for the human perception of faces (e.g. Yin, 1969;Carey and Diamond, 1977;Bruce, 1988;Rizzo et al, 1987;Tanaka and Farah, 1993;Tanaka and Sengco, 1997;Collishaw and Hole, 2000).…”

“…This suggests that face recognition is a task that can be solved, at least to a certain level, by a general neural system that has a reasonable degree of plasticity. The finding that bees can reliably recognise faces may seem surprising in the context that there are human subjects who suffer from prosopagnosia and are unable to recognise the faces of familiar persons, despite having reasonably normal visual processing (Rizzo et al, 1987;De Renzi and di Pellegrino, 1998;Duchaine, 2004). However, there is evidence that subjects with prosopagnosia may covertly recognise individual faces and that the inability to be able to report recognition is due to limitations on the activation of associated memory for a face (Tranel and Damasio, 1985), even though the visual system has captured sufficient information to allow for a recognition (Tranel and Damasio, 1985;Rizzo et al, 1987).…”

“…The finding that bees can reliably recognise faces may seem surprising in the context that there are human subjects who suffer from prosopagnosia and are unable to recognise the faces of familiar persons, despite having reasonably normal visual processing (Rizzo et al, 1987;De Renzi and di Pellegrino, 1998;Duchaine, 2004). However, there is evidence that subjects with prosopagnosia may covertly recognise individual faces and that the inability to be able to report recognition is due to limitations on the activation of associated memory for a face (Tranel and Damasio, 1985), even though the visual system has captured sufficient information to allow for a recognition (Tranel and Damasio, 1985;Rizzo et al, 1987). The results in this current study show that even bees are capable of recognising human faces and thus supports the view that the human brain may not need to have a visual area specific for the recognition of faces Tarr and Gauthier, 2000;Tarr and Cheng, 2003).…”

Neural Activation during Covert Processing of Positive Emotional Facial Expressions

“…However, there is extensive evidence of covert facial recognition from studies in both normals and prosopagnosics (Bruce and Young, 1986;DeHaan et al, 1987;Bruyer et al, 1983;Rizzo et al, 1987;Tranel and Damasio, 1985;Barrett and Rugg, 1989;Barrett et al, 1988;Uhl et al, 1990). Selective lesions may also result in an inability to recognize facial expressions (Shuttleworth et al, 1982).…”