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Are faces special?. Prosopagnosia. Brain damage can produce problems in face recognition - even own reflection (Bodamer, 1947) Prosopagnosia usually results from localized brain damage. Prosopagnosia. Farah (1990) reported that 94% of prosopagnosia patients had damage in the right hemisphere
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Prosopagnosia • Brain damage can produce problems in face recognition - even own reflection (Bodamer, 1947) • Prosopagnosia usually results from localized brain damage
Prosopagnosia • Farah (1990) reported that 94% of prosopagnosia patients had damage in the right hemisphere • Damage usually occurs in the ventral occipital or temporal lobes. • This led to the idea of a face-specific module that resides in the right ventral occipitotemporal regions of the brain
The Thatcher Illusion Features analysed independently Each feature coded relative to gravity
The inversion effect • Humans are most attuned to upright faces • Yin (1970) studied patients with Right hemisphere damage • Recognition test with pictures of faces and houses • Items presented upright and upside down • R hemisphere patients did as well as normal subjects in recognising inverted faces, but were worse at recognising upright faces
The inversion effect • Yin’s interpretation = when faces are upright they are processed by special mechanism in the right hemisphere • Faces presented upside down do not stimulate this mechanism and are treated like objects
Face detection cells • First face detection cells were discovered by Gross et al (1972) • Monkey temporal cortex • Cells did not respond to simple stimuli nor to other complex objects
Brain activity - Faces vs. objects FFA – fusiform face area From FMRI in awake humans