Memory for faces

Good snippet on today

Prosopagnosia is an inability to recognise faces. It most commonly occurs after brain injury, although this week’s New Scientist reports on a recently completed study on a type of inherited prosopagnosia, suggesting a genetic basis for face recognition.

The research was an international effort, led by husband and wife team, geneticists Thomas and Martina Gr¬łter. Notably, Thomas has a particular interest in this area, as he has prosopagnosia himself

What is it like having prosopagnosia ? For example, do faces seem strange or distorted to you?

Faces look perfectly normal, they just fade in my memory very quickly. I can recognize emotions as well as other people, maybe better.

Very interesting. Three points

1. I had never really thought of prosopagnosia in terms of normal perception of faces with weak to negligible memory trace. All the cognitive neuropsychology textbooks paint a much more cataclysmic picture of face being percieved as ‘flat and featureless’ or jumbled, confusing, etc. They, of course, are talking about acquired prosopagnosia but definitely seem to always be complete emphasis on the perceptual aspects of the system. It is interesting to me how easily I overlook the role of memory in face/object/etc recognition.

2. from anecdotal evidence I think it is fair to say that face recognition ability is on a spectrum in general population, so i’d like to hope any diagnostic measures they develop can capture this range of competances even at mild deficiency. most cog neuropsych test seem to have ‘normals’ performing at ceiling.

3. whatever they do find it will be at most a gene [necessary] for face recognition but not necessarily sufficient. in fact very far from it. obviously we know this it is always the bit that gets left out by journalists. Although I guess you might call it ‘the gene for not having prosopagnosia.’

About caspar

Caspar is just one monkey among billions. Battering his keyboard without expectations even of peanuts, let alone of aping the Immortal Bard. By day he is an infantologist at Birkbeck Babylab, by night he runs
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1 Response to Memory for faces

  1. kevin desimone says:

    to say that faces he views appear “normal” and that his problem seems to be related to memory, rather than perception, is suspect.

    you’re right in saying that the deficit is perceptual for patients acquiring prosopagnosia, and so his deficit may be slightly different on account of genetic variation (ant not acute trauma of some sort).

    you have to wonder, though, how much insight he has into his own condition. i would tend to believe that he has no conception of “normal” faces–for a number of reasons.

    Think of it this way. El Greco was a Spanish artist (1541-1614) who had a tendency to paint his human figures as slight elongated along the head-to-foot axis. Anatomically-minded art historians began to wonder if he had some sort of ocular or otherwise visual deficit that could account for this constistent elongation of what appeared to be an attempted 1:1 mapping of human subjects onto canvas. Who knows–perhaps he had a mis-shapen eyeball, resulting in a focused retinal image that differs slightly from the general population (e.g., myopia).

    Well, this turns out to be false. If he had a malformed eyeball (or dyfunctional perceptual module), he would preceive the world this way–elongated, say. And, if he intended to create a 1:1 mapping of the world onto canvas in the form of human figures, the painting itself would be a subject of his perceptual mishap. So, he would draw an elongated figure as he perceived an elongated figure, neither of which turn out to actually be elongated. he’s simply being consistent.

    alas–this may be a moot point. Daniel Dennett argues that, as far as the distinction between perception and memory, as elicited through verbal reports, is concerned there simply is no fact of the matter.

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