Posted by alexandra_k on December 22, 2004, at 17:09:03
A Familiarity Mechanism
I have already mentioned that Ellis and Young (1990) consider the anomalous experience to arise from a breakdown of the affective pathway. They do not explicitly consider the function of this pathway except to maintain that its breakdown results in the anomalous experience that is relevant to the Capgras delusion. I would like to suggest, however, that the function of the affective pathway may be a low level face recognition system. It may be plausible to think that there would be an evolutionary advantage to being able to quickly recognize whether people are familiar or strangers. We would be at an advantage if we had a low level system that could monitor for threat potential so that we could relax when the people around us are familiar and are unlikely to pose a threat.
There would also seem to be a benefit in taking such a system to be fairly low level so as to function unconsciously, as attentional and cognitive resources would be freed up for alternative activities. If this is plausible then we would seem to have an independent reason to believe in a fast, low level, primitive face recognition system. It would seem plausible that if this mechanism were to be faulty or defective then the content of the delusional experience would be that ‘this person is unfamiliar to me’. If it is indeed a low level system then this may also go some way towards explaining why it is that the delusional subject cannot just ignore the message that the person is a stranger despite others trying to argue them out of their delusion. The mechanism may not be able to be brought under the conscious control of the subject, or learning how to consciously inhibit the ‘stranger danger’ signal may take a bit of time.The anomalous experience of subjects with the Capgras delusion occurs reliably whenever the subject experiences the face of their loved one, and aside from this anomalous experience the delusional subject may well have normal experiences. This would seem to go some of the way towards explaining why it is that some subjects with the Capgras delusion do not have any other delusional beliefs, and it also seems to explain why they have the particular variety of delusion that they do. The ‘alarm bells’ signal that something is wrong, but more than that, they signal just what is wrong; namely that the person in front of them is unfamiliar to them.
poster:alexandra_k
thread:432996
URL: http://www.dr-bob.org/babble/write/20041210/msgs/432996.html