Greg Detre
1/03/01
DSM IV definition of dlusion
Capgras delusion, anti-evolutionists?, I am dead (Cotard�s), thoughts being inserted into my mind
subjects act on delusions as though ordinary beliefs
but the patient understands the words, seemingly
2 models of the explanation of belief
laws governing beliefs/desires/intentions etc.
in terms of other beliefs/desires etc. that rationalise the belief
role of rationality � psychological explanation as
subsuming phenomena under laws (theory theory, e.g. Fodor)
showing why it�s rational/seemed like a good idea at the time
Jaspers
delusions are un-understandable, cannot be given psychological explanations
because they�re irrational, cannot be explained
see them as epiphenomena of underlying biological disorder, e.g. syphilis
Maher
delusions as rational responses to very unusual (i.e. anomalous) experiences
respects the idea that psychological explanation rationalises belief
Young on the Capgras delusion
spouse replaced by imposter
2 visual systems in facial recognition
system of overt recognition
affective response to face
Capgras = opposite of prosopagnosia
recognition vs affective response \ rationally concludes that things are not as they seem
Cotard delusion (Young cont.) � linked with depression + suicide
some kind of affective deficiently to recognised faces
but they link the deficiency to themselves
one patient had (externalising) Capgras/(internalising) Cotard in sequence, depending on whether suspicious/depressive mood
delusions then are broadly rational responses affected in detail by attributional biases (int/externalising)
but why doesn't the patient accept a more plausible belief than Capgras?
Garety � reasoning biases
jump to conclusions with insufficient evidence
Frith on schizophrenia
�words were forced through my lips� � alien control
�it�s like my mind working, but it isn't me� � thought insertion
DIAGRAM
without the efference copies going to the central monitor, my visual observation will come as a surprise � feel like alien control
he extends to model with conscious thoughts + introspection instead of body movements + visual observation
need a system like this for controlled, planned thought
�/span> formal thought disorder in schizophrenia � incapable of consecutive, connected thought
thus the sense of being the agent of a thought = match at the central comparator between the efference copy + introspection
again, this idea of thoughts from elsewhere is shown as a rational response
why do they think that they thoughts come from somewhere specific (alients, gameshow host etc.)?
Frith doesn't seem to fully explain this
is Frith�s model regressive? isn't the conscious thinking not implicated in the originating executive process behind the motor instructions
but I don't consciously decide what conscious thoughts to have�
could replace/mediate �conscious thoughts� with long-term beliefs, desires, dispositions etc.
could ignore rationality, and just exhibit the delusions as the products of law-governed mental processes
when view someone as irrational, undermine the idea that they understand the words they use
but they seem to act appropriately on the basis of their beliefs
do Cotard patients flip???
if so, doesn't seem like a rational inference�
Campbell thinks that a rapid transition doesn't tell much, but he�s not too sure about the time course
without the efference copy � central monitor, are schizophrenics less inhibited???
is Frith�s model biologically plausible???
Frith�s work (cognitive neuroscience of schizophrenia)� is about finding biological bases
compare with Jaynes???
Kotard is a generally bewildered emotional state
could part of the problem in discussing consciousness be that we are all subtly different consciously???