explanations of prosopagnosia

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prospagniosa intro

Sometimes know as face blindness- a disorder of face perception where the ability to recognize faces is impaired- ability to recognize other objects MAY be relatively intact

However most prospangosics have some problem with object recognition as well

Some people with the disorder unable to recognize their own face 

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prospagniosa intro

  • Acquired proso condition following acute damage to part of the brain specialized for prossessing faces
  • Developmental proso refers to a cogential form of the disorder which is inheried by about 2.5% of the population

Research by Grueter at al 07 studied between 2/4 generations of 7 affected families and found 38 cases of proso

The patient’s scores on a recognition test below that of an age and education matched comparison group- suggests significant   genetic contribution to face recognition- results could be explained by the mutation of a single gene 


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explanations- its a unique face specific problem

Proposes that people with prosopag- only have problems with reconisining  faces suggesting that there  are specific face recognition centers within the brain as the B/Y model suggest.  

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explanations- its a unique face specific problem

According to B/Y when presented with a face the face recognition units are activated and the face is compared to the brains dater base of stored memories to see if someone is familiar

  • Evidence suggest that the part of the brain that deals with this is called the right fusiform gyrus
  • If it finds a match- the anterior temporal cortex (ATC) brings up a store of facts about the person e.g. name
  • Also assist with the identification process
  • This equates to the personal identity nodes and name retrieval systems if the B/Y model
  • With proso 3rd step of face recognition is not functioning properly   - likely that damage to the right fusitfrom gyrs (FFA) responcibale for failure to recognize faces in acquired proso
  • This theory of the causes of proso is stating that face recognition uses a different mechanism then other types of recognition
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evidence

Idea that face and object recognition may involve separate systems in the brain- supported by PET scans and fMRI scans- provide evidence that the right fusiform  gyrus is more active during face recognition then during other object recognition

Downing et al found that FFA was singifincnaly more strongly activated when Ps shown faces then other object categories  

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evidence continued

Many researchers such as Barton et al believe that face recognition involves specific parts of the brain and the process involved are different to the process involved in the recognition of other objects  

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evidence continued

Case study supports proso- being as face specific problem

W.J middle age professional man who developed prosos following a series of strokes

Unable to recognize the face of a famous person when showed alongside two unfamilor faces

Later change career and went in to sheep farming/ although he was unable to recognize human faces he could recognize his sheep which are seen as objects

This would seem to show that human face recognition uses a different mechanism then other objects 

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its not a face specific problem

This proposes that people with proso also have difficulty with recognizing other objects suggesting that there are not specific areas of the brain for face recognition 

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evidence

Researcher’s suggest that the process of face recognition is no different to the process involved in reconisining any other object

Gauthier/Tarr 02 found that the FFA was activated in keen bird watches when identifying birds but not cars and in car enthusiasts when identifying cars but not birds

Perhaps the FFA used for recognizing things that are very important to us or need fine discrimination

Because of the importance of other people to humans we become particularly sensitive to faces and adapt at recognising faces but this process is learnt   rather than innate and specialized 

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evidence

Also evidence suggestS that prosopansics often have problems recognizing other everyday objects suggesting that FACE RECOGNITION MAY NOT BE A SPECIFIC FUNCTION 

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general evaluation

In many of the studies of proso- Ps ability to recognize  a standard set of unfamiliar faces is measured- studies can be criticized  for lacking ecological validity  since the processing of unfamiliar faces is very different    to the processing of familiar faces

Also in their everyday lives prosopagnosics find the inability to recognize the familiar faces of their friends and family  most problematic so this area of research is more important

It is difficult to test face recognition as it would involve a separate tests for every person 

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general evaluation

It is not always useful to compare face recognition with other object recognition

Face recognition may be just harder

After all it involves distinguishing between members of the same category (faces) all of which have similar features 

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general evaluation

Much of the research into prosopangnosia is based on case studies

We cannot guarantee that the data from one prosopagnosics would generalize to other people

Also prosopagnosics tend to be studied by one researcher or a small team- difficulty for other researchers to verify the finings  

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general

Research into proso has helped therapist design new ways helping suffers to recognize faces prosopangoistics are encouraged to use other non facial cues such as voice, cloths ect they are also encouraged to devise a mental check list when they meet some one  

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