Face perception - HLP2 Flashcards
What happens to monkey cells when you show them lots of images of faces (including cartoons)?
They show cell selectivity and certain cells will respond to the faces
What are grandmother cells?
Very specific cells that will respond to one object only e.g. your grandma
What are 4 problems with grandmother cells?
- there aren’t enough cells in the brain (maybe?)
- death of a cell would result in very specific object recognition losses, which we don’t see
- evidence for population coding in the temporal cortex (activates lots of cells at once)
- very difficult to prove their existence as you would have to test every cell
Why does the Thatcher illusion happen?
Upright = features analysed holistically
Inverted = holistic processing impaired, features analysed independently, each feature coded relative to gravity
What are the types of features we recognise in faces? What is an important thing about the features that allows for recognition?
- internal - eyes, mouth, nose etc
- external - hair, shape of face/head
- configuration is important - the features need to be in the right place
Which types of features are most important for recognising familiar and unfamiliar faces?
- internal = familiar
- external = unfamiliar
What evidence is there that cells specialise to internal or external facial features?
Nathan the monkey had cells that responded to the whole face and eyes covered, but not just the eyes - and cells the other way around
Some cells also respond to feature combinations - so only to the face as a whole
What evidence is there that the ability to recognise faces is learnt?
We recognise the faces of our own race better than others if we spend more time with them
Participants got better at recognising faces of other races when they spent time adapting to faces of that race
What is face adaptation?
The suppression of face cells allowing for the non-common features to stand out more - leading to better recognition
What does face adaptation suggest about separate cells?
separate cells code different identities
What evidence is there for cell sensitivity to familiar faces?
A monkey has separate cells that each responded individually to specific people he knows (DP and PS, regardless of orientation or expression)
What did they find in cells of epilepsy patients regarding cells sensitivity to individual faces?
A cell that responds to Jennifer Aniston, and a cell that responds to Hallie Berry (even her wearing a mask and just her name written out)
Why are the Jennifer Aniston cells probably not grandmother cells?
we can’t possibly test if they respond to something else too so we don’t know
What is view centred coding?
cells in the temporal cortex will respond preferentially to a certain view of the face
What is object centred coding?
Always respond to the object, regardless of angle/viewpoint
