face recognition

Question 1

early model of face recognition - bruce and young

Answer 1

• Modular model in that different sub-functions are processed independently.
  
  • Distinct pathways for recognising familiar faces vs recognising expressions etc.
  • Parallel pathways dealing with facial expression, facial speech, and “visually derived semantic information” such as sex, age and race.
    1. Different representation constructed for different purposes and for familiar vs unfamiliar faces.
    2. For recognition, a familiar face activates a “face recognition unit” - faces previously encountered.
    3. FRUs are linked to “person identity nodes”, gateways to semantic information about the person.
• PINs are linked to name generation.

Question 2

early evidence for bruce and young

Answer 2

• Memory loss diary study (Young, Hay and Ellis, 1985) - most common errors:
  
  1. Person not recognised
  2. Feeling of familiarity without identity
  3. Person recognised but no name retrieved
  4. Person misidentified
     * Repetition priming found for familiarity decisions but not gender or expression decisions (Ellis et al,1990)
     * Familiarity does not influence:
  5. Gender decisions (Bruce 1986)
  6. Expression analysis (Young et al, 1986)
• Humans can selectively attend to identity or emotion in sorting tasks (Etcoff, 1984)

Question 3

neurological support for bruce and young

Answer 3

• Neuropsychological support for parallelism:
  
  • Double dissociation between the processing of facial expression and face recognition.
  • Some have a deficit in identity but not expression and vice versa
  • Identity - expression (Bruyer et al, 1983)
  • Identity - expression (Humpherys et al, 1993)
  • Neuro-imaging support for parallelism:
  • Different cortical sites are active in the processing of identity versus emotion.
  • Inferior occipital and lateral fusiform gyri activity: identity - expression (Sergent et al, 1992)
• Amygdala and superior temporal sulcus activity: identity - expression (Posamentier and Abdi, 2003)

Question 4

challenges of semantic priming

Answer 4

• ‘Semantic’ priming - a face is responded to faster if it follows a closely related face compared to an unrelated face (Bruce and Valentine, 1986).
• No means to account for this using Bruce and Youngs model.

Question 5

interactive, activation and competition (IAC model)

Answer 5

• McClelland (1981) proposed parallel distributed networks that have interactive activation and competition built in as basic processes.
  
  • Concepts and category learning.
  • Semantic information is ‘pooled’
  • Knowledge is represented in pools
  • Relationships between different bits of knowledge are represented in the connections between the pools
  • Connections within a pool are mutually inhibitory.
• Connections between pools are mutually facilitatory.

Question 6

IAC model summary

Answer 6

• FRUs signal face familiarity, PINs are modality-free gateways to semantic information.
  
  • Details of connectivity and spread of activation and inhibition clarifies.
  • No separate nodes for names; simply part of semantic information.
  • Can explain more empirical data than earlier models.
  • Relative timing of familiarity, semantic access, and naming
  • Repetition priming
  • Semantic priming
• Cross-modal semantic priming

Question 7

What do we use to recognise faces?

Answer 7

• Human beings are exceptionally capable of recognising individual faces.
  
  • The challenge of reliably individuating faces is made apparent by the fact that all faces share a basic configuration.
  • Every individual face consists of facial features such as eyes, nose, and a mouth that have the same first-order relations such as two eyes above a nose and mouth.
• Although these features are ample for rendering the percept of ‘a’ face, they are wholly inadequate in rendering a percept of ‘that’ face.

Question 8

what about second order relationships

Answer 8

• While there are instances of features that are rather distinctive and sufficiently accurate in signalling the identity of an individual, they are rare.
• Thus, it has been suggested that the efficacy of face coding for the purposes of recognition must exploit second order relations i.e., the fine-grained spatial interrealtionship between “features”.

Question 9

second order account challenges

Answer 9

• Hole, George, Eaves and Rasek (2002): stretching, squashing, shearing alter second order relationships but faces remain easily identifiable.
• Hole, George and Dunsmore (1999): negative face are very difficult to recognise despite preserving configural information.

Question 10

where does face processing happen

Answer 10

• It is widely distributed.
  
  • Some core aspects localisable in the superior temporal sulcus and the inferior temporal cortex.
• This is where we see face selective neurons.

Question 11

hierarchal accounts of processing

Answer 11

• Cells in the inferior temporal cortex are selective to complex stimuli giving credence to hierarchical theories of object perception.
  
  • According to this view early visual cortex codes elementary features such line orientation and colour.
  • Outputs are combined to form detectors of higher-order features such as corners or T-junctions.
• Cells at the highest level in the hierarchy code specific shapes such as hands or faces.

Question 12

summary

Answer 12

• Models of face recognition divide the task into that of recognising familiar individuals from that of deciphering other information from faces such as sex and expression.
  
  • The Bruce and Young model has been extremely useful as a basic description of face processing.
  • The IAC model captures many features of human facial recognition and related effects such as semantic priming.
  • It remains unclear exactly how face recognition is achieved - some kind of “configural” processing occurs but recognition processing as it often claimed.
• Face processing is widely distributed in the brain but with some core functions localizable in the superior temporal sulcus and the inferior temporal cortex.