High-Level Perception Flashcards
What are hypercomplex cells?
Respond to bars of light. They have a larger receptive field than complex cells and may combine the signals from multiple complex cells.
What are simple cells?
Cells that respond to a particular orientation of a bar of light in a specific region of their visual field.
They are tuned - selected for a particular visual stimulus.
They provide input directly into complex cells.
What are complex cells?
Respond to a bar of light anywhere within their receptive field.
They provide input into hypercomplex cells.
Which part of monkey brains respond to faces?
Temporal cortex cells (IT, STS)
What are grandmother cells?
Specificity - respond to one object only
Generalisation - respond to this object in many instances.
Explain the Thatcher Illusion.
Upside down does not look as grotesque as upright when features are inverted.
Upright: features are analysed holistically
Inverted: Holistic face processing impaired - analysed independently.
Which features affect face familiarity?
External features are more important for unfamiliar faces
Internal features are more important for famous faces
Do face cells detect features?
Cells show selectivity but for different parts of the face.
Is the ability to recognise faces innate or learnt?
Learnt
What does face adaptation tell us?
- face coding mechanisms subject to adaption like lower-level cells
- face adaption causes suppression of face cells
- separate cells coding different identities
adaptation calibrates our visual system to the statistics of the social environment
Is the Jennefer Aniston cell a grandmother cell?
No, they seem selective but we can’t be sure that it is a grandmother cell.
How do STS (superior temporal sulcus) cells respond to face view?
The movement of the face causes the cell to fire.
Some cells will respond only to one angle, while some will respond to any angle.
What is egocentric coding in face perception?
When cells show view-sensitive coding
What is allocentric coding in face perception?
Doesn’t matter about where you’re seeing the object from, it’s about the object itself.
What is object centred coding?
When cells respond to all views of the face - object centred coding.
What do we use to work out where someone is attending?
The directed that someone is attending can be cured by the posture of the head but the eye information is also important.
You can also work out where someone is attending from their body posture information.
List which parts of the body are most important in social attention, in order of most to least important.
Eyes > head > body.
What makes a face attractive? (5)
Symmetry. Averageness. Secondary sexual traits. Skin health and colour. Hormone levels and fertility.
How does brain asymmetry affect facial processing?
Judgements of face identity, sex, age, attractiveness are biased to the left side of the face.
Because right hemisphere is specialised for face identification and emotion.
How does averageness affect facial attractiveness?
Non-average faces may indicate genotypes that are homozygous for deleterious alleles - people with unusual faces probably result from rare or uncommon genes.
How does secondary sexual traits affect facial attractiveness?
Male and female faces differ in their shapes - advertise the quality of an individual in terms of their hereditable benefits.
How does skin health and colour affect facial attractiveness?
Healthy-looking faces appear more attractive
How do hormone levels and fertility affect facial attractiveness?
Masculine characteristics - long term medical health, reproductive potential, physical strength.
Female characteristics in males - long term relationships
Female preference of faces is affected by hormone levels.
What do neurones in V4 specialise in?
Colour
What do neurones in V5 specialise in?
Motion:
Direction, speed, moving dots/bars
What are the properties of V5 cells?
- Larger receptive fields than V1 (about 3-8 degrees)
- Not sensitive to colour
What other visual areas are there in the brain outside of the occipital lobe?
Medial Superior Temporal Sulcus (MST) - motion sensitive
What are the properties of MST cells?
- Larger receptive fields than V5 cells
- Sensitive to translation, expansion, contraction, rotation
What is biological motion?
A motion that comes from actions of a biological organism.
What are different percepts from biological motion? (6)
- Actions
- Hand actions, facial actions, speech
- Gender
- Emotion
- Body weight
- Identity
What are point light stimuli?
points of light that are moving and you see them as a coordinated pattern and you derive an animate biological being from this information.
What is the pSTS?
Posterior superior temporal sulcus
How does the pSTS relate to biological motion?
It’s the region of the brain that appears to be involved in that subjective experience of animate moving body performing actions.
How does STS relate to biological motion?
STS will respond to biological motion figures in many cases.
How are inverted biological motions processed?
They are difficult to recognise.
How does sound affect biological motion recognition?
It improves biological motion recognition.
How is biological motion pervasive? (4)
- Infants preferentially observe biological motion (not autistic ones).
- Other social actions can be recognised
- Emotion can be derived from biological motion faces
- Other animals e.g. cats can discriminate biological motion.
What did Puce et al 2001 find with the STS?
There is STS activation in biological motion, but also when imagining biological motion and with facial biological motion.
How does the MTG differ from the STS in biological motion?
STS responds to the nature of moving human stimuli whereas the MTG (middle temporal gyrus) responds to rigid motion