Movement Flashcards
What are conditions necessary for phi motion/apparent motion?
Light flashes must be close together and within a short time interval, too far appart or too long a time between flashes = no perceived motion
How is motion detected locally?
Detects movement in direction opposite to local inhibition
What cells are responsible for motion perception?
V5 cells, damage to V5 cells results in “motion blindness” and an inability to track fast movements
How does bottom up processing work?
- Low level feature detectors
- Mid level pattern detetors
- High level object detectors
What is the top-down processing model?
- Memorized concepts
- High level object identifiers
- Mid level pattern detectors
How do expectations mold perception?
Lower threshold for likely items
Are there more ascending or descending connections in the brain?
- More descending
- Only 3% of V1 input layer synapses are from the LGN
How does context affect perception?
- Recognition of objects is easier within the correct context
- Detection of a letter is easier in a word
What is the payoff matrix?
Consideration of the costs of misses and false alarms (as well as the payoff of hits and correct rejections)
What is perceptual priming?
Where an image is flashed quickly and is not recollected but induces a bias on behaviour and recognition
What are fixations and saccades?
fixations - when the eye is still (3-4 per second)
saccades - jumps between fixations
Why can we not see our own saccades?
‘feed-back’ from stretch receptors in eye muscles
‘feed-forward’ from planed movements
‘efference copy’ of commands to move eyes cancels image movement
