Test 2 Weeks 4 & 5 PSYC122 Flashcards
How low can you go?
Absolute Threshold
Can you tell the difference?- how big does the difference have to be to notice it
Discrimination Threshold
Seen, present
Hit
Seen, absent
Miss
Absent, I see something
False alarm
Absent, I don’t see anything
Correct rejection
How well can you distinguish between when the stimulus is present or absent, means you have a high hit rate AND a low false alarm rate.
Sensitivity
Presented with the same stimulus intensity, different participants might respond differently not because they have different perceptual sensitivities, but because they are more/less biased in responding to the task- bias to say yes/bias to say no
Response bias
Allows us to separate sensitivity from response bias
Signal Detection Theory
Discrimination threshold increases proportionally to baseline/reference stimulus increase.
Weber’s law
smallest perceivable difference
Just noticeable difference (JND)
Weber’s fraction
JND/baseline- e.g. 50 and 54= 4/50
Wavelength
colour
Kinetic energy
temperature
Chemical shape
aroma
Vibration
texture
Frequency
Pitch
Amplitude
loudness
Tissue Damage
pain
electromagnetic energy, roll right over things (radio waves, microwaves)
big wavelengths of light
electromagnetic energy, x-rays and cosmic rays very they go right through objects
tiny wavelengths of light
Photo-receptor- mostly in the periphery. Respond to light of all wavelengths. High sensitivity/low resolution, used in low light
Rods
Photo-receptor- Centred in the middle of the retina (fovea). Respond to different wavelengths (red/green/blue). High resolution/low sensitivity
Cones
Colour perception is mediated by cones
Trichromatic Theory
most sensitive at short wavelengths (blue)
s-cones
most sensitive at medium wavelengths (green)
m-cones
most sensitive at long wavelengths (red)
l-cones
one type of cone
monochromat
two types of cones
dichromat
Males – dichromats- not fooled by camouflage, lookouts
Females – dichromats and trichromats- foraging
Callitrichids
brain takes shadow into account and converts the image accordingly
Colour constancy and Lightness constancy
objects maintain their properties even when the context changes their physical characteristics
Perceptual constancy
information comes out the optic nerve and crosses over at that spot towards one of the visual cortex
optic chasm
visual pathway from eye to brain
Information received by retina, object in left visual field, lands on the outside of right retina (temporal retina)/inside edge of left retina (nasal retina) and vice versa, information goes to Lateral geniculate nucleus (LGN) which is a bundle of cells in thalamus, sensory relay station, right visual field goes to left primary visual cortex, left visual field goes to right primary visual cortex
connects the two brain hemispheres, e.g. cut for epilepsy treatment, had specific vision problem, two sides don’t coordinate, hemispheres have different views of the world, can still function, left hemisphere produces speech, left side didn’t see anything so didn’t say anything, left hand (controlled by right hemisphere) can point to the shape shown
corpus callosum
cues that depend on using two eyes
Binocular Cues
can use information from only one eye
monocular cues
objects further than fixation will hit the fovea inwards
Uncrossed disparity
objects closer than the fixation will hit the fovea outwards
Crossed disparity
left and right fields of vision provide slightly different visual images when focusing on a single object, used by our brain to perceive depth
Retinal Disparity
when things get closer your eyes need to move inwards to keep track, brain keeps track of eye movement to monitor positions of objects in space
vergence
depth perception cue in which objects that are closer, appear to move faster than objects that are far away
motion parallax
Using incoming information to drive perception, data-driven, stimulus driven, involuntarily, salience e.g. colour, movement, size, loudness
Bottom-up processing
Using our knowledge or experience to drive
perception, conceptually-driven, voluntarily, Current needs e.g. Goals, Tasks, Relevance, Motivation, goal-driven
Top-down processing
images that have more than one perceptual interpretation
Bistable images
change in a visual stimulus is introduced and the observer does not notice it
change blindness
experiment where one of the interlocutors was switched for another half way through, Did they notice the change?
Young adults: yes- between ages of 20-30
Older adults: no- over 30 do not notice
Simons & Levin (1998)
Simons & Levin (1998) experiment 2, dressed as construction workers
Did you notice the change?
Young adults: 75% no
processes that do not need attention
Automatic processes
processes that need attention
Controlled processes
Searching for one feature (colour, shape) can be done automatically. It “pops out”. It takes the same amount of time, no many how many items you have to search.
Searching for a combination of features requires controlled attention. You need to apply attention to each item, one at a time. More items requires more time.
Feature Integration Theory
The ability to prioritise some information while ignoring other information
Selective Attention
Dichotic Listening- Cherry (1953)
in one ear you hear one message, you need to do shadowing, keep listening and repeating, other message to other ear, attended channel and unattended channel, you only need to shadow one ear, manipulated what was going to the other ear
People noticed: Male to female, Forward to backward
People didn’t notice: English to German, Any content
Filtering quite a bit of information, physical differences/characteristics are noticed
Broadbent (1958)
1, 7, 5/8, 9, 3- one number in each ear at the same time, reporting from one ear and then switching to other ear where other digits were still sitting in sensory memory
Attention narrows the flow of information into awareness based on physical characteristics- use attention to select one channel of information at a time
Broadbent’s Filter Theory
Treisman (1960)
half the sentence in one ear, half in the other (meaning wise)
Attended messages pass through clearly. Unattended messages are weakened. Sometimes they break through. Breakthrough happens when the unattended message reaches a threshold. Relevant/expected/important messages have a low threshold. Irrelevant/unexpected/boring messages have a high threshold.
Treisman’s Attenuation Model
MacKay (1963)- test sentences
They threw stones at the bank, ambiguous word, use context to interpret it, river or money in other ear, threw stones down by the stream, they threw stones at the building- people who heard river in other ear are more likely to choose option 1, and vice versa- understand the meaning of something even if we are not aware of having been exposed to it, process things outside of our awareness
We process everything for meaning, but only selected information makes it into our awareness.
Deutsch & Deutsch Late Selection Model
Attention is a flexible pool of resources
* If primary task is demanding:
no resources left
→ early selection
→ no distraction
* If primary task is easy
leftover capacity
→ late selection
→ distraction
low v high perceptual load
Load Theory, Nilli Lavie
Forster & Lavie (2008)
k or n, low perceptual load v high perceptual load + distractions (pokemons)- faster with no distractor, but less distracted on high
