Perception and Attention Test 1

acuity

smallest detail that can be resolved

snellen E test

for visual acuity

eye doctors visual acuity test

your distance/ normal distance 20/20

researchers definition for acuity

smallest angle of a cycle of grating

• smaller better

how acuity varies

1. same object size + different distance

2. different object size + same distance

rods and acuity

• larger receptive fields

• only in peripheral

• less acuity

• (circles between lines)

Visual crowding

clutter on peripheral object detection

• other stimuli nearby- appear jumbled

• simplify peripheral imaged by averaging

Spatial frequency

number of grating per unit of visual angle

naive realism

we perceive the world as it is

idealism

only reality is that of the mind

• internal cut off from external

• matrix

• descartes

representative realism

• perceive external world indirectly and imperfectly by sensory data

perception

giving meaning to sensation

• interpretation

• context important

• not always accurate

sensation

ability to detect a stimulus

bottom up

• data based

  • incoming stimuli

top down

• knowledge based

• based on previous knowledge

why self driving cars dont work

cant interpret ambiguous information

threshold

limit to what we can sees

scaling

measuring private experience

signal detection theory

measuring difficult decisions in presence of noise

• just noticeable difference

• criterion

• sensitivity

sensory neuroscience

the biology of sensation and perception

just noticeable difference

smallest detectable difference bw 2 stimuli

absolute threshold

min amount of stimulation for a person to detect for 50% of time

webers law / fechners

measuring the intensity of a stimulus and how intense you perceive it

• applies to all senses

stevens law

not all stimuli are the same

scaling methods

• electric shock vs light

criterion

how much evidence to say there

sensitivity

how easy to see difference bw presence and abcense

perception =

stimulus + previous knowledge

doctrine of specific nerve energies

which nerves are stimulated not how

rate coding

how fast firing = intensity

tuning curves

tuned to stimulus

specificity coding

• implausible

• grandmother cell

  • respond to only one stimulus

population coding

pattern of firing across a large number of neurons

MRI

anatomical

EEG

temporal good = time sensitive tasks

• avg bc of noise

FMRI

good spatial

• control - reaction

• blood flow

cornea

window into eye

aqueous humour

watery fluid in anterior chamber

lens

focuses light onto back of the eye

iris

colour that regulates light entering the eye

retina

light sensitive membrane in the back of the eye

• rods and cones

  • image is focused on

ophthalmoscope

back surface of patients eyes called fundus

accommodation

lens changing shape = refracting power

presbyopia

accommodation gets worse with age (refracting problem)

emmetropia

no refractive error

refractive problems

focuses in front or behind

myopia

before retina

• nearsightedness

hyperopia

behind retina

• farsightedness

astigmatism

unequal curving of retina

rods

• night

• no colour

• high convergence

• peripheral

cones

• daytime acuity

• colour

• low convergence = same no matter the pattern

• for fovea

macular degeneration

destroy cone rich fovea

• blind spot in centre

• age

retinitis pigmentosa

destroy peripheral rod receptors

• tunnel vision

• hereditary

light movement

light - photoreceptor - horizontal and bipolar cells - out optic disc

center-surround receptive fields

filter for incoming info - best fit

fuzzy stimulus

sine waves

strong stripes

square waves

180 response

negative

0 response

positive

90 response

no response

270 response

no response

parvocellular

• low contrast

• colour

• slow

• sustained response

magnocellular

• monochrome

• high contrast

• low spatial resolution

• fast

koniocellular

bw mag and parv

magnocellular

for large fast moving objects

parvocellular

for fine spatial details of stationary objects

circular receptive fields are where

retina and lgn

elongated receptive fields are in the

cortex

cortex receptive fields respond

orientation selectivity

lgn and retina receptive field response

spatial frequency

simple cells

• edge and stripe detectors

  • need to be aligned

complex cells

no defined region

• respond to bar of light anywhere

hypercolumns

neurons with same orientation preference is arranged in columns vertically

adaptation

reduction in response bc of prior stimulation = knocks out receptor

tilt aftereffect

template based

run out of neurons for every possible view

feedforward process

do detection without feedback

gestalt

• good continuation

• similarity

• proximity

• texture segmentation

• parallelism

• symmetry

• common region

• connectedness

which are in conflict

similarity and proximity

camouflage

animals exploit gestalt principles

perceptual committees

all grouping principles come together

where

parietal / dorsal

what

temporal/ ventral

agnosia

failure to recognize objects - temporal

pandemonium

demons are neurons

template

match representation with representation in the same shape

structural description

relationship of different parts

biedermans

• by identities and relationship of parts

deep neural networks

grandmother cells

bayesian approach

current stimulus (chance) and prior knowledge (belief)

thatcher illusion

not viewpoint invariant

aphantasia

cant create mental images

hyperaphantasia

extremely vivd mental imagery

modality

same sense makes it harder to detect stimulus

analog guy

kosslyn

propositional guy

plyshyn

epiphenomenon

happens at same time but doesnt cause eachother

tacit knowledge

just knowing to scan a map

unilateral spatial neglect

neglect half of visual field

propagnosia

cant recognize face

unfamiliar faces

external parts of faces

familiar faces

internal features