Psych 104 unit4c

Bottom-up processing

• Begins with raw sensory input → perception

• Sensory organs → primary sensory cortex → association cortex

Top-down processing

• Expectations, prior knowledge → interpret input

• Association cortex → primary sensory cortex

Selective attention

• Reticular activating system

• Frontal cortex

• Senses compete for attention, filter out irrelevant

Filter theory of attention

• By Broadbent

• Mental filter allows us to pay attention to important and ignore unimportant stimuli

• Filtered out before meaning is processed

• Tested using dichotic listening - seemed unaware of unattended ear

Cocktail party effect

• Even when in deep conversation, can immediately notice when your name was said

• Filter theory doesn’t support this

Inattentional blindess

• Poor at detecting things in plain sight if we are not paying attention

• The invisible gorilla experiment (50% of people didn’t see a person in a gorilla suit)

Change blindness

• Failure to detect obvious changes in environment

• More likely to make mistakes if have an attractive passenger

Gestalt principles

• 5 main ways to group and interpret stimuli - proximity, similarity, continuance, closure, figure & ground

• Automatic

Perceptual sets

• Increase readiness to perceive stimuli in a certain way

• Confirmation bias, believing is seeing, seeing is believing

Perceptual constancy

• The brains ability to perceive objects as stable and unchanging even though they’re not

• Size, colour, shape constancy

Binocular disparity

• Difference between images from each eye

• High disparity - objects are close

• Low disparity - objects are far

Binocular convergence

• Focus on bear objects = eyes turn inwards

• Brain uses amount of convergence to estimate difference

Stroboscopic movement

Seeing s images in rapid successions

PHI phenomenon

Motion seen as smooth an continous

Ames room illusion

• Distorted room

• Due to relative size principle

Muller-Lyer illusion

• Cultural effect

• One line looks shorter due to learned association with arrowheads

Ponzo illusion

Converging lines enclose 2 objects of identical size, thus perceive farther object to be larger

Perceptual adaptation

Can change perception to adapt to changing sensory experiences