Cog Psych Chapter 2

perception

uses previous knowledge for us to gather and interpret stimuli from our senses

Combines Top down (previous knowledge) and bottom up (visual stimuli) processing

Bottom up processing

when you asses the characteristics of something (size, shape, color) before evaluating it as a whole.

• Part of the early stages of perception

Top down processing

matching stimuli from info in our long term memory

• part of the later stages of perception

object/pattern recognition

identifying complex sensory stimuli by PERCEIVING THE PATTERN AS SEPARATE TO THE BACKGROUND

• this is achieved by the visual system

what are the two types of perceptual stimuli

• distal (the object) stimuli —- ex: a pen

• proximal stimuli: the information your sensory receptors register on your retina

what is the retina

the back portion of your eye that has millions of neurons that transmit sensory info

what does our visual system receive help from?

sensory memory.

• large storage system for the five senses

• includes iconic and visual memory

• allows us to hold brief mental images

what is the two part process of visual stimuli getting registered to the sensory system?

1) visual info is registered onto the retina

2) the primary visual cortex (occipital lobe) begins the basic processing

• portion of the brain where the eyes are combined

how does gestalt psych fit into perception. can the roles be reversed?

we use figure and ground for perceiving our surroundings

• figure — a distinct shape w/ defined edges

• ground —- the left overs of the image (the background)

both roles can be reversed in an ambiguous figure ground relationship (optical illusions)

what is a subtype to ambiguous figure ground relationships?

illusionary contours — when we see the edges even when they’re not physically there

Theories on how we perceive

feature analysis and the recognition by components theory

what is the feature analysis theory?

when the visual stimulus is made up from smaller components—-distinctive features.

• explains why we recognize the letters of the alphabet/2-dimensional patterns, they’re consistently the same shape

• Feature detectors in the visual system are present at birth

• pioneered by Elanor Gibson

what did leaner Gibson find?

that humans need a long time to decide if two letters are the same if they carry similar features

P and R versus O and L

recognition by components theory

founded by biederman

• how we recognize 3-dimmensional shapes

• things are represented by geons (think of letters being combined into words)

BUTTT

• we are less likely to recognize objects at unusual perspectives

• this is fixed by the viewer centered approach

how many geons are usually needed to classify objects

3

what is the viewer centered approach

we see things in varying perspectives compared to a rigid 3D model

how dow the word superiority effect tie in with Top down processing

we are more likely to recognize letters more accurately/rapidly when it appears in a meaningful word

what are “smart mistakes” within Top down processing?

change blindness: when we fail to detect change in an object/scene

inattentional blindness: when we fail to notice new detail in a scene

• gorilla walking across basketball court

how do we recognize faces?

facial stimuli is a special form of stimuli and has privileged status in our perceptual system

• we recognize faces on a holistic (recognition) basis —- based on its gestalts

which brain area is MOSTLY responsible for facial recognition

fusiform face area

what is the face inversion effect

we are more likely to recognize uprights faces instead of upside down faces

what happens during speech perception

auditory system records the sound vibrations we hear

• we perceive 15 sounds per sec, 900 per minute

what is a phoneme

a basic unit of language. english has 40-45 phonemes.

phoneme pronunciation can be affected by ISV and Co articulation

what is inter-speaker variability

variability in phoneme pronunciation. this can be caused by

• gender

• age

• regional dialect

what is co articulation

when your mouth is in the same shape it was when saying the previous phoneme

what is the mcgurk effect

visual cues enhances our speech perception. activated in the superior temporal sulcus

what is the speech mechanism approach

humans process speech quicker than other stimuli because we are born with a phonetic module ‘

• phonetic module: allows us to process ambiguous phonetic information accuracy

this theory suggests that speech does not rely cognitive functions

general mechanism approach

speech perception is a learned ability, not a specil phonetic module

• this is supported by our need of visual cues for auditory understanding