Chapter 3 sensation and perception

geons

"basic primitives"-simple 3 dimensional geometric forms: combined form of geometric ions -Bierdman: representations of 3D objects are composed of letters combined and recombined in different ways -matched to info. stored in memory to yield recognition *when we recognize objects we break them down into their components and note where the components join together

inversion effect

-behavioral evidence: more effort to recognize an upside down face -upright faces are much easier to process than inverted faces

configural theory

-combination of template feature, recognition by components -deals with limitations of RBC models -individual instances are not stored; what is stored is an exemplar or representative element of a category (prototype) -recognition based on distance between perceived item and prototype -specific faces described by deviations from the prototypical face -predictions -assumes we learn about the entire set of configuration of stimuli presented on any given trial (classical conditioning: associate entire compound stimulus to unconditioned stimulus and not forming separate associations between associations between elements and unconditioned stimulus)

2 components to matching objects which are stored in memory to yield recogntions

1. find edges in objects: enables us to determine which edges maintain the same relationship to one another regardless of viewing orientation 2. we scan regions of pattern where lines intersect

whole report condition

A method to detect *iconic memory*. In this condition, researchers flash a grid of letter son a screen for a split second and participants attempt to recall as many as possible. -report as many letters after they can

thalamus

A structure in the forebrain through which all sensory information (except smell) must pass to get to the cerebral cortex.

partial report condition

An experimental condition in Sperling's (1960) research in which only a randomly selected portion of the entire stimulus display was to be reported (in contrast with whole report condition). -one row was to be reported

RBC model

Biederman discovered several facts about object recognition yet theory is incomplete. - emphasis on importance in verticies: tied to bottom-up processes and object recognition are influenced by context/prior knowledge -object's identity occurs as fast as identifying that something there is a stimulus being presented

cones

Cone-shaped visual receptor cells; located in retina; works best in bright light; responsible for viewing color; greatest density in the fovea

retina

Contains sensory receptors that process visual information and sends it to the brain

rods

Located in the periphery of the retina, these are sensory receptors for vision that work best in reduced illumination, and only allow perception of achromatic colors, low sensitivity to detail and are not involved in color vision.

binocular vision

The ability to merge visual images from both eyes, thereby providing depth perception and a three dimensional view of the world.

perception

The act of becoming aware through the senses

fovea

The central focal point in the retina, around which the eye's cones cluster. (most accurate/precise vision)

lens

The transparent structure behind the pupil that changes shape to help focus images on the retina.

prototypical face

What makes a face attractive (average representation) -average female face for a particular face pop. -veridical (real) image of an exemplar face -exaggerating differences between average female face for a particular face pop. and veridical image of an exemplar face -by disrupting holistic (configural) processing, it becomes easier to process the individual parts -face inversion -top-down and context effects in object recognition

retinal disparity

a binocular cue for perceiving depth; by comparing images from the two eyeballs, the brain computes distance - the greater the disparity (difference) between the two images, the close the object

iconic memory

a momentary sensory memory of visual stimuli; a photographic or picture-image memory lasting no more than a few tenths of a second (visual sensory imagery)

sensation

all about whole- influence of cognition: reception of stimulation from environment and encode it into nervous system

visual persistance

apparent persistence of visual stimulus beyond physical duration *perception

MT

area that allows us to see objects as constant/stable during movement (parietal/temporal/occipital)

prosphagnosa

can't recognize familiar faces or even his own face due to injury

connectionist modeling

computational approach that is often used in cognitive science, involves massive # of mathematical computations (each unit in connectionist layer is VERY connected w/many or all units in next layer -impacts of each experience is computed

parallel processing (Pandemonium)

computational demons work simultaneously, trying to match its own feature while others do the same

face inversion

configural effects often disappear when stimulus is inverted- top-down processing of faces

top-down effects in object recognition

context can often help in object identification: later identification of objects is more accurate when objects is embedded in coherent context -alters object interpretation

holistic

dealing with something as a whole rather than by its individual parts

binocular cues

depth cues, such as retinal disparity, that depend on the use of two eyes

contralaterality principle

each eye transmits info. to both hemispheres (retina gathers info. from contralateral field) left field of vision is from right hemisphere and right field of vision is from left hemisphere but some info. is processed in both simultaneously

proximity

elements near to another or are grouped together

similarity

elements visually similar in some way

common fate

entities that move together are grouped together

visual cortex(Pandemonium)

exists for simple features

bipolar cells

eye neurons that receive information from the retinal cells and distribute information to the ganglion cells

saccades

eyes sweep from one point to another

face vs object recognition

faces recognized differently than other objects -faces are special! -people are fast at recognizing faces

change blindness

failure to notice change in visual stimuli

innattention blindness

failure to see objects we look at directly because we aren't paying attention

computational demons

feature analyzers, each one has a single simple feature and matches it in stimulus pattern

dynamic icons

iconic images that contain movement -visual perception: not process of flipping through successive snapshots but it is process of focusing on visually attended elements of successive fixations: each fixation encodes dynamic segments of visual environment

beta movement

illusory-brain fills in any jumps in position producing illusion of motion

hidden units

input level is internal(always one step removed from either input/output) -connections in connectionism -creates connections between input and output -input: receives info. (senses) and distributes signal throughout network-spread activation

sight process

light enters eye and focus and inverted by lens and projected onto the retina: 1.rods, cones 2. bipolar cells 3. ganglion cells (axons of ganglion: cells converge at rear of eye to form optic nerve where action potential occurs and info. gets sent to thalamus and then to the occipital lobe

data demons

little mental demons who try to identify patterns

trans-saccadic memory

memory used across eye movements -object files: iconic representation of individual objects used to track events

focal attention

mental process of visual attention (mental redirection/attention when partial cue was presented)-perception -visual attention: bridge between succesive events in visual memory: occupied by eye's saccades

compression

message reaching cortex is already processed and summarized (record of stimuli)

pandemonium

model of pattern recognition: demons

race effect

more accurate in recognizing faces of other faces: people focus more on the features than entire face

perceptual pattern recognition

nature of distal objects based on proximal image reaching retina

feature detectors

nerve cells in the brain that respond to specific features of the stimulus, such as shape, angle, or movement

span of apprehension

number of items recallable after any short display

figure-ground

part of image is foreground

output units

passes info. to other parts of brain which generate appropriate response for certain situation

decay

passive process like fading -inference: forgetting caused by effects of intervening stimulation/mental process

fixations

pauses in eye movement-cycles register separate scenes

temporal integration

perceiving two separate events as if they occurred at the same time

phi phenomenon

perceptual illusion occurs as light moves/flows

verbal overshadowing

performance impairment that occurs when people try to explain verbally their perceptual experiences that are not easy to describe -expert: represent holistically-can hurt recog. -less expert: features- may help

closure

person closes up image that has missing gaps

bottom-up data driven processing system

processing is driven by stimulus pattern, the incoming data -processing starts w/ bottom demons and goes to higher demons

input units

receives information and distributes signal throughout networks; simple visual detectors (feature-detector level)

cognitive demons

represent different letters of alphabet (one per letter) look for curve and horizontal bar for "G"

icon

results indicate there is a large amount of info. available in icon (contents of iconic memory) visual image residing in iconic memory

sequence of encoding visual infor.

select part of it for further processing, planning subsequent movements (active, rapid)

cognition and vision

sensory perceptual objects-individual items or Gestalts

rapid serial visual perception

sentence is present word- by - word at rapid rate -repetition blindness -deja vu: but expects not to see it again

template approach

stored models of categorizeable patterns -canonical view: simplicity and economy: (value)(preferred viewing angles for many objects)

agnosia

the inability to recognize familiar objects.

decision demon

the loudest cognitive demon-has final say in recognizing and categorizing pattern

optic nerve

the nerve that carries neural impulses from the eye to the brain

ganglion cells

their axons make up the optic nerve that sends visual impulses to the lateral geniculate nucleus in the thalamus

peripheral vision

thousands of rods converge in single bipolar cell

conceptually driven effects

top-down: missing ingredient: context- higher level knowledge influenced by lower level processes -feature detectors: instructions to shut off certain features during perception processing -top-down: surrounding info. and your own knowledge

vision

triggered when reflection of light from objects hit eye -illlusion

Gestalt

use FMRI to identify characteristics of perception (ambiguous in stimulus)

backward masking

visual stimulus inferred w/ memory of prior stimulus at that location (interfering w/ perception of earlier image)

expertise hypothesis

we develop expertise with face recognition -featural vs holistic processing -experts use holistic info. and not features (top-down processing) -difficulty recognizing facial features in isolation from other faces

recognition by components theory

we recognize objects by breaking them down into their parts, and then look up this combination in memory to see which object matches it (top-down-memory)

good continuum

when object is interrupted people assume that it continues in regular fashion