Cognitive Psychology Exam 1

what is cognitive psychology?

the scientific study of the mind and mental processes

cognition involves:

perception, attention, memory, representation of knowledge, language, problem-solving, reasoning and decision making
-all include hidden processes

Donders (1868)

-mental chronometry
-simple RT task
-choice RT task
-mental responses cannot be measured directly but can be inferred from the participant's behavior

simple RT task

person pushes a button quickly after a light appears

choice RT task

participant pushed one button if light is on the right side, another if the light is on the left
- 1/10 s longer than simple RT

choice RT - simple RT \=

time to make a decision

Helmholtz (~1860s)

unconscious inference
-some of our perceptions are the result of unconscious assumptions we make about the environment
-we infer much about what we know about the world

Ebbinghaus (1885)

-learned lists of nonsense syllables
-tracked repetitions to perfect memory
-after some time, he relearned the list
short intervals \= fewer repetitions to relearn
-savings \= (initial repetitions - relearning repetitions)/initial repetitions

behaviorism

-a new approach proposed by Watson
-eliminate the mind as a topic of study
-instead study directly observable behavior

Watson (1920)

"Little Albert" experiment
-examined how pairing one stimulus with another affected behavior

Skinner (1950s)

-interested in determining the relationship between stimuli and response
-operant conditioning

Tolman (1938)

-trained rats to find food in a 4 armed maze
--2 competing interpretations
-what happens when the rats are placed in a different arm?
--navigated specifically where they previously found food

To understand complex cognitive behaviors:

-measurable and observable behavior
-make inferences about underlying cognitive activity
-consider what behavior says about how the mind works

the cognitive revolution

-shift from behaviorists' stimulus-response relationships to an approach that attempts to explain behavior in terms of the mind
-information processing approach
-early computers

information-processing approach

actively process information (not passively respond)

early computers approach (1950s)

processed information in stages

Cherry (1953)

-dichotic listening
-participants were able to focus only on the message they were shadowing

Broadbent (1958)

-flow diagram representing what happens as a person directs attention to one stimulus
-unattended information does not pass through the filter

Cognitive Science

-interdisciplinary study of the mind
--psychology, computer science, cognitive anthropology, linguistics, neuroscience, philosophy
-goal: finding ways to study and understand the workings of the mind

neurons

cells specialized to receive and transmit information in the NS
-each has a cell body, axon, and dendrites

cell body

mechanisms to keep neuron alive

axon

transmits electrical signal to other neurons

dendrites

receives information from other neurons

sensory receptors

specialized to respond to information received from the environment

action potential

-neuron receives signal from the environment or other neurons
-information travels down the axon of that neuron to the dendrites of another neuron
-input to dendrites
-strong enough input crosses a threshold and the cell fires a brief electrical charge that travels down an axon
--generated by the movement of charged ions in and out of channels in the axon's membrane

all-or-nothing response

when activity exceeds the threshold, a neuron will fire; below the threshold it will not
-intensity is always the same

snapse

the space between an axon of one neuron and the dendrites of another

how neurons communicate

synaptic vesicles open and release chemical neurotransmitters
-neurotransmitters cross the synapse and bind with receptors on the receiving dendrites

neurotransmitters

chemicals that affect the electrical signal of the receiving neuron

inhibitory neurotransmitters

decrease the likelihood that a neuron will fire

excitatory neurotransmitters

increase the likelihood that a neuron will fire

how neurons process information

not all signals received lead to an action potential
-an action potential occurs only if the threshold level is reached
--interaction of inhibition and excitation

feature detectors

neurons that respond best to a specific stimulus

Hubel & Wiesel (1965)

-simple cells and complex cells

simple cells

neurons that respond best to bars of light of a particular orientation

complex cells

neurons that respond best to an oriented bar of light with a specific length

specificity coding

firing of specifically tuned neurons, specialized to just respond to a specific stimulus

population coding

pattern of firing of a large number of neurons

sparse coding

pattern of firing of only a small group of neurons, with the marjory of neurons remaining silent

method: brain imaging

-magnetic resonance imaging (MRI)
-functional magnetic resonance imaging (fMRI)
-subtraction technique measures brain activity during presentation and during a control
-difference in activation determines what areas of the brain are active during manipulation

method: event-related potential (ERP)

-measure electrical activity on the scalp and make inferences about underlying brain activity
-averaged over a large number of trials to calculate ERPs
-advantage: continuous and rapid measurements
-disadvantage: does not give precise location

localization of function

-specific functions are served by specific areas of the brain
--cognitive functioning breaks down in specific ways when areas of the brain are damaged

lobes of the cerebral cortex

frontal, parietal, occipital, temporal

frontal lobe

-reasoning and planning
-language, planning, thought, memory, motor functioning

parietal lobe

touch, temperature, pain, and pressure

temporal lobe

-auditory and perceptual processing
-language, hearing, memory, perceiving forms

occipital lobe

visual processing

limbic system

hippocampus, amygdala, thalamus

hippocampus

forming memories

amygdala

emotions and emotional memories

thalamus

processing information from vision, hearing, and touch senses

fusiform face area

-responds specifically to faces
-temporal lobe
-damage to this area causes prosopagnosia (inability to recognize faces)

parahippocampal place area (PPA)

responds to places (indoor and outdoor scenes
-temporal lobe

extrastriate body area (EBA)

responds to pictures of bodies and parts of bodies

language

-language production is impaired by damage to Broca's area
--frontal lobe
-language comprehension is impaired by damage to Wernicke's area
--temporal lobe

distributed processing in the brain

-in addition to localization of function, specific functions are processed by many different areas of the brain

parallel processing

processing of several aspects of the stimulus simultaneously
--the brain divides a visual scene into subdivisions such as color, depth, form, movement, etc.

perception

the process of recognizing, organizing, and interpreting information from the senses
-involves a process similar to reasoning and problem solving
-not an exact copy of "the world"
-based on our past experience and expectations

inverse projection (optics) problem

a retinal image could have been produced by an infinite number of objects
-objects can be hidden or blurred
-objects look different from different viewpoints

bottom-up processing

-perception may start with senses
-incoming raw data
-energy registering on receptors

top-down processing

-perception may start with the brain
-person's knowledge, experience, expectations

process of bottom-up

-light passes through several layers of cells before reaching the rods and cones
--light activates a photoreceptor
--transmitted to ganglion cells, which send information toward the brain

blind spot

-the region where the optic nerve leaves the eye
-no photoreceptors are present in the blind spot

process of top-down

-involves making inferences based on context, guessing from experience, and basing one perception on another
-occurs quickly, automatically

size-distance relationship

-perceived size is a function of both bottom-up and top-down
bottom-up: the size of the image on the retina
top-down: the perceived distance of the object; the size of the object relative to other objects in the environment

Helmholtz's theory of unconscious inference

some of our perceptions are the result of unconscious assumptions
-we use our knowledge to inform our perceptions

likelihood principle

we perceive the world in the way that is "most likely" based on our past experiences

old view of perceptual organization

structuralism; perception involves adding up new sensations

new view of perceptual organization

Gestalt psychologists; the mind groups patterns according to the laws of perceptual organization
-the whole is greater than the sum of its parts

figure-ground assignment

the process of determining what belongs to a foreground object (figure) and what belongs to the background (ground)

law of good figure (gestalt)

-simplicity or prägnanz
-every stimulus pattern is seen so the resulting structure is a simple as possible

law of good continuation (gestalt)

lines tend to be seen as following the smoothest path

law of similarity (gestalt)

similar things appear grouped together

law of familiarity (gestalt)

things are more likely to form groups if the groups appear familiar or meaningful

law of common fate (gestalt)

things moving in the same direction appear to be grouped together

gestalt laws of perceptual organization

-often provide accurate information about environmental properties
-reflect experience
-experience is important but does not overcome perceptual properties
-heuristics

heuristic

-"rule of thumb"
-provides best guess solution to a problem
-fast and often correct

algorithm

-procedure guaranteed to solve a problem
-slower
-definite result

light-from-above heuristic

we perceive shadows as specific information about depth and distance

occlusion heuristic

we assume objects continue, even if occluded

neurons and the environment

-neurons become tuned to respond best to what we commonly experience; also to things that occur regularly
--horizontals and verticals
--experience dependent plasticity
--semantic regularities and scene schemas

Mooney images

images that when turned upright, provide a clear percept of a face

movement facilitates perception

movement helps us perceive things in our environment more accurately than static, still images

the interaction of perception and action

our actions in the environment help update perceptions

single dissociation

one function is lost, another remains
-different mechanisms

double dissociation

requires two individuals with different damage and opposite deficits
-different mechanisms AND independent

what stream

identifying an object

where stream

identifying the object's location

Ungerleider and Mishkin (1982)

-brain ablation with monkeys
--object and landmark discrimination

mirror neurons

neurons that respond the same way when actually performing an act and when observing someone else perform the act

attention

the process of concentrating on specific features of the environment or on certain thoughts or activities

types of attention

selective, limited, overt and covert

research method: dichotic listening

-participants could not report the content of the message in the unattended ear
-however, unattended ear is still being processed at some level
--cocktail party effect
--change to a tone is noticed

where does the attention filter occur?

-early in processing
-late in processing

early selection model

Filters message before incoming information is analyzed for meaning
-Broadbent's filter model

intermediate selection model

attended message can be separated from unattended message early in the information processing system
-Treisman's attenuation theory

late selection model

A model of selective attention that proposes that selection of stimuli for final processing does not occur until after the information in the message has been analyzed for meaning
-ex/ McKay (1973)

Broadbent's Filter model

-early selection model; filters message before incoming information is analyzed for meaning

sensory memory

holds sensory information for a short period

filter

-identifies attended message based on physical characteristics
-only attended message is passed to the next stage