1st cog experiment: Mental chronometry

1. reaction time:1 choice

2. choice reaction time: 2 choices

ChoiceRT-SimpleRT=time to make decision

Unconscious inference: some of our perceptions are the result of unconscious assumptions we make about environment

We infer much of what we know about the world based on previous experiences

• Method of Savings: learn list of nonsense syllables, relearn list on later occasion & see how many fewer trials needed to master list
• studied forgetting curve by varying dely btw learning & re-learning session
• repition aids recall, recall difficulty increases w/ list length

• founded 1st psych lab
• introspection: trained observer provides rigorous, unbaised report of every element of conscious experience (when presented w/ stimulus)
• hearing a 5-note vs 1-note chord on piano

• focus on observable behvaior; reject mentalism
• all behavior can be explained in S-R units
• Pavlov: Classical conditioning (UCR-CR)
• Skinner: Operant con. (+- reinforcement)
• experimental techniques most beneficial

1. humans can learn by observing reinforcement of other ppl's behavior

2. although not rewarded themselves, they can behave as if they had been

3. can only be explained w/ assumption of internal evaluative cog. processes

4. Behaviorists used rats for studies & try to generalize it to humans w/ out testing on humans

5. generalization problematic b/c rats & human similarity is unclear

• Skinner: explained how O.C. can be used to explain language aquisitoin
• Chomsky: humans produce sentences they never heard before & thus couldn't be rewarded for

• Canadian neurosurgeon treating epilepsy
• open brain surgery while patients awake
• revealed amazing insights into brain structures serving dif. cog functions

• human cognition is like a computer

input→input processor→memory unit→arithmetic unit→output

• humans are symbol manipulators: we encode, store, retrieve & manipulate symbolic data store in memory

1. behavioral: Experimental method-design experiments that give insight into cog processes (ex: Donders, mental rotation)

2. Physiology: Imaging fMRI & PET: which brain regions support which cog. processes

3. Modeling: mathmatical/computer model of cog processes

• believed mind processes mental images by decomposing them into mathmatical proposition (code)
• PROPOSITIONAL theory
  

• believed brain manipulates mental images that resemble true preceptions
• ANALOG theory
• think mental images of an inner picture

• impossible to prove something to be true (verification) but it is possible to prove something to be false (falsification)
• Popper: "A good theory needs to be falsifiable" ex: All men are mortal (we cannot observe all men dying b/c we eventually die ourselves)

• by gathering empirical (observable) data objectively (ex: making sure experimenter doesn't influence results)
• predictions need to be translated into paradigm (well-defined procedures, materials, & measurement methods
• select independent & dependent variables
  

• permanent features of participant that might influence cog. preformance.
  
• ex: IQ, sex, race, age, education, concentration ability, mental or physical disorders
  

• factors that temporarily affect a participant's normal abilities
• ex: illness, stress, drug use, sleep deprivation
  

• what participants are instructed to do
• ex: asked to read something for "fun" or for testing IQ?
  

• the way stimuli are presented
• ex: using real objects or computer images to test mental rotation?
  

• type of material presented
• ex: presented auditorily or on paper
  

• the environment in which the task is administered
• ex: things are best recalled in environment in which material is learned

• Mental chronometry: the longer the time needed, the more computation required by brain in order to produce response after stimulus presentation (SRT, CRT) Donders
  
• Measures of accuracy/frequency: number of correctly recalled words in a list. Ebbinghaus
• Measures of physiology: blood flow in brain (PET, fMRI), electrical activity, hormonal changes
  

• variable that moves around along w/ the independent variable
• makes results difficult to interpret
• ex: 2 experimenters studying memory: both experimenters asked subjects to recall words. Experimenter 1 offers cookies while other experimenter does not; cookies could serve as motivation to better remember words on the list
  

• experiment:
• experimental vs control group
• sampling & random assignment
• sample size (larger=better)

1. random sampling: selecting participants randomly from population
2. random assignment: chance assignment to condition
   *random sampling is not typically accurate b/c most labs use psych majors

1.  random selection from population of interest not feasible

2. for many variables, random assignment impossible (ex: organismic variables such as gender, height)

3. for other variables, random assignment unethical (ex: drug studies, effect of violent videos on behavior of kids)

4. those limitations should be considered when interpreting & generalizing results

• advantage: no possibility of carryover/practice effects
• disadvantage: twice as many participants necessary, some effects may be attributable to dif. subjects (ex: dif personalities can effect outcome)

• advantage: there are no subjective differences btw varibles to account for
• disadvantages: practice effects (preforming same task twice), carryover effects (expectations from prior trial)

1. objectivity: will the same measurements be obtained when another experimenter measures?

2. reliability: applying the same test to the same subject should produce the same result if test is 100% reliable (measurement outcomes shouldn't be influenced by certain factors, should be able to replicate on dif subjects & get same results)

3. validity: to what degree does the measurement really measure what it intends to? Is it really testing memory performance or something else?

1. nerouns:

1.form basic units of nervous system

2. Ability to communicate via electro-chemical processes

3.change structure as result of experience (ex: drug use)

1. anatomically

2. physiologically

1. have specialized projections (dendrites & axons)

2. electrical signal w/in neuron but chemical process when communicating

3. neurotransmitters released into synapse

extends from soma; responsible for transmitting the neruon's signal from the soma to the terminal buttons

typically splits into little branches w/ terminal buttons at end

neuron stimulated→produces action potential that travels down axon (propagation)→AP reaches terminal buttons→neurotransmitters released into synapse→neruotrans bind onto specific receptors

*if excitatory, neural firing increases

sum of all postsynaptic inputs (excitatory & inhibitory)

neuron will fire AP only if:

net stimulation>threshold

1. inside of neuron is negative relative to outside (Na+ and K+) (-70mV)

2. Protiens(-) have difficulty moving thru cell→ desire to bond w/ neurons outside cell

3. have to pass thru specialized channels (closed when nerve @ rest)

4. K+ protiens flow into cellextracellular space carrying out positive charge, until their movement is balanced by build-up of negative charge on the inner surface of the membrane

5. concentration gradient of potassium ions must first be set up. This work is done by the ion pumps/transporters and/or exchangers and generally is powered by ATP.

1. caused by exchange of ions across the neuron membrane

2. signal triggers opening of Na+ channel→Na+ rushed into cell (causing it to become +)→K+ channels open→K+ flows out of cell & binds w/ other K+ ions→ loss of K+ ions causes cell to become negative again 

3. -55mV+ activates action potential

1. change in membrane potential that returns the membrane potential to a negative value after the depolarization phase of AP  has just changed cell to +.

2. Repolarization results from the movement of K+ out of the cell.

3. Typically the repolarization phase of an action potential results in hyperpolarization, attainment of a membrane potential that is more negative than the resting potential.

a change in a cell's membrane potential that makes it more negative.

It is the opposite of a depolarization.

1. Action Potentional: neuron either fires or it does not

2. firing strength does not change, but firing rate can change

3. when AP reaches end of axon, synaptic vessicles release neurtrans. which are picked up by dendrites

1. Training (learning) can increase # of synapses & improve transmission of existing synapses

1.increases # of sites that release neurotrans.

2. increase in reuptake-rate of neurotrans.

3. increase production of neurotrans.

4. increase release probability of neurotrans.

1. increase in # of receptors

2. increase in receptor size

1. using microelectrodes that measure electrical signal emmited by neuron

2. determines amounts of APs occuing in brain

1. a hypothetical neuron that represents a person's grandmother (or more generally, any specific concept or object)

2. a G-cell gets activated when a person "sees or hears" his/her grandmother

1. states that specific stimulus is coded by unique pattern of activity of a group of neurons

2. opposite of Grandmother cell theory

3. multiple cells code a single stimulus so a small # of neurons can code many stimuli

1. gray matter: consists of regions of neuron cell bodies

2. white matter: consists of regions of axons (mylein sheath)

1. a large # of cell bodies grouped together

2. each cell in nuceli has particular function ex: lateral geniculate nucleus in thalamus is part of visual pathway

a large collection of axons in CNS; tracts carry info to various parts of brain

ex: optic nerve tract carries info from eyes to occipital lobe in brain

1. sequential analysis: systematic, logical interpretation of info

2. interpretation & production of symbolic info: language, math, abstraction & reasoning

*damage to left hemisphere causing challenges in right hem. for speech production

1. hollistic functioning: processing multi-sensory input simultaneously to provide "hollistic" picture of one's environment

2. nonverbal & spatial skills

3. "mute" (speech production disabled if damage to left hem.)

1. cerebral cortex: all higher cog functions (ex: problem solving, memory planning) and recieving/processing of sensory info

2. basal ganglia: group of neurons central to motor functions (damage=tremors; associated w/ Parkinson's)

3. limbic system: hippocampus, amygdala & septum. L-system supports learning/memory, emotion & spatial behavior

4. thalamus: relays sensory inputs to appropriate areas, associated w/ sleep control

5. hypothalamus: controls endocrine system & autonomic nervous system (ex: temp regulation, hunger, thirst) & associated w/ survival behavior (sex, aggression)

makes up 80% of brain

2 cm below scalp

divided into several lobes

surface is gray (neuronal cell bodies)

underlying tissue white (myelinated axons)

1. speaking, motor processing, all higher mental processes, cognitive control, attention, short-term memory

2. contains Broca's area: language production

1. auditory processing, language, long-term memory, perceiving forms

2. includes Wernicke's area: language comprehesion

1. both are organized in areas that receive input from certain parts of body

2. the size of area not related to size of body part, but rather sensitivity (weird picture of enlarged & shrunken body parts)

1. involved in planning, execution, and control of movement

2. electrical stimulation would result in movement

1. receives input from senses for pressure, texture, temp and pain

2. electrical stimulation=sensation of being touched

1. used to visualize soft tissue (brain, muscles)

2. magnetic current causes water protons to align, when magnetic force removed, protons return to natural alignment, releasing energy (dif tissues release dif energy)

1. measures signal changes in the brain that are due to changing neural activity

active neural areas need OX2

hemoglobin carries OX2 in the blood

hemoglobin is magnetic

oxygenated & deoxygenated hemoglobin have dif magnetic properties

when OX2 released @ active neural site, hemoglobin=more magnetic

deoxygenation of hemoglobin in active sites is what fMRI picks up

1. compare activity in experimental & control task that differ only in the process of interest

*experiment: observing brain activity when manipulating object

*must have control task that captures everything BUT manipulation of object (just holding it)

1. experience-expectant: some neurons or networks need input during critical time periods or they will never properly develop

ex: Genie's parents locked her in closet for 13 yrs, never learned to speak

1. other neurons or networks can be modified by experience throughout life

ex: cab drivers have dif shaped neural networks due to their job

Blakemore & Cooper's selective cat rearing

(experiment w/ neural plasticity)

1. cat only exposed to vertical lines therefore neurons didn't respond properly to certain environmental inputs (horizontal turns)

2. kitten blind in 1 eye b/c never connected to visual cortex & never developed feature detectors for horizontal lines

1. human visual system which might be specialized for facial recognition

2. experiment using greebles (shapes w/ face-like features)

3. after training, FFA was able to identify greebles as faces

1. reception or registration of physical stimulation & encoding it into the nervous system

2. ex: presence of tone or light

1. processes by which we recognize, organize & make sense of the sensory info

2. ex: identifying a voice, face

1. the mental represenation of a stimulus that is perceived

2. a product of one's interpretation of the sensation

*we perceive OUR interpretation of object, not actual object itself

1. cog processes keep certain things constant while others change; incoming sensory info→percept

2. ex: Greek Parthenon: built columns that budlged out in center to create illusion of perfectly symmetical building

1. automatically implement 2D context which causes us to see distorted images

ex: coglab where we had to compare 2 lines and state which was longer (inward facing arrows made line appear shorter)

1. optical: focusing light on the retina

2. sensory: transduction to light projected on the retina & projection of neural signal to higher brain

transduction: conversion of light energy into neural code/signal (done by cells in retina)

1. eye can be compared to camera:

lens=optical part of eye

film=sensory part of eye

perceptual constancy

sensation≠perception

1. environment isn't static; perceiver or/and environment moves=images of same objects that are projected on retina change constantly

ex: sensation of same object differs

2. percept stays the same

ex: object perceived as having same color, size & shape

1. despite changes of a stimulus' size on the retina as a function of varying distance, the perceived size of the stimulus stays constant

2. OR same size on retina, but perceived as different size

ex: coin experiment

1. depth cues that are based on 2 dif angles from which our eyes sense the same objects

1. based on feedback from muscles of eye

2. trying to fixate on a close object=eye turning inward (& vice versa)

3. info from eye muscles is used by visual system to judge how far object is away from you

1. eyes 6cm apart: provide slightly dif images of same object

2. difference refered to as "disparity"

3. the greater disparity, the closer objects must be

1. perceiver starts w/ small bits of info from environment that get combined in various ways to form a percept

ex: approaching a tree & using clues from environment to figure out dog is standing behind it

1. person's knowledge, prior experience or expectations influence perception

2. this knowledge guides selection & combination of info

ex: looking at pile of rope; know from prior experience rope is 1 long piece & not seperate pieces

1. perception starts at bottom (sensory input) & works its way up to higher brain

2. unidirectional: info flows 1 way (irreversible)

3. processes influenced by expectations or previous knowledge

1. processing stimuli by breaking them down into features (instead of seeing whole object)

2. feature detection cells in visual cortex & retina (these neurons increase firing rate when stimuli are present)

1. assumes upon viewing objects, humans break object into simple geometric components (called geons)

2. 36 geons that combine in many ways & perceived from many angles

1. geons not detailed enough to allow for distinctions humans have little trouble w/ (ex: telling dif btw Honda & Toyota)

2. mental rotation theory questions ability to identify objects from many angles

3. objects in nature do not have specific geons (ex: cloud)

1.several letters of specialized "demons" function as feature detectors. Demons "scream" when they detect 1 featue they specialize in

2.Image d's (basic encoding of image)→feature d's (scan for certain feature)→cognitive d's (rep. letters of alphabet)→decision d (listens to screaming of cog d's & decides what letter is being presented)

1. preattentive stage: objects analyzed into seperate features (ex: red ball→red+round)

2. focused attention stage: combine features

object→preattentive→focused attention→perception

1. presented 4 shapes & 2 #'s for 1/5 second

2. asked them to report which #'s they saw along w/ shape & its color

3. at begining of perceptual process, each feature exists independently: "redness", "tilted line", "curvature"

4. attention plays role: if #'s can be ignored, hardly any false conjunctions

5. top down: if subjects told they'll see carrot, always report seeing orange triangle

1. no definition that determines what can/cannot be a considered a feature

2. if there are dif sets of features for dif classes of objects, how does perceiver know which ones to use to perceive object BEFORE he knows what object is (bottom-down)

3. if same set of features for all objects, list=huge and decrease speed of perception

1. any model of perception thus needs to incorporate context & expectation

2. T-D processes are directed by expectations derived from context, past learning or both

3. T-D: processes have to interact w/ B-U processes: otherwise not able to perceive anything you didn't expect

1. identification of target picture faster when it fits w/in a previously viewed scence conceptually

ex: showed participants kitchen scene, then flashed 3 objects (2 didn't belong [mailbox & drum]), then asked which object belonged

*context speeds up perception

1. segregation of a display into objects (figure) & background (ground)

2. also called form perception

3. elements perceived as part of ground=seen as more shapless, less formed, farther away

4. form-perception is a cog. task we perform quickly & easily

ex: optical illsion: black wine glass & white faces

1. "the whole is more than the sum of its parts"

2. perception of forms not based on analysis of every sensation→synthesize into percept

3. assumed these "laws" were inate; many criticize they are only heuristics

Law of Prgnanz

(Gestalt principle)

1. of all possible ways of interpreting a display, we tend to select the simplest organization & most stable shape/form

ex: example of olympic sign

1. elements of a display that are closer to each other are grouped together & perceived as 1 form

ex: example w/ the blue dots or the 6 lines close together that appear as 3 seperate lines

1. elements that are similar to each other are grouped together

ex: example of blocks w/ dif colored columns

1.we group together objects whose contours form a continuous straight or curved line

ex: celtic knot

1. elements that move together are grouped together

ex: large swarm of bees or flock of migrating geese

1. located in temporal lobe

2. 'what" pathway

3. involved in recognition, identification and categorization of visual stimuli (objects)

1. located in parietal lobe

2. the "where" pathway

3. involved in spatial attention, determining an object's locaiton, and communicates w/ regions that control eye  & hand movements

1. experiment w/ monkey: phase1: asked to identify which object had reward under it

phase 2: asked to locate which platform target object was near

2. during experiments, brain areas (depending on which phase) lit up

3. brain areas also lit up when seeing person do exact same action (picking up object)→mirror neurons