cognitive science

  1. Conditional Independence-- Joint probability of a sequence
    Make the Markov assumption, creating a bigram of conditional probablilities

    • P(w1,w2,w3,w4)=
    • P(w4:w3)P(w3:w2)P(w2:w1)P(w1)
  2. Damage to Broca's area
    damage to posterior region of frontal lobe (left hemisphere)=Anterior

    • -language production is impaired, oral and written -language comprehension is intact
    • -not strictly motor difficulty, can still utter sounds
    • -speech lacks function words like but, and, behind
    • -often accompanied by partial paralysis on right side.

    Broca's Aphasia= impaired syntax
  3. Damage to Wernicke's area
    • Lesions to posterior part of the temporal lobe (left hemisphere)
    • Speech intact; understanding of speech is lost--word salad
    • Impaired comprehension of language
    • Wernicke's Aphasia= Impaired semantics
  4. Which hemisphere is dominant in language?
    • Left Hemisphere, specialized for:
    • -abstract symbol processing
    • -precise temporal control of articulators (evolution of language)
    • -linguistic processing
  5. Language in Alzheimer's disease
    • Temporal lobe degeneration
    • -semantic memory loss
  6. Language in Parkinson's disease
    • Degeneration of dopamine producing neurons in substantia nigra of basal ganglion
    • -suppression of motor activity (hypokinesia)
    • -syntax (hypo)
  7. Language in Huntington's disease
    • Degeneration of basal ganglion neurons in caudate nucleaus
    • -hyperkinesia (unsuppressible movements)
    • -typical errors are unsuppressed repetitions of regular past tense morpheme-- walkeded, dugged
    • -syntax (hyper)
  8. Oxytocin
    • Hormone synthesized in the hypothalamus and release by the pituitary gland
    • -induced maternal behavior
    • -plays role in orgasms for men and women
    • -generates trust
    • -down-regulates stress hormones
    • -reduces sociophobic behavior
    • -positive social contact becomes more rewarding
  9. Microsatellites
    • repeating sequences of 1-6 base pairs of DNA
    • when in the promoter region, they effect promoter function

    • different lengths of microsatellites can
    • have opposite effects, depending on where they occur.
    • When microsatellites occur in the promoter region of the gene, they effect how much RNA (and hence protein)that gene produces.
    • However,
    • depending on exactly where in the promoter region they occur, the longer the microstaellite is, either the more or the less protein is made.

    • seratonin transporter gene= anxiety
    • dopamine transporter gene=AD/HD
    • enzyme tyrosine hydroxylase=manic depression
    • vasopression reception gene=monogomy
  10. Selective Attention
    • • Selective attention is differentially processing different “sources” ofinformation. Can include ignoring some information while “attending” to others and/or enhanced processing of one source of information.
    • • “Sources” can be different modalities (vision + touch), differentimage locations, different types of information (color + shape)
    • • In some situations, we are able to apply selective attention and in others it is difficult to do so (e.g, Stroop effect.)
  11. How do we comprehend sentences?
    Semantics and syntax dictate what words are acceptable and the internal structure of a sentence. “Figuring out” each word’s syntactic role is parsing
  12. Bottleneck Theory 1
    • Image Upload 1
    • people are capable of processing stimili simultaneously but must perceive them one at a time
    • First stimulus must be fully perceived before the second can be, but thereafter response selection and production can of the first stimulus can proceed while the second stimulus is being perceived
  13. Bottleneck Theory 2
    • Image Upload 2
    • response selection causes the bottleneck
    • Stimulus 1 and 2 can be perceived at the same time but response 2 cannot be produced until response 1 is completeed
    • increasing evidence from experiments supports this theory
  14. Bottleneck Theory 3
    • Image Upload 3
    • both stimuli perception and response selection for the two tasks proceed at the same time, but the second response cant be produced until the first response is completed
  15. Divided Attention
    • Doing more that one thing at once
    • -processing stages:
    • -perception
    • -response selection
    • -response production
  16. Modularities in visual processing
    • information from the left and right visual hemisphere is initially processed separately by the left and right hemisphere
    • alot of early visual processing areas, each contain a retinotopic map of visual space
    • Within V1 each region of space is represented by a hypercolumn contain neurons that respond to different orientations
    • When info. leaves V1 divide into separate pathways, temporal and parietal
    • Within pathways separate areas are specialized for different functions
  17. Visual "How" Pathways
    • Parietal:
    • -Where
    • -spatial relationships
    • -motion
    • -landmark discrimination
    • Temporal:
    • -What
    • -pattern identity
    • -object discrimination
  18. High Amplitude Sucking Procedure
    • Infant given a pacifier that contains sensor to monitor sucking rates
    • Each time infant sucks the pacifier a stimulus is played
    • Becomes habituated to the stimulus
    • Presentation of a novel stimulus increased sucking rate
  19. Lingual Progression
    • Newborns can make all the phonemic contrasts of the worlds languages
    • Through experience with native language only those contrasts consistent with their language is retained
    • Interpretation: Over course of development, processing resources are reallocated to sharply distinguish phonemic contrasts that matter in the native language
  20. Visual Search
    • using maps to scan for an object
    • -maps: defining characteristics of the object ex. shape, color, etc.
    • -difficultyof search is linear with number of maps
    • harder visual search uses serial processing--sequential
  21. Retinotopiv Organization of visual areas
    each visual area of tha brain has its own map of what we see
  22. Prior
    The hypothesis, P(H)
  23. posterior
    • the hypothesis updated by the data
    • P(H:D)
  24. Liklihood
    P(D:H), how likely the data is true given the hypothesis is true
  25. Marginalization
    what you put in the denominator to add to one

    • in Bayes rule, marginalization= P(D)
    • P(D)= P(D:H) P(H) + P(D:~H) P(~H)
  26. Frequentists
    • Probability as an expected frequency
    • P(A)=1: A will always occur
    • P(A)=0: A will never occur
  27. Subjectivists
    • Probability as a degree of belief
    • P(A)=1: A is true
    • P(A)=0: A is false
  28. Predictive Reasoning
    Given a known hypothesis, how likely is the data?


    Given multiple possible hypotheses, how likely is the data?

    P(D) = P(D|H=h1)p(h1) + P(D|H=h2)p(h2) + P(D|H=h3)p(h3)
  29. Inductive Reasoning
    Start with prior P(H)

    Observe data D

    Compute posterior

    lP(H|D) = P(H) * P(D|H) / P(D)

    • nuses model of the world: P(D|H),
    • P(D)

    • Example
    • lMy prior is there are “even odds”
    • that Molly likes me

    • I observe that when someone likes
    • me, they smile at me 80% of the time , but overall only 40% of the people smile
    • at me.

    • Given that Molly smiled at me,
    • how likely is it that she likes me?
  30. Conditional Independence
    p(word1,word2| topic) =

    • p(word1|topic) p(word2|topic)
    • allows for scaling
  31. Bayesian Inference
    How to predict future data when you have multiple hypotheses?

    • P(D=dfuture)
    • = Sum
    • p(D=dfuture |H=hi)p(H=hi|D=dpast)

    • 1.
    • Find belief in each hypothesis, hi, based on past data, dpast,
    • using Bayes rule
    • 2.
    • Find probability of future data, dfuture
    • , given each hypothesis, hi
    • 3.
    • Predict future data by “averaging” (marginalizing) over the different
    • hypotheses
  32. Markov Transistion Matrix
    • A Markov transition matrix is a square matrix describing the probabilities of moving from one state to another in a dynamic system. In each row are the probabilities of moving from the state represented
    • by that row, to the other states. Thus the rows of a Markov transition matrix each add to one. Sometimes such a matrix is denoted something like Q(x' | x) which can be understood this way: that Q is a matrix, x
    • is the existing state, x' is a possible future state, and for any x and x' in the model, the probability of going to x' given that the existing
    • state is x, are in Q
  33. Hidden Markov Models
    Sequence of hidden states are the “meanings” (what the word refers to) and words are the percepts

    The (Markov) Language Model says how likely each meaning is to follow other meanings

    • All meanings of “banks” may
    • produce the same percept
  34. Experimental Techniques
    • –Identification of sound
    • (phonemes)

    • –Discrimination of two sounds
    • (phonemes)

    • –Habituation (phonemes in infants)
    • sucking paradigm
    • –Eye tracking (visual world paradigm)

  35. Representative Heuristic
    people judge the probability or frequency of a hypothesis by considering how much the hypothesis resembles available data

    Insensitivity to priors

    Insensitivity to sample size

    Misconception of chance

    Insensitivity to predictability

    Misconception of regression to the mean
  36. Regression to the Mean
    • •After making an excellent landing, a pilot in training is praised by the
    • instructor. Next landing is worse.

    •After making a bad landing, a pilot in training is scolded by the instructor. Next landing is better.

    If you do really well on one thing, you have a greater probability of doing worse next time regardless of positive or negative reinforcement
  37. Availability Heuristic
    •Many decisions require an estimate of relative frequency. Examples, which is more likely:

    • •<death from car accident, death
    • from stomach cancer>

    •<homicide, diabetes>

    •Availability Heuristic: The ease with which things come to mind is used as an index of frequency.
  38. Framing Effects
    How a question is worded can have a large effect on how it is answered. In the example above, one formulation emphasizes gains, while the other emphasizes losses
  39. Dual Process Model of Thinking
    • •people have to distinct ways of thinking about the evidence they encounter
    • –System 1 (heuristics)
    • –System 2 (slower, effortful thinking) logic
  40. Brain Areas that correlate with subjective value
    • -medial prefrontal cortex
    • -posterior singulate cortex
    • -ventral striatum
  41. Lateral Intraparietal Area
    Neurons in parietal cortex (LIP) integrate/compare value information, at least for perceptual decisions, and their responses determine what choice is made

    • -firing rate of neurons increase gradually over time as the stimulus comes on
    • -the firing increase is faster when the motion strength is stronger
    • -expected of a signal integrating info.
  42. McGurk Effect
    lip movements + speech sound = speech perception

    • demonstrates parallel and interactive processing and based on multiple sources of info.
    • brain makes reasonable assumption that both sources are informative and fuses the two
  43. Incremental Discrimination
    resolving speech ambiguity is done incrementally in real time and late arrive info. can effect interpretation of earlier info.
  44. The Visual World Paradigm
    method for studying how speech understanding unfolds overtime and what types of information is used to resolve ambiguity

    measures where people look as they follow spoken instruction ie frog on napkin study
  45. Ultimatum game
    some gain from exchange, and one player makes a take it or leave it offer of how to divide the gain

    • 2 players- Proposer and Responder bargain over amount
    • Good for measuring how people feel about the allocations of money between themselves and others
    • rejections are "negative reciprocities", reciprocate unfair offer by rejecting and punishing the proposer
  46. Nash Equilibrium
    solution to how the problem of how rational players would play

    idea: players would adjust their strategies until no player could benefit from changing

    A set of moves by all players is a Nash equilibrium if changing one of the moves leads the player who changed to be worse off.
  47. Strictly Dominant Strategy
    a strategy or choice of move is strictly dominant if a player is better off by choosing it, no matter what the other players do
  48. Pareto Optimality
    An outcome of the game is pareto optimal if there is not other outcome that makes every player at least as well off and at least one player strictly better off. A pareto optimal outcome cannot be improved upon without hurting at least one player
  49. Continental Divide
    Cooperation game-- players want to conform to what others do

    in a game choosing 1-15, 3 and 12 are equilibriums,

    called a continental divide because medians below 7 converge towards the equilibrium of 3 and medians above 8 lead towards 12. The "seperatrix" between 7 and 8 divides the game into regions
  50. Beauty Contest and Iterated Dominance
    • N players chooses a number, x, between 0-100 and take an average of those and multiply by an integer p<1 ex. 0.7
    • players who choose the closest number win
    • Used to determine whether people practice the 4th, 5th or higher degree of reasoning
    • people usually perfom a couple iterations and goal is to be only one step above the average

    0 is the equilibrium
  51. Phenomenal Consciousness
    • What it is like to experience something, perceptual experiences:
    • -tasting licorice smelling the sea
    • -bodily sensations, pain nausea
    • -felt reactions, passions, emotions
    • -felt moods, happy depressed, calm, bored
  52. Access Consciousness
    • Self awareness
    • introspection, memory
    • high order or extended consciousness
  53. Functions of Consciousness
    • -Definition and context setting
    • -Adaptation and learning
    • Editing, flagging, debugging
    • Recruiting and control
    • Prioritizing and access control
    • Decision making or executive function
    • Analogy forming
    • Metacognitive and self-forming
    • Auto-programming and self maintenance
  54. Dual Thought Mechanisms
    • -unconscious/conscious
    • -heuristic/reasoned
    • -emotional/rational
    • -fast/slow
  55. Origins of Consciousness
    • Emotion-body state, ex. chemical
    • Awareness= Phenomenal Consciousness:
    • -peception of body state and relation of self to environment
    • -feelings
    • Self Awareness= Access Consciousness:
    • -brain devices that represent continuity of the same individual organism
    • -require P-type
  56. Binding of Multi-Modal perception and consciousness
    • accomplished by synchronized gamma oscillations:
    • -different areas synchronized oscillations when they are unifying parts of the perceptual field or other percepts into a single gestalt
  57. Oscillations
    rhythmic or repetitive activity of neurons in the central nervous system

    • 3-8 hertz= theta oscillations
    • 30-80 hertz= gamma oscillations

    effect the timing and liklihood of spike output
  58. Theory of Mind
    • assuming others have minds by making analogies to one's own and based on reciprical nature of social interaction
    • Allows one to attribute thoughts, desires, and intention to others, and predict or explain action and posit their intentions
    • Innate potential in all humans
  59. False belief Task
    child is given a scenario: Sally and Anne have a basket and box respectively. Sally places a marble in her basket and goes for a walk. Without Sally seeing, Anne takes the marble and puts it into her own box. When Sally returns where does she think the box is?

    • Passing this test shows that someone understands that others have beliefs that may be wrong
    • an understanding of how knowledge is formed
    • people's beliefs are based on knowledge
    • mental states can differ from reality
    • peoples behavior can be predicted by mental states
  60. Precursors to Theory of Mind
    • Understanding attention of others
    • Understanding intention of others
    • Ability to imitate others' lies
  61. Symptoms of Autism
    • Difficulty determining intention of others
    • Lack understanding of how their behavior affects others
    • Deficit in social reciprocity
    • Difficulty in verbal and non verbal communication
    • Difficult making relationships and interacting with others
    • Difficulty in communicating emotions
    • Lack pretend play
  62. Memes
    Strings of data, postulated unit cultural ideas, symbols or practices transmitted from one mind to another

    • Like viruses can manipulate the host
    • Co-evolved with genes
    • language is digital and productive
  63. Ferret Experiment
    lesioning of the auditory pathway in newborn ferrets

    after rearing the ferrets into adulthood recordings are made of the auditory cortex

    ferrets respond to visual stimuli in the auditory cortex

    • experiment does not work in lesioned adult ferrets
    • proves plasticity of the cortex
  64. Owl localization
    auditory localization adjusts to match vision, if prism goggles are used early in development, before the critical period
  65. Critical Period
    Time during development where experience allows adjustment to altered input, neurally and behaviorally

    Or a time when normal experience is necessary for normal development
  66. Temporal discounting
    objects tend to lose value over time

    • indifference amount= point where 50% of people take the money
    • subjective value= actual value/indifference amount
  67. Forced Looking Experiment
    • In a forced choice looking experiment, there are two targets on each
    • trial, and (in the case of the infant studies), which one the infant
    • looks at is measured. This leads to data that characterize the
    • probability that one target is looked at over another.
  68. Free Looking Experiment
    • In a free looking experiment, the amount of time an infant spends
    • looking at a single target (as opposed to looking anywhere else in the
    • scene) is measured.
  69. Vassopressin
    similiar to Oxytocin, appears only in males

    increase territoriality and aggression

    longer microsatellite chain increases "good" paternal characteristics, but more copies of that RS3 334 section of the gene decrease these characteristics. (in humans)
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cognitive science