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History and some Cognitive

Neuroscience (Chapters 1 & 2)

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History

Timeline showing early experiments studying the mind in the 1800s

and events associated with the rise of behaviorism in the 1900s

Gustav Fechner!

1801-1887

Psychophysics!Fechner color effect:!http://www.itp.uni-hannover.de/~zawischa/ITP/benhamtop.html!

Fechner"s Law – a subjective sensation is proportional to the logarithm of the stimulus intensity!

S = K Log I!S = Psychological sensation!I = Physical intensity of the stimulus!

I * 3 = S + S!I * 3 * 3 = S + S + S!

Geometric increase in stimulus intensity leads to an additive increase in sensation.!

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Unconscious inference

•# Some of our perceptions are the

result of unconscious assumptions

we make about the environment

•# We infer much of what we know

about the world

Hermann Von Helmholtz!

1821-1894

Influenced Ebbinghaus, Wundt, Helmholtz!

Math Modeling!The mind and body are different sides of one reality.!

"Every sensation, presents itself as an indivisible unit; and it is quite impossible to read any clear meaning into the notion that they are masses of units combined."!

William James!

1842-1910

Gustav Fechner!

1801-1887

Timeline showing early experiments studying the mind in the 1800s

and events associated with the rise of behaviorism in the 1900s

Pavlov (1849-1936) Thorndike (1874-1959)

History

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Pavlov (1849-1936)

Thorndike (1874-1959)

Classical (Pavlovian) Conditioning!(Dogs)!CS – !UCS –!UCR – !CR –!

Law of Effect!(Cats)!Puzzle Box!Precursor of $Operant" or $Instrumental" Conditioning!

Alpha, Beta Tests (ASVAB)!$Active Learning"!

Pavlov’s Discovery:

Classical

Conditioning

Timeline showing early experiments studying the mind in the 1800s

and events associated with the rise of behaviorism in the 1900s

Pavlov (1849-1936) Thorndike (1874-1959)

History

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Timeline showing early experiments studying the mind in the 1800s

and events associated with the rise of behaviorism in the 1900s

Pavlov (1849-1936) Thorndike (1874-1959)

History

Early experimental psychology:

Behaviorism Influential figures: !John B. Watson, !B. F. Skinner!

•#Guiding Principles:!–# Only focus on that which is observable.!

–# Explain behavior; not thought, the mind, consciousness, etc.!

•#Contribution to Cognitive Psychology!–#Emphasis on rigorous experimentation.!–#Powerful theories of learning!

•# Classical Conditioning (Ivan Pavlov)!

–# e.g., Pavlov!s dog learned relationship between bell and food.!

•# Operant Conditioning (Edward Thorndike)!

–# e.g., A dog learns to sit for a treat.!

Burrhus Skinner!

1904-1990

John Broadus Watson

1878-1958

“Give me a dozen healthy infants, well-formed, and my own specified world to bring them up in and I'll guarantee to take any one at random and train him to become any type of specialist I might select – doctor, lawyer, artist, merchant-chief and, yes, even beggar-man and thief, regardless of his talents, penchants, tendencies, abilities, vocations, and race of his ancestors. I am going beyond my facts and I admit it, but so have the advocates of the contrary and they have been doing it for many thousands of years. [Behaviorism (1930), p. 82]!

John Broadus Watson

1878-1958

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The Decline of Behaviorism

•# A controversy over language acquisition!

•# Skinner (1957)!

–#Argued children learn language through operant conditioning!

•# Children imitate speech they hear!

•# Correct speech is rewarded

•# Noam Chomsky (1959)!

–#Argued children do not only learn language through imitation and reinforcement!

•# Children say things they have never heard and can not be imitating !

•# Children say things that are incorrect and have not been rewarded for!

–#Language must be determined by inborn biological program (LAD)!

–# “Colorless green ideas sleep furiously”

The Decline of Behaviorism

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•# What happens when the rats are placed in a different arm of the

maze?!

•# The rats navigated to the specific

arm where they previously found food!

–#Supported Latent Learning, not

stimulus-response learning!

Edward Chace Tolman

1886-1959

(a)#Rat initially explores the maze; !

(b)#then learns to turn right to obtain food at B when it starts at A; !(c)#when placed at C, the rat turns left to reach the food at B.

•#Tolman (1938)!

Limitations of Behaviorism

•# Failures to account for aspects of human behavior!

•# Over-emphasis on animal experimentation!

•# Language!•# Skinner suggested language was learned through basic

principles of operant conditioning.!

•# i.e., we learn to say what is rewarded!

•# Fails to account for Generativity of language.!

•# The creation of novel utterances %

that have never been rewarded in the past.!

•# e.g., Chomsky (linguist)

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!#Failure to consider intervening mental processes!

"#Behaviorism:!

"#Cognitive Psychology:!

Stimu

li Response

s

Stimu

li Mental

Processes Response

s

"#Stimulus (memorize this list)!

!# lion, onion, Bill, firefighter, carrot, %

zebra, John, clerk, Tom, nurse, cow!

"#Response (recall)!

!# lion, zebra, cow, onion, carrot, %

firefighter, clerk , nurse, John, Bill, Tom!

"#Mental Processes!

!# Strategies, grouping, reorganization, etc

The Cognitive Revolution

•# Shift from behaviorist"s stimulus-response relationships to an approach that attempts to

explain behavior in terms of the mind

FIG 1.12

Timeline showing events associated with the

decline of the influence of behaviorism (above the

line) and events that led to the development of

the information-processing approach to cognitive

psychology (below the line).

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!#Philosophy!!#Think about mental processes!

!#Structuralism (Introspection)!!#Try to directly tap into mental processes!

!#The What of experience!

!#Behaviorism!

!#Study stimulus-response relationships!

!#Ignore mental processes!

!#Cognitive Psychology!!#Study stimulus-response relationships!

!#Make inferences about mental processes!

!#The How of experience!

!#Mathematical Modeling!

Overview of Different Approaches

Stimu

li Mental

Processes Response

s

The rebirth of the study of the mind

•# The digital revolution!–# Information Processing: inputs are

transformed, in stages, to generate outputs.!

–#Flow diagrams for digital computers.!

•# Flow diagrams for the mind.!–#Colin Cherry (1953): selective attention.!

–#Broadbent"s information processing model of

attention.

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A model for selective attention!

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How can you stay focused on your

conversation?!

You must filter out extraneous

information.

Filter Detector Inputs To memory

“I hate that Shaw guy.”!

Attention can still be broken into.!

(we will explore these ideas more in

chapter 4).

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Studying the Mind

•# To understand complex cognitive behaviors:

•# Measure observable behavior

•# Make inferences about underlying cognitive

activity

•# Consider what this behavior says about how

the mind works

Researching the Mind

•# Behavior approach measures relationship

between stimuli and behavior

•# Physiological approach measures

relationship between physiology and behavior

•# Both contribute to our understanding of

cognition

Researching the Mind – Memory Consolidation

•# Memory for recent events is fragile

•# If processing is disrupted, recent memories

can fail to be consolidated

•# New information can interfere with memory

consolidation

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Researching the Mind – Memory

Consolidation

•# Behavior approach

•# Muller and Pilzecker (1900) had participants

learn two lists of words

•# Independent variable:

•# One group learned the second list immediately after the first list

•# The other group experienced a six-minute delay

between learning the lists

•# Dependent variable:

•# Memory (recall) for the first list of words

Results of the Gais et al. (2007) experiment in which memory for

word pairs was tested for two groups. The sleep group went to

sleep shortly after learning a list of word pairs. The awake group

stayed awake for quite a while after learning the word pairs. Both

groups did get to sleep before testing, so they were equally rested

before being tested, but the performance of the sleep group was

better.

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Cognitive Science •# Interdisciplinary study of the mind

•# Psychology

•# Computer science

•# Cognitive anthropology

•# Linguistics

•# Neuroscience

•# Philosophy

•# Physiology

•# Molecular Biology

•# Physics

•# Education

Timeline showing early experiments studying the mind in the 1800s

and events associated with the rise of behaviorism in the 1900s

Descartes

1596-1640

Broca

1824-1880 Wernicke 1848–1905 Luria (1902-1977)

Pavlov (1849-1936) Thorndike (1874-1959)

Cognitive Neuroscience!

•# The microstructure of the brain

•# Neurons

•# Glia

•# Hold neurons in place,

•# Supply nutrients and oxygen to neurons

•# Insulate neurons from one another

•# Destroy pathogens and remove dead neurons.

•# Also involved in communication

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History of Neuroanatomy

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a) Action potentials are recorded from neurons with tiny microelectrodes that are positioned inside or right next to the neuron’s axon. These potentials are displayed on the screen of an oscilloscope and are also sent to a computer for analysis. (b) An action potential recorded by a microelectrode looks like this. The inside of the axon becomes more positive, then goes back to the original level, all within 1 millisecond (1/1,000 second). (c) A number of action potentials displayed on an expanded time scale, so a single action potential appears as a “spike”.

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Microstructure: The Neuron

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•# the voltage between two points is equal to the electrical potential difference between those points.

•# Electric potential is the energy required to move a unit electric charge to a particular place in a static electric field

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Microstructure: The Synapse

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