Danger of calling yourself a Psychologist
Danger of calling yourself a Psychologist
• Scientific Psychology bears little resemblance to
“pop” psychology, fortune telling, phrenology, or
astrology
• Subjective, no scientific base
Objective data collection
Subjective data collection
Systematic observation
Hit or miss observation
• Psychology is not just a fancy name for common
sense
• Psychological research often produces findings
that contradict popular beliefs
Reliance on evidence
Ignoring counterevidence
Goal of Experimental Psychologists
• Goals of psychology include:
• description of behaviour using careful
observations
• explanation identifying the cause(s) of behaviour
• prediction allows for specification of the
conditions under which a behaviour will or will
not occur
What is Psychology?
•
Psychology is the science of brain (mental)
processes and behaviour
(Behaviour is an emergent property of the brain)
•
Psychology values:
• critical thinking
• empirical evidence
• systematic research methods
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Psychology as a Science
• Critical Thinking
• The ability and willingness to assess claims and
make objective judgments on the basis of wellsupported reasons and evidence, rather than
anecdote
• Define your terms
• Examine the evidence
• Consider other interpretations
Psychology as a Science
• Hypothesis
• A statement that attempts to predict or to
account for a set of phenomena
• Specifies relationships among events or variables
and are empirically tested
• The predictions should be specific enough to
expose the hypothesis to disconfirmation
(falsifiability)
• Predict what will happen
• But also what will not happen
Characteristics of Good Theories
• General
• Incorporating existing facts and observations within a
single framework (broad explanatory power)
• Testable
• generate hypotheses that can be tested. Verifiable
through direct observation (Falsifiable)
• Tentative
• Skeptical attitude, questioning possible problems with
method or design and questioning assumptions,
inferences, deductions
• Parsimonious
• the simplest theory (with fewest assumptions) is
preferred
How to judge Theories
• Experiments
• Rigorous methods
• Highly controlled to determine cause and effect
• Should be repeatable within and between
laboratories
• Data
•
•
•
•
Quality
Ability to predict
Ability to explain
Ability to control
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Why is it difficult to investigate
learning & memory?
• People have little conscious awareness of mental processes
• thought to be beyond objective, scientific study because of its
“hidden” character
• investigated with indirect methods
Scientific Inference
• When study learning often do not make direct
observation of the processes involved
• Not a problem because ALL science must make
careful inferences of the unobservable, based on
logic, and data from observable events
• On the basis of observations make inferences
Experimental Variables
• To test a hypothesis, an experimenter defines the variables of
the hypothesis:
• Cause: Independent variable (IV)
• What you manipulate
• Observable
• Effect: Dependent variable (DV)
• What you measure to test your hypothesis
• Observable
• Intervening variable — unobservable process that helps
explain relationship between IV and DV
• Not observable
• Extraneous variable — what you (try to) control
Experimental Observation
• Change value of one variable (the IV) while all
other variables (noise) stay the same
• Observe whether there is a change in response
measure (the DV)
• General procedure:
• Random assignment
• Different treatment
• Compare groups
• Controls
• important for determining causality
• the only difference is the presence or absence
of the IV
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The Scientific Method
Scientific Inference
Research Questions
Hypotheses
If DV depends on IV,
then causation can be
logically inferred
Study Design
Observation of variables
Relationship among variables
Conclusion from Research
Intervening Variable
Independent Variable
(“Cause”)
Intervening
variable
Hours since last meal
Hunger
Hours without water
Thirst
Time devoted to study
Learning
Dependent Variable
(“Effect”)
Operational Definition
• Some variables are concrete and observable (e.g.,
kissing); others are abstract (e.g., love)
• Objectively observable event represents the
occurrence of some internal, subjective event
Amount of food eaten
Amount of water drunk
Score on exam
• Clearly defined set of procedures for obtaining a
measure of the construct of interest
• Procedure is specified precisely enough to allow
replication by others
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Operational Definition
• Objective measure
• Measurable behaviour
• Capture the essence of the concept or construct of
interest
• Are there “bad” operational definitions?
• E.g., define “height” as the number of times that
participants hit their heads when entering the
testing area
Between-Subject Design
• Independent group
• Random assignment
• Matched group
• Control of extraneous variables that may obscure
effect of IV
• Matched on relevant characteristic
APA Ethical Guidelines (humans)
Within-Subject Design
• More powerful design
• Repeated measures
• Control over error variance
•
•
•
•
informed consent
awareness of risks
confidentiality
deception can be used ONLY if benefits justify it
and there is no other way to do the study
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APA Ethical Guidelines (animals)
General-Process Approach
• Researchers must ensure “appropriate
consideration of [the animal’s] comfort, health, and
humane treatment”
• Animals may not be subjected to “pain or stress”
when an alternative procedure is available
• Strict rules concerning housing and care
• Animal care and use committees
• Include a “lay person”
• Reviewed for scientific merit
• Reviewed to ensure all current animal welfare
guidelines have been met
• Adopted by animal learning researchers (chemist and
physicists too!)
• Explain the greatest variance of observable
phenomena with the smallest number of general laws
• Formulate laws to organize and explain a diversity of
events
• Learning phenomena are products of elemental
processes that operate consistently across situations
• Evidence that principles of learning have
considerable generality in diverse species (especially
vertebrates)
Different levels of analysis
Learning & Memory
Level of Analysis
Whole organism
How experience changes an organism
Learning Mechanism
Area of Psychology
Behavioural
Development
Cognition
Clinical
Learning Perspective
process of adaptation of behavior to experience
Physiological
Psychology
EVENT
Behavioural
Neuroscience
Memory (Cognitive) Perspective
the permanent records that underlie this adaptation
Basic
Neuroscience
EVENT
Neural circuits
Neurochemicals
Neural systems
Neural networks
Neurons
Molecular
Cellular
Change in Behavior
Change in what organism knows
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Learning-Performance Problem
• The only way we can study learning is by observing
performance, but….
• Performance does not always reflect learning!
The Brain Changes its Functioning in
Response to Experience
• Learning
• how experience changes the brain
• Memory
• how changes are stored and subsequently reactivated
• What brain structures are involved in processes of learning
and memory?
Effects of Bilateral Medial Temporal
Lobectomy
• H.M. – an epileptic who had his temporal lobes removed in
1953
• His seizures were dramatically reduced – but so was his
ability to form new memories
• Mild retrograde amnesia and severe anterograde amnesia
• Retrograde (backward-acting)
• unable to remember the past
• Anterograde (forward-acting)
• unable to form new memories
• While H.M. is unable to form most types of new long-term
memories, his STM is intact
Assessing H.M.
• Digit span – H.M. can repeat digits as long as the time
between learning and recall is within the limits of short-term
storage
• Mirror-drawing task – H.M. exhibits improvement with
practice. He is able to show skill memory – demonstrating
that he can learn some things (also rotary-pursuit and a
drawing task) – although he is not aware of it
• H.M. readily “learns” responses through Pavlovian
(classical) and operant conditioning
• H.M. can learn some things, but has no memory of having
learned them
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Parallel learning systems
Scientific Contributions of H.M.’s Case
• Medial temporal lobes are involved in memory
• Short-term memory (STM) and long-term memory (LTM)
are distinctly separate
• H.M. is unable to move memories from STM to LTM, a
problem with memory consolidation
• Memory may exist but not be recalled – as when H.M.
exhibits a skill he does not know he has learned
• H.M. forms new implicit memories, but not new explicit
memories
conscious
declarative
HIPPOCAMPUS
TEMPORAL LOBE
mutual inhibitory
unconscious
non-declarative
BASAL GANGLIA
knowledges
skills, motor and cognitive
adaptive behaviour
rule like behaviour = habits
extinguishable
not-extinguishable
Time course:
conscious
control
incrementally acquired
habit
associations
The switch from spatial working memory (place learning)
to habit learning (response learning)
day 1 - 7
day 8...
Goal
start
go to
place
Principles of Learning
habit:go left
start
place learners
Hippocampus
response learners
Basal ganglia
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Who needs to know about the
principles of learning?
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•
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•
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Cognitive Psychology
Behavioural Neuroscience
Physiological Psychology
Developmental Psychology
Clinical Psychology
What is learning? NOT
• Students do not have a monopoly on learning
• NOT specific to classroom
• NOT specific to age
• NOT specific to humans
Diversity in Definitions of Learning
• You may want to learn all of the facts in this text
• Acquisition of readily available knowledge
• I want to learn about the neural mechanisms of
learning
• Discovery of previously unknown information
• All parents want their children to learn good
manners
• Change behaviour patterns
• Some people may want to learn how to play tennis
• Acquire new behaviour and new knowledge
What is learning? NOT
• As a psychological concept
• NOT correctness of response
• NOT deliberate attempts to remember
• NOT referring just to observable responses
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Common Definitions of Learning
• A relatively permanent change in the ability to
exhibit a behaviour (knowledge) as the result of
experience
• Enduring change in the way an organism responds
based on it experience
• Enduring change in the mechanisms of behaviour
involving specific stimuli and/or responses that
results from prior experience with those stimuli and
responses
What is learning?
• Because learning examines causes that alter
behaviour through prior experience
• And causes cannot be observed directly
• Learning must involve inferring causality from the
results of your experimental manipulations
Learning
• Learning allows us to:
• To use past experience to predict the future
• To adapt to a rapidly changing environment
• To exert control over our environment
• Behaviour is what changes when learning occurs
• Behaviour, in science, anything the organism
does that can be measured
What is learning?
• Psychologists are interested in:
• Process
• Events that change behaviour
• Product
• Long-term changes in behaviour
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What is learning?
• E.g., Raccoons and Trashcans
• Process (Acquisition phase)
• Period in which animal is acquiring a new skill
• Organized plan of action or haphazard luck
• What factors determine duration in face of
obstacles?
• Product (Performance of learned behaviour)
• How will intermittent success influence
frequency of behaviour?
• Will the behaviour generalize?
Learning
• Experience (nurture) is the key to learning
• a relatively permanent change in behaviour
brought about by experience
• distinguishes between maturation and experience
• distinguishes between short-term changes in
performance and actual learning
Learning
• Three assumptions of learning theories
• Responses are learned rather than innate
• Learning is adaptive
• Experiments can uncover the laws of learning
and these laws will apply to:
• Different species
• Different situations
• Different behaviours
Learning
• Learning is inferred from behaviour, but isn’t
behaviour (intervening variable)
• Some things “look” like learning that are not
learning
• Just because change in performance cannot be
automatically considered to reflect learning
• Temporary, physical states, e.g., Fatigue
• Change in physiological or motivational state
• Maturation
• Drugs
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Any of these represent learning?
Why use Animals?
• An infant who stops thumb-sucking?
• Children being able to use language?
• A patient who has a lobotomy and no longer
manifests psychotic behaviour?
• A plant being pinched back and then growing more
dense foliage and flowers?
• Harry throwing his cigarettes away after 30 years of
smoking two packs a day?
• A computer that uses its first 100 tabulations to
influence its choice of opening moves in a chess
game?
• Human behaviour is incredibly complex, thus
animals serve as a model to understand behavioural
complexity
Why use Animals?
Why use Animals?
• Evolutionary continuity of the brain and nervous
system
• Necessary for theoretical and methodological reasons
• Information about the physiology of learning processes
• Ethical considerations may prevent the use of human
subjects in experimental situations
• Animal models allow investigations to be simpler, better
controlled
• Validity of animal models depends on the similarity
between the animal model and human behaviour in
relevant features of the behaviour being studied
• Experimental Control
• Reliable! Always show up to experiments
• Minimize the placebo effect—not motivated to
behave a certain way due to preconceptions
• Food & water — how much, when, where, what
kind
• Light cycles — length of day
• Temperature
• Past history: genetic and socialization
• Simpler System
• Animals used to identify basic components of
learning
• Principles of Learning
• Developed from animal research
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Why use NOT Animals?
• Difficult to address complex human functions
• Language, reading, problem solving
• Ethics
• Even though very strict ethical guides, are the
scientific advances worth it?
Latent Learning
• In the 1930’s, Tolman’s Maze Study
• Rats were allowed to explore a maze without a
food reward while two other groups were trained
using a reward
• Food rats quickly learn to follow the correct path
(they run to the end)
• Non-food rats just wander around
• Day 11 one group of non-food rats were given
food at the end of the maze
Why use Animals?
• Preverbal Humans
• Infants do not talk so are not able to tell us what
they see or hear
• Must develop methods to assess what they are
“learning”
Latent Learning
• After only 1 or 2 rewarded trials, these rats were
shown to do as well as rats that had been trained
with rewards
• Rats in the third group learned about the
layout of the maze while they were ‘just
wandering around’
• no behavioural evidence of this learning until
the situation changes (i.e., motivated to get to a
particular part of the maze quickly)
• I.e., the rats had formed some kind of a “map”
of the maze! LATENT LEARNING
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Tolman’s Study on Latent Learning
Take Home Message
• Many species, including humans, rely on learning
for survival
• Although most people pay more attention to
acquiring new behaviours, learning not respond is
just as important as learning to make new responses
(Figure adapted from Tolman & Honzik, 1930, p. 267)
• Diversity of Learning
• Learning can result from special instructional
training (classes) and from common contacts
with the environment
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