What is Psychology? 11-06-03 10:10 PM
We will be learning the science of psychology rather than clinical psychology
and our goal is to understand the human thought and behavior.
What does psychology teach us? Teaches how we think, feel, develop,
learn, interact and grow. It also teaches us to use scientific methods to
collect and evaluate information and derive a conclusion based upon it. It
teaches us not to believe something without solid proof.
History of Psychology
- Greek words Psyche (soul) and logos (study of) which means study of soul.
- Psychology is only about 150 years old. Before this, study of mind was
philosophy and physiology (the functions of a organism or any of its parts)
Early Century Philosophers influence:
Greek Philosophers Aristotle and Plato asked questions:
• How do we learn to remember?
• Where does knowledge come from?
• Mind and Body were two different entities that worked together.
• The Mind controlled the mechanical movements of the body and
received information about the outside world through sense organs.
1800 Century Physiologist influence:
• Different areas of the brain serve different functions.
• Nerves transmit messages in the form of electrical impulses. The
impulses travel along different channels
• Particular areas of the body are connected to particular areas of the
brain and played a role in different functions.
• used Muller’s technique to destroy certain areas of an animals
brain. By doing so, he studied the particular area’s function.
• By using the method, he analyzed which areas controlled heart
rate, breathing and processing of visual and auditory reflexes.
Helmholts: • Nerve impulses do not travel at the same speed an electrical
current passes through a conductive wire. Nerve impulses travel at
about 90 feet/second.
Psychology began to emerge out of roots of Philosophy and Physiology.
Birth of Psychology (1879):
• Wilhelm Wundt opens first lab devoted to study of psychology.
Believed that scientific methods could be used to study conscious
• 1881 Launched first Scientific journal promoting psychological
Introduction to Levels of Analysis
• Learning, Social Psychology, Cognition, Evolution, Neuroscience,
• Ivan Pavlov performed an experiment where he gave a dog food
and rang a bell each time. The dog learned to associate food with
the sound of a bell. The bell acted as a que for the dog.
• Humans also use such que for digestive processes and various
other daily activities. We can use this technique to cure phobias.
• Focused on breaking down mental processes into their most basic
• Researches used introspection (analyze own experiences and
reported on them)
• focused on the purpose of consciousness and behavior.
Behaviorism (derived from functionalism): • John B. Watson (Father of Behaviorism)
• The mind is a black box that takes input and gives output. The
processing information is to complex to understand and is “outside
the domain of science.”
• BF Skinner -> You can learn everything about an organism by
simply studying it’s behavior. Organism will repeat a behavior if it
leads to something pleasant
• Proper Scientific methods can be used to unlock the black box (the
• Analyzes Thought, Attention, Memory, Language, and Problem
• Models used to explain complex processes. Models raise questions
and may become outdated when new data is presented. Thus, a
new revised model must be made to explain these changes.
• Models: Abstract representations of how the mind functions. Can
be used to make testable predictions and design experiments.
• early scientists drilled holes into the patients skull to look at the
• X-rays, MRI, CT Scanning
• Neuroimaging through MRI can allow us to non invasively see the
brain. Structural MRI allows us to see the physical makeup of
brain. Functional MRI allows us to see what brain is actually doing
at the time.
• Francis Crick: Where does human Consciousness come from? Why
do we behave the way we do?
• All behavior can be linked to the brain. Our understanding of the
brain is incomplete.
• Influence of individual on a group • Influence of group on a group
• Influence of group on individual
Social psychologists have to be aware of Ethical considerations as they may
have to cause Distress or Deception to create a social situation.
Evolution and Development:
• Developmental psychologists study the development of behavior
over a single lifespan.
• Evolutionary psychologists study the development of behavior over
a much larger period of time. Thousands to millions of years.
• When studying subjects such as infants, special techniques must be
constructed to understand behavior correctly (infant + pictures).
CASE STUDY ON DEPRESSION TO FIGURE OUT
DIFFERENCES BETWEEN EACH TYPE OF
• What are the behaviors associated with depression and how can
they be altered?
• They use Therapy to reverse the problem.
• What negative thought processes are driving depression?
• Therapy to reverse the negative thoughts about ones self.
• Aaron beck: depression is fueled by one’s negative thoughts
towards self, world, future.
Neuroscience Approach: • What changes in the chemical/structural balance of the brain lead
• Potential drug treatment to restore chemical/physical balance
• Hippocampus region smaller in individuals suffering from
• How does a person’s relationship affect their depression?
• Study the importance of having a support group such as peers or
family to fighting depression.
• What genetic or environmental factors lead to depression?
• Why wasn’t the depression gene eliminated through evolution?
• In a social species, depression may be beneficial as it may lead to a
increase in peer support. –Marcello Spenilla
• Nature/Nurture argument. Introduction to Scientific Research 11-06-03 10:10 PM
The Scientific Method:
• We cannot use sources such as Friends, Media or Personal
o Biased information that may not be accurate
• Scientists have a 7 Step method with following Goals:
o Trying to minimize biases
o Making sure information is valid
o Avoiding conflicting information
o Avoid Overseeing important data
o Avoid Confounding Variables. Variables other than
independent variable which may have effect on results.
The Seven Steps
o Theory: By reading the work of other scientists, we can
construct a general set of ideas on how the world works.
o Hypothesis: A set of statements that form the basis of the
experiment you are conducting. These statements guided by
theories make predictions about the relationship between
o Research Method: Constructing method by which to test the
hypothesis. (Hardest Part)
o Collecting Data: Taking measurements of the outcomes of
the test. (Avoid Bias)
o Analyze Data: understand the data collected and discover
trends/relationships between variables.
o Report Findings: findings are published in scholarly journals
after rigorous review. The journals are also tested by the
scientific committee for accuracy.
o Revise theories: Preexisting theories about the world may
be modified to include new research. (Fix what the reviewers
tell you to do. Usually reviewers find flaws with findings and
we must fix them)
Conducting an Experiment Experiment is a scientific tool used to measure the effect of one variable on
• Testing a Hypothesis:
o Anecdotal evidence: Evidence gathered from others or self
§ Cannot be used to conduct scientific experiment
§ Your experiences may not be the same as what others
in the larger population may have experienced
§ Your personal experience does not represent the
experience of others in the same conditions
§ Other factors may have played a role in influencing your
• Using the Experiment
o An experiment is a scientific tool used to measure the effect
of one variable on another
o Independent variable: the variable manipulated by the
o Dependent Variable: the variable that is being studied and
is not under control by scientist.
• Introducing a subject that is not under the influence of the
• This subject must have a similar behavior to the subject being
tested. For example, is test marks under the influence of caffeine
was the research topic, both subjects should be equally motivated
and have the same level of intelligence.
Using Control Groups
o We should have more than one participant in each condition.
The experimental subject may possess superior/inferior
abilities than that of the control subject. o Experimental group receives the manipulation of the
independent variable. The Control group does not receive
o As discussed before, participants in both groups should be as
similar as possible in ability, intelligence and other aspects.
o Within-Subject Design: A single participant acts as both the
control and the experimental group. He performs some tests
using the independent variable, and then performs other tests
without using the variable.
o Expensive and Time consuming
o Practice Effect: Experience leads to better performance over
course of experiment.
o Subject being tested may be bias and perform better on
purpose for the experimental test?
Between Subject Designs
o One group of subjects is the experimental group whilst the
other is the control group
o Once again, subjects should be similar as possible in every
• Population: The general group of people we are trying to learn
about. For example, the effects of caffeine on undergraduate
• Random Sample: Our test subjects should be randomly chosen
from this general group of population to represent a majority or
group without bias towards one.
• Sample: The chosen participants of the population who we conduct
tests on. DO NOT PICK A TOO SPECIFIC SAMPLE GROUP as
this will not present the general population.
• Random Assortment: Assign subjects to the experimental/control
group on random to avoid any biases towards a group of subjects. Conducting an Experiment
• Subject Biases
o Placebo Effect: the experimental group should not know
that they are influenced by the independent variable. The
placebo effect may occur, in which individuals respond to a
treatment that has no medical effect. The experimental group
may think that they are being given the miracle drug, will be
motivate and perform better for other reasons than the drug
§ Do not tell participants whether they are in
experimental or control group!
o Participant bias: participants actions in experiment
influence results outside the manipulations of the
o Blinding: When participants do not know whether they are in
experimental or control group or which treatment they are
• Experimenter Biases
o Actions made by the experimenter unintentionally or
deliberately, to promote the result they hope to achieve
o Don’t even tell the experimental which group do the
sample belong to!
o Double Blind studies: Neither the experimenter or sample
know which group they belong to. 11-06-03 10:10 PM
Working with Raw Data
o Statistics allow for analyzing, summarization, and
interpretation of data collected.
Types of Descriptive Statistics
o Descriptive statistics allow us to view data information at a
glance and gives us an overall idea of the results of the
o A Histogram is a type of graph that is used to report the
number of times a group of value occurs in a data set. On the
x-axis of such a graph is the group of values, whilst on the y-
axis is the frequency that dataset occurs.
o Type of graph illustrating the distribution of how frequent
values appear in the data set.
o Distribution with a characteristic of Smooth, Bell and
symmetrical-shaped curve around a single peak.
o Things such as IQ and test scores fall under this typical
Measure of Central Tendency
o Mean: The most commonly used. It is found by averaging the
data set. It can be misleading when a outlier is present in
the system. The value for the mean can drop/increase
dramatically depending on outliers which are extreme points
distant from others in the data set.
o Median: The median is the centre value in an organized data
set. It tells us what the middle point of our data is without
influence of outliers. o Mode: Appears most frequently in the set and tells us what
the most typical response was. It is the only method out of
the 3 discussed that can be applied to something outside of
Measures of Variability
o Standard deviation: tells us how spread out the data figures
are. The higher the standard deviation, the more spread out
the graph is. The lower the standard deviation, the less
o The standard deviation of a dataset is essentially the average
distance of each data point from the mean.
• The resulting dataset from the experimental group and the control
group must vary to a degree before we can conclude that the
independent variable had an effect.
• If the experimental and control group perform only slightly
different, perhaps the independent variable had no effect. It may
have been by random chance that one group may have performed
• Inferential Statistics: Statistics that allow us to use results from
samples to make inferences about overall, underlying populations.
• Alternate Populations
o In a experiment, we are trying to represent the results of a
few individuals to hypothesize the effect of the independent
variable on an entire population.
o The Control group and an Experimental group may be
classified as two different populations. One population
represents people under the influence of the independent
variable, whilst the other population represents people who
are not under the influence of the independent variable. This
is referred to as alternate populations. o If the independent variable has no effect, both groups
represent a common population.
o Compares each data point from the experimental and control
group to calculate the probability of getting results by chance.
o Is the difference between my control and experimental group
large enough to conclude that the independent variable may
have had an effect?
o A value expressing the probability calculated by the t-test
o The p-value must be less than 0.05 to conclude that
independent variable had an influence
o A p-value of less than 5% means that the probability of
receiving results by chance is unlikely
o Statistically significant à P-value less than 0.05
• Statistical Significance
o Difference between 2 groups is due to some true difference
between the properties of the 2 groups and not random
o The different results obtained are not a result of random
• Introduction to Observational Research
o Used for studies that may have ethical concern
o Scientists observe the effect of variables of interest on
subjects without actually performing any manipulation
o Example: Rather than asking subjects to start smoking to
study lung cancer, a scientist may use data collected on
cancer vs smoking from existing smokers (experimental
group) and non smokers (control group) • Correlation
o Measure of Strength of the relationship between 2 variables
o Correlation Coefficient: Symbolized by letter R it
represents the degree with which 2 variables are correlated.
o +1 coefficient: variables are perfectly positively correlated.
o -1 coefficient: variables are perfectly negatively correlated.
o 0 coefficient: As relation between variables get weaker,
coefficient correlation approaches zero
• Correlation is not Causation
o The relationship between two variables does not always prove
o An external factor or confounding variable may be the
cause of the correlation of two variables.
o For example: ice cream and allergies may be correlated but
pollen in the air during hotter months when ice cream is
eaten is the true reason for this pattern. 11-06-03 10:10 PM
Introduction to Learning:
Two Types of Learning
o Classical Conditioning: Allows us to associate two different
events. An organism is able to respond to a signal (stimuli)
before a event occurs. For example, a dog presented with a
conditional stimuli may salivate even before he is given food.
In nature this event produced positive outcomes. For
example, salivating may make digestive processes easier.
o Instrumental Conditioning: Allows us to associate actions
• Invented by Ivan Pavlov also known as Pavlovian Conditioning
• Pavlov discovered that organisms can learn to associate different
stimuli to different events and produce a conditional response.
• Tested hypothesis on dogs by presenting a conditional stimulus in
the form of a metronome. Every time the metronome was
activated, the dog was presented with food. Eventually, the dog
learned to associate the rhythm of the metronome with food and
salivated even when no food was presented.
• Contingencies form when a animal learns to associate a signal to
a specific event.
• Unconditional Stimulus: Naturally/Automatically triggers a
response without any learning required.
• Unconditional Response: The response that naturally occurs
when a unconditional Stimulus is presented. For example, salivating
when food is presented is a unconditional response generated by
the body. It is Biologically programmed.
• Conditional Stimulus: A stimulus usually paired with the
unconditional stimulus. At the beginning, the stimulus is neutral and
has no effect. However, through learning we learn to associate a
conditional response when presented with a conditional stimulus.
The conditional response may be similar to the unconditional
response. o The conditional Stimulus must be presented before
Unconditional stimuli. Repeated trials of training must be
preformed where the CS and US are paired before the CS can
generate a response on it’s own.
• Conditioned Response: A response generated by the Conditional
• Acquisition is the process by which a contingency between a CS
and US is learned. In other words, it is the rate at which a subject
learns to associate conditional stimulus with a unconditional
stimulus and thus produce a response.
• When conditional stimuli is being learned through repeated trials,
evidence shows that a significant amount of learning takes place
during the first initial trial. Although some learning occurs during
the additional trials, it is not as great as what occurred during the
• Some contingencies can be formed in a single trial. For
example, a rat learns to associate a certain food and sickness in a
single trial. For the rest of it’s life it will avoid the food.
o CS = Taste US = Sickness CR/UR = Aversion
o The specific taste of the food is permanently associated with
aversion, regardless of whether sickness may occur.
• How long do the effects of a learning trial last?
o As long as the Conditional stimuli proves to be a reliable
queue to the Unconditional stimuli, the contingency will be
maintained. If the Conditional stimuli no longer accurately
queues the Unconditional stimuli, the contingency between
the two will fade.
• Extinction: The loss of the Conditional Response when the
Conditional Stimuli no longer accurately predicts the Unconditional
stimuli. • If we present the conditioned stimuli multiple times without the
presence of the unconditional stimuli, eventually the subject will no
longer display a response to the conditioned stimuli.
• When extinction occurs, the subject does not unlearn the
association between the conditioned stimuli and the unconditional
stimuli. Rather, a inhibitory response is learned that contradicts
with the contingency present between the
• After a period of rest, the presentation of a conditioned stimuli will
once again trigger a conditional response, proving that the original
CS US association is not unlearned. 11-06-03 10:10 PM
Generalization and Discrimination
• Stimulus Generalization: Stimuli that are similar to the learned
conditioned stimulus will also produce a conditioned response.
o For example, we may have been bitten by a specific breed of
dog and may have learned to associate that breed with the
unconditioned stimulus of Dog bite. This means that every
time we see that breed of dog, we will produce a response.
o However, when we are presented to other breeds of dogs, we
will still produce a response even if that breed has never bit
• The Generalization Gradient
o An individual has been conditioned to associate 500hz tone
with electrical shock and thus the conditioned response of
o As we move away from the 500hz tone either by
increasing/decreasing the frequency, we can see that the
conditioned response is still present but varying.
o Frequencies near the 500hz mark produce a strong response
similar conditioned response. Frequencies further away from
500hz produce a weaker conditioned response.
o When charting the level of response (y-axis) vs. Frequency
tone (x-axis), the highest point is at 500hz and the graph
decreases as we move farther away.
o Stimulus similar to the conditioned stimulus produce a
higher level of conditioned response than those that
are not similar. (50hz < 450hz)
• Generalization and Extinction
o We can diminish the conditioned response to a conditioned
stimuli by repeatedly presenting a subject with the
conditioned stimulus without presenting the unconditioned
stimulus. (For example, present a dog without the dog bite)
o When this occurs, the entire Generalized gradient is effected
and the strength of the Conditioned response is weakened as
a result. (Scared feelings towards dogs weakened) • Discrimination Training
o Restricts the range of Conditioned Stimuli that may invoke a
o For example, we may restrict the conditioned response
towards a certain breed of dog by continuously showing a
picture of it.
o Unlike Extinction, the rest of the generalization
gradient remains intact. Discrimination just narrows
down the conditional stimuli that invoke the conditional
• CS+ and the CS-
o Through discrimination training, we can shape the level
of conditioned response generated in a generalized
conditioned stimuli. We can completely remove the
level of conditioned response towards a certain portion
of a generalized stimuli.
o CS+ refers to the portion of a generalized conditioned stimuli
that predicts the presence of the unconditioned stimuli and
produced a response.
o CS- refers to the portion of a generalized conditioned stimuli
that predicts the absence of the unconditioned stimuli. This is
typically the portion which produces zero conditioned
response after discrimination training
§ For example the 500hz (CS+) sound is followed by the
unconditional stimulus of shock while the 600hz (CS-)
stimuli is followed by nothing. After discrimination
testing, the subject will not react to the 600hz stimuli
while they will react to all the other generalizations of
the conditioned stimuli (ranging from 0hz-580hz)
§ CS 600hz à US None à UR/CR NONE
CS 500hz à US Shock à US/CR Fear of Shock
Phobias and Therapies
Conditioning and Fear o Phobia: Fear of certain situations, things, activities or people.
o Treating of Phobias: Present the conditioned stimulus
repeatedly without presenting the unconditioned stimulus.
This will fade the conditioned response over time.
§ For example, present the subject snakes (conditioned
stimulus) without the snake bite (unconditioned
stimulus) in order prevent Fear or snakes (conditioned
§ This can be difficult as the subject will most likely want
to avoid facing their phobia.
o Implosive Therapy: subject must confront the phobia in
order to suppress conditional response. The conditioned
stimulus is presented without the unconditioned stimulus.
o Systematic Desensitization: Uses the generalization
gradient in order to combat a phobia.
§ conditioned stimulus that occurs at the far end of the
curve are extinguished before moving onto the major
stimuli that occur near the middle.
§ A subject with a fear of dirt might be exposed to paper
confetti and other items before being exposed to dirt.
Homeostasis and Compensatory Responses
• Our body also learns to create conditioned stimuli based on
• For example, coca-cola increases blood-sugar level which in turn
requires insulin to be released. Therefore, the body learns to
recognize the sweet taste of cola and produces a conditioned
response of releasing insulin automatically, regardless of whether
the cola contained sugar or not.
• Our body uses Classical conditioning in order to prepare the body
for challenges to homeostasis.
• Environmental queues play a role in promoting drug intake.
• When drug intake occurs, the body counters the effect of the drug
in order to maintain homeostasis. These effects include increase of pain sensitivity and respiration and become the Unconditioned
Responses to the drug.
• Drug intake usually occurs at a particular period of the day, at a
certain location, under a certain mood. The body learns to associate
these environmental factors and turns them into a Conditioned
• When the subject is present in such environment, the body
automatically initiates processes that promote homeostasis,
regardless of whether the subject has taken the drug or not. The
body has learned that the environment conditions usually result in
drug intake and performs homeostatic activities to counter the drug
effects. This body has created Conditioned Response.
• This is why addicted individuals tend to crave a certain drugs
only when present in a certain environment. Their bodies are
initiating processes that have the opposite effect of what the
Withdrawal and Environmental Specification
• As an individual increases his intake of a drug in a specific familiar
environment, his tolerance (CR) towards the drug builds up and
the effect of the drug weakens.
o Exposure to Drug taking Environment (CS) produced a
counter-adaptation effect (CR) which generates desire
to take drugs
• Usually occurs when drug users intake a type of drug in a new
• When taking drug in a new environment, no conditioned response
occurs as the body has no conditioned stimuli. Therefore, only
natural unconditioned processes act on the body and no built up
tolerance is present. This increases the risk of overdose. 11-06-03 10:10 PM
Instrumental Conditioning: Involves explicit training between voluntary
behaviour and their consequences. It is not naturally formed contingency
unlike the ones found in Classical Conditioning examples. Learning the
contingency between behaviour and consequences.
Thorndike's Experiment (puzzle box)
• Placed cat in a box with a door which could be opened by pulling a
• The cat must open door in order to reach food outside the box
• The action of pulling on rope must be learned through many
• Each attempt, the time it takes vs the number of trials decreases
• Random behaviour that did not lead to escape occurred less and
• The POSITIVE BEHAVIOUR was motivated, whilst negative was
• Animals = No consciousness applied to behaviour unlike humans.
The Law of Effect
-Thorndike experiment, behaviour like rope pulling stamped in
- Stamped in behaviour produces a favourable consequence.
- Behaviour that do not produce a favourable consequence.
- These behaviour are typically eliminated through learning.
- Animal will learn to favour the stamped in behaviour over this.
Eventually, the cat will form a contingency between pulling rope and reward.
The Law of Effect:
- Behaviours with positive consequences will be stamped in
- Behaviours with negative consequences will be stamped out. Types of Instrumental Conditioning
- Reinforcer: Any stimulus presented after a response.
- Positive Reinforcers may promote a certain response.
- Negative Reinforcer may inhibit a certain response.
- Presenting/Removing positive and negative reinforcer modifies
- Presentation of positive reinforcer
- Increases a certain behaviour
- Presenting puppy with treat every time it sits on command will
- Presentation of a Negative reinforcer
- Leads to a decrease in behaviour
- Punishment by parents decreases unwanted behaviour
- Controversial due to ethical implications
- B.F. Skinner: When punishment is used, authority figure may
become signal for pain.
- Removing a positive reinforcer
- Decrease in a certain behaviour as a response
- Removing positive reinforcer is a situation a person wants to avoid
- Example. Time out in kindergarten. All the other kids can play but
- Removal of negative reinforcer
- Constant negative reinforcer presented that the learner wants to
- Increase in the Target Behaviour. The response must be presented soon after the behaviour is performed. If
the response is presented later, contingency may not form between
behaviour and response may not form.
Acquisition and Shaping
- Contingencies: Learns between a stimulus and a biologically
- instrumental: Contingency between a response and consequences.
- Response rate for a new behaviour.
- Accumulive Recorder --> Like a lie detector
- Graphing responses: X-axis (time), Y-axis ( # of Responses per Trial)
- The subject learned the contingency between behaviour and
response by itself.
- Example: Pigeon will learn to peck keyhole in order to get a grain of
- Behaviour and Response learned without explicit training by
- Complex behaviour and responses cannot be effectively auto-
- Shaping takes a complex behaviour, splits it into components and
then through reward training builds up to the final complex
- B.F. Skinner --> Pigeons playing ping 11-06-03 10:10 PM
Generalization and Discrimination
The discriminative Stimulus
o The discriminative stimulus tells the subject when a certain
contingency is present between a response and it’s
o For example, a particular environment or person may
signal the activation of a certain behaviour in order to
receive a particular response. The Discriminate
stimulus is the environment/person.
o S-Delta is a queue that indicates when a contingency between
the conditioned stimulus and response is not valid to obtain a
o Unlike a conditioned stimulus, which autonomously produces
a conditioned response through reflex, the discriminative
stimulus simply sets the occasion when a response is valid
and likely to generate a positive reinforcement. The response
is typically voluntary by the subject.
o Like in classical conditioning, the subject may react to
stimulus that is similar to the discriminative stimulus.
o The closer in resemblance the discriminative stimulus is, the
higher the rate of response. The further the resemblance of
discriminative stimulus, the lower the rate of response.
o In the presence of adults that resemble a child’s parents, the
child may behave more politely in order to get praise.
§ Adults: Discriminative stimulus
§ Politeness: Response
§ Praise: Reinforcement
Discrimination and Extinction
o Discriminative Stimulus Extinction
§ If the Discriminative stimulus is present and generates
a response but, the response does not generate a
positive reinforcement, the subject will unlearn the contingency between a DS and a response and will not
display a certain behaviour.
o Generalization Extinction
§ Stimulus that appear to be similar to the Discriminative
stimulus do not present positive reinforcement to a
generated response in behaviour. Eventually the subject
will learn to disassociate the generalized stimulus and
not perform a particular response.
§ The response will only be generated in this case when
the exact Discriminative stimulus is present.
SD and S-Delta
o Experiments conducted with S-Delta and SD produce more
effective results that can be analyzed by a generalization
Schedules of Reinforcement
o Continuous vs. Partial Reinforcement
§ Continuous reinforcement occurs when a response leads
to a reinforcement on every single occasion. This is
generally rare in the real world.
§ Partial Reinforcement schedule is one where a particular
response does not always initiate a reinforcement.
o Fixed Ratio vs. Interval Partial Reinforcement
§ Ratio Responses: reinforcement given based on the
number of trials made by the subject.
ú FR1 Reinforcement = each response initiates a
reinforcement. FR10 = every 10 response
initiates a reinforcement.
§ Interval Time: This type of schedule presents the
subject with a reinforcement after a certain set period
of time since the last response was reinforced.
ú FR1minute = reinforcement after every response
initiated after 1 minute period. FR10minute =
reinforcement after 10 minute response.
o Fixed Constant vs. Variable § Random Reinforcement based on some sort of a mean.
§ For example, on a VI10 schedule, although the time
when reinforcement is given are random, the average
time between response and reinforcement will be 10
o Fixed Ratio
§ A schedule with a very high FR may result in a loss of
§ Cumulative Record: Time (x-axis), # of responses per
§ Following reinforcement, a subject will pause with
inactivity before once again responding.
§ The pause with inactivity may be a result of the subject
lacking motivation to performing a response.
o Variable Ratio
§ Reinforcements are made on a random response basis
around a average figure.
§ The Lower the Variable ratio, the higher the rate of
response and thus the larger the slope between # of
responses and Time.
o Variable Interval
§ Reinforcement is delivered on a random time basis
around a average figure.
§ For example, a machine may have a VI of 10. This
means that the average of all the responses by a
subject in which reinforcement was present must equal
Extinction and Schedule
• Partial reinforced behaviour is less prone to extinction than
continuous reinforced behaviour.
• When continuous reinforcement stops, the subject immediately
realizes of this abrupt change and will decrease responding
• In a partial reinforcement schedule, abrupt changes take a while for
a subject to realize. • Partial Reinforcement better option if we want a behaviour
to be maintained. 11-06-03 10:10 PM
Introduction to Memory
• Thoughts, representations, mental processes make up cognition
• Cognitive factors provide qualities which allow humans to be
classified as humans.
• What is memory?
o The fundamental process which allows us to store and recall
o Memory is a result of complex processes.
• Common Memory Metaphors
o NOT ACCURATE REPRESENTATIONS OF HUMAN
MEMORY. They can be misleading in various ways.
§ Video Camera
ú Memory may be classified using a video-camera
analogy. We store information in a medium and
replay it at a later moment in time
ú Accurately preserves moments to be played back
at a later time
§ Filing Cabinet
ú We store information and organize it to be
accessed at a later time.
§ Computer Metaphor of memory
ú RAM (Random Access Memory) = Short term
ú Hard Disk = Long term memory
ú Specialized components responsible for handling
memory at different times.
• Problems with memory Metaphors
o Video Camera
§ The memory captured through the video camera
remains the same. This type of memory does not
change and is Vivid and accurate despite the amount of
time in past.
§ Human memory is varying and certain moments may
become vague or disappear entirely. Also, memories
may vary depending on the interpretation made by
individuals and personal details. Studying memory through scientific means
• The Questions we must ask:
o How does memory acquisition function?
o How are we able to store memory?
o How are we able to retrieve memory from the system?
• The importance of Cues
o We can navigate through the vast array of memory stored in
our brain with relative effortlessness.
o Environmental cues, social cues and other factors may spark
the recall of a particular memory.
§ For example, during conversations we recall various
moments that may be buried deep in the mind. In this
case, one memory acts as a cue to trigger another
o Early memory interpreters of memory relied on the
Behaviorist theory in order to test memory functions. These
individuals nevertheless studied the relationship between cues
and encoding and retrieval mechanisms.
• Hermann Ebbinghaus
o Memory is a serial learning task.
o Each word in a word list served as a cue to trigger the recall
of the consequent word which followed. Each word in a list
connected to a word before and after it.
o The experiment:
§ Exposed himself to a list of random words with no
meanings. During the encoding phase he tried to
memorize the words. During the recall phase he tried
to recall the list of words.
§ Used nonsense words to minimize the affect of learning
the words due to prior experiences and other factors.
§ How long could memories be maintained?
ú Number of remembered words plotted against a
ú Highest # of words at beginning, fewer and fewer
words near the end. The forgetting curve. Testing memory theories using scientific models
• Cognitive models are generated in order to explain complex
functions like memory.
• Models organize and describe data and make testable predictions
that can be studied in the controlled settings of the lab.
• Phases of cognitive model
o Encoding phase
§ A subject is exposed to a list of items, words, pictures.
The control group is distracted while exposed to this
list. The test group is focused and is told to learn the
list of words.
o Retrieval phase
§ Subjects asked to recall the presented information from
the encoding phase.
o Recall test
§ Subject asked to freely recall as many items of the list
as they could remember.
o Recognition test
§ Ask the subject to identify whether the item is new and
not presented in the encoding phase, or whether it was
old and presented during the encoding phase.
o Both the Recall and Recognition methods test the ability to
remember items from the encoding phase
Popular memory models
• The multi-store model
o Memory is composed of short and long-term storage systems
o New information is initially stored in a short term memory
buffer (similar to RAM in computer).
o The long term memory system can store memories
transferred from the short term buffer (Similar to transfer of
data from RAM to Hard disk Log files).
o Rehearsal may influence memory transfer from short-tem to
long-term. • George Miller
o Short term memory has typical capacity of 7 +- 2 items.
§ This is why phone numbers are 7 digits long!
o Short term memory fades as soon as rehearsal of info stops.
§ We may be override the capacity of 7+-2 items by
reorganizing information into meaningful packets or
§ For example, letter groupings that form words pack a
large amount of information without straining short-
• Models have a strong ability to make testable predictions about how
• If short term and long term memory are distinct, we should be able
to manipulate variables and observe the effect produced on each
The Serial Position Curve
• When a recall test is performed, a common trend shows that
memory performance is better for items early and later in the list.
o Memory performance is good for items encoded earlier in the
o In relation to Multi-store model, the items at the beginning
of the list have most opportunity to be rehearsed. These
items may have the best potential to enter long-term memory
and be permanently stored.
§ This can explain why memory performance for these
items is stellar.
o Items at the middle of the list have less opportunity for
rehearsal. Items at the end of the list are the most recent and
are present in the current short term memory. This can
explain why their recall rate is high.
• Recency effect
o Last 7 items remain in the short-term memory. This results in
their performance. • Improving Primacy
o If the primacy effect depends on our ability to rehearse, then
we should see a change in the primacy effect by influencing
o For example, the primacy effect should change depending on
the interval of time given to practice the list of words.
Reducing the amount of time given to memorize a list of
words would decrease the rehearsal level and reduce primacy.
• Diminishing Recency
o Disruption after the encoding stage should effect the recency
significantly. Disruptions would affect the content of the short
term memory storage.
Levels of Processing
• The levels at which items are encoded has a direct effect on the
ability to recall them.
o Shallow Level
§ Items encoded at this level require little effort and is
often directed at the physical characteristics of a
ú Is the word capitalized?
§ Memory performance is poor
o Deeper Level
§ More effort given in order to memorize the item. A
great deal of semantic (meaning based characteristics).
ú Does this word fit into the sentence, I walked my
§ Memory performance is much better.
• Levels of processing principle
o The more we try to understand and organize material, the
better we remember it.
Storage and Retrieval related
• Memories in reality are not simple lists of items but are richly
detailed and in context with the world around us.
• Environmental cues are incorporated in addition to learned items. Encoding specificity
• Memory encodes all aspects of specific experiences
• For example, when we encode a word in a memory experiment, we
encode various aspects such as:
o The properties of the room
o The chair that you’re sitting on
o The font-type
• When recalling a item in the future, the items mentioned above can
act as cues.
Loftus and False Memories (Tricking people into believing memory)
• Elizabeth Loftus and false memories experiments
o Subjects presented to 4 experiences. 3 were real whilst the
fourth was fake.
§ The fake memory was made up by the experimenter
and was described in great detail.
o On the first interview, all subjects identified fake experience
o By the third interview however, the fake experience was
classified as real by over 20% of the subjects.
o Shows that MEMORY IS HIGHLY CONSTRUCTIVE.
• False memory implantations (Bizarre fake memories)
o Could people be tricked into believing a bizarre and fake
o Repeatedly imagining à False memory generation
o Memory can be tricked into believing bizarre events.
Memory and it’s flaws (Attributive view of Memory)
• Memory is a Reconstructive process
• Memory is a open interpretation of a event altered suggestions
• The ease with which a experience is processed
• Familiar processes are processed more fluently than non-familiar
processes. • A sense of familiarity increases fluency and the ease by which we
may recall an event.
• Ties together causes with effects. Fluency must be present in order
to create a attribution.
Memory Illusions (modification of attribution of fluency and effect on
• Being Famous Overnight
o Individuals were made to read a list of names. Next, the
individuals waited 24 hours and were told to identify famous
names from a new list presented.
o The individuals interpreted the names from the list before and
interpreted them famous names. Group A, which did not have
the delay did not do this.
o False Fame Effect:
§ Old fictional names create a processing fluency.
§ Immediate test group do not produce fluency associated
with names presented. Overnight test group developed
a fluency for the names.
Memories are not necessarily something we store and recall in a
system, memories are reconstructed upon demand. We actively
• The memory system is a pile of basic building blocks
• Memory system able to construct experiences that may have not
occurred 11-06-03 10:10 PM
Introduction to attention
• Attention allows one to navigate through a world filled with
• Without being able to focus a limited amount of our resources, we
would not be able to perform simple tasks such as converse with
others, enjoy a piece of music, understand a joke or learn new
• We need to identify what Attention is, Build a cognitive model which
we can use to test our theories, and explain the hypothesis
• Unfortunately, Attention covers a area of a wide range of topics. We
cannot simply generate one theory or hypothesis in order to explain
it. NO SINGLE DEFINITION FOR ATTENTION.
• Our conscious ability to attend to something that is relative
to our goals.
• William James
o Attention implies withdrawal from some things in order to
deal effectively with others.
• Attending something (focusing) causes the object tot be inattentive
to other objects in the surrounding.
• We may be attentive of something at first but may become
inattentive if more important stimuli are present during a time.
• Some stimuli have a stronger grasp towards our attention than
• Irrelevant background information makes it increasingly
difficult to attend and identify the important information.
o We usually turn radio down when we are driving and need to
make important decisions. The radio creates a background
noise that needs to be minimized.
Automatic and Controlled Attention
o Involuntary attention o Something that automatically grasps your attention.
o Fast, efficient manner and grab attention
o Some ques are more noticeable and lead to stronger
and quicker association when paired with events.
§ SALIENT information is anything that naturally
pops out at us.
o Autonomic processes influenced by learning. For example, we
learn to drive a car almost autonomously and regulate various
different functions (clutch, accelerator, brake) without
specifically attending to them.
• Controlled process
o Conscious attention
o We may decide whether to pay attention to or ignore. Usually
slow due to more cognitive effort required.
The spotlight model
• Our attention spotlight focuses on only part of the environment at a
• Attention can be directed across a visual scene. This occurs when
we are looking for a particular person in a crowd of people.
Spatial Cueing Paradigm
• Three squares present on the screen.
• One of these squares is highlighted. Shortly after, one of the three
squares is filled in.
• Researchers found that when the highlighted square is the one
which is also filled in, the response time is faster than when the
highlighted square differs from the square that was filled in.
• The highlighted box is quick due to it’s use of automatic process.
The Consciously controlled is slower.
• THE QUE AUTOMATICALLY ATTRACTS SPOTLIGHT to the location. If
the target is displayed in the que, the perception is amplified and
the response is quick. If the target appears in the unqued location, the target is acquired more slowly because the attention spotlight
was towards the automatic location.
• Attention moves faster than the eye. We may be attentive
towards something even before we see it.
• At situations such as parties, there may be a lot of background
noise competing for attention. Despite this, we are able to single
out a specific noise to focus our attention towards.
• Collin Sherry: cocktail party effect
o Subjects exposed to 2 speakers, both producing a different
o Subjects told to focus on one message over the other.
o Gender, pitch of speech and various other factors effect
ability to filter.
Difference between Filter and spotlight model
• The Filter model assumes that we tune out everything besides the
object of focus.
• The spotlight model suggests that the point of focus is enhanced
and thus our focus is leans toward that point.
Broadbent’s single filter model
• The attention filter selects sensory information on the
characteristics of physical basis.
• This information is further processed.
• Information that does not pass through the initial filter is irrelevant
and is completely voided from further analysis.
• Broadbent’s test:
o Dual speakers, each displaying a different message.
o Subject told to focus to message being relayed by only one of
o The subject has no problem recalling data from the ear which
o Subject seems to completely ignore the message from the
opposite ear. o According to Broadbent, the attentive ear is the only
one which allows information to enter and undergo
deeper processing. The information from the
inattentive ear is discarded.
• Von Wright.
o A stimulus was presented each time a certain word was
relayed during a conditoning paradigm.
o When the word was presented in the unattended ear after
conditioning, a response was generated. This showed that the
information from the unconditioned ear was also processed.
o Some information about sound and meaning is able to pass
through the initial filter.
Triesman’s Dual Filter Model
• In contrast to Broadbent’s test, the Triesman’s model proposes two
filters, one filters physical things, whilst the other filters Symantic
• Information first passes through physical filter
• Semantic filter evaluates information for meaning. What is the
deeper meaning and relevance of the stimuli?
• Participant receives an input in one ear completely opposite to the
input received in the other ear.
The Stroop Task:
• Subjects presented to a colored word and asked to name the color