Impression of Psychology
With hopes of satisfying curiosity, many people listen to talk-radio counselors and psychics to
learn about others and themselves.
Dr. Crane (radio-shrink) Psychic (Ball gazing)
The Need for Psychological Science
Intuition & Common Sense
Many people believe that intuition and common sense are enough to bring forth answers regarding
human nature.
Intuition and common sense may aid queries, but they are not free of error.
Limits of Intuition
Personal interviewers may rely too much on their “gut
feelings” when meeting with job applicants.
Psychological Science
1. How can we differentiate between uniformed opinions and examined conclusions?
2. The science of psychology helps make these examined conclusions, which leads to our understanding of how people feel, think, and act as they do!
The Need for Psychological Science
The biases and errors of people’s everyday judgments illustrate the need for:
1. Skepticism2. Humility3. Critical Thinking
The Need for Psychological Science
Critical Thinking thinking that does
not blindly accept arguments and conclusions examines
assumptions discerns hidden
values evaluates evidence
The Amazing Randi--Skeptic
Goals of Psychology
Describe Explain Predict Control
behavior and mental processes
Scientific Method Formulate testable questions
Develop hypotheses Design study to collect data
Experimental Descriptive
Analyze data to arrive at conclusions Use of statistical procedures Use of meta-analysis
Report results Publication Replication
The Need for Psychological Science Theory
an explanation using an integrated set of principles that organizes and predicts observations
For example, low self-esteem contributes to depression.
Hypothesis a testable prediction often implied by a theory People with low self-esteem are apt to feel more
depressed.
Research would require us to administer tests of self-esteem and depression.
Individuals who score low on a self-esteem test and high on a depression test would
confirm our hypothesis.
Research Observations
The Need for Psychological Science
The Need for Psychological Science
Operational Definition a statement of procedures (operations)
used to define research variables Example-
intelligence may be operationally defined as what an intelligence test measures
Testing the effects of vitamin C on the health of students could be measured by the number of colds experienced during the month.
The Need for Psychological Science
Replication repeating the essence of a
research study to see whether the basic finding generalizes to other participants and circumstances
usually with different participants in different situations
Thinking Critically …
Description The Case Study
The Survey
Naturalistic Observation
Thinking Critically …
Correlation Correlation and Causation Illusory Correlation Perceiving Order in Random
Events
Thinking Critically …
Experimentation Exploring Cause and Effect
Evaluating Therapies
Independent and Dependent Variables
Description
Psychologists describe behavior using case studies, surveys,
and naturalistic observation
Description
Case Study Psychologists
study one or more individuals in great depth in the hope of revealing things true of us all Is language uniquely human?
Case Study
A clinical study is a form of case study in which
the therapist investigates the problems associated
with a client.
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Clinical Study
Defined as a thorough, exhaustive study of a person. It includes personal, educational, family and work histories.Advantage:
A wealth of background information about one person
Disadvantages:Information cannot be generalized to others; also, researcher’s biases can influence subject’s behavior.
The Case Study Method
Description
Survey technique for ascertaining the self-
reported attitudes or behaviors of people usually by questioning a representative,
random sample of people
Survey
Wording can change the results of a survey. Even subtle changes in the order or wording of
questions can have major effects.
Q: Should cigarette ads and pornography be allowed on television? (not allowed vs. forbid)
Wording Effect
The Survey Method
Defined as asking questions of a carefully selected group of people and tabulating their answers.
Information can be gathered about feelings, opinions, and behavior patterns.
Interpretation difficult; people lie; sample may not be representative.
Advantage:
Disadvantages:
Description
False Consensus Effect tendency to overestimate the extent
to which others share our beliefs and behaviors
Population all the cases in a group, from which
samples may be drawn for a study
Samples and Sampling
Sampleselected segment of the population
Representative sampleclosely parallels the population on relevant characteristics
Random selectionevery member of larger group has equal change of being selected for the study sample
Survey
Random SamplingIf each member of a
population has an equal chance of inclusion into a
sample, it is called a random sample
(unbiased). If the survey sample is biased, its results are not valid. The fastest way to know about the
marble color ratio is to blindly transfer a few into a smaller jar and
count them.
Description
Naturalistic Observation observing and
recording behavior in naturally occurring situations without trying to manipulate and control the situation
Naturalistic Observation
Observing and recording the behavior of animals in the wild and recording self-seating patterns in a multiracial school
lunch room constitute naturalistic observation.
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The Naturalistic Observation Method
Defined as observing behaviors in their natural settings.
Disadvantages:Researcher cannot interact with the subject.
Researcher may interpret subject’s responses incorrectly.
Correlation
When one trait or behavior accompanies another, we say the two correlate.
Correlation coefficient
Indicates directionof relationship
(positive or negative)
Indicates strengthof relationship(0.00 to 1.00)
r = 0.37+
Correlation Coefficient is a statistical measure of the
relationship between two variables.
Coefficient of Correlation
Numerical indication of magnitude and direction of the relationship between two variables Positive correlation— two variables
vary systematically in the SAME direction
Negative correlation— two variables vary systematically in OPPOSITE directions
Perfect positivecorrelation (+1.00)
Scatterplot is a graph comprised of points that are generated by values of two variables. The slope
of the points depicts the direction, while the amount of scatter depicts the strength of the
relationship.
Scatterplots
No relationship (0.00)Perfect negativecorrelation (-1.00)
The Scatterplot on the left shows a negative correlation, while the one on the right shows no relationship between
the two variables.
Scatterplots
Data
Data showing height and temperament in people.
Scatterplot
The Scatterplot below shows the relationship between height and temperament in people. There
is a moderate positive correlation of +0.63.
CorrelationThree Possible Cause-Effect Relationships
(1)Low self-esteem
Depression
(2)Depression
Low self-esteem
Low self-esteem
Depression
(3)Distressing events
or biologicalpredisposition
could cause
could cause
could cause
or
or
and
Illusory Correlation
The perception of a relationship where no relationship actually exists. Parents conceive children after adoption.
Confirming evidence
Disconfirming evidence
Do not
adopt
Disconfirming evidence
Confirming evidence
Adopt
Do not conceiveConceive
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Two Random Sequences
Your chances of being dealt either of these hands is precisely the same: 1 in 2,598,960.
Order in Random Events
Given large numbers of random outcomes, a few are likely to express order.
Angelo and Maria Gallina won two California lottery games on the same day.
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Experimentation
Like other sciences, experimentation is the backbone of psychology research.
Experiments isolate causes and their effects.
Exploring Cause and Effect
Many factors influence our behavior.
Experiments (1) manipulate factors that interest us, while other factors are kept under (2) control.
Effects generated by manipulated factors isolate cause and effect relationships.
Exploring Cause & Effect
Experimentation Experiment
an investigator manipulates one or more factors (independent variables) to observe their effect on some behavior or mental process (the dependent variable)
by random assignment of participants the experiment controls other relevant factors
Experimentation Placebo
an inert substance or condition that may be administered instead of a presumed active agent, such as a drug, to see if it triggers the effects believed to characterize the active agent
Double-blind Procedure both the research participants and the
research staff are ignorant (blind) about whether the research participants have received the treatment or a placebo
commonly used in drug-evaluation studies
Hindsight Bias is the “I-knew-it-all-along” phenomenon.
After learning the outcome of an event, many people believe they could have predicted that very outcome.
We only knew the dot.com stocks would plummet after they actually did plummet.
Hindsight Bias
Overconfidence
Sometimes we think we know more than we actually know.
Anagram
BARGEGRABE
ENTRYETYRN
WATERWREATHow long do you think it
would take to unscramble these anagrams?
People said it would take about 10 seconds, yet on average they took about 3 minutes (Goranson, 1978).
The Hawthorne Effect refers to the fact that some subjects will alter their behaviors simply because they know that they are part of an experiment, regardless of what is being done to them.
Experimentation
Experimental Condition (group) the condition of an experiment that
exposes participants to the treatment, that is, to one version of the independent variable
Control Condition (group) the condition of an experiment that
contrasts with the experimental treatment serves as a comparison for evaluating the
effect of the treatment
Experimental Design
Random sample— every member of the population being studied should have an equal chance of being selected for the study
Random assignment— assigning subjects to experimental and control conditions by chance.
Randomization helps avoid false results
Experimentation Independent Variable
the experimental factor that is manipulated
the variable whose effect is being studied Dependent Variable
the experimental factor that may change in response to manipulations of the independent variable
in psychology it is usually a behavior or mental process
Conducting Psychology Experiments
Hypothesis• Scientific method• Hypothesis formulation
=
Operationalization• Operationalization: to put an experiment into a form
that allows researchers to test the hypothesis• Independent variable: the variable that researchers
control
Independent variable
Dependent variable
• Dependent variable: the variable that researchers are studying
• What other questions should the researchers ask?
Operationalization• Confounding variables• Reliability• Validity
What else might cause nightmares?
What makes a movie scary?
SCARY
= ?
How can we tell if a child has had a
nightmare?
Experimenting, Recording Results, Conclusion
Recording the resultsConducting the experiment
Drawing conclusions
does cause
Correlation vs. Causation
Correlation versus causation: just because two things are related doesn’t mean one thing caused the other
Just because happened and then
happened
doesn’t necessarily mean that
caused
Replication and Theory Development
• Replication• Theory
development
==
=
Experiment 1 results
Experiment 2 results
Experiment 3 results
THEORY:
=
X amount of sleeping pills helps the healthy person with insomnia to sleep better.
Sleeping pills
Experimental Group
# of people whohad restful nights
PlacebosIndependent Variable
Groups
Dependent Variable # of people who had restful nights
The hypothesis proves to be incorrect. People taking the sleeping pill over a period of days had more insomnia than before. They had less restful sleep than the people in the control group.
Hypothesis
ControlGroup
Basic Ethical Guidelines for Psychological Researchers
Do no harm.Accurately describe risks to potential subjects.Ensure that participation is voluntary.Minimize any discomfort to participants.Maintain confidentiality.Do not unnecessarily invade privacy.Remove any misconceptions caused by deception
(debrief).Provide results and interpretations to participants.Treat participants with dignity and respect.
Evaluating Media ReportsEvaluating Media Reports• Be skeptical of sensationalist claimsBe skeptical of sensationalist claims
• Goal of “shock” media is ratingsGoal of “shock” media is ratings
• Look for original sourcesLook for original sources
• Separate opinion from dataSeparate opinion from data
• Consider methodology and Consider methodology and operational definitionsoperational definitions
• Correlation is not causalityCorrelation is not causality
• Skepticism is the rule in science.Skepticism is the rule in science.
Experimentation
FAQ
Q1. Can laboratory experiments illuminate everyday life?
Ans: Artificial laboratory conditions are created to study behavior in simplistic terms. The goal
is to find underlying principles that govern behavior.
FAQQ2. Does behavior depend on one’s culture?
Ans: Even when specific attitudes and behaviors vary across cultures, as they often do, the underlying processes are much the same.
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FAQ
Q3. Does behavior vary with gender?
Ans: Yes. Biology determines our sex, and culture further bends the genders.
However, in many ways woman and man are similarly human.
Ethical Issues
Is it right to experiment on animals?
What limits should there be?
FAQQ4. Why do psychologists study animals?
Ans: Studying animals gives us the understanding of many behaviors that may have
common biology across animals and humans.
D. Shapiro, © Wildlife Conservation Society
FAQ
Q5. Is it ethical to experiment on animals?
Ans: Yes. To gain insights to devastating and fatal diseases. All researchers who deal with animal research are required to follow
ethical guidelines in caring for these animals.
Ethical Issues Is it right to experiment on
people? What limits should there be?
FAQ
Q6. Is it ethical to experiment on people?
Ans: Yes. Experiments that do not involve any kind of physical or psychological harm beyond normal levels encountered in daily
life may be carried out.
FAQ
Q7. Is psychology free of value judgments?
Ans: No. Psychology emerges from people who subscribe to a set of values and judgments.
© Roger Shepard
FAQ
Q8. Is psychology potentially dangerous?
Ans: It can be, but it is not. The purpose of psychology is to help humanity with
problems such as war, hunger, prejudice, crime, family dysfunction, etc.
Statistical Reasoning
Statistical procedures analyze and interpret data allowing us to see what the unaided eye misses.
Composition of ethnicity in urban locales
Frequency Distribution
Frequency Distributions• 1. What are they?
– Tables– Graphs
• Bar• Histogram
Distributions
Percentile Rank--the percentage of scores that fall below a particular score. You can never have a percentile rank of 100 because you are part of that 100. (You can’t exceed yourself!)
Bar Graphs (histograms)-- Percentile ranks and distributions can be represented in bar graphs or histograms.
Histogram
Statistical Reasoning
Our Brand Brand BrandBrand X Y Z
100%
99
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Percentagestill functioningafter 10 years
Brand of truck
Statistical Reasoning
Our Brand Brand Brand Brand X Y Z
100%
90
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40
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Percentagestill functioningafter 10 years
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Statistical Reasoning Mode
the most frequently occurring score in a distribution
Mean the arithmetic average of a distribution obtained by adding the scores and then
dividing by the number of scores Median
the middle score in a distribution half the scores are above it and half are
below it
Median
Separates the upper and low half of distribution
1) mean and median not necessarily equal
2) median much less sensitive to extremes
Mode
• Most common value• Always present in the distribution• May be more than one mode• Used mainly with nominal data• Plays minor role in statistical
inference
Statistical Reasoning
A Positively Skewed Distribution
15 20 25 30 35 40 45 50 90 475 710
70
Mode Median Mean
One Family Income per family in thousands of dollars
Skewed Distributions
PositiveMean > Median
NegativeMean < Median
Measures of Variation
Range the difference between the highest and
lowest scores in a distribution
Measures of Variation
Standard Deviation: A computed measure of how much scores vary around the mean.
Table 1.4Myers: Psychology, Eighth EditionCopyright © 2007 by Worth Publishers
Variation
Normal Curve--a bell-shaped curve that describes the normal distribution of many types of data. Most scores fall near the mean and fewer and fewer fall near the extremes. In a normal curve the mean, median and mode are all near the middle.
Making Inferences
A statistical statement of how frequently an obtained result occurred by experimental
manipulation or by chance.
Correlation
Regression toward the mean— falling back to the norm. It can fuel the illusion that uncontrollable events correlate with out actions.
Statistical Inference
When is it safe to generalize from a sample?
1.Representative Samples are better than biased samples.
2.Less-variable observations are more reliable than those that are more variable.
3.More cases are better than fewer. Larger samples are better than smaller ones.
4.As the size of a sample increases, the size of the standard deviation is most likely to decrease
When is a difference significant?
When sample averages are reliable and the difference between them is large we say the difference has statistical significance (it reflects a real difference not due to chance or variation between samples). For psychologists this difference is measured through alpha level set at 5 percent.
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