Myers

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Myers PSYCHOLOGY (7th Ed)

• Chapter 1
• Thinking Critically with Psychological Science
• James A. McCubbin, PhD
• Clemson University
• Worth Publishers

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The Need for Psychological Science

• Psychologists, like all scientists, use the
  scientific method to construct theories that
  organize observations and imply testable
  hypotheses

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The Need for Psychological Science

• Hindsight Bias
• we tend to believe, after learning an outcome,
  that we would have foreseen it
• the I-knew-it-all-along phenomenon
• Overconfidence
• we tend to think we know more than we do

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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
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The Need for Psychological Science

• Theory
• an explanation using an integrated set of
  principles that organizes and predicts
  observations
• Hypothesis
• a testable prediction
• often implied by a theory

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The Need for Psychological Science
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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

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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

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Description

• Psychologists describe behavior using case
  studies, surveys, and naturalistic observation

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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?
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Description

• Survey
• technique for ascertaining the self-reported
  attitudes or behaviors of people
• usually by questioning a representative, random
  sample of people
• Random Sample
• a sample that fairly represents a population
  because each member has an equal chance of
  inclusion

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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

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Description
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Description

• If marbles of two colors are mixed well in the
  large jar, the fastest way to know their ratio is
  to blindly transfer a few into a smaller one and
  count them

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Description

• Naturalistic Observation
• observing and recording behavior in naturally
  occurring situations without trying to manipulate
  and control the situation

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Correlation

• Correlation Coefficient
• a statistical measure of the extent to which two
  factors vary together, and thus how well either
  factor predicts the other

Indicates direction of relationship (positive or
negative)
Correlation coefficient
r .37
Indicates strength of relationship (0.00 to 1.00)
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Correlation

• Scatterplot
• a graphed cluster of dots, each of which
  represents the values of two variables
• the slope of the points suggests the direction of
  the relationship
• the amount of scatter suggests the strength of
  the correlation
• little scatter indicates high correlation
• also called a scattergram or scatter diagram

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Correlation
Scatterplots, showing patterns of correlations
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Correlation
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Correlation
55 60 65 70 75
80 85

• Scatterplot of Height and Temperament

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Correlation

• Three Possible Cause-Effect Relationships

could cause
(1) Low self-esteem
Depression
or
(2) Depression
Low self-esteem
could cause
or
Low self-esteem
(3) Distressing events or biological predispositio
n
could cause
and
Depression
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Illusory Correlation

• Illusory Correlation
• the perception of a relationship where none exists

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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.

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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

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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

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Experimentation

• Experimental Condition
• the condition of an experiment that exposes
  participants to the treatment, that is, to one
  version of the independent variable
• Control Condition
• the condition of an experiment that contrasts
  with the experimental treatment
• serves as a comparison for evaluating the effect
  of the treatment

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Experimentation

• Random Assignment
• assigning participants to experimental and
  control conditions by chance
• minimizes pre-existing differences between those
  assigned to the different groups

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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

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Experimentation
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Research Strategies

• Design of the subliminal tapes experiment

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Statistical Reasoning
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Statistical Reasoning
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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

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Statistical Reasoning

• A Skewed Distribution

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Statistical Reasoning

• Range
• the difference between the highest and lowest
  scores in a distribution
• Standard Deviation
• a computed measure of how much scores vary around
  the mean
• Statistical Significance
• a statistical statement of how likely it is that
  an obtained result occurred by chance

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Stats Stuff

• Descriptive Statistics
• used to describe the basic features of the data
  in a study . They provide simple summaries about
  the sample and the measures
• Inferential Statistics
• used to describe systems of procedures that can
  be used to draw conclusions from datasets arising
  from systems affected by random variation, such
  as observational errors, random sampling, or
  random experimentation

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Frequently Asked Questions about Psychology

• Can laboratory experiments illuminate everyday
  life?

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Frequently Asked Questions about Psychology

• Does behavior depend on ones culture?
• Culture--the enduring behaviors, ideas,
  attitudes, and traditions shared by a large group
  of people and transmitted from one generation to
  the next

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Frequently Asked Questions about Psychology

• Does behavior vary with gender?

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Frequently Asked Questions about Psychology

• Why do psychologists study animals?
• Is it ethical to experiment on animals?
• Is it ethical to experiment on people?

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Frequently Asked Questions about Psychology

• Is psychology free of value judgments?

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Frequently Asked Questions about Psychology

• Is psychology potentially dangerous?