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General Psychology Ch. 1

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					Myers’ PSYCHOLOGY
(7th Ed)

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

The Need for Psychological Science

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

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

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

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

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

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

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?

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

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

Description

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

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

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)

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

Correlation

Perfect positive correlation (+1.00)

No relationship (0.00)

Perfect negative correlation (-1.00)

Scatterplots, showing patterns of correlations

Correlation
Height and Temperament of 20 Men
Height in Subject Inches Temperament Height in Subject Inches Temperament

1 2 3 4 5 6 7 8 9 10

80 63 61 79 74 69 62 75 77 60

75 66 60 90 60 42 42 60 81 39

11 12 13 14 15 16 17 18 19 20

64 76 71 66 73 70 63 71 68 70

48 69 72 57 63 75 30 57 84 39

Correlation
95 Temperament 90 scores 85 80 75 70 65 60 55 50 45 40 35 30 25 55

60

65 70 Height in inches

75

80

85

Scatterplot of Height and Temperament

Correlation
Three Possible Cause-Effect Relationships
(1) Low self-esteem could cause Depression

or
(2) Depression could cause

Low self-esteem

or
Low self-esteem (3) Distressing events or biological predisposition

could cause

and Depression

Illusory Correlation
 Illusory Correlation
 the perception of a relationship where none exists
Adopt Conceive
confirming evidence

Do not conceive
disconfirming evidence

Do not adopt

disconfirming evidence

confirming evidence

Two Random Sequences
 Your chances of being dealt either of these hands is precisely the same: 1 in 2,598,960.

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

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

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

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

Experimentation

Research Strategies
Subliminal tape content
Self-esteem Memory

Tape label
Self-esteem

 Design of the subliminal tapes experiment

Memory

Statistical Reasoning
Percentage still functioning after 10 years
100%

99
98 97 96 95

Our Brand Brand Brand Brand X Y Z Brand of truck

Statistical Reasoning
Percentage still functioning after 10 years
100% 90 80 70

60
50 40 30

20
10 0

Our Brand Brand X

Brand Brand Y Z

Brand of truck

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

Statistical Reasoning
A Skewed Distribution

15 20 25 30 35 40 45 50 70 Mode Median Mean

90

475

710

One Family

Income per family in thousands of dollars

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

Frequently Asked Questions about Psychology

Can laboratory experiments illuminate everyday life?

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

Frequently Asked Questions about Psychology

Does behavior vary with gender?

Frequently Asked Questions about Psychology

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

Frequently Asked Questions about Psychology

Is psychology free of value judgments?

Frequently Asked Questions about Psychology

Is psychology potentially dangerous?


				
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