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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.
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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 • 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 • 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
Perfect positive correlation (+1.00) No relationship (0.00) Perfect negative correlation (-1.00) Correlation Scatterplots, showing patterns of correlations
Height and Temperament of 20 Men Height in Inches Height in Inches Temperament Temperament Subject Subject 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 90 85 80 75 70 65 60 55 50 45 40 35 30 25 Temperament scores Height in inches Correlation Scatterplot of Height and Temperament 55 60 65 70 75 80 85
Correlation Three Possible Cause-Effect Relationships could cause (1) Low self-esteem Depression or (2) Depression could cause Low self-esteem or Low self-esteem (3) Distressing events or biological predisposition could cause and Depression
Conceive Do not conceive confirming evidence disconfirming evidence Adopt disconfirming evidence confirming evidence Do not adopt Illusory Correlation • Illusory Correlation • the perception of a relationship where none exists
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
Subliminal tape content Self-esteem Memory Tape label Self-esteem Memory Research Strategies • Design of the subliminal tapes experiment
100% 99 98 97 96 95 Percentage still functioning after 10 years Our Brand Brand Brand Brand X Y Z Brand of truck Statistical Reasoning
100% 90 80 70 60 50 40 30 20 10 0 Percentage still functioning after 10 years Our Brand Brand Brand Brand X Y Z Brand of truck Statistical Reasoning
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
15 20 25 30 35 40 45 50 90 475 710 70 Mode Median Mean One Family Income per family in thousands of dollars Statistical Reasoning A Skewed Distribution
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?