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Thinking Thinking Critically with Critically with Psychological Psychological

ScienceScience

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Impression of Psychology Impression of Psychology With hopes of satisfying curiosity, many With hopes of satisfying curiosity, many

people listen to talk-radio counselors and people listen to talk-radio counselors and psychics to learn about others and themselves.psychics to learn about others and themselves.

Dr. Crane (radio-shrink)

http://ww

w.nbc.com

http://ww

w.photovault.com

Psychic (Ball gazing)

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The Need for Psychological The Need for Psychological ScienceScience

Intuition & Common SenseIntuition & Common Sense

Many people believe that intuition and Many people believe that intuition and common sense are enough to bring forth common sense are enough to bring forth

answers regarding human nature.answers regarding human nature.

Intuition and common sense may aid Intuition and common sense may aid queries, but they are not free of error.queries, but they are not free of error.

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Limits of IntuitionLimits of Intuition

Personal interviewers may Personal interviewers may rely too much on their rely too much on their “gut feelings” when “gut feelings” when

meeting with job meeting with job applicants.applicants.

Taxi/ G

etty Images

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Errors of Common SenseErrors of Common Sense

Try this !Try this !

Fold a piece of paper (0.1 mm thick) 100 Fold a piece of paper (0.1 mm thick) 100 times. How thick will it be?times. How thick will it be?

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800,000,000,000,000 times the 800,000,000,000,000 times the distance between the sun and distance between the sun and

the earth.the earth.

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Hindsight Bias is the “I-knew-it-all-along” Hindsight Bias is the “I-knew-it-all-along” phenomenon.phenomenon.

After learning the outcome of an event, After learning the outcome of an event, many people believe they could have many people believe they could have

predicted that very outcome. We only knew predicted that very outcome. We only knew the dot.com stocks would plummet after the dot.com stocks would plummet after

they actually did plummet.they actually did plummet.

Hindsight BiasHindsight Bias

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OverconfidenceOverconfidenceSometimes we think we know Sometimes we think we know more than we actually know. more than we actually know.

AnagramAnagram

BARGEBARGEGRABEGRABE

ENTRYENTRYETYRNETYRN

WATERWATERWREATWREATHow long do you think it How long do you think it would take to unscramble would take to unscramble

these anagrams?these anagrams?

People said it would take People said it would take about 10 seconds, yet on about 10 seconds, yet on

average they took about 3 average they took about 3 minutes (Goranson, 1978).minutes (Goranson, 1978).

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Psychological SciencePsychological Science

1.1. How can we differentiate between How can we differentiate between uniformed opinions and examined uniformed opinions and examined conclusions?conclusions?

2.2. The science of psychology helps The science of psychology helps make these examined conclusions, make these examined conclusions, which leads to our understanding which leads to our understanding of how people of how people feel, think, and actfeel, think, and act as they do!as they do!

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The Scientific AttitudeThe Scientific Attitude

The scientific attitude is composed of The scientific attitude is composed of curiosity (passion for exploration), (passion for exploration), skepticismskepticism

(doubting and questioning) and (doubting and questioning) and humility humility (ability to accept responsibility when wrong).(ability to accept responsibility when wrong).

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Critical ThinkingCritical Thinking

Critical thinking Critical thinking does not accept does not accept arguments and arguments and

conclusions blindly.conclusions blindly.

It examines It examines assumptions, assumptions,

discerns hidden discerns hidden values, evaluates values, evaluates

evidence and evidence and assesses assesses

conclusions.conclusions.The Amazing Randi

Courtesy of the Jam

es Randi E

ducation Foundation

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Scientific MethodScientific Method

Psychologists, like all scientists, use Psychologists, like all scientists, use the scientific method to construct the scientific method to construct

theories that organize, summarize and theories that organize, summarize and simplify observations.simplify observations.

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AA TheoryTheory isis an an explanationexplanation that that integrates principles and integrates principles and organizesorganizes

and and predictspredicts behavior or events. behavior or events.

explainsexplains

organizesorganizes

predictspredicts

for example, low self-esteem contributes to for example, low self-esteem contributes to depression.depression.

TheoryTheory

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AA Hypothesis is a testable prediction, Hypothesis is a testable prediction, often prompted by a theory, to enable often prompted by a theory, to enable

us to accept, reject or revise the us to accept, reject or revise the theory.theory.

e.g. e.g. People with low self-esteem are apt to People with low self-esteem are apt to feel more depressed.feel more depressed.

HypothesisHypothesis

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Research would require us to Research would require us to administer tests of self-esteem and administer tests of self-esteem and

depression. Individuals who score low depression. Individuals who score low on a self-esteem test and high on a on a self-esteem test and high on a depression test would confirm our depression test would confirm our

hypothesis.hypothesis.

Research ObservationsResearch Observations

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Research ProcessResearch Process

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Types of data and designTypes of data and design

DescriptionDescription The Case StudyThe Case Study

The SurveyThe Survey

Naturalistic ObservationNaturalistic Observation

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CorrelationCorrelation Correlation and CausationCorrelation and Causation Illusory CorrelationIllusory Correlation Perceiving Order in Random Perceiving Order in Random

EventsEvents

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ExperimentationExperimentation Exploring Cause and EffectExploring Cause and Effect

Independent and Dependent Independent and Dependent VariablesVariables

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DescriptionDescription

Case StudyCase Study

A technique in which one person is studied in depth A technique in which one person is studied in depth to reveal underlying behavioral principles.to reveal underlying behavioral principles.

Is language uniquely human?

Susan K

uklin/ Photo R

esearchers

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Case StudyCase Study

A clinical study is a A clinical study is a form of case study in form of case study in which the therapist which the therapist

investigates the investigates the problems associated problems associated

with a client.with a client.

http://behavioralhealth.typepad.com

Clinical StudyClinical Study

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SurveySurvey

A technique for ascertaining the self-A technique for ascertaining the self-reported attitudes, opinions or behaviors of reported attitudes, opinions or behaviors of

people usually done by questioning a people usually done by questioning a representative,representative, randomrandom sample of people. sample of people.

http://ww

w.lynnefeatherstone.org

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SurveySurvey

Random SamplingRandom Sampling

If each member of a If each member of a population has an equal population has an equal chance of inclusion into chance of inclusion into a sample, it is called a a sample, it is called a

random sample random sample (unbiased). If the survey (unbiased). If the survey

sample is biased, its sample is biased, its results are not valid.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.

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SurveySurvey

Wording can change the results of a survey. Wording can change the results of a survey.

Q: Should cigarette ads and pornography be Q: Should cigarette ads and pornography be allowed on television? (not allowed vs. allowed on television? (not allowed vs.

forbid)forbid)

Wording EffectWording Effect

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SurveySurvey

(who agrees to respond?)(who agrees to respond?)

Response RateResponse Rate

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Response BiasesResponse Biases

Social DesirabilitySocial Desirability Response SetsResponse Sets

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Naturalistic ObservationNaturalistic ObservationObserving and recording the behavior of animals in the Observing and recording the behavior of animals in the wild and recording self-seating patterns in a multiracial wild and recording self-seating patterns in a multiracial school lunch room constitute naturalistic observation.school lunch room constitute naturalistic observation.

Courtesy of G

ilda Morelli

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Descriptive MethodsDescriptive Methods

Case studies, surveys, and naturalistic observation describe

behaviors.

SummarySummary

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CorrelationCorrelation

When one trait or behavior accompanies When one trait or behavior accompanies another, we say the two correlate.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 Correlation Coefficient is a statistical measure of the statistical measure of the relationship between two relationship between two

variables.variables.

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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.

ScatterplotsScatterplots

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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.

ScatterplotsScatterplots

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or

Correlation and CausationCorrelation and Causation

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Illusory CorrelationIllusory Correlation

The perception of a relationship where no The perception of a relationship where no relationship actually exists. Parents conceive relationship actually exists. Parents conceive

children after adoption.children after adoption.

Confirming Confirming evidenceevidence

Disconfirming Disconfirming evidenceevidence

Do notDo not

adoptadopt

Disconfirming Disconfirming evidenceevidence

Confirming Confirming evidenceevidence

AdopAdoptt

Do not Do not conceiveconceiveConceiveConceive

Michael N

ewm

an Jr./ Photo Edit

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Given random data, we look for order and Given random data, we look for order and meaningful patterns.meaningful patterns.

Order in Random EventsOrder in Random Events

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

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Order in Random EventsOrder in Random Events

Given large numbers of random outcomes, Given large numbers of random outcomes, a few are likely to express order.a few are likely to express order.

Angelo and Maria Gallina won two Angelo and Maria Gallina won two California lottery games on the same day.California lottery games on the same day.

Jerry Telfer/ S

an Francisco C

hronicle

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ExperimentationExperimentation

Like other sciences, experimentation is the Like other sciences, experimentation is the backbone of psychology research. Experiments backbone of psychology research. Experiments

isolate causes and their effects.isolate causes and their effects.

Exploring Cause and EffectExploring Cause and Effect

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Many factors influence our behavior. Many factors influence our behavior. Experiments (1) manipulate factors that Experiments (1) manipulate factors that interest us, while other factors are kept interest us, while other factors are kept

under (2) control.under (2) control.

***Effects generated by manipulated factors ***Effects generated by manipulated factors isolate isolate cause and effectcause and effect relationships. relationships.

Exploring Cause & EffectExploring Cause & Effect

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An An Independent VariableIndependent Variable is a factor is a factor manipulated by the experimenter. The manipulated by the experimenter. The effect of the independent variable is the effect of the independent variable is the

focus of the study. focus of the study.

For example, when examining the effects of For example, when examining the effects of breast feeding upon intelligence, breast feeding upon intelligence, breast breast

feedingfeeding is the independent variable. is the independent variable.

Independent VariableIndependent Variable

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AA Dependent VariableDependent Variable is a factor that may is a factor that may change in response to an independent change in response to an independent variable. In psychology, it is usually a variable. In psychology, it is usually a

behavior or a mental process. behavior or a mental process.

For example, in our study on the effect of For example, in our study on the effect of breast feeding upon intelligence, breast feeding upon intelligence,

intelligenceintelligence is the dependent variable. is the dependent variable.

Dependent VariableDependent Variable

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Assigning participants to experimental Assigning participants to experimental (Breast-fed) and control (formula-fed) (Breast-fed) and control (formula-fed)

conditions by random assignment conditions by random assignment minimizes pre-existing differences minimizes pre-existing differences

between the two groups.between the two groups.

Random AssignmentRandom Assignment

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In evaluating drug therapies, patients In evaluating drug therapies, patients and experimenter’s assistants should and experimenter’s assistants should

remain unaware of which patients had the remain unaware of which patients had the real treatment and which patients had the real treatment and which patients had the

placebo treatment. placebo treatment.

Evaluating TherapiesEvaluating Therapies

Double-blind ProcedureDouble-blind Procedure

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ExperimentationExperimentationA summary of steps during experimentation.A summary of steps during experimentation.

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ComparisonComparisonBelow is a comparison of different Below is a comparison of different

research methods.research methods.

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Describing DataDescribing DataA meaningful description of data is A meaningful description of data is

important in research. Misrepresentation important in research. Misrepresentation may lead to incorrect conclusions.may lead to incorrect conclusions.

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Measures of Central Measures of Central TendencyTendency

Mode:Mode: The most frequently occurring The most frequently occurring score in a distribution.score in a distribution.

Mean:Mean: The arithmetic average of scores The arithmetic average of scores in a distribution obtained by adding in a distribution obtained by adding the scores and then dividing by the the scores and then dividing by the number of scores that were added number of scores that were added together.together.

Median:Median: The middle score in a rank-The middle score in a rank-ordered distribution.ordered distribution.

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Measures of Central Measures of Central TendencyTendency

A Skewed DistributionA Skewed Distribution

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Measures of VariationMeasures of Variation

Range:Range: The difference between the highest The difference between the highest and lowest scores in a distribution.and lowest scores in a distribution.

Standard Deviation:Standard Deviation: A computed measure of A computed measure of how much scores vary around the mean.how much scores vary around the mean.

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Standard DeviationStandard Deviation

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Making InferencesMaking Inferences

A statistical statement of how frequently an A statistical statement of how frequently an obtained result occurred by experimental obtained result occurred by experimental

manipulation or by chance.manipulation or by chance.

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Making InferencesMaking Inferences

1.1. Representative samples are better than Representative samples are better than biased samples.biased samples.

2.2. Less variable observations are more Less variable observations are more reliable than more variable ones.reliable than more variable ones.

3.3. More cases are better than fewer cases.More cases are better than fewer cases.

When is an Observed Difference Reliable?When is an Observed Difference Reliable?

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Making InferencesMaking Inferences

When sample averages are reliable and the When sample averages are reliable and the difference between them is relatively large, difference between them is relatively large,

we say the difference has statistical we say the difference has statistical significance.significance.

For psychologists this difference is measured For psychologists this difference is measured through alpha level set at 5 percent.through alpha level set at 5 percent.

When is a Difference Significant?When is a Difference Significant?