PsychologyPsychology

The Study of Human BehaviorThe Study of Human Behavior

Purpose of PsychologyPurpose of Psychology

-To describe behavior- To predict behavior

- To change behavior

Common sense says…Common sense says…Opposites AttractOpposites Attract

Birds of a FeatherBirds of a FeatherStick TogetherStick Together

Out of SightOut of SightOut of MindOut of Mind

Absence Makes theAbsence Makes theHeart Grow FonderHeart Grow Fonder

Ways to Study BehaviorWays to Study Behavior

Observe TestAskNaturalistic Experimental method

longitudinalCase study

survey

Cross section

How to universalize How to universalize Who does it apply to….

Sample Random selectionassignment

Population(Stratified)

Cause - EffectOperational Definition; to operationalize

Dependent VariableIndependent Variable

Controlled Variables

Between Group Design vs. With-in Group Design

OperationalizeOperationalize

8 A psychologist wants to know if counseling will make people less depressed

2 How do different types of jokes affect a person’s sense of humor.

3 Overall senior girls are prettier than junior girls but the juniors are less insane

4 People who make over $300,000 a year tend to be snobs 5 School spirit is at an all time low

6 The Rolling Stones are the best rock group ever.

7 College athletes are not as smart as regular students

1 People dream more If they have eaten a big meal 3 hours before sleep

Billy is on a new behavior program, will it make him act more friendly toward others

HypothesisUtilize the following format

If-----(IV)

Then -----(DV)

ErrorsEvery (experiment)Study (Subject Selection)Can (Control/Confounding)Be (Bias)Pretty (Practice Effect)Dirty (Demand Effect)

Experiment DesignExperiment DesignMost general of the errors. There are Most general of the errors. There are many, many ways to botch the many, many ways to botch the design of an experiment.design of an experiment.

Subject SelectionSubject SelectionSelection must be randomSelection must be randomAssignment must be randomAssignment must be randomIf subject reflect the populationIf subject reflect the population

Confounding VariablesConfounding VariablesOther variablesOther variables-that could cause the behavior-that could cause the behavior-stuff not accounted for-stuff not accounted for

Control ErrorsThings not kept the same for all subjects

BiasBiasExperimenter BiasExperimenter BiasResearcher influences resultsResearcher influences resultsE.g.E.g.– The experimenter mood, The experimenter mood, – facial expressionfacial expression– actionsactions

Practice EffectPractice EffectYour subjects get better as they do it Your subjects get better as they do it longer.longer.E.g.E.g. - Most tests of manual dexterity - Most tests of manual dexterity– Color discriminationColor discrimination

Demand EffectDemand EffectSubjects intentionally do act the way Subjects intentionally do act the way the experimenter expects them to.the experimenter expects them to.Examples:Examples:– The good subject – The subject tries to “help” The good subject – The subject tries to “help”

the experimenter by doing whatever it takes to the experimenter by doing whatever it takes to confirm the hypothesisconfirm the hypothesis

– The negative subject – The subject tries to The negative subject – The subject tries to destroy the credibility of the study.destroy the credibility of the study.

EthicsConsentProtectionConfidentialityDebriefingAnimal Studies

Types of Statistics in Psychology

Descriptive Statistics: Describe data to get meaning

Inferential Statistics: Use data for drawing conclusions

Descriptive StatisticsDescriptive StatisticsCentral TendencyCentral Tendency

Measures of VariabilityMeasures of VariabilityStandard ScoresStandard Scores

Bell CurveBell Curve

Measures of Central TendencyMeasures of Central TendencyA number describing a typical score A number describing a typical score around which the other scores fallaround which the other scores fallMean = averageMean = averageMedian= score that in the middle; Median= score that in the middle; half the values fall and half belowhalf the values fall and half belowMode = most frequently occurring Mode = most frequently occurring scorescore

Measures of VariabilityMeasures of VariabilityProvide a single number that tell us Provide a single number that tell us how spread out the scores are how spread out the scores are Range = Difference between the Range = Difference between the highest and lowest scoreshighest and lowest scoresStandard Deviation = how much a Standard Deviation = how much a typical score differs from the mean of typical score differs from the mean of a group of scoresa group of scoresZ Score: how many standard Z Score: how many standard deviations above or below the mean deviations above or below the mean

Bell CurveBell CurveNormal Curve: Bell-shaped curve, Normal Curve: Bell-shaped curve, most scores in the middle and very most scores in the middle and very few extremely high and low scores few extremely high and low scores

Mean, Median & Mode all equalMean, Median & Mode all equalWhen it isn’t – skewed right or leftWhen it isn’t – skewed right or left

Fig. A.3 Fig. A.3 The normal curve. The normal curve is an idealized mathematical model. However, The normal curve. The normal curve is an idealized mathematical model. However, many measurements in psychology closely approximate a normal curve. The scales you see many measurements in psychology closely approximate a normal curve. The scales you see here show the relationship of standard deviations, z-scores, and other measures to the here show the relationship of standard deviations, z-scores, and other measures to the curve.curve.

Fig. A.4 Fig. A.4 Relationship between the standard deviation and the normal curve.Relationship between the standard deviation and the normal curve.

Inferential Statistics Inferential Statistics

Statistical Significance: Degree to which Statistical Significance: Degree to which an event is unlikely to have occurred by an event is unlikely to have occurred by chance alonechance alone

p<_ .05p<_ .05

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CorrelationShows a relationship between 2

variables

Corelation Co-efficient between-1 and 1 (slope)

Bell Curve

Study ChartStudy Chart

Correlation

Professor Perry is interested in testing Professor Perry is interested in testing whether the amount of time a person spends whether the amount of time a person spends with children affects his attitudes toward with children affects his attitudes toward having children of his/her own. She randomly having children of his/her own. She randomly chooses a sample and randomly assigns chooses a sample and randomly assigns them to two groups. Group 1 spends 5 hours them to two groups. Group 1 spends 5 hours a day for a week with a group of children. a day for a week with a group of children. Group 2 spends 1 hour a day for a week with Group 2 spends 1 hour a day for a week with the same group of children. At the end of the the same group of children. At the end of the week, Professor Perry measures their week, Professor Perry measures their attitudes with a survey. attitudes with a survey.