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Thinking Critically With Psychological Science

Thinking Critically With Psychological ScienceResearchEveryday Sources of KnowledgeCommon senseAuthorityReasoningUnsystematic observationScientific methodScientific MethodSet of orderly steps used to analyze and solve problemsObjectively collected informationEmpirical evidence observations of publicly (confirmable) observable behaviorOperational definitions use operations of measurement to describe observations

How does research begin?

Research StepsStepsIdentify questions of interestFormulating an explanationTheory: broad explanationHypothesis: prediction stated in a way that it can be testedCarrying out research designed to support or refute

Who participates in the study?Sample

Representative of larger group or population of interest

Small group of humans or animals

Unrepresentative sample misleading or biased test of hypothesis

Replication of research removes most doubt

Sampling

How do psychologists observe and describe behavior?Descriptive studies recording of behaviors that have been recorded systematicallySimplest method of scientific inquiryDescribe behavior and mental processesMost widely usedSurvey method ask peoples opinionsCase study one individualNaturalistic observation watch, describeArchival research using already collected data - newspapersClinical method observe in clinic settingAll have advantages and disadvantages

What type of research study?

How do psychologists observe and describe behavior? Correlational Studies

Correlational method: measure two variables for statistical relationship

Variable: anything that can be assigned a numerical value

Uses quantitative measures

Correlational ResearchCorrelational Studies

Correlation coefficient

Measures each variable

Indicates strength ( - 1 to 0 to 1) and direction (negative or positive) of relationship

Correlation does not mean causation could be a third factor involvedPositive correlation both factors increase more study, better gradesNegative correlation as one factor increases, the second factor decreasesMore study, less recreationNo relationship (close to zero) number of hours studied and height

CORRELATION IS NOT CAUSATIONLack of interest could be affecting test performance not hours studied

Correlation coefficientsPerfect positivecorrelation (+1.00)No relationship (0.00)Perfect negativecorrelation (-1.00)Examples of Correlational Research

Example of Cause and Effect Relationships(1)Low self-esteemDepression(2)DepressionLow self-esteemLow self-esteemDepression(3)Distressing eventsor biologicalpredispositioncould causecould causecould causeororandExperimental ResearchTests relationship of two or more variables

Allows conclusions about cause-and-effect

Quantitative measures of behavior compared in different conditions created by researchers

Evidence supports or rejects hypothesis

Experimental DesignElements

Independent variable gets manipulated

Dependent variable amount of change

Experimental group exposed to independent variable or conditions expected to create change

Control group presents normal behavior used for comparison

Random assignment Experimental control

Comparing Research MethodsResearch Method Basic Purpose How Conducted What is ManipulatedDescriptive To observe and Case studies, surveys, Nothing record behavior and naturalistic observationsCorrelational To detect naturally Computing statisticalNothing occuring relationships; association, sometimes to assess how wellamong survey one variable predictsresponsesExperimental To explore causeManipulating one orIndependent and effectmore factors and usingvariable(s)random assignmentto eliminate preexistingdifferences among subjectsSummary: Types of research

Issues that come up in researchInternal validity the extent to which changes in the dependent variable can be attributed to the independent variableConfounding variable a variable whose unwanted effect on the dependent variable might be confused with that of the independent variableSubject bias what the subject expects the study to be aboutExperimenter bias what the researcher expectsExperimenter effects the personality, dress Pygmalion effect the subject performs better because of experimenterDouble blind technique

Types of Random Assignment Placebo controlPlacebo effect: provides no active effectUse in identical conditions for control and experimental groups

Blind experimentResearchers blind to group membership of participants to rule out experimenter bias

Strongest experiments double blindResearchers and participants kept blind

Descriptive Statistics: summarized data for large groups of participantsCentral tendency asks what the average score is like in the distribution of scoresMean: Statistical average of all scoresMedian: The fiftieth percentile (half of the scores are above this score, half are below)Mode: The most frequent scoreVariability asks how dispersed the scores are relative to the average score or meanStandard deviation: How far the average participant score deviates from the average (square root of the variance)

Bell Curve and BeyondStandard score (z score) scores on a normal curve can be described as their distance from the mean of the distribution using SD units It allows you to compare scores from different distributionsPercentileThe score at or below which a particular percentage of scores fallBell Curve and SkewnessSkewness - when scores are bunched up on either side of the bell curveLOOK AT THE TAIL OF THE SKEWScores bunched at the high end = negative skewTest is too easyScores bunched at the low end = positive skewTest is too hard

Inferential Statistics Is the difference between the two groups caused by our manipulation or by chance?We test the null hypothesis we predict that there will be no effect of the independent variableNo difference btw the groups fail to reject the null hypothesisDifference between the two groups reject the null hypothesis

BUT IS THIS BY CHANCE OR FOR REAL?Statistical SignificanceWe are looking for true difference between groups a statement of probability the larger the difference between the groups, ______ likely it is by chance.Psychologists accept .05 as being statistically significantA probability of less than 5% that the results occurred by chanceThe results are more likely to be statistically significant if:Samples are largeThe differences between the two means is largeThe variability within the groups is smallInferencesInternal validity the extent to which changes in the dependent variable can be attributed to the independent variable rather than a confounding variableExternal validity the extent to which the results of a research study can be generalizedReliable safe to generalize from a sampleRepresentative sampleMore cases are better than fewerIssues with Experimental ResearchComplex real-world issues are not easily studied in the laboratoryLab studies may have problems in external validityEvaluating Research

APA Ethical Guidelines for Research

IRB- Internal Review BoardBoth for humans and animals.

Animal ResearchClear purposeTreated in a humane wayAcquire animals legallyLeast amount of suffering possible.

Human ResearchNo Coercion- must be voluntaryInformed consentAnonymityNo significant riskMust debrief

Ethics of ResearchRespecting the rights of human research participants involves:Informed consent is an explanation of a study and the responsibilities of experimenter and participantDeception involving the subjects must be justifiedConfidentiality of study information must be maintainedDebriefing refers to explaining the research process to the subjects at the end of the studyAnimal research must be justified and must minimize discomfort to participants

Chapter 2 QuizThe Research Enterprise in Psychology34Dont forget to write your answers on a separate piece of paper to grade when youre done!1. Organized sets of concepts that explain phenomena area) independent variablesb) dependent variablesc) hypothesesd) theories352. Students will be able to read a statement printed in the Comic Sans font faster than the same statement written in the Lucida Calligraphy font.The previous statement is a(n)a) hypothesisb) theoryc) replicationd) operational definition363. A theory isa) a tentative statement about the relationship between two or more variablesb) a system of interrelated ideas used to explain a set of observationsc) a statement of research results that have been proven to be correctd) a preliminary proposal that has yet to be tested374. Theoretically, random assignment should eliminatea) sampling errorb) the need to use statisticsc) concerns over validityd) many confounding variables385. When subjects in the experimental group put a puzzle piece in the wrong place, the experimenter unconsciously winced. The experimenter did not wince when subjects in the control group put a piece in the wrong place.The wincing of the experimenter must be eliminated because it isa) fraudulentb) a demand characteristicc) a confabulationd) a confounding variable396. The two basic types of statistics area) descriptive and inferentialb) central tendency and variabilityc) sampling and correlatived) parametric and nonparametric407. Of the following, which research method is most effective for studying unusually complex or rare phenomena?a) controlled experimentb) surveysc) naturalistic observationd) case study418. Of the following, which research method would be most appropriate for investigating the rel