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8/12/2019 Methods in Psychology Webp

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Why Use Experimental Methods?

A true experiment is the best method forfinding out whether one thing really causesanother


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Experimental Researchin Social Psychology

Why learn experimental methods?

1. Inevitably, we will be called upon to do research insome form.

2. Understanding research methods prepares us toevaluate the research we read about.

3. Training in social psychology improves ability toreason about everyday problems (Lehman,Lempert & Nisbett, 1988)


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Why Use Other Methods?

1. The researcher is not interested in acause and effect relationship

2. There are some situations whereexperiments are unethical orimpossible

3. Researchers may use nonexperimentalmethods to supplement experimentalresearch


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Understanding through Prediction, Controland Theory Building

Theory

A set of statements designed to explain a set of phenomena;more encompassing than a hypothesis

Hypothesis

A statement, usually designed to be tested by anexperiment that tentatively expresses a cause-and-effect relationship with variables.


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What Makes a Good Theory?

Incorporates existing facts

It is testable

Predictions made by the theory are

supported by the findings of new research

It conforms to the law of parsimony


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From Theory to Testable Questions

Operational DefinitionA specific, observable response that is used tomeasure a concept


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Self-Report Measures

Socially DesirableResponding a formof responding thatinvolves giving

answers that portraythe respondent in apositive light


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Behavioural MeauresMeasurement by observing behaviour

Often unobtrusive


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Experimental Research

Validity the ability of a test to measure what it wasdesigned to measure.Are we really measuring what we say we are?

Reliability and Validity


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Reliability the repeatability of a

measurement.

Basically, the extent to which themeasurement device yields the

same approximate results whenutilized repeatedly under the sameconditions.

Reliability


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Correlational Research Purpose: Predicting behaviour and/or looking for

relationships between variables Research tactics:

Statistical correlations based on two or more variables


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Correlational Research

SurveysA correlational study in

which the researchersasks questions torespondents

Representative samplesthrough random sampling


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Archival ResearchInvestigations that are based on preexistinginformation


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Observational StudiesResearchers watch participants and codemeasure from the observed behaviour


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Observational StudiesParticipant-Observation Research a researcher

joins an ongoing group to observe membersbehaviour.


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Possible Causal Relation


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Interpreting Correlation Coefficients


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Generating Research Ideas

The Functional Approach toTheory Development

Part of the scientific processinvolves building on previousresearch in order to attempt toclarify issues and lead to newdiscoveries.


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From An Idea to the Lab

Experimental Realization the transformationof the concepts of the hypothesis intospecific, observable events

Experimental realism refers to the impact theexperiment has on the subjects

Mundane realism refers to how similar theevents in lab are to the events that typicallyhappen in real life.


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n Experimental research determinescause and effect relationships

n Three essential characteristics:

1. The researcher manipulates onevariable (the independent variable)2. The researcher measures whether

this manipulation produces changein a second variable (the dependentvariable)

3. The researcher tries to control forextraneous (or confounding)variables.


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Independent, Dependent, andExtraneous Variables

Independent Variable

variable that is manipulated in anexperiment


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Dependent Variable

variable whose values are (in principle)the result of the manipulation of one ormore independent variables


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Extraneous (Confounding) VariablesPotential source of error in an experiment; mustbe held consant across conditions


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Random Assignment a procedure in whicheach participant is equally likely to take partin any of the experimental conditions


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Demand CharacteristicsCues in a study that suggest to participants howthey are supposed to respond.


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Internal and External Validity

Internal Validity:Refers to how well a study is run (research design,operational definitions used, how variables weremeasured, what was/wasnt measured, etc.)

External Validity:The extent to which a studys results can be generalized toother people or settings.


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Double-blind procedures minimize bothparticipant placebo effects andexperimenter bias.

Placebo effect an effect on behaviour thatis caused by an inert substance thatcannot be distinguished from a realmedication by the patient or subject.

Threats to the Validity of ResearchExperimenter Bias (Experimenter Expectancy Effects)


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Single-Factor Experiment

Single Factor ExperimentA study that involves only one independentvariable


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Experimental Concerns

Experimental RealismThe extent to which the setting of the studyfeels realistic and involving to participants and

elicits spontaneous behaviour


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Experimental Concerns

Mundane RealismThe extent to which the studys setting looksand feels like the outside world.


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Keys to Successful Experimental Studies

1. keep complete records of observations and dataanalyses in a form that other researchers canunderstand and evaluate

2. standardize all procedures3. use operational definitions4. minimize bias and control confounds


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Strength:

conclusions about cause-and-effect can be drawn

Weaknesses:artificial nature of experiments

ethical and practical issues

Strengths and Weaknesses of Experimental Research


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Ethics

Human Experiments at Holmesburg Prison


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Ethics (Human)

Minimize harm to participants (physical or mental)

Participants should not be exposed to harmful ordangerous research procedures

If an investigation requires some deception of participants, the researcher is required to explain and

correct any misunderstandings as soon as possible

Maximize benefits of research to participants andsociety


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Ethics (Human)Subjects should be fully informed about the nature of theresearch

Informed consent to participate must be voluntary

Should not intrude on private lives of participants without permission

Information about participant should be kept anonymous or

confidential unless they agree to make it public

Vulnerable populations should be treated with special care.

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