2 Basic Steps for Conducting Scientific Research Step 1: Formulate a hypothesis1.Step 4:Report the resultsStep 2:Design a studyStep 3: Collect & analyze data
3 The Scientific Process TheoryRevise TheoryHypothesesEmpirical TestsReplicateNot SupportedSupportedConfidence in theory decreasesConfidence in theory increasesDiscard Theory
4 Types of psychological research Experimental ResearchExperimentsDescriptive/Correlational ResearchSurveysObservationNaturalisticContrivedCase Studies
5 ExperimentsExperiments - Do changes in one variable (X) cause changes in another variable (Y)?Independent Variable (X)condition or event that is manipulated by experimenterDependent Variable (Y)variable that is affected (hopefully) by manipulating independent variableExtraneous Variable(s)any variable other than independent variable that may influence dependent variable
6 ExampleA study was conducted to examine the effects of temperature on aggression. Participants were randomly assigned to one of three conditions (low [70o-72o], moderate [80o-82o], or a high [90o-92o] temperature room).While in the room an assistant irritates the participants.Participants were later given a chance to “evaluate” the assistant and told that low ratings would cause the assistant to be fired.
8 Research Methods Confounding of Variables occurs when independent and extraneous variables are linked togethermakes it impossible to tell which variable affected dependent variable
9 Research Methods Minimize confounding with consistent procedures Minimize confounding with random assignmentparticipants have an equal chance of being assigned to any group or condition in the study.the goal of random assignment is to equally distribute potential extraneous variables in each group.
10 Variations in experimental design Use 1 group of participants who act as their own control group (e.g., expose each participant to each temperature)Manipulate more than 1 independent variable at a time (temperature & humidity)Measure more than 1 dependent variable at a time (aggression & helping)
11 Pros and Cons Advantages of Experimental Research Allows conclusions about cause & effect relationships between variablesDisadvantages of Experimental ResearchExperimental conditions are artificialdo results “generalize” to the real world?Some questions can’t be tested in an experiment
12 Correlation/Descriptive Research AdvantagesStudy phenomena that can’t be studied in a labriotseffects of supervisor behavior on employeeseffects of job loss on couples’ relationship qualityeffects of smoking on physical healthVery realisticresults can be generalized to other settingsDisadvantagesless control over extraneous variablesdifficult to measure behavior as precisely (compared to lab experiments)cannot demonstrate cause and effect relationships
13 CorrelationThe extent to which one variable can be understood on the basis of anotherTwo properties of correlation coefficientdirection (positive or negative)magnitude (strength of the relationship)