Personality Assessment, Measurement, and Research Design

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Personality Assessment, Personality Assessment, Measurement,Measurement,

and Research Designand Research Design

Chapter 2Chapter 2


Personality DefinedPersonality Defined

Personality is the set of Personality is the set of psychological traitspsychological traits and mechanisms and mechanisms within the individual that are organized within the individual that are organized and relatively enduring and that and relatively enduring and that influence his or her interactions with, influence his or her interactions with, and adaptations to, the environment and adaptations to, the environment (including the intrapsychic, physical, (including the intrapsychic, physical, and social environment).and social environment).


Sources of Personality DataSources of Personality Data

•Self-Report Data (S-Data)Self-Report Data (S-Data)

•Observer-Report Data (O-Data) Observer-Report Data (O-Data)

•Test-Data (T-Data) Test-Data (T-Data)

•Life-Outcome Data (L-Data)Life-Outcome Data (L-Data)


Self-Report Data (S-Data)Self-Report Data (S-Data)

• Information provided by a person, Information provided by a person, such as through a survey or such as through a survey or interviewinterview

• Individuals have access to a wealth Individuals have access to a wealth of information about themselves of information about themselves that is inaccessible to anyone elsethat is inaccessible to anyone else


Self-Report DataSelf-Report Data

•S-data personality testsS-data personality tests– Unstructured items—open-Unstructured items—open-

endedended– Structured items—response Structured items—response

options providedoptions provided


Self-Report DataSelf-Report Data

•Limitations of S-dataLimitations of S-data– People may not respond People may not respond

honestlyhonestly– People may lack accurate self-People may lack accurate self-

knowledgeknowledge


Observer-Report Data (O-Observer-Report Data (O-Data) Data)

• Information provided by someone Information provided by someone else about another personelse about another person

•Key features of O-dataKey features of O-data– Provide access to information not Provide access to information not

attainable through other sourcesattainable through other sources– Multiple observers can be used to Multiple observers can be used to

assess a personassess a person


Observer-Report DataObserver-Report Data

•Selecting observersSelecting observers– Professional personality assessorsProfessional personality assessors– People who actually know the target People who actually know the target

personperson•Often in better position to observe target’s Often in better position to observe target’s

natural behaviors than professional natural behaviors than professional personality assessorspersonality assessors

•Allows for assessment of multiple social Allows for assessment of multiple social personalities personalities

•Because of relationship to target, however, Because of relationship to target, however, observer may be biasedobserver may be biased



•Naturalistic vs. Artificial Naturalistic vs. Artificial ObservationObservation

– Naturalistic observation: Observers Naturalistic observation: Observers witness and record events that occur in witness and record events that occur in the normal course of lives of the the normal course of lives of the participantsparticipants

– Artificial observation: Occurs in artificial Artificial observation: Occurs in artificial settings or situationssettings or situations



• Naturalistic observation has the advantage Naturalistic observation has the advantage of being able to secure information in of being able to secure information in realistic context, but at the cost of not realistic context, but at the cost of not being able to control events witnessedbeing able to control events witnessed

• Artificial observation has the advantage of Artificial observation has the advantage of controlling conditions and eliciting controlling conditions and eliciting relevant behavior, but at the cost of relevant behavior, but at the cost of sacrificing realismsacrificing realism


Test-Data (T-Data) Test-Data (T-Data)

• Information provided by standardized Information provided by standardized tests or testing situationstests or testing situations

• Idea is to see if different people Idea is to see if different people behave differently in identical behave differently in identical situationssituations


Test-DataTest-Data

•Situation designed to elicit Situation designed to elicit behaviors that serve as indicators behaviors that serve as indicators of personalityof personality

•Elicited behavior “scored” without Elicited behavior “scored” without reliance on inferencereliance on inference


Test-DataTest-Data

•LimitationsLimitations– Participants might try to guess what trait Participants might try to guess what trait

is being measured and then alter their is being measured and then alter their behavior to create certain impressionsbehavior to create certain impressions

– Difficult to know if participants define Difficult to know if participants define testing situation as intended by testing situation as intended by experimenterexperimenter

– Researcher might influence how Researcher might influence how participants behaveparticipants behave


Test-DataTest-Data• Mechanical recording devices, e.g., Mechanical recording devices, e.g.,

“Actometer” used to assess children’s “Actometer” used to assess children’s activityactivity– StrengthsStrengths

•Not hampered by biases of human observerNot hampered by biases of human observer

•May be used in naturalistic settingsMay be used in naturalistic settings

– DisadvantageDisadvantage•Few personality dispositions lend Few personality dispositions lend

themselves to mechanical assessmentthemselves to mechanical assessment


Test-DataTest-Data

•Physiological dataPhysiological data– Includes information about a Includes information about a

person’s level of arousal, reactivity person’s level of arousal, reactivity to stimuli—potential indicators of to stimuli—potential indicators of personalitypersonality

– Functional magnetic resonance Functional magnetic resonance imaging (imaging (ffMRI)MRI)


Test-DataTest-Data

•Physiological dataPhysiological data– Key benefit is that it is difficult to fake Key benefit is that it is difficult to fake

responsesresponses– DisadvantagesDisadvantages

•Often used in artificial laboratory settingOften used in artificial laboratory setting

•Accuracy of recording hinges on whether Accuracy of recording hinges on whether participant perceives situation as participant perceives situation as experimenter intendedexperimenter intended


Test DataTest Data

•Projective TechniquesProjective Techniques– Person presented with ambiguous Person presented with ambiguous

stimuli and asked to describe what stimuli and asked to describe what she sees; assumption is that she sees; assumption is that person “projects” personality onto person “projects” personality onto ambiguous stimuliambiguous stimuli


Test DataTest Data

•Projective TechniquesProjective Techniques– Strengths: May provide useful Strengths: May provide useful

means for gathering information means for gathering information about wishes, desires, fantasies about wishes, desires, fantasies that a person is not aware of and that a person is not aware of and could not reportcould not report

– Disadvantages: Difficult to score, Disadvantages: Difficult to score, uncertain validity, and reliabilityuncertain validity, and reliability


Life-Outcome Data (L-Data)Life-Outcome Data (L-Data)

• Information that can be gleaned from Information that can be gleaned from events, activities, and outcomes in a events, activities, and outcomes in a person’s life that is available for public person’s life that is available for public scrutiny—e.g., marriage, speeding scrutiny—e.g., marriage, speeding ticketstickets

• Can serve as important source of “real Can serve as important source of “real life” information about personalitylife” information about personality


Issues in Personality Issues in Personality AssessmentAssessment

•Links among different data sourcesLinks among different data sources

•Fallibility of personality Fallibility of personality measurementmeasurement– All sources of data have limitationsAll sources of data have limitations– Results that replicate through Results that replicate through

“triangulation” are most powerful“triangulation” are most powerful


Evaluation of Personality Evaluation of Personality MeasuresMeasures

•ReliabilityReliability

•ValidityValidity

•GeneralizabilityGeneralizability


ReliabilityReliability

•Degree to which measure Degree to which measure represents “true” level of trait represents “true” level of trait being measuredbeing measured

•Types of reliabilityTypes of reliability– Test-retest reliabilityTest-retest reliability– Inter-rater reliabilityInter-rater reliability– Internal consistency reliabilityInternal consistency reliability


ValidityValidity

• Degree to which test measures what Degree to which test measures what it claims to measureit claims to measure

• Types of validityTypes of validity– Face validity Face validity – Predictive or criterion validityPredictive or criterion validity– Convergent validityConvergent validity– Discriminant validityDiscriminant validity– Construct validityConstruct validity


GeneralizabilityGeneralizability

• Degree to which measure retains validity Degree to which measure retains validity across different contexts, including different across different contexts, including different groups of people and different conditionsgroups of people and different conditions

• Generalizability subsumes reliability and Generalizability subsumes reliability and validityvalidity

• Greater generalizability not always better; Greater generalizability not always better; what is important is to identify empirically what is important is to identify empirically contexts in which a measure is and is not contexts in which a measure is and is not applicableapplicable


Research Designs in Research Designs in PersonalityPersonality

•Experimental MethodsExperimental Methods

•Correlational StudiesCorrelational Studies

•Case StudiesCase Studies


Experimental MethodsExperimental Methods

• Used to determine causality—Used to determine causality—whether one variable whether one variable causescauses another another

• Two key requirements:Two key requirements:– Manipulation of variablesManipulation of variables– Ensuring that participants in each Ensuring that participants in each

experimental condition are equivalent to experimental condition are equivalent to each othereach other


Correlational StudiesCorrelational Studies

• Correlation is a statistical procedure Correlation is a statistical procedure for determining whether there is a for determining whether there is a relationship between two variablesrelationship between two variables

• Designed to identify “what goes with Designed to identify “what goes with what” in nature, and not designed to what” in nature, and not designed to identify causal relationshipsidentify causal relationships

• Major advantage is that it allows us Major advantage is that it allows us to identify relationships among to identify relationships among variables as they occur naturallyvariables as they occur naturally


Correlational StudiesCorrelational Studies

•Correlation coefficient varies from Correlation coefficient varies from –1 (perfect negative relationships) –1 (perfect negative relationships) through 0 (no relationship) to +1 through 0 (no relationship) to +1 (perfect positive relationship)(perfect positive relationship)

•Correlation does not indicate Correlation does not indicate causationcausation– Directionality problemDirectionality problem– Third variable problemThird variable problem


Case StudiesCase Studies

• In-depth examination of the life of one In-depth examination of the life of one personperson

• AdvantagesAdvantages– Can find out about personality in great detailCan find out about personality in great detail– Can give insights into personality that can be Can give insights into personality that can be

used to formulate a more general theory that is used to formulate a more general theory that is tested on a larger sampletested on a larger sample

– Can provide in-depth knowledge about an Can provide in-depth knowledge about an outstanding figure, such as a political or outstanding figure, such as a political or religious figurereligious figure


Case StudiesCase Studies

•DisadvantageDisadvantage– Results based on the study of Results based on the study of

single person cannot be single person cannot be generalized to othersgeneralized to others


When to Use Experimental, When to Use Experimental, Correlational, and Case Study Correlational, and Case Study DesignsDesigns

• Each design has strengths and weakness; Each design has strengths and weakness; strength of one is weakness of anotherstrength of one is weakness of another

• Which design a researcher uses depends Which design a researcher uses depends on the research question and the goal of on the research question and the goal of researchresearch

• Taken together, three designs provide Taken together, three designs provide complementary methods for exploring complementary methods for exploring personalitypersonality


Summary and EvaluationSummary and Evaluation

• Decisions about data source and Decisions about data source and research design depend on the research design depend on the purpose of studypurpose of study

• There is no perfect data sourceThere is no perfect data source

• There is no perfect research designThere is no perfect research design

• But some data sources and some But some data sources and some methods are better suited for some methods are better suited for some purposes than for otherspurposes than for others

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Personality Assessment, Measurement, and Research Design