Chapter 2 Psychological Methods. Conducting Research Forming a research questionForming a research question Forming a hypothesisForming a hypothesis Testing.

Chapter 2Chapter 2Psychological Psychological

MethodsMethods

Conducting ResearchConducting Research• Forming a research questionForming a research question• Forming a hypothesisForming a hypothesis• Testing the hypothesisTesting the hypothesis• Analyzing the resultsAnalyzing the results• Drawing conclusionsDrawing conclusions• ReplicationReplication• New QuestionsNew Questions

• Examples:           (a) Testing the effects of

ritalin medication on the attention spans of

children with ADHD           (b) Examining the

reliability of eyewitness testimony

in young children

The Psychological Method at The Psychological Method at work:work:

• The “Mozart effect” is an increase in The “Mozart effect” is an increase in spatial reasoning scores after spatial reasoning scores after listening to a Mozart piano sonata.listening to a Mozart piano sonata.

• Rats learned to complete a T-maze Rats learned to complete a T-maze more quickly if they had been more quickly if they had been exposed in utero and reared hearing exposed in utero and reared hearing a Mozart piano sonata.a Mozart piano sonata.

Surveys, Samples, and Surveys, Samples, and PopulationsPopulations

• Survey MethodSurvey Method

• Populations and SamplesPopulations and Samples

• Selecting SamplesSelecting Samples

• Generalizing ResultsGeneralizing Results

• Volunteer BiasVolunteer Bias

Surveys:Surveys:• People are asked to respond to a series of People are asked to respond to a series of

questions about a particular subjectquestions about a particular subject• Written questionnaires or interviewing Written questionnaires or interviewing

orallyorally• Problems with Surveys:Problems with Surveys:

– HonestyHonesty– ConfidentialityConfidentiality– Please the interviewerPlease the interviewer– Ex. 1960’s survey of tooth brushingEx. 1960’s survey of tooth brushing

SurveysSurveys

Populations and Samples:Populations and Samples:

• What groups of people they wish What groups of people they wish to examine and how they are to examine and how they are selected.selected.–Target PopulationTarget Population: the whole : the whole

group you want to study or group you want to study or describedescribe

–Sample PopulationSample Population: part of the : part of the target populationtarget population

Target PopulationTarget Population for “Text for “Text messaging Usage”?messaging Usage”?

TEENAGERSTEENAGERS

Now a sample population Now a sample population from that Target from that Target

Population?Population?• Girls that text messageGirls that text message• Hispanics that text Hispanics that text

message message • Ages from 18-20 only, that Ages from 18-20 only, that

text message text message

Selecting SamplesSelecting Samples• Select samples that Select samples that

scientifically ensure they scientifically ensure they represent the populationrepresent the population–RandomRandom- selected by chance- selected by chance

–StratifiedStratified- subgroups in the - subgroups in the population are represented population are represented proportionallyproportionally

Random SampleRandom Sample

Stratified SampleStratified Sample

Generalizing ResultsGeneralizing Results

• Not using the words “all” Not using the words “all” because of the resultsbecause of the results

• Researchers are careful about Researchers are careful about generalizing their finding to generalizing their finding to group other than those form group other than those form which samples were drawnwhich samples were drawn

Volunteer BiasVolunteer Bias• Volunteers differ, Volunteers differ,

sometimes, form sometimes, form those who do not those who do not volunteer.volunteer.

• Want to get those Want to get those that do not want to that do not want to take the survey, to take the survey, to take it. take it.

• Avoid surveying Avoid surveying many enthusiastic many enthusiastic volunteers volunteers

Methods of Methods of ObservationObservation

• The Testing MethodThe Testing Method

• The Case-Study MethodThe Case-Study Method

• Longitudinal and Cross sectional Longitudinal and Cross sectional MethodsMethods

• The Naturalistic-Observation MethodThe Naturalistic-Observation Method

• The Laboratory Observation The Laboratory Observation

• Methods of Analyzing ObservationsMethods of Analyzing Observations

Testing MethodTesting Method• IQ Test-IQ Test- tests learning ability tests learning ability• Aptitude Test-Aptitude Test- specific abilities specific abilities

– MusicalMusical– MechanicalMechanical– VocationalVocational

• Personality Tests-Personality Tests- character traits and character traits and temperament temperament – OutgoingOutgoing– AggressiveAggressive– Psychological ProblemsPsychological Problems– AnxietyAnxiety– DepressionDepression

Testing MethodTesting Method

Case Study MethodCase Study Method• In depth investigation of an In depth investigation of an

indivudal or a small group indivudal or a small group ( Ex. Genie); faulty in that ( Ex. Genie); faulty in that people have problems with people have problems with past experiencespast experiences

• Freud used this for his Freud used this for his psychoanalytic theorypsychoanalytic theory

Case StudyCase Study

LongitudinalLongitudinalSelected group of Selected group of participants and then participants and then observe them over a period observe them over a period of time (years). Observe how of time (years). Observe how they change over time. This they change over time. This is very time consuming, is very time consuming, expensive, and riskyexpensive, and risky

Cross sectionalCross sectional• Selected sample that includes Selected sample that includes

people of different ages to get people of different ages to get the same result on a “cross the same result on a “cross section” of the population.section” of the population.

• May not be as accurateMay not be as accurate

• Much faster and cheaperMuch faster and cheaper

Naturalistic-Naturalistic-ObservationObservation

• Also known as a “Field Also known as a “Field Study”Study”

• Observe people or animals in Observe people or animals in their natural habitats.their natural habitats.

• Cannot interfere with the Cannot interfere with the organism they are observingorganism they are observing

Naturalistic Observation

• Dian Fossey studied Mountain Gorillas in Rwanda and Zaire.

• She spent years watching and studying these Gorillas

• She was murdered in 1985

Naturalistic Observation

• Jane Goodall studied chimpanzees in Tanzania

• She has studied them for 40 years

Naturalistic Observation

• Meerkat Meerkat Manor is an Manor is an example of example of naturalistic naturalistic observationobservation

Naturalistic ObservationNaturalistic Observation

Naturalistic Observation• Watching

students eat lunch could be considered Naturalistic Observation

• Maybe you can watch teachers eat…

Laboratory Laboratory ObservationObservation

• Observe in a laboratory rather Observe in a laboratory rather than in the fieldthan in the field

• Laboratory is any place that Laboratory is any place that provides the opportunity for provides the opportunity for observation or experimentationobservation or experimentation

Methods of Analyzing Methods of Analyzing ObservationsObservations

• CorrelationsCorrelations- a measure of how closely one thing is related to another.– Positive Correlation- one variable

increases, the other also increases, or as one decreases so does the other.  Both variables move in the same

– Negative Correlation- one two variables tend to move in the opposite direction

Positive CorrelationsPositive Correlations• Achievement increased,

salary increases

• Temperature increases, anger increases

Negative CorrelationNegative Correlation• The number of The number of

pages printed and pages printed and the amount of ink the amount of ink left in your printer left in your printer are negatively are negatively correlated. The correlated. The more pages more pages printed, the less printed, the less ink you have left.ink you have left.

Limits of CorrelationLimits of Correlation

• Does not reveal the cause Does not reveal the cause and effectand effect

The Experimental The Experimental MethodMethod

• Independent and Dependent Variables

• Experimental and Control Groups

• Placebo Effect• Single Blind Studies• Double Blind Studies

Independent VariableIndependent Variable

• The factor that The factor that researchers manipulateresearchers manipulate

Dependent VariableDependent Variable• The factor that is being The factor that is being

measured and that may change measured and that may change in response to the manipulating in response to the manipulating the Independent Variablethe Independent Variable

ExperimentExperiment• Warm temperature causes

aggression in humans

• Temperature is the independent variable (being manipulated)

• Aggression is the dependent variable, because it reacts to the manipulation of the independent variable.

Experimental GroupsExperimental Groups

• The group that received the The group that received the treatmenttreatment

Control GroupControl Group• The group that does not The group that does not

receive the treatment receive the treatment

Controlled ExperimentControlled Experiment

• An experiment An experiment conducted with conducted with both a both a control control group and an group and an experimental experimental group. group.

Placebo Effect• The person’s belief in The person’s belief in

the treatmentthe treatment

• Expectations. Hoping Expectations. Hoping to feel better. to feel better.

• Ex. Sugar TabletsEx. Sugar Tablets

• PlaceboPlacebo-substance or -substance or treatment that has no treatment that has no effect apart from a effect apart from a person’s belief in it.person’s belief in it.

Single Blind StudiesSingle Blind Studies• Participants do not Participants do not

know whether they know whether they received the received the treatment or nottreatment or not

• Do not know if they Do not know if they are in the are in the experimental group experimental group or the control groupor the control group

Double Blind StudiesDouble Blind Studies• Both participants and researchers are Both participants and researchers are

not aware of who received the placebo not aware of who received the placebo or the real treatment. or the real treatment.

• Otherwise, records are kept from both Otherwise, records are kept from both so that the outcome will not be skewed.so that the outcome will not be skewed.

• Information is taken by data analysis Information is taken by data analysis that is not involved with the experimentthat is not involved with the experiment

Ethical IssuesEthical Issues• Research with people

• Research with animals

• Ethics in using data

Research with PeopleResearch with People

• ConfidentialityConfidentiality- records are private- records are private

• Informed consent-Informed consent- people agree to people agree to participate in research study only participate in research study only after they have been given a after they have been given a general overview of the experimentgeneral overview of the experiment

• DeceptionDeception- only in specified - only in specified conditions (pg 46) conditions (pg 46)

Research with animalsResearch with animals

• Psychologists only use Psychologists only use animals when there is no animals when there is no alternative.alternative.

• Some believe that the Some believe that the benefits outweigh the benefits outweigh the harm harm

Ethics in Using DataEthics in Using Data

• Objectivity in producing Objectivity in producing and presenting dataand presenting data

• ““Be willing to disregard Be willing to disregard hypothesis if it is hypothesis if it is incorrect after research”incorrect after research”

Statistics

• Classify the types and uses of statistics in psychological research; include descriptive statistics and inferential statistics.

Descriptive StatisticsDescriptive Statistics Descriptive statistics are used to Descriptive statistics are used to describedescribe the basic features of the data in a study. the basic features of the data in a study. They provide simple summaries about the They provide simple summaries about the sample and the measures. sample and the measures.

In simple terms, descriptive statistics can be thought of as being just a straightforward

presentation of facts

Inferential statisticsInferential statistics

• You are trying to reach conclusions that extend beyond the immediate data alone .

Quantitative DataQuantitative DataMeasures of Central TendencyMeasures of Central Tendency

• Mean- Average

• Median- Middle

• Mode- Most Frequently occurring

.

Example:

Find the measures of central tendency Find the measures of central tendency for the data set 3, 7, 9, 4, 5, 4, 6, 7, and for the data set 3, 7, 9, 4, 5, 4, 6, 7, and 9.9.

A. Mean = 6, median = 6 and modes are 4, 7 and 9B. Mean = 6, median = 6 and mode is 4C. Mean = 6, median = 6 and modes are 4 and 9D. Mean = 6, median = 9 and modes are 4, 7 and 9