The Scientific Method State/define Issue

Psychological Research zTwo forms of psychological research: yBasic research seeks answers for purpose of increasing knowledge. xe.g. What role do the frontal lobes play in memory? yApplied research seeks answers for specific problems. xe.g. What types of memory strategies and rehabilitation strategies are most effective for people with frontal lobe injuries?

The Scientific Method Operational Definition ystatement of procedures (operations) used to define research variables yie: intelligence may be operationally defined as “what an intelligence test measures” Conceptual Definition Dictionary definition Something formed in the mind; a thought or notion

The Scientific Method zTheory ygeneral explanation why behavior occurs zHypothesis ytestable prediction yoften derived from previous theory yExample: I predict A will cause B I predict A will influence B

The Variables zDependent Variable> what is being studied ? value of DV depends on value of IV zIndependent Variable> causes change in DV zConfounding Variable> unforeseen cause “Hawthorne Effect”

Statistics in Psychology zPopulation –collection of all units or elements of interest zSample – portion of population selected to represent whole z Replication yrepeating procedures of research study with another sample of participants ycan results be repeated?

Comparing Research Methods Research Method Basic Purpose How Conducted What is Manipulated Descriptive To observe and Case studies, surveys, Nothing (Goal: Describe) record behavior and naturalistic observations Correlational To detect naturally Computing statisticalNothing (Goal: Predict) occurring relationships; association, sometimes to assess how wellamong survey one variable predictsresponses Experimental To explore causeManipulating one orIndependent (Goal: Explain) and effectmore IVs and usingvariable(s) random assignment to eliminate preexisting differences among subjects

Scientific Data Collection 1. Case Study indepth observation of one person 2. Survey questionnaire about attitudes or behavior 3.Observation observing and recording behavior in situations 4. Experiment variables are manipulated to determine cause & effect

Experiment zExperimental Group yparticipants are exposed to independent variable (treatment) zControl Group yparticipants do not receive independent variable ycomparison group to see effect of independent variable (treatment) zNote: the measure (DV) is taken for both groups

Good Samples zRepresentative Sample ya perfect reflection of population, only smaller in size zRandom Sample yfairly represents population because each member of sample had equal chance of being chosen

Experiment zRandom Assignment yassigning participants to experimental and control groups by chance yminimizes preexisting differences between those assigned to different groups

Experiment zSingle-blind Procedure yResearch participants don’t know if they are getting placebo or active agent. zDouble-blind Procedure yparticipants don’t know … yresearch staff doesn’t know …(blind) Who is getting active agent vs. placebo?

Experiment zPlacebo yinert substance (e.g., sugar pill) instead of an active agent (e.g., drug) yplacebo administered to trigger same reaction as active agent (IV) zPlacebo Effect yany effect on behavior caused by a placebo

Variability zRange – distance between largest and smallest score zVariance – index of average amount of dispersion using all scores in distribution zStandard Deviation – square root of variance; like variance, standard or typical distance of a score from mean

Reliability zReliability-consistency of scores obtained by same person when examined with same test on different occasions, time, places zIf your height remained the same at your house, then at school, & then at the doctor’s office, it would be reliable. You would not trust a measurement device that varied greatly.

Analysis of Data zTypes of statistics yDescriptive – Arithmetic formulas for summarizing and describing research data yInferential – Used for analyzing data to test hypotheses xIs the difference meaningful? xStatistical significance

Central Tendency zMean – (average) computed by summing all scores in set, dividing by total number of scores zMedian – midpoint of distribution; divides distribution into 2 equal halves zMode – score with greatest frequency

Correlation Coefficient (r) (Pearson r) ymeasure that shows extent to which two variables change together ypermits investigators to see link or association between variables ygood for prediction yNote: correlation does not imply causation! zCorrelations refer to looking at relationship between two variables without manipulating

Is this causation or correlation? The more soy sauce sold in Newnan the higher church attendance.

A leads to B 1+1=2 You jump because I pinched you.

Normal Curve 68% 95% 99% Mesokurtic

r = -.09 No Correlation

Positive Correlation Commuting distance of workers Worker tardiness

Strong Positive Correlation (11 and 21)

Negative Correlation Amount of Work Experience Waste Produced

Strong Negative Correlation

Experimental Issues Controls important for determining causality yonly difference between experimental & control groups is presence or absence of IV. Placebo effects represent changes in behavior that are related to expectations of a treatment. yplacebo effects are controlled by a “blind” control group Experimenter bias expectations influence participant’s behavior. yexample: Clever Hans, the horse who could do math ycan be controlled using double blind procedures Hindsight Bias  belief, after learning an outcome, that one would have foreseen it  “I-knew-it-all-along” phenomenon

Ethical Guidelines zAPA Guidelines yTruth in reporting yTreatment of participants zSpecial guidelines for I/O psychologists yLegal and profession obligations yManagement vs. employees

Ethical Issues in Research zRespecting the rights of human research participants involves: y Informed consent an explanation of study and responsibilities of experimenter and participant. y Confidentiality study information must be maintained. y Debriefing explaining research process to participants at end of study. y Deception involving participants must be justified.

APA Ethical Guidelines (animals) z“appropriate consideration of [the animal’s] comfort, health, and humane treatment.” zAnimals may not be subjected to “pain or stress” when alternative procedure is available.