Research methods
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Research Methods. Learning How We Know What We Know. Why Scientific Method is Important. Avoids pitfalls in human logic: Human intuition Hindsight bias Overconfidence Confirmation bias False consensus effect Promotes critical thinking & healthy skepticism

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Research Methods

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Research methods

Research Methods

Learning How We Know What We Know


Why scientific method is important

Why Scientific Method is Important

  • Avoids pitfalls in human logic:

    • Human intuition

    • Hindsight bias

    • Overconfidence

    • Confirmation bias

    • False consensus effect

  • Promotes critical thinking & healthy skepticism

  • Allows for stronger, more reliable conclusions to be drawn


Descriptive methods

Descriptive Methods

  • Goal: Describe behavior, and that’s it.

  • Two main types of descriptive methods:

    • Naturalistic Observation

      • Researchers do not intrude on the natural behaviors

      • Avoids Hawthorne Effect

      • Examples: Jane Goodall (chimpanzees); Dian Fossey (mountain gorillas)

      • Cannot draw conclusions about behavior

      • Cannot generalize to others


Descriptive methods1

Descriptive Methods

  • Two main types of descriptive methods:

    • Case Studies

      • In-depth study of one person/group

      • Necessary for some types of research:

        • Child abuse, crime, physical injuries, mental illness, etc.

      • Examples: Genie, brain injury cases

      • Cannot generalize to others

      • Numerous case studies culled together can draw limited conclusions


Inferential methods

Inferential methods

  • Infer conclusions about variables

  • Stronger than descriptive studies

  • Main types of inferential methods:

    • Correlations

      • Show relationships between variables

        • Direct (positive) correlation: variables vary together

        • Inverse (negative) correlation: variables vary separately

      • CORRELATION DOES NOT MEAN CAUSATION!


Inferential methods1

Inferential methods

  • Correlations (continued)

    • Correlation Coefficients: number indicating the strength and direction of a relationship

    • Range from -1 to +1

      • -1 indicates the strongest inverse relationship

      • +1 indicates the strongest direct relationship

      • 0 indicates no relationship


Research methods

Graphing Correlations: Scatterplots


Research methods

Example of Typical Scatterplot


Inferential methods2

Inferential Methods

  • Correlations (continued)

    • How are correlations obtained?

      • Surveys: essential elements

        • Representative sample

          • Obtained through random sampling

        • Questions/Statements

          • Multiple Choice

          • Yes/No

          • Rank Order

          • Likert Scale


Inferential methods3

Inferential Methods

  • Correlations (continued)

    • How are correlations obtained?

      • Longitudinal studies

        • Same group over long period of time

      • Cross-Sectional studies

        • Several cohort groups at the same time


Research methods

Problems with Interpreting Correlations

Directionality:

Third Variable:


Inferential methods4

Inferential Methods

  • Main types of inferential methods:

    • Experimentation

      • Can determine cause & effect relationships

      • Strongest methodology available

      • One factor is manipulated

      • Another factor is measured

      • Control of all variables is important!

        • Confounding variables must be controlled!


Inferential methods5

Inferential Methods

  • Steps in the experimental process:

    • Form a hypothesis

      • Two main types of hypotheses:

        • Null hypothesis states that no relationship exists between/among the variables

          • Scientific notation: H0

        • Alternative hypothesis states the predicted relationship between/among variables

          • Scientific notation: HA

        • Experiments test the null hypothesis, not the alternative


Inferential methods6

Inferential Methods

  • Steps in the experimental process:

    • Create an operational definition of variables in the hypothesis

      • Written in behavioral terms

      • Not designed to be “all-inclusive”

      • Identifies independent and dependent variables


Inferential methods7

Inferential Methods

  • Independent & Dependent Variables

    • DV: the variable that is measured by the researchers

      • AKA: the “effect” in the study

      • Easier to identify, because it’s what the researchers are hoping will happen in the study

    • IV: the variable that is changed/manipulated by the researchers

      • AKA: the “cause” in the study

      • It’s what the researchers hope is causing the DV

      • Must be something researchers can change

        • Age, gender, IQ, etc., are not IVs – they are “variables of interest”


Inferential methods8

Inferential Methods

  • Identify the following IVs & DVs:

    • Exposing children to public television improves reading skills.

    • Rewarding comments will make people work harder on an assembly line.

    • A young monkey will prefer to spend time with a pretend mother monkey covered in cloth who provides no milk over a pretend mother monkey covered in wire who provides milk.

    • People who have psychotherapy are less likely to have psychological problems in the future.

    • Being polite to others tends to make people more cooperative.

    • Extroverted people are more fun at parties.


Inferential methods9

Inferential Methods

  • Steps in the experimental process:

    • Determine the population of participants

      • Acquire a representative sample from the population by random sampling.

      • Divide sample into two main groups through random selection:

        • Experimental group receives the independent variable.

        • Control group does not receive the independent variable.


Inferential methods10

Inferential Methods

  • Steps in the experimental process:

    • Ways to group participants:

      • Within-subjects design

        • AKA: pre/post design

        • Ps are compared to each other

        • Is less susceptible to individual differences

        • Is more susceptible to “practice effects”


Inferential methods11

Inferential Methods

  • Steps in the experimental process:

    • Ways to group participants:

      • Between-subjects design

        • Ps are divided into two groups and compared to each other

        • Is more efficient

        • Avoids “practice effects”

        • Is more susceptible to individual differences

          • Way to address problem: Matched-subjects design

          • Match Ps according to a predetermined variable (age, gender, IQ, etc.) and make sure each group shares same individual characteristic.


Inferential methods12

Inferential Methods

  • Steps in the experimental process:

    • Ways to control variables:

      • Placebo-control groups

      • Blind studies

        • Single-blind: Ps don’t know which group they are in.

        • Double-blind: Ps and people conducting the study don’t know which group the Ps are in.

        • Helps control expectation effects, demand characteristics, and researcher bias

      • Control environmental conditions


Inferential methods13

Inferential Methods

  • Steps in the experimental process:

    • Conduct the study

    • Conduct statistical analysis

      • Descriptive statistics

        • Measures of central tendency: mode, median, mean, range, standard deviation

      • Inferential statistics

        • Determine statistical significance

          • p = .05 – There is a 95% likelihood that the results of the study are NOT due to chance.


Ethics

Ethics

  • Ethics guidelines keep research from harming participants.

    • Main principles:

      • The benefits of the study must outweigh the harm to the participants.

      • Informed consent must be obtained.

        • Must know they are in a research study

        • Must be allowed to back out of the study at any time without penalty

      • Participants must be debriefed about the true intentions of the study afterward.


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