Chapter 1 Notes: Psychology Research Methods

Scientific method in psychology

  • Psychologists use the scientific method to study mental processes and behavior.
  • Step 1: Formulate a theory
    • A theory is an explanation of how some mental processes or behavior occur.
    • Formulation involves a literature review: explore scientific articles and relate findings to your ideas.
  • Step 2: Develop a testable hypothesis
    • A hypothesis is an answer to a theory's question and consists of testable predictions that should be observed if the theory is correct.
  • Step 3: Test with a research method
    • Systematic collection of data to prove or disprove a hypothesis.
    • Three main types of research methods: descriptive, correlational, experimental.
  • Step 4: Analyze the data
    • Data analysis determines whether a significant effect was found.
  • Step 5: Show the result and conduct more research
    • Do not cherry-pick; unethical reporting only data that supports the hypothesis.
  • Replication
    • Repeating an experiment to confirm results.

Types of research methods

  • Descriptive methods, Correlational methods, Experimental methods.
  • Descriptive methods describe what is occurring.
  • Correlational methods test the relationship between variables.
  • Experimental methods investigate what causes an outcome and test causality-by manipulation.

Descriptive methods: describe what is occurring

  • Three types: case studies, observational studies, self-reports.
  • Case studies
    • Involve intense examinations of one person, organization, or a few individuals.
    • Often used for people with psychological disorders.
    • Advantage: can provide lots of data.
    • Disadvantage: can be very subjective if the researcher has a preexisting theory; bias can influence what is observed, investigated, and recorded.
    • The results from single case studies cannot be extended to other people or organizations.
  • Observational studies
    • Systematically assess and code observable behavior, either with or without an intervention.
    • Potential issues: observer bias (researcher bias) and reactivity/reactive effects from participants.
    • The Hawthorne effect: participants change behavior because they know they are being observed.
  • Hawthorne effect (illustrated example)
    • At the Hawthorne Works (Western Electric plant, Illinois) from 1929–1933, researchers altered lighting, pay incentives, and break schedules.
    • Result: productivity increased when observed, regardless of the specific change.
    • Takeaway: being observed can influence behavior.
  • Self-reports
    • Descriptive method using questionnaires or interviews to gather data from many people quickly.
    • Self-report bias must be considered.

Correlational methods: describe relationships between variables

  • Purpose: explain how variables are naturally related in the real world.
  • Procedure: measure two factors and determine the degree of association between them.
  • Key limitation: researchers do not manipulate variables and cannot infer causation.
  • Important caveats:
    • Correlation is not causation:
    • Directionality problem: which variable influences the other?
    • Third-variable problem: a third factor may drive both observed variables.
  • Example discussed in notes:
    • Time spent on Facebook and feelings of depression: correlation observed, but causation unclear.
    • Directionality: does Facebook use cause depression (A → B) or does depression increase Facebook use (B → A)?
    • Third variable possibility: a third factor (e.g., tendency toward social comparison, or c) could drive both Facebook use (a) and depression (b), explaining the relationship (c → a and c → b).
  • Learning tip about causation in correlational research
    • Consider directionality and third-variable issues when interpreting correlations to avoid erroneous conclusions.
  • Mathematical note (important): define how a linear relationship is quantified
    • The strength and direction of a linear relationship between two variables can be summarized by the correlation coefficient rr, with
    • r = rac{ ext{Cov}(X,Y)}{\sigmaX \, \sigmaY} = rac{
      ext{sum}{i=1}^n (xi - ar{x})(yi - ar{y})}{\sqrt{ ext{sum}{i=1}^n (xi - ar{x})^2} \sqrt{ ext{sum}{i=1}^n (y_i - ar{y})^2}}
    • Note: values of rr range from -1 to 1, indicating the strength and direction of the relationship.

Experimental methods: test causation by manipulation

  • Experimental methods test causal relationships by manipulating an independent variable and measuring the effect on a dependent variable.
  • Key variables:
    • Independent variable (IV): the variable the experimenter manipulates to examine its impact on the dependent variable.
    • Dependent variable (DV): the variable that is measured and observed.
  • Operational definitions
    • Variables are defined in terms of specific, observable operations to ensure objective measurement.
  • Groups and controls
    • Control group: a comparison group that does not receive the experimental intervention or receives a neutral treatment.
    • Experimental (treatment) group: receives the intervention of the IV.
    • A control is necessary to determine causality by isolating the effect of the IV.
  • Confounds
    • A confound is anything that affects the DV and may unintentionally vary between experimental conditions; a source of error.
  • Population and sampling
    • Population: the general group the experimenter wants to knowledge about.
    • Sampling: the process used to select people from the population to participate.
    • Sample: the subset of people chosen to participate in a study.
    • Convenience sample: a sample of people conveniently available (e.g., college students).
    • Random sampling: a sample that fairly represents the population by giving each member an equal chance of being chosen.
  • Random assignment
    • Random assignment (randomization): placing participants into experimental conditions such that each participant has an equal chance of being assigned to any level of the IV.
  • Internal validity and control
    • The integrity of an experiment depends on controlling extraneous variables so that observed effects can be attributed to the IV.

Ethics and research oversight

  • Informed consent
    • People must be told about the research and must be free to participate or withdraw.
  • Institutional review and standards
    • A group or board (e.g., IRB) reviews proposed research to ensure it meets accepted ethical standards.
  • Practical implications
    • Researchers must balance scientific inquiry with protection of participants' rights and well-being.

Terms to know (quick reference)

  • Theory: an explanation of how mental processes or behavior occur; developed via literature review.
  • Hypothesis: testable predictions derived from a theory.
  • Descriptive methods: describe what is occurring; types include case studies, observational studies, self-reports.
  • Case study: in-depth examination of a single case or a few cases; high data yield but limited generalizability and potential subjectivity.
  • Observational study: systematic observation and coding of behavior; vulnerable to observer bias and reactivity (Hawthorne effect).
  • Hawthorne effect: behavior changes due to awareness of being observed.
  • Self-report: data collected via surveys, questionnaires, or interviews; subject to biases.
  • Correlational method: examines relationships between variables without manipulation; cannot establish causality; subject to directionality and third-variable problems.
  • Experimental method: manipulates IV, measures DV, uses random assignment and control groups to infer causality; controls confounds.
  • Independent variable (IV): manipulated by the experimenter.
  • Dependent variable (DV): measured outcome.
  • Operational definition: precise, observable definition of a variable.
  • Confound: an extraneous factor that can affect DV and vary across conditions.
  • Population, sampling, sample: concepts describing who is studied and how participants are selected.
  • Random sampling: equal chance of selection for each member of the population.
  • Random assignment: equal chance of assignment to any condition.
  • Ethics: informed consent, IRB oversight, and adherence to professional standards.

Module assignment notes (chapter 1)

  • Directions: use notes to answer the following statements or questions in your module activity.
  • 1) Systematically evaluate information or research conclusions best supported by evidence.
  • 2) Experimental psychology began in what year? (Note: answer not stated in transcript; refer to course materials for the year.)
  • 3) This descriptive research method involves intensive examination of one person.
  • 4) In an experiment, which group does not receive the experimental treatment?
  • 5) Group responsible for reviewing proposed research to ensure it meets standards.
  • 6) Means that people must be told about the research and that they can choose to participate or not.
  • 7) In an experiment, what is the variable that the experimenter manipulates?
  • 8) What are six strategies that will have major impact on your ability to succeed in this course?
  • 9) Placing participants into the condition of an experiment in which each participant has an equal chance of being assigned to any level of the IV is called what?
  • 10) Accept standards of ethical guidelines that guide people’s behavior (e.g., professional ethics).
  • Answer these questions based on your notes and then complete the online assignment in the module.
  • Note: all answers should be grounded in the content from these notes.