Intro to Experimental PSYC

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Intro to Experimental PSYC
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Major Topics

• Research -- what it is.
• Planning a research project.
• Selecting the research units (subjects) from
  which data will be collected.
• Constructing or obtaining the instruments used to
  collect data.
• Relative merits of commonly employed research
  designs.
• Analysis of the data.
• Preparing a research report.

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Trochim on Social Sciences Research

• Trochim opines that research in the social
  sciences (including psychology) is
• theoretical,
• empirical
• nomothetic, and
• probabilistic

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A Scientific Theory

• A model of how basic constructs and measured
  variables are related to one another.
• Constructed by induction inferring the general
  from the specific.
• Generates predictions (hypotheses) by deduction
  inferring the specific from the general.

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• Tested by attempting to falsify.
• From theory, derive hypotheses.
• Gather relevant data.
• If data match hypotheses, theory supported.
• If not, modify theory or abandon it.

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• Is not just a hunch.
• Explains all known facts in domain of interest.
• Must be refutable.

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Exploratory Research

• Not all psyc research is theory-driven.
• I can wonder about the relationship between X and
  Y without any guiding theory.
• Exploratory research provides the raw materials
  from which theories are refined.

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Empiricism

• Epistemology
• origins and nature of human knowledge
• Rationalism
• knowledge through thought
• Pythagoreans, Socrates
• Empiricism
• knowledge through sensory experience

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Nomothetic

• Applies to the general case.
• We study individuals
• to explain, predict, and control behavior
• not just in one individual, but in most.
• As opposed to idiographic.
• where the focus is on a single individual.

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Probabilistic

• Our interest is in the entire population
• for example, correlates of perceived
  attractiveness in all humans.
• But our data (sample) represents only a small
  proportion of that population.
• So our conclusions cannot be free of possible
  error
• must be stated in probabilistic terms.

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Three Basic Types of Research

• Descriptive (Univariate)
• Relational
• Causal

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Descriptive Research

• Univariate work with only one variable at a
  time.
• Example How many people dream in color?

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Relational Research

• Determine how variables are related to one
  another.
• Is age related to dreaming in color?
• Is sex/gender related to dreaming in color?
• Is arousal of certain brain areas related to
  dreaming in color?

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Causal Research

• Is X a cause of Y?
• If I manipulate X, will Y change?
• Establish that X and Y are related.
• Rule out (noncausal) alternative explanations.
• Employ experimental methodology.
• Eliminate confounds.

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Third Variable Problems
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Research and Time

• Cross Sectional Research
• Compare political attitudes of 20 vs 50 years
  olds.
• Differences due to maturation or ??
• Longitudinal Research
• Follow multiple cohorts, measure at 20, 30, 40,
  50 years of age.
• Repeated Measures and Time Series

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Patterns of Relationships Between Continuous
Variables

• None
• Positive Linear
• Negative Linear
• Curvilinear
• See Bivariate Linear Correlation.

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Hypotheses

• Null hypotheses
• Alternative hypotheses
• Nondirectional hypotheses
• Directional hypotheses
• Sharp/Point null hypotheses
• Loose/Range null hypotheses

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A Research ProjectFrom Start to Finish

• Formulating the Initial Broad Question
• Experiencing a practical problem.
• Familiarity with past research and theory.
• RFP requests for research proposals.
• Curiosity about everyday experiences.
• my curiosity regarding attitudes about animal
  research

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Narrow Down the Question

• Want a question that can be well addressed in a
  single research study.
• Focus in on one or a few parameters
• Theory may suggest which parameters are most
  important
• Or you just might have a hunch while sitting on
  the couch watching the news.
• How is misanthropy related to attitude about
  animals?

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The Research Hypothesis

• Theory, insight, or hunch may suggest an answer
  to the question posed.
• This becomes the research hypothesis.
• Ethical cost/benefit analysis and a relationship
  between misanthropy and attitudes about animals.

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Operationalization

• How to manipulate or measure the concepts in the
  research hypothesis.
• Manipulate misanthropy by exposing some subjects
  to depictions of evil humans.
• Develop questionnaire to measure misanthropy.

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Reviewing the Literature

• Has somebody else already answered this question?
• If so, what additional research is suggested by
  those results?
• Have others addressed similar questions?
• How did others operationalize constructs, recruit
  subjects, get grants, analyze the data, and so
  on.

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Procedural Details and Feasibility

• Prepare a step-by-step plan.
• Can you afford it?
• If not, are there less expensive methods?
• How many subjects will you need?
• How can you motivate your subjects?
• From whom will you need permission, cooperation,
  or assistance?

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• Are there statistical procedures available to
  analyze the data you will collect in a way that
  will answer your question?
• Can you conduct such analysis yourself or will
  you have to hire a research statistician?

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Gathering Analyzing the Data

• Consider conducting a pilot study.
• You can count on some things going wrong. Be
  prepared to deal with them.
• Screen your data to determine if you can analyze
  them the way you intended to. If not, adopt
  alternative analysis.
• Be on the lookout for unanticipated findings and
  be prepared to shift your attention to them.

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Using Your Statistical Results to Answer Your
Question

• If your question was simple, your design
  experimental, and your results what you expected,
  this is a breeze.
• Otherwise, be ready to sweat it out.

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Writing a Research Report

• Share your results with the world.
• Use the style appropriate for your discipline.
• For most psychologists, that is the style of the
  American Psychological Association.
• I have taught you the basics of APA style.

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Research Validity

• Will your research lead to conclusions that fit
  the available data and stand up to criticism.
• Statistical Conclusion Validity
• Internal Validity
• Construct Validity
• External Validity

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Statistical Conclusion Validity

• Determine the extent to which variables are
  related.
• Power
• Efficiency of Estimation
• Robustness

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Internal Validity

• Is there a causal relationship between these
  variables?
• Experimental research
• Various threats to internal validity

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Construct Validity

• Have we operationalized our constructs well?
• We have demonstrated a relationship between our
  measured variables.
• Does this make us confident that there is a
  relationship between the underlying constructs?

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External Validity

• Can we generalize the results?
• to other types of subjects
• to other situations
• to other measurements of the constructs
• etc.

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Issues in Research Ethics

• Coercion
• Privacy
• Deception
• Discomfort or Harm
• Right to Service

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Reducing Ethical Problems

• Institutional Review Boards
• Preserve participants anonymity
• Obtain informed consent
• Reduce risk of harm when possible