1 / 14

Understanding Quasi-Experiments: Lab vs. Natural Settings in Psychological Research

This overview explores the key differences between laboratory and natural experiments in psychological research, focusing on the concepts of internal and external validity. It discusses the control of variables, practical limitations, and the goals of both basic and applied research. Key threats to internal validity, such as history, maturation, and selection biases, are examined alongside the challenges of generalizability in external validity. The text also highlights the importance of various research designs, including single-subject and psychophysical approaches, emphasizing correlation versus causation.

truly
Télécharger la présentation

Understanding Quasi-Experiments: Lab vs. Natural Settings in Psychological Research

An Image/Link below is provided (as is) to download presentation Download Policy: Content on the Website is provided to you AS IS for your information and personal use and may not be sold / licensed / shared on other websites without getting consent from its author. Content is provided to you AS IS for your information and personal use only. Download presentation by click this link. While downloading, if for some reason you are not able to download a presentation, the publisher may have deleted the file from their server. During download, if you can't get a presentation, the file might be deleted by the publisher.

E N D

Presentation Transcript

  1. PSYC 235: Research Methods ALT DESIGN

  2. Quasi Experiments

  3. Differences between lab and natural experiments • Control • Internal validity • External validity • Basic and applied goals • Consequences • Practical limitations • GOALS – to ENHANCE internal and external validity

  4. Control – threats to internal validity • History (events other than tx) • Maturation • Repeated testing • Instrumentation changes • Regression to the mean • Selection and interaction with selection • Subject mortality and attrition

  5. External Validity - generalizability • Subjects • Situations • Task • Time

  6. Basic and applied goals

  7. Subject variables: e.g. developmental research • Correlation does not equal causation!!!! • Cross sectional • Longitudinal • Time lag • Cross sequential • Major confounds of each

  8. Combining Quasi and True IV • E.g. age + ritalin, diagnosis + task difficulty, gender + video content • Importance of the interaction

  9. Natural Treatments – ex post facto • Smoking in the psychiatric ward • Improving the basic design • Non-equivalent conrtol group

  10. Interrupted time series • Will lowering the BAC from .1 to .08 reduce drunk-driving fatalities? • Do people drink more in college than at other times )or other places)? • Do women who wear more makeup make more money than women who don’t? • Would eliminating PSYC 235 from the curriculum increase the number of psychology majors?

  11. Small n research • Nomothetic versus Idiographic • Advantages of each • Disadvantages of each

  12. Small n: Applied Behavior Analysis • Skinnerian versus statistical traditions • Designs • AB • ABA • ABAB • Alternating treatments (e.g. ABCA) • Example: Behavioral Contrast • Multiple baseline designs

  13. Psychophysical designs • Signal detection theory • Discriminability (d’) • Bias (B)

More Related