Mastering Research Methods in Biological Psychology

1. Research Methods Used at the Biological Level of Analysis IB Psychology

2. Triangulation • Research conducted at each of the levels of analysis should have method of triangulation on the same topic from the other two levels of analysis. • Triangulation means that the research is supported/complemented by other forms of research.

3. Key Things to Remember • Always pay attention to sampling when reading a study. • Samples are often limited, and it is usually hard to get a representative sample. • This limits the interpretation of the research.

4. Experiments • Only method showing cause and effect! • Ethics determines whether a biological experiment can be run on humans. • Manipulated conditions may cause harm. • When researchers alter the brain or gene expression. • Suffer from poor ecological and population validity unless they have triangulation with other findings.

5. Case Studies • Used when scientists want to follow the case of a human with a particular type of damage. • Help scientists describe data collected over time, and on things that cannot be created in the lab. • May be the ONLY way some phenomenon can be studied.

6. Case Studies • Case studies raise questions about strong claims that point researchers in new directions. • Suffer from poor external validity and are hard to replicate.

7. Postmortem Studies • Allow researchers to directly study brain tissue. • Often case studies. • Cause and Effect cannot be easily determined. • Main Advantage is pinpointing specific brain locations for further study.

8. Neuroimaging Technologies • PET and fMRI provide hard evidence about what the brain is doing. • Imaging Technology does NOT reveal why the brain differences are there.

9. Correlation • Used to analyze data in biological studies for two reasons: • Ethics might prevent a scientist from conducting research. • Correlation may be the only way to study a topic. • Correlations are NON-EXPERIMENTAL and show RELATIONSHIPS; not cause and effect.

10. Correlation • The correlation statistic is also used in two ways: • Show differences between preexisting groups. • Show the relationship between an IV and DV. • For a correlation to have much meaning it needs to be strong at least .80.

11. Specific Methods for Genetic Research • All genetic research has a specific goal in mind and is appropriate for that goal. • These studies use questionnaires to gather much of the data: • Reliability • Validity • Self-Report

12. Twin Studies • Tell researchers if genes are likely contributors to behavior but never identify a specific gene. • Assume that environments are the same between twins. • Greatest limitation is that twins do not share the exact same environment.

13. Adoption Studies • Tell researchers if genes are likely contributors to behavior but never identify a specific gene. • If an adopted child resembles the adopted parent and not the biological parent, it should be because of the environment. • Limitations are a long time-frame, and “selective placement” of adopted children.

14. Linkage Studies • The first attempt to locate a specific gene that contributes to behavior. • Cannot EVER tell you which gene causes behavior. • The trait with the known location becomes the “marker”. • This allows investigators to make predictions about a genetic variation that may contribute to behavior.

15. Association Studies • Often follow successful linkage studies. • Point scientists in the direction of possible genes contributing to behavior. • Test ACTUAL genes that may be implicated in behavior.

16. Gene-Environment Correlation Studies • Examine how genes interact with the environment. • Caspi study is an example.