1 Psychology 304: Brain and Behaviour Lecture 2

2 Research Methods 1.What types of research methods do biological psychologists use? 2.What ethical considerations do biological psychologists face?

3 Biological psychology relies upon the scientific method— that is, systematic and objective observation. Several steps are involved in conducting research using the scientific method: What types of research methods do biological psychologists use?

4 Theory Hypothesis Operationalization Research Data Interactive Relationship

5 Biopsychological research involves four types of studies. 1. Experimental studies  Designed to examine cause and effect relationships between variables.

6  In conducting an experiment, a researcher: (a) randomly assigns participants to groups that will receive different levels of the hypothesized “causal” or independent variable (IV). (b) administers a distinct treatment (i.e., level of the IV) to each group. (c) measures the hypothesized “effect” or dependent variable (DV) for each group.

7 Participants Group A Group B Random Assignment Treatment A Posttest A Simple Experiment Treatment B Posttest

8  Example: Lester and Gorzalka (1988). Randomly assigned female rats to one of two treatment groups: Treatment Group A: Copulated with one male, then with a second male, and then with the original male again (i.e., 1, 2, 1). Treatment Group B: Copulated with one male, then with a second male, and then with a third male (i.e., 1, 2, 3).

9 Results: Treatment Group A Treatment Group B Mean Lordosis Duration (Minutes)

10 Conclusion: Females who lose sexual interest in males that they have previously copulated with will display renewed sexual interest when presented with a novel male.

11 2. Quasi-experimental studies  Designed to contrast two or more existing groups on a variable of interest.  Used when an experiment cannot be conducted due to ethical or practical limitations.  Participants are not randomly assigned to groups. As a result, causal conclusions cannot be drawn.

12  Example: Acker, Ron, Lishman, & Shaw (1984). Contrasted detoxified male alcoholics obtained from an alcoholism treatment centre to non- drinking males obtained from diverse sources. Found that the alcoholic sample: (a) performed relatively poorly on measures of perceptual, motor, and cognitive ability, and (b) had sustained brain damage, as revealed by brain scans. Possible confounds: Education level, number of head injuries, drug use, diet.

13 3. Correlational studies  Designed to examine the extent to which 2 naturally-occurring variables covary.  Correlations are typically measured by the Pearson product-moment correlation coefficient (r). This index measures the extent to which a linear relationship exists between 2 variables. Magnitude of r: strength of relationship between variables. Sign of r (+ vs. -): direction of relationship between variables.

14  Example: Morris, Udry, Khan-Dawood, and Dawood (1987). Examined the correlation between testosterone levels among midcycle women and frequency of sexual intercourse. Found a positive correlation of.62 (p<.01), indicating that higher midcycle testosterone levels are associated with greater frequency of sexual intercourse.

15 4. Case studies  Designed to examine a single case or subject.  An excellent source of testable hypotheses.  Example: Parkin (2003): “The case of NA and the perils of a miniature foil.”

16 What ethical considerations do biological psychologists face? Both human and nonhuman animals are the subject of biopsychological research. The use of nonhuman animals in biopsychological research is based on the assumption that there is evolutionary continuity in the brain. The comparison of biological processes and behaviour across species is referred to as the “comparative approach.”

17 Biological psychologists confront a host of ethical considerations when conducting research with both human and nonhuman subjects. Examples: Drug vs. placebo administration to humans with HIV. Cortical lesions among non-human primates.

18 The use of nonhuman subjects for studies that are not acceptable for humans continues to generate debate. Informative websites that are relevant to this debate are: onlineethics.org/reseth/mod/regan.html

19 Research Methods 1.What types of research methods do biological psychologists use? 2.What ethical considerations do biological psychologists face?