Transcript What types of research methods do biological psychologists use?

Psychology 304:
Brain and Behaviour
Lecture 2
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Research Methods
1. What types of research methods do biological
psychologists use?
2. What ethical considerations do biological psychologists
face?
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What types of research methods do biological
psychologists use?
• Biological psychology relies upon the scientific method—
that is, systematic and objective observation.
• Several steps are involved in conducting research using
the scientific method:
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Theory
Hypothesis
Operationalization
Interactive
Relationship
Research
Data
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• Biopsychological research involves four types of
studies.
1. Experimental studies
 Designed to examine cause and effect relationships
between variables.
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 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.
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A Simple Experiment
Group A
Participants
Treatment A
Posttest
Random Assignment
Group B
Treatment B
Posttest
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 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).
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Results:
Mean Lordosis
Duration (Minutes)
Treatment Group A
35
Treatment Group B
35
30
30
25
25
20
20
15
15
10
10
5
5
0
0
1st Qtr
Male 1
Male 2
1st Qtr
Male 1
Male 1
Male 2
Male 3
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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.
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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.
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 Example: Acker, Ron, Lishman, & Shaw (1984).
Contrasted detoxified male alcoholics obtained
from an alcoholism treatment centre to nondrinking 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.
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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.
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 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.
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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.”
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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.”
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• 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.
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• 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:
www.apa.org/science/anguide.html
www.the-aps.org/pa/humane/pa_resource.htm
www.fbresarch.org/About/FAQ.htm
onlineethics.org/reseth/mod/regan.html
www.stopanimaltests.com
www.peta.org/about/faq-viv.asp
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Research Methods
1. What types of research methods do biological
psychologists use?
2. What ethical considerations do biological psychologists
face?
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