Critical Thinking in Biology
Case Example: Brain and Behavior
This case introduces the concept of testability.
A common impediment to scientific progress is failure to frame testable questions. Pseudoscience may employ untestable metaphors as explanations for alleged healing powers and may invoke unmeasurable variables. (Wilhelm Reich, the psychotherapist, championed "orgone rays," touch therapists cite "energy fields," traditional Chinese medicine cites qi, and traditional Indian medicine (Ayurveda) cites the tridosha.)
An example follows:
Why do some people have little difficulty quitting smoking? Well, the answer is Will Power. This is what psychotherapists term "intrinsic motivation” (motivation coming from within the person) an underlying need for competence and self-determination.
1) How would you decide if this claim were justified?
2) How would you investigate the claim?
a. Use any background knowledge you have to suggest test of an alternate hypothesis that might occur to you.
ANALYSIS OF A BIOLOGY NEWS REPORT
Case Example: Reproductive Health
This case provides skills and practice in evaluating a report of a scientific investigation, and introduces students to the need for evidence-based medicine.
Exposure of students to a diversity of health care claims is an important component of a biology education. Health care is a multi-billion dollar biology-based industry, but with many examples of pseudoscience, deception and fraud. Scientific reasoning is an indispensable tool for the citizenry in evaluating health care claims.
Alternative therapies such as homeopathy, reflexology, acupressure, and therapeutic touch are often of interest to us and our families, and can be critically examined in a biology course on a topical basis, e.g., iridology when studying the biology of the eye. We can critique the evidence for alternative medicine against a rigorous scientific protocol. Pathologist and consumer advocate Marcia Angell has repeatedly stated that there are but two kinds of medicine: that which has been adequately tested and that which has not (Angell and Kassirer 1998).
Example:
Your task is to decide whether or not the claim in the report is justified by the evidence cited in the report.
The 11 November 1998 issue of the Journal of the American Medical Association reported that a Chinese remedy used on pregnant women improves the position of the fetus for an easier birth. The treatment reduces the risk of breech (rump-first) births.
The treatment involved heating an acupuncture point upon the smallest toe ("moxibustion"). Two hundred and sixty women with poorly positioned fetuses were studied. Half of the women were randomly selected to receive moxibustion. The other women ["controls"] received no treatment. The investigators found that the untreated women had significantly more breech births. The authors stated that previously no randomized controlled trial [like this one] had ever been conducted.
Form your decision using the following five criteria:
Outcome measure: Was the promised treatment outcome actually measured to determine if it occurred?
Control: Was the outcome of the treatment group compared to the outcome of an otherwise similar untreated group?
Replication: Was the treatment replicated, that is tested on an adequate number of subjects to rule out coincidence?
Randomization: Were subjects assigned to the treatment or control in an unbiased manner?
Reproducibility: Has other research produced similar evidence?
Plausibility: Are the results consistent with established science?