Asking the Right Questions, A Guide to Critical Thinking, 8th Ed

140 Chapter 10
In this study, the researcher probably began with the hypothesis that eating
celery causes reduction of aggressive impulses, and he found evidence consistent
with that hypothesis. But let us offer several rival, or different, causes
for the same findings.
1. Research participants were highly suggestible, and the expectation of low
levels of aggression was responsible for the reported differences; like the
sugar pill placebo effect in medicine, believing that eating celery lowers
aggression might have stimulated a number of physical and mental
processes that caused participants to feel less aggression.
2. Participants wanted to please the researchers; thus, they reported feeling
low levels of aggression, even though they did experience some aggressive
feelings.
3. Nothing is known about the women involved in the study. It is entirely
plausible that those who eat celery are health conscious, and thus are
more likely to exercise. The increased amounts of exercise can be an outlet
for aggression, and thus lower feelings of aggression. Those who do
not eat celery regularly may not exercise as often and thus do not have an
outlet for their aggression.
Now, let's leave the research laboratory for a moment and move to the
national pages of our newspapers and examine an argument related to crime
statistics.
Since 1993, the levels of serious violent crime in the United States have decreased
steadily. It is obvious that the heavy focus we place on law enforcement is no longer
necessary. People are becoming civic minded and are choosing to no longer pursue
a life of crime. Money spent on law enforcement can now better be spent elsewhere.
The hypothesis offered by the writer is that people's increasing civic engagement
is the cause of the decrease in violent crimes over the last 12 years. But, let's again
generate some plausible rivalcauses:
1. Violent crime rates have decreased because of the increased focus on law
enforcement the writer is specifically calling to be cut. An increased
concern with law enforcement, and not the civic concerns of citizens,
caused violent crime levels to decrease.
2. Recent legislative actions have increased the punishments associated with
violent crimes. These increased punishments make the costs of committing
a violent crime far outweigh the benefits of committing violent
crimes. People are not more civic minded, rather they are looking out for
their own personal interests.