Russel-Research-Method-in-Anthropology

130 Chapter 5
each sexual act; (2) They sometimes use condoms; or (3) They don’t use condoms
at all. Let the experiment run a few years. Then see how many of the
couples in which condoms are always used remain serodiscordant and how
many become seroconcordant—that is, they are both HIV-positive. Compare
across conditions and see how much difference it makes to always use a
condom.
Clearly, no one could conduct this experiment. But Davis and Weller
scoured the literature on condom efficacy and found 25 studies that met three
criteria: (1) The focus was on serodiscordant heterosexual couples who said
they regularly had penetrative sexual intercourse; (2) The HIV status of the
participants in each study had been determined by a blood test; and (3) There
was information on the use of condoms. The 25 studies involved thousands of
participants, and from this meta-analysis Davis and Weller established that
consistent use of condoms reduced the rate of HIV transmission by over 85%.
If you look around, there are natural experiments going on all around you.
On January 1, 2002, 12 of the 15 members of the European Union gave up
their individual currencies and adopted the euro. Greece was one of the 12,
Denmark wasn’t. Some researchers noticed that many of the euro coins were
smaller than the Greek drachma coins they’d replaced and thought that this
might create a choking hazard for small children (Papadopoulos et al. 2004).
The researchers compared the number of choking incidents reported in Danish
and Greek hospitals in January through March from 1996 through 2002. Sure
enough, there was no increase in the rate of those incidents in Denmark (which
hadn’t converted to the euro), but the rate in Greece suddenly more than doubled
in 2002.
True Experiments in the Lab
Laboratory experiments to test theories about how things work in the real
world is the preeminent method in social psychology. Cognitive dissonance
theory, for example, predicts that people who come out of a tough initiation
experience (marine recruits at boot camp, prisoners of war, girls and boys who
go through genital mutilation, etc.) wind up as supporters of their tormentors.
In a classic experiment, Elliot Aronson and Judson Mills (1959) recruited 63
college women for a discussion group that ostensibly was being formed to talk
about psychological aspects of sex. To make sure that only mature people—
people who could discuss sex openly—would make it into this group, some
of the women would have to go through a screening test. Well, that’s what
they were told.
A third of the women were assigned randomly to a group that had to read a