Russel-Research-Method-in-Anthropology

112 Chapter 5
Dependent variables in people can be physical things like weight, height,
systolic blood pressure, or resistance to malaria. They can also be attitudes,
moods, knowledge, or mental and physical achievements. For example, in
weight-loss programs, you might measure the ratio of body fat to body mass
as the dependent variable. If you are trying to raise women’s understanding of
the benefits of breast-feeding by exposing them to a multimedia presentation
on this topic, then a preliminary test of women’s attitudes about breast-feeding
before they see the presentation is an appropriate pretest for your experiment.
You don’t always need a pretest. More on this in a bit, when we discuss
threats to validity in experiments.
Step 4.
The intervention (the independent variable) is introduced.
Step 5.
The dependent variables are measured again. This is the posttest.
A Walkthrough
Here’s a made-up example of a true experiment: Take 100 college women
(18–22 years of age) and randomly assign them to two groups of 50 each.
Bring each woman to the lab and show her a series of flash cards. Let each
card contain a single, three-digit random number. Measure how many threedigit
numbers each woman can remember. Repeat the task, but let the members
of one group hear the most popular rock song of the week playing in the
background as they take the test. Let the other group hear nothing. Measure
how many three-digit numbers people can remember and whether rock music
improves or worsens performance on the task.
Do you think this is a frivolous experiment? Many college students study
while listening to rock music, which drives their parents crazy. I’ll bet that
more than one reader of this book has been asked something like: ‘‘How can
you learn anything with all that noise?’’ The experiment I’ve outlined here is
designed to test whether students can, in fact, ‘‘learn anything with all that
noise.’’
Of course, this experiment is very limited. Only women are involved. There
are no graduate students or high school students. There’s no test of whether
classic rock helps or hinders learning more than, say, rhythm and blues, or
country music, or Beethoven. And the learning task is artificial. What we
know at the end of this experiment is whether college-age women learn to
memorize more or fewer three-digit numbers when the learning is accompanied
by a single rock tune.