Time magazine presents a story this month about a line of research on materialism. The full story is accessible here.

One of the studies conducted by the research team, led by psychologist Galen Bodenhausen, was on the effect of calling people "consumers" versus "individuals."

In one of the study’s tests, participants were presented with the following hypothetical scenario: There is a water shortage, and four people (including the participants) must share a well. Sometimes in the experiment, participants were called “consumers,” and other times they were referred to as “individuals.” And apparently, words can be powerful.

The “consumers” rated themselves as less trusting of others to conserve water, less personally responsible and less in partnership with the others in dealing with the crisis. The consumer status, the authors concluded, “did not unite; it divided.”

a) In this experiment, what was the independent variable ? What was the dependent variable?

b) Because this is an experiment, you may be able to make a causal claim from this research. What would the causal claim be?

c) What internal validity concerns might you raise about this study? If you were the authors, how would you have ensured internal validity in this experiment?