Resistance is futile. At least that's what Dr. Eric Knowles, a professor of social psychology at the University of Arkansas, is trying to prove, reports The Economist. Knowles compares resistance to water in a tank. It is "in some sense a thing and can thus be used up and replenished," he says. "The task of the persuader is to drain the tank. That of the consumer is to keep it full enough to resist undesirable changes." Though some worry that this knowledge can be used coercively, Knowles argues that it has educational value. And with politicians and salesmen using persuasive tricks already, "Who can afford not to read on?"