Andrew Gelman's recent post on distinguished researchers who did less than distinguished work for the tobacco industry reminded me that I've been meaning to do some posts on Robert B. Cialdini's Influence (either the textbook or the mass market edition. They're both pretty much interchangeable).
For those not familiar with the book, Cialdini takes some well-established principles of influence such as the impulse to reciprocate and shows how these effects can be seen in psychological studies, historical anecdotes, news stories, everyday incidents and, most famously, marketing campaigns, then he wraps up by putting things into an evolutionary psych context that, God help me, actually appeals to common sense.
There's a lot of cool stuff in Cialdini's book (just the part about the "brainwashing" of Korean War POWs is worth the price of admission), but the relevant points for the Gelman post are:
1. When you give a researcher money while nominally refusing to dictate results (which, I suspect is how this normally works), you create a sense of obligation. This leads to cognitive dissonance -- the researchers wants to see him or herself as honest but at the same time wants to repay the company, which can only be done through bad research. The dissonance is often resolved by adjustment of personal beliefs (the researcher convinces him or herself that the research really does back up the company's position).
2. People tend to underestimate how much and how easily they can be influenced. Doctors insist that small gifts from drug companies don't influence them despite numerous studies that show the technique to be highly effective.
3. Subsidized research is dangerous.
I'm working from memory here and not doing Cialdini justice. He has tons of supporting evidence and numerous persuasive examples of these phenomena. Fascinating book, particularly for anyone with a marketing background. If I ever get caught up, I'll have more posts on this.
UPDATE: based on some feedback, I refined my position somewhat in the comments section.