RACHEL MARTIN, HOST:
So when you recycle paper or an empty bottle, do you get that warm little feeling because maybe you think, hey, I've done something right for the world? Well, maybe you shouldn't get that feeling because there's some new social science research out there that suggests recycling can have a downside. Why are you always bringing negative news?
SHANKAR VEDANTAM, BYLINE: (Laughter).
MARTIN: Shankar Vedantam, NPR social science correspondent, here to rain on our recycling parade. Hi, Shankar.
VEDANTAM: Hi, Rachel.