Mark Lepper: 3 ideas worth knowing

3 ideas from Mark Lepper, each explained in a minute and credited to the original work. Free on Savvy.

Paying kids to draw made them draw less for fun
In a classic experiment, children who already loved drawing were split into groups: some got an expected reward for drawing, some got an unexpected reward, and some got none. Only …
— Mark R. Lepper, David Greene & Richard E. Nisbett, Undermining Children's Intrinsic Interest with Extrinsic Reward: A Test of the 'Overjustification' Hypothesis
Even after you're told the evidence was fake, the belief it created sticks
Researchers gave people false feedback on a task, then fully explained the feedback had been randomly assigned and meant nothing. People's opinions of their own ability barely move…
— Lee Ross, Mark Lepper & Michael Hubbard, Perseverance in Self-Perception and Social Perception: Biased Attributional Processes in the Debriefing Paradigm
A grocery store display with fewer jams sold ten times more of them
Sheena Iyengar and Mark Lepper set up tasting booths offering either 6 or 24 flavors of jam. The bigger display drew more browsers, but only 3% of them bought a jar — versus 30% at…
— Sheena Iyengar, Mark Lepper, When Choice is Demotivating: Can One Desire Too Much of a Good Thing?

Five ideas worth knowing, every week