[alexbock]

They performed this with and without that payment.

"This paper reports results from two novel experiments designed to distinguish sincere from expressive partisan differences in responses to factual questions. In both experiments, all subjects were asked factual questions, but some were given financial incentives to answer correctly. ... In our second experiment, we therefore implement a treatment in which subjects were offered incentives both for correct responses and for admitting that they did not know the correct response."

[throwaway729]

But if there's no payout then there's no incentive to say don't know. Whereas if there is a payout then the optimal strategy is clearly "dont know", assuming equal payouts for correct and dont know. Why would you take the risk of being wrong?

[hx87]

Quote from paper:

> The amount paid for “don’t know” responses was also assigned randomly, and was a fraction of the amount offered for a correct response: 20% of the payment for a correct response with probability .33, 25% with probability .33, and 33% with probability .33.

[throwaway729]

Thanks, that's exactly what I was looking for but it's hard on a phone.

Qwrusz's comment may be relevant here.