While writing a post on the roles of personalization in email marketing I came across an interesting series of studiesover at Psyblog suggesting that promising rewards can have negative effects on overall performance in both children and adults. This has interesting implications for email marketers who often base their campaigns on "reward" models, where subscribers are likely to get something for signing up.

Lepper et al., 1973found that a series of children were given rewards for drawing. Those who were told before they started drawing that they would be rewarded drew less over the next several days; those told after the initial drawing session drew about twice as much over the next six days; and those surprised by the reward drew the most (though only a few percent more than the second group).

Similarly studies of adult smokers (Curry et al., 2009) found that those rewarded performed well initially, but bell behind in the long run.

In email marketing a clear and defined promise can more readily entice readers to take a small action (like, say, sign up) but at the same time those who are already inclined to do so may be less likely to continue through in the long run.

On the other hand, surprising your audience with stuff like coupons and other intensives may have a positive effect, increasing long term interaction and customer relationship.

Well, it's something to test.