My thinking on this topic dates back well before the Alfie Kohn book, to the early 1980s when I ran into a great article on "gaming" incentive plans.

The article presented long strings of attempts to come up with a metric that couldn't be gamed, always ending in failure. If the metric called for more production, the workers produced quantity over quality. If the metric only counted "good" units, the workers sped the line up enough to hit the metric (even if it meant producing even more bad units). If the metric put a ceiling on failed units, the workers slowed the line down enough to stay under the ceiling. And so on.

The article was compelling because, faced with workers finding a way around the metric, the reader automatically said, "Well, of course--but you could solve that by making the metric be X." Except that the article was always one or two steps ahead of you, coming up with that metric, and the reporting on how it was evaded by workers at some plant or office. It was really quite humbling to find that all your ideas had been tried and found wanting.

Sadly, I saw that article in some paper journal, and I don't remember enough about it to find it again.

Really, though, I base most of this on my own experience. I've just seen too many incentive plans over the years. I've seen some that were severely de-motivating, and I've seen others that were only a little de-motivating. I've seen some that paid out large bonuses (which are great to get), and I've seen others that paid no bonus at all. But I've never seen one that made employees more creative or more collaborative. I've never seen one that made employees try harder to produce good products or please the customer. All the plans I've seen either did nothing (except waste some time and generate some grumbling and ill-will) or else caused workers to spend time doing stuff that was something other than the most useful thing they could have been doing. (Because, after all, if it hadn't been for the incentive plan, that's what they would have been doing.)

Alfie Kohn's book was important in the evolution of my own thinking on this topic, though. The article I mention, and my own experience, offered some emperical evidence that incentive plans don't work. Kohn's work, though provides a basis for understanding why they don't work. With that understanding, it's not such a big jump to conclude that they never work (for any job that's not utterly trivial).