underachievement; effectivity praise for effort is reinforced?

Don't praise your child for their intelligence, but do praise them for their effort says this article on praising intelligent children describing one of the origins of underachievement. I would say there is also a reward-angle to this. The reward is bigger when effort is emphasised as contributing to the successful solution of a problem than when there is no relation to effort. This means there is a reinforcement of the effect reported in the article.