Saw this on the Beeb and thought it was interesting. Does it tally with experiences?
I know my naturally competitive DS gets a buzz out of being top, keeps a mental league table for just about everything, and quickly gives up on anything he feels he's not very good at.
Also curious as to how the effect plays out in selective grammar schools? Do all those high flying boys get a wake up call once they're among others with similar attainment, or does the fact that they've been 'selected' in the first place carry them through on a high?