Career concerns and ambiguity aversion

Why do people have ambiguity aversion, preferring, a gamble with a 50% chance of success to one whose expected probability of success is 50% but where that 50% is an unbiased estimate? The answer modelled here, in the spirit of the career concerns literature, is learning: a risk-averse person does not wish observers to learn whether he is good or bad at estimating probabilities. He therefore prefers a gamble with objective probabilities. (C) 2010 Published by Elsevier B.V.