Risk aversion can be defined either by the negative sign of the second derivative of the utility function or by the rejection of any mean-preserving increase in risk. The more recent notions of prudence and temperance have so far been defined exclusively by the sign of the third and the fourth...

Since Fishburn and Porter [1976], it has been known that a first- order dominant shift in the distribution of random returns of an asset does not necessarily induce a risk-averse decision maker to increase his holdings of that improved asset. To obtain the desired comparative statics result, one...