Ad-hoc contracting allows to quickly react to changes which could be neglected or noticed too late in case of constant contracting. But always deciding anew, e.g., how much and what to order in commercial and what to buy in private life, is too cumbersome. To capture the cognitive burden of...

Overall, 72 subjects invest their endowment in four risky assets. Each com-bination of assets yields the same expected return and variance of returns. Illusion of expertise prevails when one prefers nevertheless the self-selected portfolio. After being randomly assigned to groups of four...