Diminishing marginal myopic loss aversion: A stress test on investment games experiments

We measure the marginal effects of two crucial dimensions of the Investment Game design of Gneezy and Potters (1997, GP97) and its replications: time frequency and time horizon. To this aim, we randomize between subjects five different time frequencies: 1 round (“High Frequency” in GP97), 3 rounds (“Low Frequency”), but also 6, 9 and 12 rounds. As for time horizon, we compare the baseline GP97 horizon (9 rounds) with smaller (3 and 6 rounds), but also higher (12 rounds) alternatives. We find that, holding the time horizon constant, subjects invest more when they evaluate their investments less frequently, but this result is significant only when time horizon is sufficiently long. We also find that lower frequencies increase the marginal investment at a decreasing rate. As for time horizon, we find that, holding time frequency constant, the higher the horizon, the lower the investment (although, as in the previous case, investment lowers at a decreasing rate). Our reduced form results also show that subjects’ behavior is sensitive to the endowment stock provided along the experiment, independently of time frequency.