The Effect of a Short Planning Horizon on Intertemporal Consumption Choices

Previous experimental results (Ballinger et al. (2003) and Carbone and Hey (2004)) have found that many agents fail to correctly take into account the length of the planning horizon also finding some support (See Carbone (2006)) for descriptive models, such as the Rolling Model. This paper presents an experimental analysis on the effect of a short planning horizon on intertemporal consumption choices. The purpose of the study is to test whether very short horizons are more easily perceived by agents, allowing them to plan optimally. This experiment tests a somewhat implicit assumption of the Rolling Model, or of similar descriptive approaches, namely that people might be able to use the optimal strategy if they are faced with shorter planning horizons. Moreover, this hypothesis is tested in the cases of decision making under certainty, risk and uncertainty, in order to analyze how these environments may affect the perception of the length of the planning horizon. Results suggest that planning periods have a significant effect on deviations from unconditional optimum in all sequences and all treatments. This finding has been interpreted as evidence of participants not using the optimal strategy. When conditional deviations are considered, results are confirmed only in the case of decision making under uncertainty. This second finding has been interpreted as suggesting that uncertainty on income seems to prevent participants from improving their decision making.