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Quarterly Journal of Economics Vol. 135 No. 2 2020

Choice Simplification: A Theory of Mental Budgeting and Naive Diversification*

Botond Kőszegi1; Filip Matějka2

1 Central European University · 2 CERGE-EI, a joint workplace of Charles University in Prague and the Economics Institute of the Czech Academy of Sciences

open access

Abstract

We develop a theory of how an agent makes basic multiproduct consumption decisions in the presence of taste, consumption opportunity, and price shocks that are costly to attend to. We establish that the agent often simplifies her choices by restricting attention to a few important considerations, which depend on the decision at hand and affect her consumption patterns in specific ways. If the agent’s problem is to choose the consumption levels of many goods with different degrees of substitutability, then she may create mental budgets for more substitutable products (e.g., entertainment). In some situations, it is optimal to specify budgets in terms of consumption quantities, but when most products have an abundance of substitutes, specifying budgets in terms of nominal spending tends to be optimal. If the goods are complements, in contrast, then the agent may—consistent with naive diversification—choose a fixed, unconsidered mix of products. And if the agent’s problem is to choose one of multiple products to fulfill a given consumption need (e.g., for gasoline or a bed), then it is often optimal for her to allocate a fixed sum for the need.

DOI
10.1093/qje/qjz043
Volume
135
Issue
2
Pages
1153-1207
Language
en
Sources
bibtex:phds-export.bib openalex crossref

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