<p>For PhD programs in behavioral economics, would it be better to double major in psychology and economics, or major in econ, with minors in psych and math?</p>
<p>I'd say go for the math and econ. You will be better prepared for rigourous work in microeconomics, experimental economics and game theory which are the main tools of behavioural economists. You'll also be better prepared for graduate school admissions, because without a significant amount of math on your transcript you may have trouble getting into a decent Ph.D program.</p>