A canonical but untested assumption in economics is that choices are determined only by preferences and budget constraints, but not by how people approach decision making. In particular, it is believed that people behave “as if they optimized”, even if they do not engage in any formal...

Large variations in retirement wealth are common, with some households accumulating hundreds of thousands of dollars and others accumulating next to nothing. We examine to what extent formal planning or simple rules of thumb contribute to these differences in wealth accumulation. In particular,...