Economists have long argued that we should pay a lot more attention to what people do and a lot less attention to what people say.  But they make little effort to justify their pro-action/anti-talk position.  The strongest support for economists’ methodological scruples actually comes from psychology, especially research on Social Desirability Bias.  Earlier today, though, I stumbled on some striking confirmation from a unexpected field: medicine. 

Choi, Riper, and Thoyre, “Decision Making Following a Prenatal Diagnosis of Down Syndrome: An Integrative Review” (Journal of Midwifery and Women’s Health, 2012) meta-analyzes research on women’s decision to abort a fetus with Down Syndrome.  As their decision becomes less and less hypothetical, women are more likely to opt for abortion.  In other words, Social Desirability Bias declines as the cost of doing what sounds good (accepting a mentally disabled child) rises:

The decision to undergo an induced abortion varied depending on whether participants were prospective parents recruited from the general population (23%-33% would terminate), pregnant women at increased risk for having a child with DS (46%-86% would terminate), or women who received a positive diagnosis of DS during the prenatal period (89%-97% terminated).

These are huge effects.  A supermajority of prospective parents says they would not terminate the pregnancy – but an even more lop-sided supermajority of parents who actually face this tragic choice takes the opposite stance. 

My question: Why do so many economists rely on half-baked philosophy of science to justify their pro-action/anti-talk position when fully-baked supportive empirical research is only a Google Scholar search away?