The Benefits of Knowledge: Mortality and Sexual Behaviour

Recent improvements in adult life expectancies in high HIV-prevalence sub-Saharan African low-income countries have reversed previous adverse trends in adult survival during the 1990s and early 2000s when the HIV/AIDS epidemic considerably reduced life expectancies. Despite these improvements, many individuals are overly pessimistic about their own survival. The presented paper provides evidence from a randomized controlled trial that provided mature adults with information about population-level mortality in Malawi. We find that one year after the intervention, treated individuals have updated upward their beliefs about the survival of others but not their own survival. Despite the lack of revising own survival probabilities, we observe changes in behavior which seems to be driven by the externalities of other people (including HIV+) living longer. The magnitude of the effect is rather large. The predicted probability of having multiple partners is 1.5 percentage point lower in the treatment group, or 15% with respect to the baseline proportion. These findings suggest that providing information about population-level mortality influences forward-looking decisions and might be a useful policy tool to reduce risky sex in sub-Saharan Africa.