of an edutainment TV series. The series was the third season of MTV Shuga, a popular serial produced by MTV Staying Alive Foundation to provide information on HIV and change attitudes and behavior relating to HIV and risky sexual behavior more generally. The experiment covered over 5000 young men and women in 80 urban and peri-urban locations in South West Nigeria: 54 locations were randomly assigned to screen MTV Shuga, while the remaining 26 screened a different serial that involved a similar demographic but made no connections to HIV.

The first question we ask is whether MTV Shuga had the desired effects. We find striking effects on knowledge about sources of transmission of HIV and its treatment, on attitudes towards HIV+ people and on a range of behavioral outcomes (both self-reported and objectively measured) eight months or more after the showing. The likelihood of testing for HIV, objectively measured through redemption of a voucher that we distributed at health camps, increased by 3.1 percentage points in the treatment compared to the control group. This corresponds to a 100 percent increase over the control group mean. Analogous effects are estimated for the self-reported measure, where the likelihood of testing increases by 2.5 percentage points. Corresponding to this effect is an improvement in treated individuals’knowledge about HIV, including sources of transmission, awareness of anti-retroviral drugs, and the need to take a second HIV test after at least three months from the first (window period). These are topics specifically covered in MTV Shuga. The effects we estimate are robust to aggregating outcomes into indexes and to correcting for multiple hypothesis testing.

We find more nuanced effects on risky sexual behavior. On the one hand, the acceptability and reported incidence of concurrent sexual partnerships significantly decreased. On the other hand, MTV Shuga did not induce greater condom use, neither as reported by respondents nor as revealed in an experimental game that our subjects played in health camps. Despite the lack of effect on condom use, we do find significant impacts on a biomarker that proxies for unprotected sex with risky partners. The likelihood of testing positive for Chlamydia, a common STD, decreased by 55 percent in response to treatment for women in our sample (the impact on men is in the same direction but statistically insignificant). This is consistent with the reduction in the number of concurrent partners, and possibly with a more general shift away from risky behaviors.

MTV Shuga worked. The next question is why. To explore the importance of emotional involvement in the narrative, we make use of measures of viewer responses from the communication literature (Green and Brock, 2000; Murphy et al., 2011) that, to the best of our knowledge, have not been used in the economics literature before. In our endline survey we asked a battery of questions on how immersed in the story the respondent was while watching the show, and how much he or she identified with the characters. Using these we construct two indexes, ‘Transportation’and ‘Identification’, and we show that the treatment effects were stronger for viewers that had higher values of these indexes. While these interaction effects 2