Interpersonal violence victimisation, HIV-related behaviours and STIs among adult, urban Indigenous and non-Indigenous gay, bisexual and other men who have sex with men in Guatemala.

Gay, bisexual and other men who have sex with men are disproportionately affected by HIV in Guatemala; interpersonal violence may increase behaviours that augment the risk of HIV in this group. Although 44% of Guatemalans identify as Indigenous, little information exists on the experiences of Indigenous sexual minority individuals. In this study, we sought to compare different forms of violence and HIV-related behaviours by Indigenous identity among gay, bisexual and other men who have sex with men; and determine if associations between violence and HIV-related behaviours differed by Indigenous identity.

Counter-Punishment, Communication, and Cooperation among Partners.

We study how communication affects cooperation in an experimental public goods environment with punishment and counter-punishment opportunities. Participants interacted over 30 rounds in fixed groups with fixed identifiers that allowed them to trace other group members' behavior over time. The two dimensions of communication we study are asking for a specific contribution level and having to express oneself when choosing to counter-punish.

Punish and voice: punishment enhances cooperation when combined with norm-signalling.

Material punishment has been suggested to play a key role in sustaining human cooperation. Experimental findings, however, show that inflicting mere material costs does not always increase cooperation and may even have detrimental effects. Indeed, ethnographic evidence suggests that the most typical punishing strategies in human ecologies (e.