We conduct experiments in urban slums to measure trust and cooperation and to see how behavior varies with demographic factors and associational measures of social capital. Overall, we find high contribution rates among Thai and Vietnamese participants in a voluntary contribution game, and we see that many participants are willing to signal their disapproval of free riding despite it being costly to do so. At the individual level, we find that behavior varies with many demographic factors and with many associational factors. However, these correlations often differ significantly between our two locations, indicating the role of culture, defined broadly.