The great equalizer? Mixed effects of social infrastructure on diverse encounters in cities

Casual encounters with diverse groups of people in urban spaces have been shown to foster social capital and trust, leading to higher quality of life, civic participation, and community resilience to hazards. To promote such diverse encounters and cultivate social ties, policymakers develop social infrastructure sites, such as community centers, parks, and plazas. However, their effects on the diversity of encounters, compared to baseline sites (e.g., grocery stores), have not been fully understood. In this study, we use a large-scale, privacy-enhanced mobility dataset of >120 K anonymized mobile phone users in the Boston area to evaluate the effects of social infrastructure sites on the observed frequencies of inter-income and inter-race encounters. Contrary to our intuition that all social infrastructure sites promote diverse encounters, we find the effects to be mixed and more nuanced. Overall, parks and social businesses promote more inter-income encounters, while community spaces promote more same-income encounters, but each produces opposite effects for inter-race encounters. Parks and community spaces located in low-income neighborhoods were shown to result in higher inter-income and inter-race encounters compared to ordinary sites, respectively, however, their associations were insignificant in high-income areas. These empirical results suggest that the type of social infrastructure and neighborhood traits may alter levels of diverse encounters.