Urban income segregation is a widespread phenomenon that challenges societies across
the globe. Classical studies on segregation have largely focused on the geographic
distribution of residential neighborhoods rather than on patterns of social behaviors
and interactions. In this study, we analyze segregation in economic and social interactions
by observing credit card transactions and Twitter mentions among thousands of individuals
in three culturally different metropolitan areas. We show that segregated interaction
is amplified relative to the expected effects of geographic segregation in terms of
both purchase activity and online communication. Furthermore, we find that segregation
increases with difference in socio-economic status but is asymmetric for purchase
activity, i.e., the amount of interaction from poorer to wealthier neighborhoods is
larger than vice versa. Our results provide novel insights into the understanding
of behavioral segregation in human interactions with significant socio-political and
economic implications.
