A behavioral reinvestigation of the effect of long ties on social contagions

Faced with uncertainty in decision making, individuals often turn to their social networks to inform their decisions. In consequence, these networks become central to how new products and behaviors spread. A key structural feature of networks is the presence of long ties, which connect individuals who share few mutual contacts. Under what conditions do long ties facilitate or hinder diffusion? The literature provides conflicting results, largely due to differing assumptions about individual decision-making. We reinvestigate the role of long ties by experimentally measuring adoption decisions under social influence for products with uncertain payoffs and embedding these decisions in network simulations. At the individual level, we find that higher payoff uncertainty increases the average reliance on social influence. However, personal traits such as risk preferences and attitudes toward uncertainty lead to substantial heterogeneity in how individuals respond to social influence. At the collective level, the observed individual heterogeneity ensures that long ties consistently promote diffusion, but their positive effect weakens as uncertainty increases. Our results reveal that the effect of long ties is not determined by whether the aggregate process is a simple or complex contagion, but by the extent of heterogeneity in how individuals respond to social influence.