| Abstract: |
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. |