  Increasingly, crowdfunding is transforming financing for many people
worldwide. Yet we know relatively little about how, why, and when funding
outcomes are impacted by signaling between funders. We conduct two studies of
N=500 and N=750 participants involved in crowdfunding to investigate the effect
of certain characteristics of ``crowd signals'' on the decision to fund. We
find that, under a variety of conditions, contributions of heterogeneous
amounts arriving at varying time intervals are significantly more likely to be
selected than homogeneous contribution amounts and times. The impact of
signaling is strongest among participants who are susceptible to social
influence. The effect is remarkably general across different project types,
fundraising goals, participant interest in the projects, and participants'
altruistic attitudes. Critically, the role of crowd signals in decision-making
is typically unrecognized by participants. Our results underscore the
fundamental nature of social signaling in crowdfunding, informing strategies
for platforms, funders, and project creators.
