  The assessment of trust between users is essential for collaboration. General
reputation and ID mechanisms may support users' trust assessment. However,
these mechanisms lack sensitivity to pairwise interactions and specific
experience such as betrayal over time. Moreover, they place an interpretation
burden that does not scale to dynamic, large-scale systems. While several
pairwise trust mechanisms have been proposed, no empirical research examines
trust score influence on participant behavior. We study the influence of
showing a partner trust score and/or ID on participants' behavior in a
small-group collaborative laboratory experiment based on the trust game. We
show that trust score availability has the same effect as an ID to improve
cooperation as measured by sending behavior and receiver response. Excellent
models based on the trust score predict sender behavior and document
participant sensitivity to the provision of partner information. Models based
on the trust score for recipient behavior have some predictive ability
regarding trustworthiness, but suggest the need for more complex functions
relating experience to participant response. We conclude that the parameters of
a trust score, including pairwise interactions and betrayal, influence the
different roles of participants in the trust game differently, but complement
traditional ID and have the advantage of scalability.
