  Group discussions are a way for individuals to exchange ideas and arguments
in order to reach better decisions than they could on their own. One of the
premises of productive discussions is that better solutions will prevail, and
that the idea selection process is mediated by the (relative) competence of the
individuals involved. However, since people may not know their actual
competence on a new task, their behavior is influenced by their self-estimated
competence --- that is, their confidence --- which can be misaligned with their
actual competence.
  Our goal in this work is to understand the effects of confidence-competence
misalignment on the dynamics and outcomes of discussions. To this end, we
design a large-scale natural setting, in the form of an online team-based
geography game, that allows us to disentangle confidence from competence and
thus separate their effects.
  We find that in task-oriented discussions, the more-confident individuals
have a larger impact on the group's decisions even when these individuals are
at the same level of competence as their teammates. Furthermore, this
unjustified role of confidence in the decision-making process often leads teams
to under-perform. We explore this phenomenon by investigating the effects of
confidence on conversational dynamics.
