We present a model and a laboratory experiment on the informativeness of
debate, varying both informational and institutional variables. The
informational variable we focus on is a novel factor affecting the extent to
which audience members can learn from exposure to unpersuasive arguments.
The more easily a listener can learn from an argument she finds
unpersuasive, the greater the risk that the speaker will alienate this
listener when she fails to persuade her. We find a strong interaction
between speakers’ responsiveness to that risk and the institutions of
debate. When listeners can learn from unpersuasive arguments, many speakers
are discouraged from attempting persuasion, irrespective of the debate rules
we consider. In contrast, when listeners cannot learn from unpersuasive
arguments, debate rules affect speakers’ willingness to engage in
persuasion.