Political
identification is the basis of enduring conflict, suggesting that political
attitudes are difficult to change. Here we show that in the 2016 U.S.
Presidential Election, political identities underwent modification in response
to salient political events. We investigate these dynamics in detail by
collecting data at periodic intervals from mid-June 2016 through the general
election (N = 3,958). We operationalize identification using prosocial giving
in Dictator Games played between supporters of competing primary candidates
recruited from Amazon Mechanical Turk. The observed dynamics differed across
political parties. In-group bias among Democrats remained high until the
Democratic National Convention, disappeared shortly thereafter, and then
returned during the final stage of the election. Bias among Republicans was
generally high until the final days of the election. The late resurgence of
bias among Democrats was not reflected in voting intentions, but may have
presaged the Democratic election loss