The streak-end rule: How past experiences shape decisions about future behaviors in a large-scale natural field experiment with volunteer crisis counselors

Decisions about future behaviors are clearly shaped by the content of past experiences, but whether the order of past experiences matters remains controversial. By analyzing the largest field experiment about prosocial behavior to date, a natural field experiment involving 14,383 volunteer crisis counselors over five years, we examine how the content and order of past experiences causally influence decisions about future behaviors — whether individuals continue volunteering or quit. Volunteers were repeatedly and randomly assigned to perform 1,976,649 prosocial behaviors that were either harder (suicide conversations) or easier (non-suicide conversations). We found that the content of past experiences mattered: Harder (versus easier) behaviors encouraged quitting. However, the order of past experiences mattered far beyond their content alone: Harder behaviors caused disproportionately more quitting if they came in long “streaks” or at the “end.” These “streak”/“end” effects reveal important practical insights for leaders and policymakers seeking to boost prosocial behavior. For instance, a reordering intervention — assigning behaviors so as to avoid creating hard “streaks” — would reduce volunteer quitting rates by at least 22%, boosting prosocial behavior and likely saving lives.