Severity of prescribed penalty and mock jurors' verdicts.

An analogy between the process of reaching a verdict by an individual juror and the testing of a statistical hypothesis leads to the predictions that as the severity of the prescribed penalty for an offense is increased, the amount of evidence required by jurors to convict will also increase and the probability of conviction will decrease. A review of the literature suggests that while historical, anecdotal, and field evidence seems to favor the latter prediction, the extant experimental work has offered little support. A study was performed with 449 undergraduates to experimentally test the predictions. The conviction rate for individual mock jurors was inversely related to the severity of the prescribed penalty, as predicted. A previous failure to confirm this prediction was attributed to an inappropriate choice of response scale. An analysis employing E. Thomas and A. Hogue's (1976) model confirmed the prediction that more evidence of guilt would be required for conviction when the prescribed penalty was severe. Thus, increasing penalties for criminal offenses may actually lower the percentage of convictions for those offenses.