Justice as a Rounding Error?: Evidence of Subconscious Bias in Second-Degree Murder Sentences in Canada

Abstract

There are few areas of law that grant judges as much discretion as the sentencing of criminal offenders. This discretion necessarily leads to concerns about the influence of biases, including those that result from subconscious processes associated with human cognition; that is to say, heuristics. In this article, the authors explore one heuristic-number preference-through an examination of all reported second degree murder parole ineligibility decisions between 1990 and 2012. Number preference leads individuals to predictably round off measurements to certain favoured numbers. The authors identify a tendency for parole ineligibility decisions to cluster around even numbers and multiples of five, without any obvious, legally-justifiable reason for such rounding. The authors propose that the phenomenon should cause concern not least because it suggests that other, less easily measurable but no less powerful, heuristics may also be at work in judicial decisions.