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. 2011 Apr 26;108(17):6889-92.
doi: 10.1073/pnas.1018033108. Epub 2011 Apr 11.

Extraneous factors in judicial decisions

Affiliations

Extraneous factors in judicial decisions

Shai Danziger et al. Proc Natl Acad Sci U S A. .

Abstract

Are judicial rulings based solely on laws and facts? Legal formalism holds that judges apply legal reasons to the facts of a case in a rational, mechanical, and deliberative manner. In contrast, legal realists argue that the rational application of legal reasons does not sufficiently explain the decisions of judges and that psychological, political, and social factors influence judicial rulings. We test the common caricature of realism that justice is "what the judge ate for breakfast" in sequential parole decisions made by experienced judges. We record the judges' two daily food breaks, which result in segmenting the deliberations of the day into three distinct "decision sessions." We find that the percentage of favorable rulings drops gradually from ≈ 65% to nearly zero within each decision session and returns abruptly to ≈ 65% after a break. Our findings suggest that judicial rulings can be swayed by extraneous variables that should have no bearing on legal decisions.

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Conflict of interest statement

The authors declare no conflict of interest.

Figures

Fig. 1.
Fig. 1.
Proportion of rulings in favor of the prisoners by ordinal position. Circled points indicate the first decision in each of the three decision sessions; tick marks on x axis denote every third case; dotted line denotes food break. Because unequal session lengths resulted in a low number of cases for some of the later ordinal positions, the graph is based on the first 95% of the data from each session.
Fig. 2.
Fig. 2.
Proportion of favorable decisions for male felons with a rehabilitation program as a function of ordinal position, months served, and previous incarcerations. These histograms reflect the first three versus the last three decisions collapsed over the three decisions sessions. They are for illustrative purposes and are based on a subsample of the data. Plus signs (+) indicate cell sizes of <20. (A) Data for prisoners with no previous incarcerations. (B) Data for prisoners with one previous incarceration. Asterisks indicate results of a difference between proportions test. *P < 0.1, **P < 0.05, ***P < 0.01.
Fig. 3.
Fig. 3.
Mean level of control variables by ordinal position. Circled points indicate the first decision in each of the three sessions; tick marks on x axis denote every third case; dotted lines denote food break. (A) Data for gravity of offense. (B) Data for previous incarcerations. (C) Data for months served. (D) Data reflecting the proportion of prisoners with a rehabilitation program. Because unequal session lengths resulted in a low number of cases for some of the later ordinal positions, the graphs are based on the first 95% of the data from each session.

Comment in

  • Overlooked factors in the analysis of parole decisions.
    Weinshall-Margel K, Shapard J. Weinshall-Margel K, et al. Proc Natl Acad Sci U S A. 2011 Oct 18;108(42):E833; author reply E834. doi: 10.1073/pnas.1110910108. Epub 2011 Oct 10. Proc Natl Acad Sci U S A. 2011. PMID: 21987788 Free PMC article. No abstract available.

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