Have you considered the opposite? A debiasing strategy for judgment in criminal investigation
| Author | Ivar Fahsing,Asbjørn Rachlew,Lennart May |
| DOI | http://doi.org/10.1177/0032258X211038888 |
| Published date | 01 March 2023 |
| Date | 01 March 2023 |
| Subject Matter | Articles |
Article
The Police Journal:
Theory, Practice and Principles
2023, Vol. 96(1) 45–60
© The Author(s) 2021
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DOI: 10.1177/0032258X211038888
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Have you considered the
opposite? A debiasing strategy
for judgment in criminal
investigation
Ivar Fahsingand Asbjørn Rachlew
International Department Norwegian Centre for Human Rights, Faculty of Law, University of Oslo, Oslo,
Norway
Lennart May
Medical School Berlin, Berlin, Germany
Abstract
Fundamental challenges in human decision-making pose a serious threat to fair evidence
evaluation, verdicts in court proceedings, and the administration of justice. Drawing on
cognitive psychology, we examined whether a consider-the-opposite approach can assist
police officers with positive guidance on how to implement crucial legal thresholds such
as the presumption of innocence. In an experiment with sworn police officers (N= 100),
we compared a consider-the-opposite condition and a control condition (with no further
instructions) and measured the formulated alternative hypotheses. The results sho w a
promising debiasing effect of the consider-the-opposite approach which may strengthen
fundamental principles of criminal law.
Keywords
Criminal investigations, confirmation bias, debiasing, evidence evaluation, investigative
management
The presumption of innocence is an international human right contained in article 14(2) of
the International Covenant on Civil and Political Rights (ICCPR). The presumption of
innocence imposes on the prosecution the burden of proving the charge and guarantees
that no guilt can be presumed until the charge has been proved beyond reasonable doubt.
1
Corresponding author:
Lennart May, Medical School Berlin, Rüdesheimer Str. 50, Berlin 14197, Germany.
Email: mail@lennartmay.com
If reasonable doubt remains, the accused must be acquitted. The ancient legal principle in
dubio pro reo (Latin for "[when] in doubt, for the accused") dictates that when a criminal
statute allows more than one interpretation, the one that favors the defendant should be
chosen (Jackson, 1988;Klamberg, 2015;Roberts and Zuckerman, 2010). Jellema (2020)
claims that proven beyond reasonable doubt standard is confusing and in lack of an ep-
istemic fundament.Strong evidence indicatesthat legal fact-finders often struggle withhow
to bring forth these core principles of law (Kassin et al., 2003;Leo, 2008;Packer, 1968;
Scheck et al., 2000). We argue that without a clear methodological and evidence-based
guidance, the fundamental principles of the law might easily be forgotten or forsaken.
From a psychological perspective, these difficulties can be explained with heuristics
and cognitive biases (e.g., Fahsing, 2016;Findley and Scott, 2006; Kahneman and
Tversky, 1973). Concerning criminal investigations, Rossmo and Pollock stated (2019):
“Biases, because they are implicit, are difficult to control. They function independently of
one’s intelligence, and awareness of their dangers makes them no easier to avoid. [...] The
development and testing of de-biasing training should be an important focus of future
efforts to improve criminal investigations and reduce the frequency of wrongful con-
victions.”(p. 832). This study aims to develop such cognitive support in order to
counteract known shortcomings in detectives’professional decisions-making.
Cognitive pitfalls in criminal investigations
Psychological research can help us understand why it is difficult to put the presumption of
innocence into practice. In general, cognitive psychology has taught us that there are
general limitations to human decision-making. We cannot process every piece of stimuli
that surrounds us on a daily basis. Instead, we have adapted for efficiency by developing
heuristics and cognitive biases to help us navigate a complex world. Heuristics and
cognitive biases describe systematic patterns in human decision-making that sometimes
lead to reasonable judgments and sometimes to severe errors (Tversky and Kahneman,
1973). Humans tend to be especially dependent on heuristics in situations with uncertainty
and incomplete information (Gigerenzer and Goldstein, 1996). Cognitive biases are
natural and automatic features of human cognition that often occur in the absence of
conscious self-interest (Nickerson, 1998) and operate without awareness (Findley and
Scott, 2006;Kunda, 1990). If not counterbalanced, heuristics and cognitive biases have
the potential to undermine criminal investigations and lead to wrongful convictions.
A growing body of empirical and anecdotal evidence shows that a lethal mix of
known heuristics and cognitive biases leads actors in criminal investigations to focus on
evidence indicating guilt while ignoring opposite evidence (Ask et al., 2011;Findleyand
Scott, 2006;Hastie et al., 2002;Kassin et al., 2013;Wagenaar et al., 1993). The most
critical cognitive bias in a fact finding process context is probably the so-called con-
firmation bias which can jeopardize criminal investigations by influencing the fair and
objective testing of alternative hypotheses (Findley,2012;Rossmo, 2009). Confirmation
bias describes the tendency to ( a) predominantly search for information in line with the
main hypothesis, (b) ignore alternative interpretations, and (c) interpret ambiguous
information in line with the main hypothesis (Ask and Granhag, 2005;Fahsing and Ask
46 The Police Journal: Theory, Practice and Principles 96(1)
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