An Imperfect Match? Crime‐related Context Influences Fingerprint Decisions

Abstract

SummaryResearch suggests that fingerprint interpretation is vulnerable to contextual influence. Specifically, as contextual information increases in emotional intensity, people appear to increase the rate at which they deem fingerprint pairs to share the same source. We investigated three alternative explanations for this finding: (i) that participants who complete multitrial experiments might make more matches over time; (ii) that the provision of any additional information could influence decision‐making; and (iii) that the effect could be limited to dichotomous response options. In Experiment 1, participants forced to make a match or non‐match decision on 96 fingerprint pairs made more matches when pairs were preceded by crime‐related photographs, relative to neutral photographs or no photographs. In Experiment 2, where an ‘unsure’ option was available, crime‐related context did not influence matches but decreased non‐matches. Further research is necessary to determine the relative contributions of emotionality and motivation to these effects. Copyright © 2015 John Wiley & Sons, Ltd.

Commentary on: Lockhart JJ, Satya‐murti S. Diagnosing crime and diagnosing disease: bias reduction strategies in the forensic and clinical sciences. J Forensic Sci https://doi.org/10.1111/1556‐4029.13453. Epub 2017 Feb 23.

“…I am concerned, however, about the authors' presentation of some of the literature relating to bias in forensic science. In particular, the authors have cited several studies conducted by myself and my colleagues' (2)(3)(4)(5)(6), but have either misinterpreted our findings, or have misused the citations to support their point. The statements in question are in the following paragraph (p. 3):…”

“…Finally, and most importantly, the authors' suggestion that these three studies (2)(3)(4) demonstrate "mixed results" is misleading. In the context of the paragraph, the statement implies that the application of a blinding approach may or may not have benefits for reducing bias in practice.…”

“…Research examining blinding approaches is still rather novel: in our review of the literature, we found relatively few studies, apart from Dror's, that have tested similar blinding procedures. These studies demonstrated mixed results [ (2)(3)(4)].…”

“…In the context of the paragraph, the statement implies that the application of a blinding approach may or may not have benefits for reducing bias in practice. I assume that the "mixed results" that the authors are referring to are only in relation to two of the cited studies (3,4). In these studies, the provision of contextual information increased participants' rate of making match decisions for fingerprint comparisons (4) but not for bitemark comparisons (3).…”

Diagnosing Crime and Diagnosing Disease: Bias Reduction Strategies in the Forensic and Clinical Sciences

“…All other contextual but potentially contaminating information (e.g., crime scene information) is withheld until a later stage when it is “unmasked.” Research examining blinding approaches is still rather novel: In our review of the literature, we found relatively few studies, apart from Dror's, that have tested similar blinding procedures. These studies demonstrated mixed results . So far, we have outlined forensic blinding in this section; we will consider the scope of clinical blinding later in this review.…”