Fillers can help control for contextual bias in forensic comparison tasks

Area of Science:

• Forensic Science
• Cognitive Psychology

Background:

• Forensic examiners face contextual information that can bias conclusions.
• Standard forensic comparisons may be susceptible to cognitive biases.

Purpose of the Study:

• To test the efficacy of the filler-control method in mitigating contextual bias in forensic fingerprint comparisons.
• To evaluate the impact of the filler-control method on accuracy and error rates.

Main Methods:

• 234 participants underwent brief training before comparing fingerprint sets.
• Fingerprint comparisons varied in match presence, ambiguity, contextual information, and presentation method (filler-control vs. alone).
• Data analyzed using d' to measure performance.

Main Results:

• The filler-control procedure reduced both correct identifications (hits) and incorrect identifications (false alarms).
• Overall performance, measured by d', was superior with the filler-control method.
• The method demonstrated effectiveness across varying levels of print ambiguity and contextual suggestion.

Conclusions:

• The filler-control method is a promising technique for reducing cognitive bias in forensic examinations.
• This procedure should be considered for routine use, especially when error rates are unknown or bias risk is high.
• The findings support the adoption of the filler-control method for verification decisions in forensic science.