Errare humanum est? Decision-making processes, cognitive bias, and motivation of fingerprint examiners

The attention that academia and forensic agencies have been giving to the decision-making process of fingerprint examiners has increased in recent years. This is largely due to the increasing awareness that experts’ decisions can suffer from cognitive bias, promoting erroneous decisions. Even though fingerprint examiners are expected to not commit errors deliberately, it is of interest to understand in detail the influences (i.e. impact on performance) that external factors such as contextual information have on their decision-making process.

This thesis begins by investigating how a group of experts (n = 41) and another of laypeople (n = 57) differ in their accuracy and response time regarding the influences of different contextual information. Although experts showed higher levels of accuracy, findings suggest that both laypeople and experts have a tendency to suffer from similar types of cognitive bias associated with the same types of contextual information promoting lower accuracy and higher response times. It seems that different types of contextual information have different types of influence in experts’ performance. Hence, this thesis analysed in a second study the accuracy and response times of 67 fingerprint examiners, from 15 forensic bureaus, based in 9 countries, during trials that simulated the Verification phase of the ACE-V process. Results showed significant differences between specific types of contextual information when compared with control trials, challenging guidelines that suggest fingerprint examiners should work within a full blind setting. Due to the diverse sample in this study, it was possible to explore differences regarding the different levels of experience, methodological approaches currently in use (i.e. numerical approach versus holistic approach) and the accreditation standards that forensic bureaus had. Findings provided insight that can be used in future developments for methodologies, accreditation guidelines, and training for fingerprint examiners.

Finally, a qualitative study was conducted in which 42 fingerprint examiners were interviewed regarding their opinions about contextual information influences and the methodologies within the ACE-V process. Results retrieved from interviews shed light on aspects of experts’ work, allowing a better understanding of the motivation and the level of cognitive enjoyment (assessed by the level of Need for Cognition) as well as the specific types of contextual information which may not influence experts’ performance negatively, but rather be a motivational factor for their work.