Eye movement evaluation of signature forgeries : Insights to forensic expert evidence

Signatures are a complex and important biometric that have widespread international acceptance for verifying individual identity. As with other security measures, there are often attempts to mislead authorities by simulating genuine signatures. The ability to reliably identify genuine signatures from simulations is an area of forensic science of high value to legal proceedings, and several studies have established an expertise effect between forensic document examiners (FDEs) and control subjects. Eye movement recordings of the visual processing of FDEs during signature evaluations reveal that examiner expertise results from an enhanced capacity to process local features in the context of global information. In addition, eye movement studies allow for an understanding of how high- and low-complexity ranked signatures are visually inspected by subjects when making simulations. We discuss the importance of understanding the context of a work environment for designing experiments to reveal mechanisms of expertise used by professionals to do their job. We, thus, look at the normal work environment of FDEs for evaluating signatures and how the requirement of understanding expertise from a legal standpoint has facilitated considerable interest in eye-tracking technologies. In particular, we argue that the accurate modelling of the work environment is central to deriving parameters for use in eye movement studies to understand the role of expertise in subjects.