Learning from the expert: Can observing the oculomotor behaviour of expert face processors improve training of face matching?

Face recognition and face matching are crucial to forensic investigations and security, in jobs such as checking passports at border control, searching CCTV footage for suspects of a crime, and in trying to identify people who have been missing either a short time or for many years. It is important to identify methods to improve face recognition and face matching.
Face recognition of unfamiliar people is surprisingly difficult in the best of circumstances. Factors that can make it more difficult include changes in age (as when the observer is trying to identify someone from an old photograph), changes in variable characteristics (as when trying to identify someone in disguise), and differences in lighting and viewpoint from when the face was learned.
One way to develop new methods is to find out why some people are better at face matching than others. As such, the first part of the proposed project tests a cross-section of the public until we identify people particularly good at face matching. We then observe how they compare faces, focusing on the eye movements they make, and ask them about the strategies they use.
The knowledge gained will then be tested to see if explicit training about strategies or implicit training through demonstrating expert's behaviour while they do the task will be effective training. Previous research in other perceptual tasks has suggested that showing the eye movements of those skilled at the task to novices as part of training will improve the rate of training. This is done by showing the trainee the image being evaluated superimposed by a dynamic representation of th eye movements a skilled person made when inspecting the image. The trainee is simply told to follow the gaze of the skilled person during this presentation. The effectiveness of this simple technique may be because people innately attend to other people's gaze to understand what in the environment those other people consider important. This following of another's gaze toward objects, called "joint attention", is a powerful learning tool in childhood. Those who do not develop joint attention, such as autistic children, also appear to be delayed in developing understanding of the goals and intentions of others. Adults, too, are involuntarily drawn to follow gaze and implicitly learn to value higher objects that others gaze at over objects the others do not gaze at.

As this "oculomotor demonstration" training method is new, it has not been fully tested. For instance, the effectiveness of training has only been tested in the short term. Therefore, this research will test whether any benefits last for a week or a month. Further, testing it on face matching provides a strong test of whether the training generalises, as it is the first task to which this training is applied for which both the stimulus and the task is familiar to the trainee. Although the average person is not particularly good at face matching, everybody has experience of it.

The outcome of this study will be reported in an international journal read by both researchers and practitioners, will be shared with people responsible for training face comparison in forensic contexts, and will inform our further research that will more directly test why this method is effective for some perceptual tasks.

Face matching errors can have devastating effects in criminal justice. For instance, a surveillance officer's mis-comparison of a photo of a terrorist suspect to the CCTV image of Jean Charles de Menenez is thought to be one of the reasons for the tragic shooting of him by police in 2005. Further, it is important to block known terrorists from entering the country, and one of the steps to doing that is to ensure that border security personnel can recognise them from their photos. Likewise, at a local level, the effectiveness of drinking banning orders is critically dependent on distribution of photos of the banned person and accurate identification of the person from those photos by security personnel at bars and off-licences.

This work will also impact criminal prosecutions. Identification evidence often represents a substantial amount of the evidence supporting a prosecution (Brewer, et al., 2005), and influences decision making throughout the forensic setting. Consequently, reliable identification evidence is essential for effective criminal investigations and the successful prosecution of criminals. Thus, our proposed research can improve the efficiency of criminal investigations and will therefore be of interest to forensic investigators attempting to maximise the reliability of identification evidence.

If the training method proves successful, this work will have an impact on society by providing the forensic community a new training method that would improve face matching. Improving forensic investigations and the effectiveness of border control will benefit society by reducing crime and terrorism, both of which have cultural and economic impacts. The forensic community includes security firms, police, UKBA, and the Home Office. The public should be safer, which will benefit quality of life.

This research would also benefit other training providers in that it tests a way of transferring the skills of an expert to those of a trainee without one on one contact. Historically, apprenticeships have been used to transfer practical skill from an expert to a trainee. As business becomes more distributed, even globalised, it is more difficult for experts to be geographically present with trainees, and so alternatives to apprenticeships are needed. If showing the eye movements of an expert provides some of the benefit of having the expert present, this could be an invaluable addition to training methods used by businesses.

If a beneficiary decided to implement the training, they would only need to identify the face-matching tasks that they use, identify one or more people particularly good at the task, use an eye-tracker to record eye movements of the expert doing the task, and develop a short training course where the trainee watches the video and practices the task. It is easy to envisage that these steps could be done in less than 6 month, which means that the timescale of impact is relatively short.

We will be advertising the project to the wider community. As the topic is engaging, this should also benefit society by giving the general public an opportunity to become involved in research.

The research assistant will gain invaluable research experience and, in particular, learn how to use an eye-tracker. That particular tool would be of benefit for a research career either in academia or in other domains (e.g., marketing).