So one of the current problems with eyewitness identification evidence is that witnesses often only identify somebody about forty percent of the time, from a line-up and also up to another forty percent of the time they will identify somebody other than the suspect from the line-up. Now then we've got the added problem that sometimes the suspect that has been identified isn't actually the culprit of a crime. So it seems that people feel under pressure to choose somebody from a line-up. So the solution would be to try and find a technique which reduces the pressure on a witness when perhaps they don't actually recognise anybody from that line up.

Children in particular seem unable to resist this compulsion to choose somebody but then again older adults over the age of sixty seem to be much more likely to choose somebody from a line up. So we've got a group of witnesses, younger children and older adults that seem to be much more at risk of making false identifications. So one of the problems we want to solve is how can we make children and older adults' identification evidence more reliable. With the eye witness research we use a technique where we show our witnesses a film of a staged crime.

So it's often just a simple theft of somebody going into an office and stealing something and then we have a delay and then after a delay, we would show our witnesses a line-up. Now they'll either see a video line up that will contain the culprit that they've seen previously. And obviously we're interested in how accurate they are at correctly identifying that culprit. But some participants will see a line-up that doesn't contain the person that they've seen previously and here we're interested in, whether they choose somebody from the line-up and thereby make a false identification because they're choosing somebody they haven't actually seen.

So what we've done with our research is we've placed a silhouette in the line-up and we've called this silhouette the mystery man. So when they see a silhouette in a line up and the culprit isn't in the line-up this can really reduce the false identification rates because it gives them somebody to choose when they don't actually recognise anybody else. Initially all the research was aimed with children because most of my background has been working with child witnesses. Children are thought to make these false identifications due to the task demands and this feeling that they have to give a positive response, whereas quite often the explanations for why older adults choose is thought to be related to misunderstanding the task instructions.

Older adults will often make more relative decisions and base their, for example, face recognition decisions on familiarity. So, they might just look at a video line-up and think 'well that person looks a little bit familiar, so it could be them'. Whereas younger adults would maybe make more of an absolute decision of 'well they look a bit familiar but I don't think that's the person from that film'. So we were really surprised that obviously using this silhouette could reduce the false choosing rate for older adults. There has been some research over the years that have used different options within a line up to allow children to choose without making a false identification.

So there have been line drawings of a mister nobody, there has been another silhouette which was used in a photo line-up and they called it a wild card. And these all had varying degrees of success, and I actually, there was one study in particular by Zajac and Karageorge where they used the silhouette in a photo array and they had such fantastic results that I was actually slightly sceptical and thought I'm going to try to replicate this study but use the UK methods of a video line up and was obviously quite surprised when actually it really worked.

Issues of realism and ethics in witness research

Research carried out in forensic psychology has not gone without criticism. In particular, research that has involved simulations in the laboratory has been questioned on the grounds of its ecological validity - in other words, how true to life it is.

For example, because the law restricts access to real jurors for research purposes, the jury decision-making process has been studied in many cases by asking psychology undergraduates to read a fairly short written description of a criminal case and to make decisions about the guilt/innocence of the defendant.

As you have seen, the identification of perpetrators has been studied by showing participants a short video of a staged crime scenario and then later asking them to select a picture of the perpetrator from an array of photographs. Psychologists themselves have debated the practical utility of the findings of such studies. Researchers have responded to criticisms by supplementing these rather basic simulations with much more sophisticated ones that have greater ecological validity, and by interviewing real witnesses to crimes and real jurors after they have served in a court case.

The use of 'field studies' also helps combat the problems associated with ecological validity. For example, rather than show a video and photographs in a laboratory setting, an eyewitness researcher might stage a 'live' crime in front of participants and then conduct an identification procedure at a police station.

In addition to ecological validity, eyewitness research may lack realism in that it is extremely difficult, if not impossible, to replicate the seriousness of the decisions faced by a real eyewitness. This is known as 'consequentiality', which refers to the fact that unlike a real witness, a participant in a research study knows that the information they provide or the face they select in a parade will not result in either an innocent person being prosecuted nor a guilty person walking free.

Ethical issues are paramount when conducting any psychological research, and particularly important when dealing with an issue as particularly sensitive as witnessing a crime. By its very nature the experience of crime is often frightening and may be painful and researchers face severe limits on the extent to which they can mimic such aspects when conducting a study.

There are a great many ethical factors to consider when planning research on eyewitnesses, including:

research should not threaten the psychological well-being, health, values or dignity of participantsparticipants should give informed consent before taking part in researchparticipants should be able to stop participating in the research at any point.

Ethical issues require careful consideration when designing a research study, particularly with regards to how realistic the research can be.

The requirement to gain 'informed consent' from a participant before they take part in the research, means the participant must be provided with details regarding what the research involves and what will happen to them. In real life, a witness does not know they are about to see a crime, but in a research study the participant must be informed in advance.

So, research on eyewitness memory has to balance ecological validity with the need to treat participants ethically. Designing research studies that are both ethical and sufficiently realistic that they produce useful results is just one of the skills the psychologists have to learn.

Eyewitness memory is just one part of forensic psychology, which also includes areas such as offender rehabilitation and understanding criminal behaviour. Before specialising in forensic psychology, it is first necessary to gain a good understanding of psychology more broadly and most researchers and practitioners do this by completing an undergraduate degree in psychology.

One reason this is an important first step, is that forensic psychology builds on knowledge gained from the many sub-disciplines of psychology, including:

Cognitive psychology - the study of mental processes (such as memory and attention)Social psychology - the psychology of social interactions and the influence that these can have on an individualDevelopmental psychology - understanding how and why our brains and behaviour change over the course of our lifespans, from young children to senior citizensClinical psychology - which is concerned with understanding, assessing and treating mental illness and behavioural problems.

Hopefully, you can see that all of the above represent important knowledge to have when trying to understand eyewitness memory and identification. In addition, an undergraduate degree in psychology also provides an understanding of how to conduct and understand research in psychology, which is another vital component of working as a forensic psychologist.

The work of psychologists in criminal justice

The research you have read about during this course represents just one part of forensic psychology to do with the role of eyewitnesses in a police investigation.

As well as issues to do with eyewitnesses, psychologists working in universities also do work of relevance to police investigations by studying detecting deception, interviewing suspects, offender profiling, vulnerable witnesses and evaluating forensic science.

A great deal of forensic psychology is actually concerned, not with police investigations, but with working with offenders. This includes understanding why people commit crimes, particularly crimes such as sexual and violent offences, working with criminals who have mental health issues and working in prison populations to try to help rehabilitate offenders and avoid recidivism.

Within the UK the term 'forensic psychologist' is a protected title which means it can only be used by people who have completed the relevant training and are on the official Health Care Professions Council (HCPC) register. To become a forensic psychologist involves post graduate study on a course that is accredited by the BPS and then time spent as a trainee psychologist. You have to meet a range of benchmarks after which you are signed off as competent to practice by a senior forensic psychologist. The BPS also offers chartership for forensic psychologists which is the gold standard of qualification however this alone does not enable people to practice and use the term forensic psychologist, the HCPC being the regulatory body of the profession.

In the UK, psychology is supported by The British Psychological Society (BPS).

In the US, psychology is supported by the American Psychological Association (APA).

The BPS and APA, and societies in many other countries, are a great way of discovering psychology, and of finding out about undergraduate and postgraduate courses in psychology.