Vulnerable and Intoxicated Witnesses: How reliable are they?

22 May 2019

Can you trust the eyewitness accounts of individuals who witnessed a crime while inebriated?  Can autistic children be credible witnesses?

To solve a crime, reconstructing what occurred in the lead up to, during and after the crime was committed is essential. As the accounts given by witnesses from the scene of the crime still form a vital part of many investigations, ensuring the completeness, accuracy and reliability of eyewitness testimony is of great importance to all justice system practitioners.  

This is where the field of cognitive psychology can help. Using empirical research, we can help discover the best means of collecting evidence and establishv whether a particular type of witness is likely to be credible, tackling preconceived notions and unfounded beliefs in the process. This research can then feed into real-life practice, helping our justice system operate more efficiently.

Recently, our Centre for Forensic and Investigative Psychology (CFIP) hosted a Vulnerable Witnesses conference to share how recent research into eyewitness testimony of vulnerable witnesses could help enhance practice. From the opening keynote by National Vulnerable Witness Adviser Dr Kevin SmithNational Crime Agency, through the talks and poster sessions, to the closing keynote from Psychologist and expert witness Dr David La Rooy, Royal Holloway, University of London, this conference challenged beliefs of the delegates (police officers, registered intermediaries, witness service and ministry of defence employees) regarding the capabilities of vulnerable witnesses (children with and without autism and intoxicated witnesses).

In this blog, we’re going to recap some of the most fascinating and surprising findings revealed by studies carried out at the University of Winchester and beyond, associated with vulnerable and intoxicated witnesses.

 Vulnerable and Intoxicated Witnesses conference

Autistic Child Witnesses

In order to support vulnerable witnesses (e.g. children, and those with autism), the justice system in England and Wales provides the option of a Registered Intermediary (RI) - an impartial, trained professional who can help facilitate communication. Whilst you may not dispute that an autistic child is a potentially vulnerable witness, research from Professor Lucy Henry, City, University of London, and Dr Rachel Wilcock (CFIP) investigates whether their recall is poorer than a typically developing child, as well as the effectiveness of RI support.

In fact, whilst children with autism may recall fewer details than a typically developing child, they are just as accurate. So what is the value of a RI? Is there any point in the training, time and cost associated with these communication experts? The answer it seems is yes.

For typically developing children a RI’s help and support increases both the amount of information they can recall and correct identifications of the perpetrator. For an autistic child however, whilst the assistance of an RI is less clear, .i.e., there is no discernible increase in the amount they recall; without a RI a child with autism may not be able to engage with the judicial process at all. The data from this interesting research is still being analysed, so make sure to look at the dedicated website for updates.

 So we know that as a vulnerable group of witnesses, autistic children may be less complete but no less accurate in their recall than a typically developing child. We also know from Dr Genevieve Waterhouse’s (CFIP) research that for a typically developing child multiple interviews can increase correct recall with only a small risk of contradictions, and not necessarily an increase in distress or anxiety for the child. What about our other vulnerable witnesses – intoxicated adult witnesses?

Vulnerable and Intoxicated Witnesses conference posters

Intoxicated Witnesses

Most of us have had at least one alcoholic drink in our lives, and based on our own experiences have preconceptions about how alcohol will affect the memory and behaviour of ourselves and others. Alcohol has a negative effect on your memory - this seems obvious, right? Of course, having consumed alcohol your memory of events will be less accurate and less complete. You won’t be as able to recall the faces of new people you have met either, will you? Whilst your intuition and that of the conference attendees may suggest that this is the case, the research tells us otherwise.

In fact, field and Bar Lab research presented by CFIP convenor Dr Wendy Kneller along with Dr Sarah Bayless (CFIP) and Dr Deborah Crossland (CFIP) indicates that after a couple of drinks your memory of a crime and identification of the perpetrator are no less accurate or complete than if you had been sober. Actually it isn’t until you are over the English drink drive limit (BAC = 0.08%) that your recall will be affected. Even then, whilst you may be less confident in your recall and ID performance the only negative effect is that you may report fewer details of the crime. You would, however, create a less accurate composite of the perpetrator (a facial representation created with an expert) even if you were under the drink drive limit.

Vulnerable and Intoxicated Witnesses conference

So, next time you are on a night out and happen to see a bag stolen or a fight started, think back to this blog and don’t be so quick to disregard your own memories because of those cheeky vodka and tonics, or pints. The research supports the accuracy of your memory, even if your confidence does not. Just bear in mind that whilst you may be able to correctly identify the perpetrator; it may be best to leave the creation of a facial composite to your sober friend. That is, if you want to have the best chance of catching your criminal.

The one-day Vulnerable Witnesses Conference for criminal justice practitioners is just one of many seminars and events run by the University’s Centre for Forensic and Investigative Psychology. Find out more about the research produced by the Centre and future events by clicking here.

Press Office  |  +44 (0)1962 827678  |  |

Back to media centre