Do you really remember that? Witness evidence in international arbitration

In an article from Fenwick Elliott’s blog, Collective Thoughts1, Claire King, looks at the future of witness evidence in the UK and  International Arbitration.  

Published in November 2021, the ICC Commission Report The Accuracy of Fact: Witness Memory in International Arbitration is fascinating and provides real food for thought for arbitral practitioners  who are about to engage in the process of taking witness statements. At its heart is the increasing scientific evidence, originally derived from criminal trials, that human memory is relatively fragile and can be “unwittingly corrupted”.  

So, what does the science say?  

The historical research into memory was primarily focused on criminal trials where individuals had to recall specific incidents.  That data suggested that not only was human memory very unreliable but also a witness’s exposure to pre- and post-event information could add to, detract from or even change a memory of the event in question.  

In light of this the ICC commissioned a study (The Accuracy of Fact Witness Memory in International Arbitration) by Dr Wade of the University of Warwick to consider the pertinence of these issues to international arbitration and a commercial setting. She developed a witness memory experiment involving 316 adults across a broad range of industries who were asked to read about a contractual agreement between two companies, revolving around the installation of an industrial floor, ultimately leading to a dispute. Some participants were then asked to imagine they were the MD of one party and some  the MD of the other party. Controls were not asked to imagine anything.  

A detailed summary of that study can be found in the report, but the results were consistent with the findings from  criminal trials. In particular, “biasing people in favour of a particular company and exposing them to suggestive post-event information affected their memory reports”. 

In other words, memory is malleable. As the report notes it is not a fixed image that can be retrieved when required. Instead, it is a “dynamic process that can be affected by subsequent events”.  

Why does this matter to international arbitration?  

Although civil law jurisdictions have traditionally relied less on witness evidence than those in common law systems, harmonisation over the years has resulted in a default approach of providing witness  evidence in international arbitrations. The report notes in particular the impact of the IBA guidelines in levelling the playing field when it comes to the presentation of witness and expert evidence. General practice is then that narrative statements from each witness are prepared and exchanged often at considerable expense. However, the rules on how such witness evidence is taken are not so clear.  

Obviously the value of witness evidence, and the weight that arbitrators should put on it, is called into question if the memories contained within are not as reliable as thought historically. That may not matter so much where witness statements are to provide context or are essentially procedural. However, for witness statements where memory is key, the question then becomes how to avoid  memory distortion.  

So how can witness evidence be made more reliable?  

Helpfully, the report goes on to provide an “open list” or menu of ideas that can be considered, where appropriate, in order to increase the accuracy of a witness’s memory. Suggestions include (but are in no way limited) to:  

  1. Ensuring interviews are carried out as early as possible when memories are fresh.  
  2. Avoiding interviews in a group where discussions modify memories.  
  3. Ensuring that someone not conducting the interview makes notes or a recording is made.  
  4. Explaining that it is what they remember that is key rather than what another person may  have told them or what they  may have read.
  5. Assuming it is true, reassuring witnesses that there will be no personal consequences to telling  what they actually recall.  
  6. Avoiding steering witnesses to a particular version of the facts.  
  7. Using neutral language. For example, don’t say “How aggressively did they react?” but instead “How did the  discussion progress?”.  
  8. Asking if there are notes from the time.  
  9. Asking for their recollections before providing them with documents. 

The report also emphasises the training of in-house counsel to ensure that, as “firstresponders”,  steps are taken to reduce the  risks of false memories creeping in at an early stage.  


The report emphasises that training of both in-house counsel, external counsel and arbitrators is important in order  to understand: (a) the strengths and weaknesses of the “recounting process”; and (b) how to aid that process to ensure the end product is as close as possible to an accurate understanding of  what happened.  

That said, it is clear that the ICC intends to adopt a flexible approach to the issue  of how witness statements are taken. This is in line with the ethos of party autonomy which sits at the heart of the arbitration process. The ICC’s approach is in stark contrast to the line now being adopted by the Business and Property Courts. Practice Direction 57A of the Civil Procedure Rules  lays down very strict rules for the process of taking witness evidence on the basis that: “human memory is a fluid and  malleable state of perception concerning an individual’s past experiences, and therefore is vulnerable to being altered by a range of influences, such that the individual may or may not be conscious of the alteration”. 

One thing is clear, those taking witness statements need to be aware of the fluidity of human memory and how best to ensure that the risks associated with that are mitigated. As such, reading this report is highly recommended and it will certainly be interesting to watch developments in this area of practice going forwards.  

Previous article | Next article

  • 1. Further insights from the Fenwick Elliott blog, headed by Andrew Davies can be found here