PI Brief Update

How to Assess Credibility in the Courtroom? - Dr Ben Goodall, Dr Hugh Koch & Poppy Gould

30/11/12. Review of publication by Porter S & Brinke L.T (2009). Dangerous Decisions: A theoretical framework for understanding how judges assess credibility in the courtroom.

The civil and criminal legal system relies on making fair and accurate decision concerning reliability, truthfulness, guilt and lying (Koch and Kevan (2005)). It is not possible to empirically evaluate the accuracy of outcomes in court. Whereas with psychological science and experiments which relies on an acceptable error rate of 5%, court decisions typically use ‘beyond a reasonable doubt’ or ‘on the balance of probability’ as their criteria. We know that human decision making is variable and at times illogical. Ultimate decision about guilt or untruthfulness are guided by subjective decisions by judges, jurors, barristers and experts.

Porter and Brinke critically examined the manner in which witnesses credibility is evaluated and presented a theoretical framework called ‘Dangerous Decision Theory’ (DDT). According to DDT, the reading of a person’s face and their emotional expression play a significant role in determining credibility. This is often then described by the judge or experts as ‘intuition’. This initial impression, which may be unreliable, can endure and have a powerful effect on how later information in interpreted. This results, or can results, in irrational influences about trustworthiness. Such non-critical tunnel vision can result in mistaken evaluation of reliability.

Witness credibility assessment is fraught with error. We all hold fake stereotypes about deception and are vulnerable to dangerous biases in evaluating evidence. The attitude that assessing credibility is a common sense skill may not help to maintain confidence in this process. However, education, training and expert testimony to improve credibility assessment in the legal process are essential to reduce the problem of unreliable decision-making. This will, as Porter and Brinkle state, ‘serve to strengthen the legal system’s role as a pillar of society’.

Koch HCH & Kevan T (2005) Psychological injuries. XPL press. St Albans.

Porter S 7 Brinke L(2009) Dangerous decision: A theoretical framework for understanding how judges assess credibility in the court room. Legal and Criminology BPS, 14, 119-134.

More information can be obtained from either via www.hughkochassocaites.co.uk.

Dr Benjamin Goodall regularly holds clinics in Hull and York.

Dr Hugh Koch regularly holds clinics in Birmingham, Bristol, Cheltenham, Cardiff, London and Plymouth.

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