Good language - high credibility

Germanist examines how witnesses’ style of language can influence the trust the police have in their statements

Anyone who is asked to make a written statement after an accident - either as a witness or as a suspect - would be well advised to talk about an "accident vehicle" rather than just about a "car" - because then there is a markedly higher chance that the police will trust this statement. The choice of words, correct grammar and coherent syntax - all these can have a big influence when it comes down to whom the authorities believe. After her analysis of several dozen statements, as well as experiments with numerous test persons, Joy Steigler-Herms arrived at a clear result. "Anyone who expresses themselves in an educated way instead of colloquially will be seen as being more trustworthy in nine out of ten cases," says the Germanist in her dissertation, which she completed at the University of Münster in 2023. It is a factor which is of decisive importance when coming to a conclusion in a case.

It is well-known that physical attractiveness, ethnicity, a professional title or the language used can all’have an influence on trustworthiness. By way of contrast, Joy Steigler-Herms wanted to know what effect the style of language has when the victim of an accident or the alleged perpetrator make only a written statement on what happened - which is standard for investigations in "easy cases". Several traffic offence departments at police stations in the Steinfurt region made 57 real-life statements from police interrogations available to her. Using a certain key, 143 policemen and women with a minimum of five years of professional experience and 64 students from the University of Münster were each presented with ten statements which they had to grade with respect to credibility, trust and competence.

The test persons did not, however, know that Joy Steigler-Herms gave some of them original statements while others were presented with statements which had had their language improved. An example: "On 17.02.2020 we was driving along (name of street) when suddenly a car from the left dashed out in front of us from out of a petrol station, just in front of the lights. When the woman driving our car flashed him, the guy in front deliberately stepped hard on his brakes 2 times, then he waited till he could see us and then he put two fingers up at us and then he turned off right towards (street name)." For purposes of comparison, Steigler-Herms turned this "colloquial description" of what happened into an "educated" text: "On 17.02.2020 we were driving along (name of street) when a vehicle left a filling station on our left and, driving above the speed limit, moved into the space in front of us. When the driver of our car, forced to brake, flashed her headlights, the driver in front braked twice - deliberately and heavily. He waited until he was able to see us, then gave us a V-sign and continued driving in the direction of (name of street)."

The assessments given by the test persons were similar: the educated version made a much better impression on both the professionals (the police) and the non-experts (the students). "The differences were similarly great as regards all three variables (credibility, trust and competence)," wrote Steigler-Herms. In the example of another case, a rear-end collision, the relevant values in the manipulated "educated" text rose from 4.1 to 5.2 on a scale of 7 - a significant improvement. But what are the "educated" characteristics which can improve the credibility of a statement? The use of relative clauses, for example, or the use of conjunctions such as "because" or "as". On the other hand, a string of main clauses tends to give a more negative impression. One thing Joy Steigler-Herms discovered, however, was that an over-frequent use of specialist jargon or foreign words had the opposite effect to that intended. One policeman described such a witness as "a show-off and a know-all".

As one consequence of her results, Joy Steigler-Herms thinks it would make sense for trainee policemen and women to be sensitised in future to such potential influences in written statements. One policeman who had taken part in the study as a test person gave his assessment of the results: "I notice now that I tend to give more credence to good language - and that appalls me."

This article appeared in the University newspaper wissen leben No. 4, 12 June 2024.

Translated by: Ken Ashton