Not surprisingly, confessions are extremely persuasive in court, but according to Jessica Klaver and colleagues, all too often these confessions are false, leading to the wrong person being found guilty.
Now Klaver's team have used an elegant laboratory task to compare two types of interrogation technique and found that it is so-called 'minimising' questions and remarks - those that downplay the seriousness of the offence, and which blame other people or circumstances - that are the most likely to lead to a false confession.
Over two hundred Asian and Caucasian students were invited to take part in what they were told was a test of their personality and typing skills. During the typing part of the task, they were warned in advance that pressing the 'Alt' key would cause the computer to crash and a loss of all data. Subsequently, when the participants were required by the task to type 'Z' (near the 'Alt' key), the researchers contrived it so that the computer duly crashed, and the participants were accused of pressing the 'Alt' key.
Next the students were subjected to either 'minimising' remarks (e.g. "Don't worry. It was just an accident" and "This programme seems not to be working lately") or 'maximising' remarks that played up both the evidence for the student being guilty and the seriousness of the alleged error (e.g. "You must have pressed it" and "We have run over 50 people on this test in the past three weeks and the computer hasn't crashed once").
Overall, 43 per cent of the students subsequently signed a confession statement, stating falsely that they had indeed pressed the 'Alt' key. Crucially, the confession rate was four times higher among the students subjected to minimising remarks as opposed to maximising remarks.
The researchers said that in real life, minimising techniques "give the suspect a false sense of security using flattery, offering legal or moral face-saving excuses for actions, conceptualising actions as accidental, blaming the victim and underplaying the seriousness of the charges."
Further analysis showed the female students were more likely to falsely confess, as were those students who scored high on a test of suggestibility. Personality factors such as self-esteem were not related to the rate of false confession.
"A continued investigation of the factors that contribute to false confessions and confession behaviour in general will greatly inform our understanding of the phenomenon and aid in efforts to prevent the occurrence of false confessions and their liberty-depriving consequences," the researchers said.
Klaver, J.R., Lee, Z., Rose, V.G. (2008). Effects of personality, interrogation techniques and plausibility in an experimental false confession paradigm. Legal and Criminological Psychology, 13(1), 71-88. DOI: 10.1348/135532507X193051