Why our memories are unreliable
Memories are not always accurate, as Law Psychologist Marko Jelicic knows. In court, the consequences can be disastrous.
Anoushka Kloosterman
Thursday 10 October 2019

Our memories are often not quite right, says Law Psychologist Marko Jelicic. It mainly affects the details – what was the colour of the bike you had when you were twelve? – but sometimes people can remember entire events that never occurred.

Usually, it’s not a problem, he explains. But in court, the consequences can be disastrous. “Witness statements frequently have a large part in criminal proceedings and then it really does matter that your memory is correct.”

Jelicic, who works for Maastricht University, will be speaking at the Leiden Institute for Brain and Cognition’s Public Day tomorrow.

He can remember one case in particular where he was called in as an expert. “The case involved a family with three children; the parents were divorced. The children – aged ten, fourteen and eighteen – lived with their mother. The little girl of ten started displaying sexually inappropriate behaviour at school. The mother suspected her ex-husband of abusing the child, so she asked her daughter some very leading questions, until the girl said: ‘Daddy did it.’

“Then the mother questioned the other children in exactly the same way, and they produced some vague stories. The mother went to the police and the father was arrested.

“At a certain point, the children’s reports became extremely weird – the children were forced to have sex with each other, the father was a member of a large child pornography ring – so the public prosecutor called in a number of experts, including me, to look at the case. We concluded that the police questioning, and the way the mother had interrogated her children, was exactly right for generating pseudo-memories.”

"If you want to recall something that happened a long time ago, you should always assume that a part is not right"

Our memory doesn’t work like a DVD; you can’t just file things away and recall them perfectly. Deep in our brains, there’s something called the hippocampus, which splits up the information collected by our senses and stores it in different areas of the brain. If you want to remember something, the hippocampus has to glue the pieces together again.

“Errors can occur in that process, for instance, if you allow yourself to be guided by fear, imagination or stereotypical information. That information can then be linked to the memory track and then you start to remember things incorrectly.”

Jelicic would like to stress that it’s not often a problem in police interviews. “The Dutch police academy trains our officers properly. But not everyone has those qualifications, or perhaps it has been a long time since they followed the course. Or maybe the witness needs a long time to think, but the police are in a hurry and feed him or her information. That’s where it can go wrong.”

Can we tell whether our own memories are real? “No”, he replies. “But if you want to recall something that happened a long time ago, you should always assume that a part is not right. I’ve had a couple of arguments with my wife about this kind of thing. Once, an owl flew against the glass of our conservatory. I remember precisely how the animal rescue ambulance came round and a fairly thickset man climbed onto its roof to get the owl. I thought: ‘I hope it doesn’t break!’ It all happened, but my wife says I wasn’t there, because I went to work and left her to sort it out.”