They Are Not Lying. They Genuinely Remember Something That Never Happened
By the BrainSnail editorial team. How these articles are written and checked, and how to tell us when one is wrong.
Producing a detailed and confident account of events that did not occur, with no intention to deceive, is a recognised clinical phenomenon and a milder version of something everybody does.
What distinguishes it from lying
The defining feature is the absence of any intention to mislead. A person producing such an account believes it, presents it without hesitation, and will supply further detail if asked. Challenged with contradicting evidence, they may amend the account and produce another with equal confidence. There is no benefit being sought and frequently no coherent motive at all. It is therefore a failure of memory and of the checking process that normally evaluates what memory produces, rather than a failure of honesty.
Where it is seen clinically
The phenomenon appears in several distinct conditions:
- •Damage to the front of the brain, particularly certain regions
- •A severe deficiency of thiamine associated with alcohol dependence
- •Some forms of dementia, especially in the middle stages
- •After certain strokes and head injuries
- •In patients whose brain hemispheres have been surgically separated
- •In some people under hypnosis or intense suggestion
The split brain experiments
The most revealing evidence came from patients whose hemispheres had been surgically disconnected to control epilepsy. Instructions shown only to the right hemisphere, which does not control speech, produced actions the person then explained confidently and incorrectly, because the speaking left hemisphere had no access to the real reason and supplied one that fitted. Asked why they had stood up, a patient who had been instructed to walk said they were going for a drink. The explanation was invented instantly, sincerely believed, and demonstrably wrong.
Why it matters for testimony
The phenomenon has direct consequences for how accounts from vulnerable people are treated. A person producing such material is not lying and cannot be caught out by the usual indicators of deception, since they display none, and their confidence is if anything higher than that of an accurate witness. Repeated questioning makes it worse, because each retelling supplies more detail that is then recalled as though it had been there all along. That is the reasoning behind protocols limiting how often a witness is interviewed and how questions are phrased, and behind treating high confidence as no guarantee of accuracy.
Why it says something about everybody
The uncomfortable implication is that the process producing these accounts is the ordinary one, running without the constraints that normally check it. Experiments with people who have no brain injury show the same pattern in weaker form, with participants confidently explaining choices they did not make, justifying positions they had not taken, and supplying reasons for preferences that were actually determined by factors they never noticed. The conclusion generally drawn is that explaining our own behaviour is largely reconstruction after the fact rather than a report of what actually caused it.
The takeaway
A detailed confident account of events that did not happen, offered with no intent to deceive and amended freely when challenged, indicates a failure of the process that checks what memory produces. It follows frontal brain damage, thiamine deficiency and some dementias. Split brain patients invent reasons for actions instantly, and unimpaired people do a weaker version of the same thing constantly.