Researchers from the Cambridge University have suggested that variation in a part of the brain may explain why some people are better at keeping track of reality than others.
They tested a group of volunteers and found differences in their ability to distinguish between real or imagined memories.
The scientists then found that normal variation in a fold at the front of the brain called the paracingulate sulcus (or PCS) might explain why some people are better than others at accurately remembering details of previous events -such as whether they or another person said something, or whether the event was imagined or actually occurred.
The finding could advance understanding of brain disorders like schizophrenia.
The researchers discovered that adults whose MRI scans indicated an absence of the PCS were significantly less accurate on memory tasks than people with a prominent PCS on at least one side of the brain.
Interestingly, all participants believed that they had a good memory despite one group's memories being clearly less reliable.
"As all those who took part were healthy adult volunteers with typical educational backgrounds and no reported history of cognitive difficulties, the memory differences we observed were quite striking," said lead researcher Dr Jon Simons from the University of Cambridge's Department of Experimental Psychology and Behavioural and Clinical Neuroscience Institute
"It is exciting to think that these individual differences in ability might have a basis in a simple brain folding variation," he added.
For the study, 53 study participants were given well-known word pairs like 'Laurel and Hardy' or given an incomplete pair such as 'Laurel and ?' and asked to imagine the missing word.
Then, they or the scientist was told to read the word pair aloud.
Later, the volunteers were given a memory test in which they tried to remember whether they had seen or imagined the second word of each pair.
They also had to remember who had read the words aloud.
Participants with absence of the PCS in both brain hemispheres scored significantly worse than the others at remembering both kinds of detail.
The research was published 5 October in the Journal of Neuroscience.