Keeping track of reality: Why some of us better at remembering what really happened

October 4, 2011

A structural variation in a part of the brain may explain why some people are better than others at distinguishing real events from those they might have imagined or been told about, researchers have found.

The University of Cambridge scientists 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 research was published today, 05 October, in the .

This brain variation, which is present in roughly half of the normal population, is one of the last structural folds to develop before birth and for this reason varies greatly in size between individuals in the healthy population. The researchers discovered that adults whose indicated an absence of the PCS were significantly less accurate on 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.

Dr Jon Simons from the University of Cambridge's Department of and Behavioural and Clinical Neuroscience Institute, who led the research, said: "As all those who took part were healthy adult volunteers with typical educational backgrounds and no reported history of , the memory differences we observed were quite striking. It is exciting to think that these individual differences in ability might have a basis in a simple brain folding variation.

"Additionally, this finding might tell us something about , in which are often reported whereby, for example, someone hears a voice when nobody's there. Difficulty distinguishing real from imagined information might be an explanation for such hallucinations. For example, the person might imagine the voice but misattribute it as being real. PCS reductions have been reported in previous studies of schizophrenia, and our results are consistent with the idea that this structural variability might directly influence the functional capacity of surrounding brain areas and the cognitive abilities that they support."

For the study, the researchers recruited 53 healthy volunteers based on their brain scans which showed either a clear presence or absence of the PCS in the left or right brain hemisphere. Participants were presented either with well-known word-pairs like "Laurel and Hardy" or with the first word of a word-pair and a question mark ("Laurel and ?"). In the latter condition, participants were instructed to imagine the second word of the word-pair. Then, either they or the experimenter was instructed to read the word-pair out aloud. After a delay, a memory test was given where participants tried to remember whether they had seen or imagined the second word of each previously-encountered word-pair, or whether they or the experimenter had read the word-pair out aloud. Participants with absence of the PCS in both hemispheres scored significantly worse than the others at remembering both kinds of detail.

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More information: The paper 'A Specific Brain Structural Basis for Individual Differences in Reality Monitoring' will be published in the 05 October edition of Journal of Neuroscience.

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not rated yet Oct 04, 2011
Maybe this is the secret behind eidetic memory ? Wow, so one lost month during pregnancy can make quite an impact. 2, uh-oh
not rated yet Oct 05, 2011
Thin ice.
For example, the person might imagine the voice but misattribute it as being real.

We have:
Subjects viewing motion and hearing sound.(synesthesia)
Subjects hearing sound from touch.

And my conjecture: All imagination is of physical origin.
In other words, it does not matter what you label imagination, the origin was "real" and is physical in nature.

So what does this all mean?
...someone hears a voice when nobody's there...

Because synesthesia and touch as sound is very real.
And why stop there?

And the imaginative explanations researchers offer here harbors disappointment to anyone reading this.
Check and reevaluate your test. Free your test from error.
not rated yet Oct 05, 2011
Hush1, are you questioning whether the PCS folds presence correlates with memory funtion, or the testing methods used to determine this? As far as the testing goes, "real" can be defined as an event witnessable by more than one individual, ie: whether the word pair was actually read aloud by either person. Pretty easy to tell the difference between "real" and "imagined" using the criteria specified in the testing methods, hence the conclusions drawn from the test are validated. "All imagination is of physical origin"....this is true, but not to both parties...only the owner of imagined events can perceive them as real.....the rest of us know that imagined events are not real.
not rated yet Oct 05, 2011
If all imagination is of physical origin, then all owners have imagination.
If just one of the owners is not physical, then the above statement is a false assumption.
Of course both statements are assumptions 'pitted' against each other.

Imagination is fun. Imagination one of the 53 healthy volunteers being deaf. Assigned to thwart the researchers. And managed to avoid the researchers assumption all volunteers possessed hearing.

Where and what is the 'detail' of memory for the subject hearing nothing?

Correlation is fine.
Assume nothing.

Or in your words with your permission to alter one word:

"Pretty hard to tell the difference between "real" and "imagined" using the criteria specified in the testing methods..."

I even imagine you saw the word I changed, even without validtion.
not rated yet Oct 05, 2011
Imagine a typo in the last word! :)

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