Does coming from a family full of "lefties" tend to make a person better at remembering events? The data from two recent experiments answer in the affirmative. This recent reasearch is reported in the jornal Neuropsychology. Stephen D. Christman and Ruth E. Propper of the University of Toledo in Ohio, studied memory as a function of family handedness.
Interestingly, people don't have to be personally left-handed to share a unique trait: There is evidence that the two brain hemispheres of even righthanders with left-handed relatives share functions more equally, interact more and are connected by a larger corpus callosum (the bundle of mediating fibres) than the hemispheres of people with right-handed relatives.
The main difference is that people who 'remember' can also recall details about the time and place at which they first learned this fact."Christman and Propper conclude that because our brains' two halves work together to help us remember events, people whose brains' halves work together more actively (people with left-handedness in their families) remember events better than they remember facts.
As a result, the authors say that memory studies should factor in the familial and probably personal handedness of participants (having a weak versus strong hand preference may also matter). Further research may help explain why episodic memory benefits from the two halves working together, whereas factual/implicit memory is better processed in one half alone.
The onset of episodic memory roughly coincides iwth the corpus callosum's maturation and myelinisation, the growth of fatty protective sheaths around nerve fibres.
In light of the findings, it would mean that a functional corpus callosum is critical in the formation of event memories and therefore expalin why its maturation in early childhood is at least partly responsible for the emergence of episodic memory.