Derya Deniz Elalmiş | PubMed Health

PubMed2005

Hand preference in Turkish population.

The distribution of hand preference (self report) was studied in siblings and their parents originating from all parts of Turkey (N = 22,461). In total sample and siblings, there were significantly more right-handed women than men, and significantly more left-handed men than women--no significant sex difference for parents' handedness. The relative number for the right-handed parents significantly exceeded that for the right-handed siblings; the relative number for the left-handed siblings significantly exceeded that for the left-handed parents. It was concluded that there may be a sex difference in hand preference, but being only about 1% more left-handed men, and only about 1% more right-handed women; the right-handedness in new generation (siblings) is less than that in old generation (parents), due to freeing from cultural pressures against the left-hand use in everyday activities.

Adolescent↗

PubMed2003

Population-level right-paw preference in rats assessed by a new computerized food-reaching test.

We re-studied the distribution of paw preference in rats using a new computerized food-reaching test, which recorded the times and time intervals between the single right- and left-paw entries. Using the traditional food-reaching test, we found that of 144 rats, 72.7% were right-handed, 19.7% left-handed, and 7.6% mixed-handed. This population-level J-shaped right-hand preference did not fit a binomial chance distribution (25:25:50). Of right -handers, 99.5% first used their right paw and 0.5% left paw; of left-handers, 98.6% first used their left paw and 1.4% right paw. Of mixed-handers, 59% first used the right paw and 41% left paw for food reaching. The time interval between putting the rat into the test cage and the first right-paw entry was significantly shorter than the first left-paw entry in total sample. Males were faster than females (shorter time intervals between right- or left-paw entries). The distribution of the time intervals between right- or left-paw entries was inverse J-shaped, which exhibited a normal distribution after taking the logarithms of the time intervals. There was no significant difference between time intervals for the left-paw entries; time intervals for the right-paw entries were significantly shorter in males than females, accentuating the role of the left brain for sex differences in motor control. The results suggested that humans are not unique in population-level right-hand preference; our new method would be suitable for new developments in handedness research.

Animals↗