Personality and Individual Differences doi: 10.1016/j.paid.2008.08.019
Handedness and behavioural inhibition: Left-handed females show most inhibition as measured by BIS/BAS self-report
Lynn Wright et al.
Abstract
This study investigated the relationship between handedness, gender and behavioural approach and inhibition using Carver and White’s (1994) BIS/BAS Scale. 112 participants took part: 46 left-handers and 66 right-handers. All participants completed Peters’ (1998) handedness questionnaire followed by the self-report BIS/BAS Scale. Significant effects of both handedness and gender on the BIS scores were found, with left-handers and females scoring significantly higher on inhibition. BIS scores were re-examined to include FFFS scores, which showed a significant effect of gender. Revised BIS scores replicated the original BIS findings. These findings are discussed in relation to handedness research.
Link
Showing posts with label Handedness. Show all posts
Showing posts with label Handedness. Show all posts
October 21, 2008
June 29, 2006
Reproductive success of left-handers
Evolution and Human Behavior (Article in Press)
Handedness and reproductive success in two large cohorts of French adults
Charlotte Faurie et al.
Abstract
Left- and right-handers in humans coexist at least since the Paleolithic, and this variation in hand preference has a heritable basis. Because there is extensive evidence of an association between left-handedness and several fitness costs, the persistence of the polymorphism requires an explanation. It is not known whether the frequency of left-handedness in Western societies is stable or not. If the polymorphism is at equilibrium and maintained by frequency dependence, it implies that the fitness of left-handers equals that of right-handers. On the contrary, if left- and right-handers have a different fitness, the polymorphism will evolve. Using two large cohorts of French adults (men and women), we investigated the relations between handedness and several estimators of the reproductive value: marital status, number of sexual partners (of the opposite sex), number of children, and number of grandchildren. Left-handers seem to have disadvantages for some life-history traits, such as marital status (for women) and number of children. For other traits, we observed sex-dependent interactions with socioeconomic status: for high-income categories, left-handed women report less sex partners and left-handed men have more grandchildren. These kinds of interactions are to be expected under the hypothesis that the polymorphism of handedness is stable.
Link
Handedness and reproductive success in two large cohorts of French adults
Charlotte Faurie et al.
Abstract
Left- and right-handers in humans coexist at least since the Paleolithic, and this variation in hand preference has a heritable basis. Because there is extensive evidence of an association between left-handedness and several fitness costs, the persistence of the polymorphism requires an explanation. It is not known whether the frequency of left-handedness in Western societies is stable or not. If the polymorphism is at equilibrium and maintained by frequency dependence, it implies that the fitness of left-handers equals that of right-handers. On the contrary, if left- and right-handers have a different fitness, the polymorphism will evolve. Using two large cohorts of French adults (men and women), we investigated the relations between handedness and several estimators of the reproductive value: marital status, number of sexual partners (of the opposite sex), number of children, and number of grandchildren. Left-handers seem to have disadvantages for some life-history traits, such as marital status (for women) and number of children. For other traits, we observed sex-dependent interactions with socioeconomic status: for high-income categories, left-handed women report less sex partners and left-handed men have more grandchildren. These kinds of interactions are to be expected under the hypothesis that the polymorphism of handedness is stable.
Link
September 26, 2005
Left-handedness and breast cancer
Breast cancer risk double for left-handed women
Women who are left-handed are at increased risk of developing breast cancer at an early age, research has suggested.
Scientists believe that women who are born left-handed may have been exposed to higher levels of sex hormones in the womb.
They are more than twice as likely to be diagnosed with pre-menopausal breast cancer, according to a study published in the online version of the British Medical Journal. Researchers from the University Medical Centre in Utrecht followed more than 12,000 women born between 1932 and 1941.
They took into account other risk factors for breast cancer, such as body weight, smoking habits, family history and socio-economic status. Even when all these were adjusted for, women who were left-handed were 2.41 times more likely to develop breast cancer before the menopause.
Link (Independent)
Homosexual women tend to be more left-handed as well.
Women who are left-handed are at increased risk of developing breast cancer at an early age, research has suggested.
Scientists believe that women who are born left-handed may have been exposed to higher levels of sex hormones in the womb.
They are more than twice as likely to be diagnosed with pre-menopausal breast cancer, according to a study published in the online version of the British Medical Journal. Researchers from the University Medical Centre in Utrecht followed more than 12,000 women born between 1932 and 1941.
They took into account other risk factors for breast cancer, such as body weight, smoking habits, family history and socio-economic status. Even when all these were adjusted for, women who were left-handed were 2.41 times more likely to develop breast cancer before the menopause.
Link (Independent)
Homosexual women tend to be more left-handed as well.
December 15, 2004
Left-handers and homicide rate
This exciting new research discovered that the prevalence of left-handedness is correlated with the homicide rate in different human populations. The explanation proposed by the authors is that left-handers have an advantage during a fight, because they can surprise their opponents. This is supported by research in competitive sports where two individuals "fight" each other. However, in the past, fights were often to the death, and hence the advantage of left-handers would be selected, because they could fool their opponents more easily.
But, this ability to "fool" one's opponent is strongest when left-handedness is rare, i.e., when the right-hander doesn't expect it. As the frequency of left-handedness increases, the advantage of left-handers will gradually decrease. The equilibrium point will be different in different human societies depending on how "warlike" they are. In completely peaceful societies, no fights occur and hence left-handers have no advantage. In a very warlike society, left-handers get to kill their unfortunate right-handed opponents more frequently; but the frequency of left-handedness cannot increase unchecked, because its effectiveness diminishes as more and more people are using the "trick" of giving left-handed strikes.
The authors looked at eight traditional societies and discovered that left-handedness and the homicide rate, a measure of violence in a society are correlated. This gives strong support to this theory for the evolution of left-handedness.
Proceedings: Biological Sciences (FirstCite)
Handedness, homicide and negative frequency-dependent selection
Charlotte Faurie and Michel Raymond
Abstract:
Humans exhibit hand preference for most manual activities in which they are specialized. Right- and left-handers have coexisted at least since the Upper Palaeolithic, and left-handers are in the minority in all human populations. The persistence of the polymorphism of handedness is a puzzle because this trait is substantially heritable and several fitness costs are associated with left-handedness. Some countervailing benefit is required to maintain the polymorphism. Left-handers may have a frequency-dependent advantage in fights--the advantage being greater when their frequency is lower. Sports data from Western societies are consistent with this prediction. Here, we show that the frequency of left-handers is strongly and positively correlated with the rate of homicides across traditional societies. It ranges from 3% in the most pacifistic societies, to 27% in the most violent and warlike. This finding is consistent with a frequency-dependent selection mechanism maintaining left-handedness in these societies.
Link
But, this ability to "fool" one's opponent is strongest when left-handedness is rare, i.e., when the right-hander doesn't expect it. As the frequency of left-handedness increases, the advantage of left-handers will gradually decrease. The equilibrium point will be different in different human societies depending on how "warlike" they are. In completely peaceful societies, no fights occur and hence left-handers have no advantage. In a very warlike society, left-handers get to kill their unfortunate right-handed opponents more frequently; but the frequency of left-handedness cannot increase unchecked, because its effectiveness diminishes as more and more people are using the "trick" of giving left-handed strikes.
The authors looked at eight traditional societies and discovered that left-handedness and the homicide rate, a measure of violence in a society are correlated. This gives strong support to this theory for the evolution of left-handedness.
Proceedings: Biological Sciences (FirstCite)
Handedness, homicide and negative frequency-dependent selection
Charlotte Faurie and Michel Raymond
Abstract:
Humans exhibit hand preference for most manual activities in which they are specialized. Right- and left-handers have coexisted at least since the Upper Palaeolithic, and left-handers are in the minority in all human populations. The persistence of the polymorphism of handedness is a puzzle because this trait is substantially heritable and several fitness costs are associated with left-handedness. Some countervailing benefit is required to maintain the polymorphism. Left-handers may have a frequency-dependent advantage in fights--the advantage being greater when their frequency is lower. Sports data from Western societies are consistent with this prediction. Here, we show that the frequency of left-handers is strongly and positively correlated with the rate of homicides across traditional societies. It ranges from 3% in the most pacifistic societies, to 27% in the most violent and warlike. This finding is consistent with a frequency-dependent selection mechanism maintaining left-handedness in these societies.
Link
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