Changes

==Handedness==

==Handedness==

[[image:handedness.jpg|600px|thumb|applause-test for handedness according to Hamer]]

[[image:handedness.jpg|600px|thumb|Applause-test for handedness according to Hamer]]

In new medicine, handedness is important as it determined the location of an eventual disease like cancer. But in relation to handedness in man, Hamer made many erroneous statements in obvious contrast to actual medical knowledge.

In new medicine, handedness is important as it is believed to determine the location of an eventual disease like cancer. But in relation to handedness in humans, Hamer made many erroneous statements in obvious contrast to actual medical knowledge.

*'''monozygotic twins and handness''': Hamer is convinced that in monozygotic twins one was always left-handed while the other was one right-handed, but he gives no exact reference for this opinion.<ref>[...] Interessant ist in dem Zusammenhang auch, daß bei eineiigen Zwillingen stets einer linkshändig und der andere rechtshändig ist [...] (from: http://www.neue-medizin.de/html/handigkeit.html)</ref><ref>Hamer RG: Vermächtnis einer Neuen Medizin. Teil 2. Die 5 Biologischen Gesetze - Grundlage der gesamten Medizin.. 7. Aufl. Amici di Dirk - Ediciones de la Nueva Medicina S.L., E-Fuengirola 1999 ISBN 84-930091-0-5</ref> This opinion can easily be checked and there exists scientific literature dealing with this issue. Incidence of left-handedness in singletons, monozygotic and dizygotic twins is around 10%-15%, and there is no source stating that left-handedness was exactly 50% in monozygotic twins.<ref>Derom, Handedness in twins according to zygosity and chorion type: a preliminary report Behav genet 1996 Jul;26(4):407<br>

*'''Monozygotic twins and handness''': Hamer is convinced that, in monozygotic twins, one was always left-handed while the other one was right-handed, but gives no exact reference for this opinion.<ref>[...] Interessant ist in dem Zusammenhang auch, daß bei eineiigen Zwillingen stets einer linkshändig und der andere rechtshändig ist [...] (from: http://www.neue-medizin.de/html/handigkeit.html)</ref><ref>Hamer RG: Vermächtnis einer Neuen Medizin. Teil 2. Die 5 Biologischen Gesetze - Grundlage der gesamten Medizin.. 7. Aufl. Amici di Dirk - Ediciones de la Nueva Medicina S.L., E-Fuengirola 1999 ISBN 84-930091-0-5</ref> This opinion can easily be checked and there is scientific literature dealing with this issue. Incidence of left-handedness in singletons, monozygotic, and dizygotic twins is around 10%-15%, and there is no source stating that left-handedness was exactly 50% in monozygotic twins.<ref>Derom, Handedness in twins according to zygosity and chorion type: a preliminary report Behav genet 1996 Jul;26(4):407<br>

In the course of the East Flanders Prospective Twin Survey (EFPTS), handedness was assessed as part of a genealogical study (Meulemans et al., 1995) in 1616 twins (808 twin pairs) aged 6 to 28. Our findings are that, in this large population-based study with known placentation and zygosity, the often observed higher frequency of left-handedness in twins is confirmed, that it appears to be independent of zygosity and chorion type, and that the belief that discordant handedness in monozygotic twins represents mirror-imaging is mythical.</ref> The autor Derom writes: ''[...] the belief that discordant handedness in monozygotic twins represents mirror-imaging is mythical [...]''.<ref>Shimizu A, Comparison of patterns of handedness between twins and singletons in Japan, Cortex 1983 Sep;19(3):345-52<br>

In the course of the East Flanders Prospective Twin Survey (EFPTS), handedness was assessed as part of a genealogical study (Meulemans et al., 1995) in 1616 twins (808 twin pairs) aged 6 to 28. Our findings are that, in this large population-based study with known placentation and zygosity, the often observed higher frequency of left-handedness in twins is confirmed, that it appears to be independent of zygosity and chorion type, and that the belief that discordant handedness in monozygotic twins represents mirror-imaging is mythical.</ref> The autor Derom writes: ''[...] the belief that discordant handedness in monozygotic twins represents mirror-imaging is mythical [...]''.<ref>Shimizu A, Comparison of patterns of handedness between twins and singletons in Japan, Cortex 1983 Sep;19(3):345-52<br>

The handedness questionnaire of thirteen items which was identical to that employed in our previous study on singletons was administered to 62 monozygotic (MZ) and 48 dizygotic (DZ) twin pairs in Japan. Information on forced conversion of hand usage in childhood was also obtained. Results indicated that the incidence of left-handedness was 3.6% and that of non-right-handedness (which includes mixed- and left-handedness) was 5.9%. There was no significant difference in the incidence of left-handedness or of non-right-handedness between MZ and DZ twin groups. The proportion of converted right-handedness in MZ twins was slightly higher than in DZ twins. MZ pairs were somewhat more concordant for handedness than DZ pairs. Item analysis indicated that the incidence of individuals who use the left hand for writing and eating was only 0.9% and 1.8%, respectively. A comparison of the results of the present survey on twins with those of our previous one on singletons revealed that the incidence of left-handedness or non-right-handedness in twins is the same as that in singletons. Twins (especially MZ twins) have experienced a forced conversion to right-hand usage more frequently than singletons.</ref>

The handedness questionnaire of thirteen items which was identical to that employed in our previous study on singletons was administered to 62 monozygotic (MZ) and 48 dizygotic (DZ) twin pairs in Japan. Information on forced conversion of hand usage in childhood was also obtained. Results indicated that the incidence of left-handedness was 3.6% and that of non-right-handedness (which includes mixed- and left-handedness) was 5.9%. There was no significant difference in the incidence of left-handedness or of non-right-handedness between MZ and DZ twin groups. The proportion of converted right-handedness in MZ twins was slightly higher than in DZ twins. MZ pairs were somewhat more concordant for handedness than DZ pairs. Item analysis indicated that the incidence of individuals who use the left hand for writing and eating was only 0.9% and 1.8%, respectively. A comparison of the results of the present survey on twins with those of our previous one on singletons revealed that the incidence of left-handedness or non-right-handedness in twins is the same as that in singletons. Twins (especially MZ twins) have experienced a forced conversion to right-hand usage more frequently than singletons.</ref>

*'''Hamerian applause-test and prayer-test'''. Hamer uses his own and controversial test for handedness, the so-called ''Applause test'' and a so-called ''Bet-Test'' (prayer-test). These simple tests have never been scientifically validated and have a pseudoscientific character. No information regarding these tests can be found in scientific databases. Using these tests, some New Medicine patients were attributed a conflicting handedness by different persons, creating some confusion.  

*'''Hamerian Applause Test and Prayer Test'''. Hamer uses his own and controversial test for handedness, the so-called ''Applause test'' and a so-called ''Bet-Test'' (prayer test). These simple tests have never been scientifically validated and are of pseudoscientific character. No information regarding these tests can be found in scientific databases. Using these tests, some New Medicine patients were attributed a conflicting handedness by different persons, creating some confusion.  

*'''Handedness and body side to cradle babies'''. Hamer is convinced that women and men would cradle their babies always on the opposite side of her dominant hand. A left-handed woman would therefore always hold her baby on the right side of her body. This is not true, and many scientific sources tell us something different. Men and women hold their baby mostly (80%) on their left side, regardless of handedness. This is also true for apes (primates). <ref>Salk L, The effects of the normal heartbeat sound on the behavior of the new-born infant: implications for mental health. World Mental Health 1960 12, 168-175</ref><ref>De Chateau, Left-side preference for holding and carrying newborn infants. Parental holding and carrying during the first week of life, J Nerv Ment Dis 1983 Apr;171(4):241-5,Four groups of adults were studied: new mothers, new fathers, fathers with older children, and males without children of their own. Nearly 80 per cent of all newly delivered mothers and fathers held their newborn infant against a point to the left of the body midline. Handedness and parity did not influence this preference, nor did the sex of the infant. The present study also demonstrates that new fathers during the neonatal period, as well as fathers with older infants, display a significantly greater preference for holding the infant to the left than males without own children and with or without experience of other children. Individual mother-father pairs held the infant on the same side of the body in the majority of couples studied. The pattern of infant-carrying showed no significant in-between group differences. The possible significance of these observations and their relation to other parental behavior are discussed.</ref><ref>Mason Giorgia, Why do humans and apes cradle babies on their left side? New Scientist, 21. July 1990, 28.</ref><ref>Sieratzki JS, Neuropsychological and neuropsychiatric perspectives on maternal cradling preferences, Epidemiol Psychiatr Soc 2002 Jul-Sep;11(3):170-6

*'''Handedness and body side to cradle babies'''. Hamer is convinced that women and men will always cradle their babies on the opposite side of their dominant hand. A left-handed woman thus was to hold the baby on the right side of her body. This is not true, and many scientific sources tell us something different. Men and women hold their baby mostly (80%) on their left side, regardless of handedness. This is also true for apes (primates). <ref>Salk L, The effects of the normal heartbeat sound on the behavior of the new-born infant: implications for mental health. World Mental Health 1960 12, 168-175</ref><ref>De Chateau, Left-side preference for holding and carrying newborn infants. Parental holding and carrying during the first week of life, J Nerv Ment Dis 1983 Apr;171(4):241-5,Four groups of adults were studied: new mothers, new fathers, fathers with older children, and males without children of their own. Nearly 80 per cent of all newly delivered mothers and fathers held their newborn infant against a point to the left of the body midline. Handedness and parity did not influence this preference, nor did the sex of the infant. The present study also demonstrates that new fathers during the neonatal period, as well as fathers with older infants, display a significantly greater preference for holding the infant to the left than males without own children and with or without experience of other children. Individual mother-father pairs held the infant on the same side of the body in the majority of couples studied. The pattern of infant-carrying showed no significant in-between group differences. The possible significance of these observations and their relation to other parental behavior are discussed.</ref><ref>Mason Giorgia, Why do humans and apes cradle babies on their left side? New Scientist, 21. July 1990, 28.</ref><ref>Sieratzki JS, Neuropsychological and neuropsychiatric perspectives on maternal cradling preferences, Epidemiol Psychiatr Soc 2002 Jul-Sep;11(3):170-6

OBJECTIVE: To assess competing explanations for the universal preference of mothers to cradle infants on their left side and to propose a relation to hemispheric asymmetry for social attachment and communication behaviour. METHODS: A review of observational, experimental, physiological, psychological, neuro-physiological, and neuro-psychological studies, including new findings on the cradling behaviour of mothers with auditory or visual impairments. RESULTS: A significant left-cradling bias is observed in both right- and left-handed mothers which cannot adequately be explained by arguments based on handedness or closer contact to the soothing sound of the maternal heartbeat. Observations of primate behaviour have led to the suggestion that the left-cradling bias may be related to a left visual field (right hemisphere) advantage for monitoring an infant's facial expressions of distress. However, more than just monitoring, cradling subserves the mother's connection with the infant. For that reason, we have suggested that left cradling might be related to a right hemisphere specialisation for emotional communication, i.e. the speech melody, smiles, signals, and stroking which mothers use to interact with their infants. Studies of mother-infant interaction show that the sound of the mother's voice is more soothing when cradling on the left, more stimulating when cradling on the right. Cradling laterality may thus be related to emotional state and behavioural intent. There is also evidence to suggest that left cradling is linked to a special role of the right hemisphere in social attachment behaviour. This function may be disturbed in mothers with post-natal depression who show abnormal right hemisphere activity. CONCLUSION: Cradling embodies the symbiotic relationship between mother and infant; various lines of evidence support the suggestion that the universal preference of mothers to cradle infants on their left side is related to a right hemisphere dominance for social attachment and communication behaviour.</ref><ref>Bogren LY, Side preference in women and men when holding their newborn child: psychological background, Acta Psychiatr Scand 1984 Jan;69(1):13-23

OBJECTIVE: To assess competing explanations for the universal preference of mothers to cradle infants on their left side and to propose a relation to hemispheric asymmetry for social attachment and communication behaviour. METHODS: A review of observational, experimental, physiological, psychological, neuro-physiological, and neuro-psychological studies, including new findings on the cradling behaviour of mothers with auditory or visual impairments. RESULTS: A significant left-cradling bias is observed in both right- and left-handed mothers which cannot adequately be explained by arguments based on handedness or closer contact to the soothing sound of the maternal heartbeat. Observations of primate behaviour have led to the suggestion that the left-cradling bias may be related to a left visual field (right hemisphere) advantage for monitoring an infant's facial expressions of distress. However, more than just monitoring, cradling subserves the mother's connection with the infant. For that reason, we have suggested that left cradling might be related to a right hemisphere specialisation for emotional communication, i.e. the speech melody, smiles, signals, and stroking which mothers use to interact with their infants. Studies of mother-infant interaction show that the sound of the mother's voice is more soothing when cradling on the left, more stimulating when cradling on the right. Cradling laterality may thus be related to emotional state and behavioural intent. There is also evidence to suggest that left cradling is linked to a special role of the right hemisphere in social attachment behaviour. This function may be disturbed in mothers with post-natal depression who show abnormal right hemisphere activity. CONCLUSION: Cradling embodies the symbiotic relationship between mother and infant; various lines of evidence support the suggestion that the universal preference of mothers to cradle infants on their left side is related to a right hemisphere dominance for social attachment and communication behaviour.</ref><ref>Bogren LY, Side preference in women and men when holding their newborn child: psychological background, Acta Psychiatr Scand 1984 Jan;69(1):13-23

In a prospective study 81 randomly selected parents awaiting their first baby were interviewed early during pregnancy and again during the week after delivery. About 80% of the women and their partners were found to hold their child to the left, and 20% to the right, irrespective of handedness. There was no relation between side preference in child holding in the couples. Common to both sexes is the trend that left-holders are more attached to and identified with the parent of their own sex whereas right-holders are more attached to and identified with the parent of the opposite sex. Right-holders have also more often had mental symptoms prior to pregnancy and were concerned about the pregnancy, delivery and health of the child at birth.</ref><ref>Bogren LY, The couvade syndrome and side preference in child holding, Acta Psychiatr Scand 1985 Mar;71(3):311-4,In a prospective study of expectant couples 20% of the men suffered from the couvade syndrome. About 80% of both women and men hold their newborn infant to the left and 20% to the right, irrespective of handedness. Compared with others, men with the syndrome more frequently developed a right-side preference in child holding. Right-holding men more often had sons than daughters. Right-holders with the couvade syndrome were more often attached to and more closely identified with their mothers than were right-holding non-sufferers.</ref><ref>Ginsburg HJ, Maternal holding preferences: a consequence of newborn head-turning response, Child Dev 1979 Mar;50(1):280-1,

In a prospective study 81 randomly selected parents awaiting their first baby were interviewed early during pregnancy and again during the week after delivery. About 80% of the women and their partners were found to hold their child to the left, and 20% to the right, irrespective of handedness. There was no relation between side preference in child holding in the couples. Common to both sexes is the trend that left-holders are more attached to and identified with the parent of their own sex whereas right-holders are more attached to and identified with the parent of the opposite sex. Right-holders have also more often had mental symptoms prior to pregnancy and were concerned about the pregnancy, delivery and health of the child at birth.</ref><ref>Bogren LY, The couvade syndrome and side preference in child holding, Acta Psychiatr Scand 1985 Mar;71(3):311-4,In a prospective study of expectant couples 20% of the men suffered from the couvade syndrome. About 80% of both women and men hold their newborn infant to the left and 20% to the right, irrespective of handedness. Compared with others, men with the syndrome more frequently developed a right-side preference in child holding. Right-holding men more often had sons than daughters. Right-holders with the couvade syndrome were more often attached to and more closely identified with their mothers than were right-holding non-sufferers.</ref><ref>Ginsburg HJ, Maternal holding preferences: a consequence of newborn head-turning response, Child Dev 1979 Mar;50(1):280-1,