Pathological left-handedness and ambiguous handedness: A new explanatory model

Soper, Henry V.; Satz, Paul

doi:10.1016/0028-3932(84)90046-0

Cited by 82 publications

(35 citation statements)

References 18 publications

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“…Another interpretation of mixed-handedness is inconsistent preference for a specific action, termed 'ambiguous' handedness (Soper and Satz, 1984), and reported as frequent in schizophrenics (Green, 1997;Satz and Green, 1999 Rust, 1989). The first study led to a surprising finding.…”

Section: Introductionmentioning

confidence: 99%

Schizotypy is increased in mixed-handers, especially right-handed writers who use the left hand for primary actions

Annett

Moran

2006

Schizophrenia Research

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Associations between schizotypy and handedness were examined in 733 undergraduates for the Sta and Unex scales of the O-Life inventory and several measures derived from the Annett hand preference questionnaire. Higher schizotypy scores were found for mixed-handers defined in various ways, including inconsistent preference for any item of the questionnaire and also the presence of either hand responses. There was a marked elevation of schizotypy scores (p < .001) for righthanded writers who prefer the left hand for other 'primary' actions (throwing, racket, match, hammer, toothbrush and scissors). This observation was replicated in 182 students assessed on the Rust Scale of Schizotypal Cognitions. Several findings agree that inconsistent hand preference is associated with a raised probability of schizotypal thinking.

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Section: Introductionmentioning

confidence: 99%

Schizotypy is increased in mixed-handers, especially right-handed writers who use the left hand for primary actions

Annett

Moran

2006

Schizophrenia Research

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“…A more viable explanation is that discordant MZ twins are affected by differential environmental factors such as differential perinatal stress that is associated with higher incidences of left-handedness (Soper & Satz 1984; see references in Sicotte et al (1999) and Hopkins et al (2000) for chimpanzees). For example, primiparae might be more exposed to birth stress (Orlebeke et al 1996); twins might influence each other and twin members lay in differential position in the womb (Geschwind & Galaburda 1985), which could affect lateralization in twins.…”

Section: Explanatory Power Of Genetic Modelsmentioning

confidence: 99%

Epigenesis of behavioural lateralization in humans and other animals

Schaafsma

Riedstra

Pfannkuche

et al. 2008

Phil. Trans. R. Soc. B

107

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Despite several decades of research, the epigenesis of behavioural and brain lateralization is still elusive, although its knowledge is important in understanding developmental plasticity, function and evolution of lateralization, and its relationship with developmental disorders. Over the last decades, it has become clear that behavioural lateralization is not restricted to humans, but a fundamental principle in the organization of behaviour in vertebrates. This has opened the possibility of extending descriptive studies on human lateralization with descriptive and experimental studies on other vertebrate species. In this review, we therefore explore the evidence for the role of genes and environment on behavioural lateralization in humans and other animals. First, we discuss the predominant genetic models for human handedness, and conclude that their explanatory power alone is not sufficient, leaving, together with ambiguous results from adoption studies and selection experiments in animals, ample opportunity for a role of environmental factors. Next, we discuss the potential influence of such factors, including perinatal asymmetrical perception induced by asymmetrical head position or parental care, and social modulation, both in humans and other vertebrates, presenting some evidence from our own work on the domestic chick. We conclude that both perinatal asymmetrical perception and later social modulation are likely candidates in influencing the degree or strength of lateralization in both humans and other vertebrates. However, in most cases unequivocal evidence for this is lacking and we will point out further avenues for research.

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“…They tend to have poor reliability on follow-up (McMeekan & Lishman, 1975). The term 'ambiguous' handedness was suggested for changes of hand between trials of the same task (Soper & Satz, 1984). In questionnaire surveys of several actions I found that if Es were recognised as criteria of nonright preference, over 50% of healthy participants would be classified as non-right-handed.…”

mentioning

confidence: 99%

Hand preference observed in large healthy samples: Classification, norms and interpretations of increased non‐right‐handedness by the right shift theory

Annett

2004

British J of Psychology

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Healthy children and undergraduates were observed for hand preference and measured for hand skill in representative samples collected over some years. Writing and throwing were observed for 2844 participants drawn from primary, secondary and higher levels of education. The 12 actions of a standard questionnaire were observed for 2388 secondary school children and undergraduates. These findings provide normative data for comparison with selected samples that may be classified in a variety of ways, including subgroups previously defined and ordered for relative hand skill. Differences between the sexes were found only for certain subgroups of right‐mixed‐handers. Undergraduates were less variable for hand skill asymmetry than schoolchildren. Interpretations in the light of the RS theory show why statistical effects for comparisons with selected groups are likely to be small. Increased non‐right‐handedness may be caused by several influences on cerebral dominance, natural and pathological.

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Pathological left-handedness and ambiguous handedness: A new explanatory model

Cited by 82 publications

References 18 publications

Schizotypy is increased in mixed-handers, especially right-handed writers who use the left hand for primary actions

Schizotypy is increased in mixed-handers, especially right-handed writers who use the left hand for primary actions

Epigenesis of behavioural lateralization in humans and other animals

Hand preference observed in large healthy samples: Classification, norms and interpretations of increased non‐right‐handedness by the right shift theory

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