Handedness

Population-level right-handedness is a defining characteristic of humans. Despite extensive research, we still do not know the conditions or timing of its emergence in human evolution. We present a review of research into the origins of handedness, based on fossil and archaeological data for hand preference and great ape hand-use. The data show that skeletal asymmetries in arm and hand bones supporting a rightsided dominance were present at least in the genus Homo, although data are more robust for Neanderthals. The evidence from tool-use, production, and cave art confirms that right-hand preference was established in Neanderthals and was maintained until the present. The great apes can provide real-life models for testing the conditions that facilitate or enhance hand preference at both the individual and group levels. The database on great ape hand-use indicates that they do exhibit hand preferences, especially in complex tasks. However, their preferences vary between tasks, and w...

Współczesne prace neuroobrazowe ujawniają istnienie, niezależnych od ręczności, różnych fenotypów rozkładu funkcji mózgowych, za którymi stoją złożone i wielowymiarowe obwody neuronalne. Eksplorację i wyjaśnienie przejść pomiędzy odmiennymi fenotypami funkcji może ułatwić badanie osób leworęcznych, wśród których znacznie częściej występują przypadki nietypowe. Szczególnie pomocne jest badanie funkcji, które są ze sobą ściśle powiązane. Dociekanie siły związków oraz kierunków segregacji funkcji jest tym bardziej informatywne, im więcej nietypowych przypadków powiązań i rozdzielności da się wykryć. Niniejsza praca przedstawia badania, które mogą dać nowy wgląd w organizację funkcjonalną mózgu na przykładzie lateralizacji/organizacji języka oraz praksji i ich skomplikowanych związków z ręcznością.

Predictions concerning the effects of handedness and attention on bimanual coordination were made from a dynamical model that incorporates the body's lateral asymmetry. Both handedness and the direction of attention (to the left or right) were manipulated in an inphase 1:1 frequency locking task. Left-handed and right-handed participants had to coordinate the planar oscillations of 2 handheld pendulums while 1 pendulum oscillated between spatial targets positioned over either the left or right hand. Predictions from the model were that participants would show a phase lead with the preferred hand, and that, although the phase lead would be greater when attention was directed to the preferred hand, the variability of relative phase would be lower. Confirmation of these predictions suggests that the dynamical perspective offers the possibility of studying handedness and attention without compromising theoretical precision or experimental control.

Brain lateralization is a common term used to describe dominance of one brain hemisphere over another for a specific function. The right hand dominance in writing, controlled by the left hemisphere, is preceded by development of communicative gesticulation and followed by development of speech in the same hemisphere. We assumed that some people are not aware of their own capability of using the other hand for tasks involving fine motor sequential movements. To prove this hypothesis, the participants were asked to perform one trained task (writing) and one less-trained task (drawing) with a dominant and a non-dominant hand. The final sample was comprised of 1189 children from 14 elementary schools and 8 high schools in the Osijek area, of which 685 elementary school children were attending 1st to 4th grade and 504 high school children were attending 3rd and 4th grade. The participants were asked to write two words, draw a specific object (a vase with flowers) and fill out a questionn...

Executive functions are proposed to underpin intelligent goal-directed behavior.  Such skills, linked through multiple neuropsychological studies to functioning of the frontal lobes, are theorized to predict achievement in non-routine activities.  Furthermore, patients with frontal lobe damage often display disorganized behavior and real-life failures such as employment instability and bankruptcy despite normal or superior intelligence.  These observations suggest that executive ability should predict real-life successes within challenging, non-routine environments, and that it is perhaps more important than intelligence.  We used the context of professional sales as a test of these hypotheses.  Ninety new-car sales personnel completed an intelligence test and five assessments previously identified as sensitive to neuropsychological impairment independently of impairments of general intelligence.  The results revealed some sex differences, e.g., saleswomen performing significantly worse than salesmen on general intelligence but significantly better on multi-tasking.  As hypothesized, general intelligence did not predict objective sales, nor did skills in abstraction, multi-tasking, or theory of mind.  However, two tests of inhibition were significant predictors of sales achieved.  This was dependent on the sex of the personnel.  Sales were predicted by verbal response suppression for men and by motor response withholding for women.  The results validate the role of executive functions in real-life achievement in challenging, non-routine, environments.  In particular, they suggest that response inhibition may be a cognitive skill that particularly contributes to real-life success, at least in the context of sales, and this depends on biological sex.  Finally, some executive functions may be better predictors of real-life success than general intelligence.

The transversely bianisotropic uniaxial medium considered in the present article can be obtained, e.g., by mixing metal helices with an isotropic base medium in such a way that the axes of the helices are randomly oriented but perpendicular to a fixed direction in space. The medium is a generalization of the well-studied chiral medium, and is somewhat similar to the recently studied axially bianisotropic uniaxial medium, which has interesting polarization properties. Plane-wave propagation in the medium is studied and the solution for the dispersion equation is given. Numerical examples for the wave numbers corresponding to the two eigenwaves of the medium are displayed. It is seen that, unlike in the axially bianisotropic uniaxial medium, there are no optical axes in the present medium, in general. © 1993 John Wiley & Sons, Inc.

The aim of this study was to investigate the personality differences between male and female students
according to brain asymmetries. 762 Subjects were chosen by random multi-session sampling method Tehran
Universities. Subjects administered the NEO-PI-R all in one session. As the sample distribution was not normal, the
results were analyzed by Mann-Whitney U. The results showed that male students had higher scores than female
students only in neuroticism (p < 0.05). Female students had higher scores in extraversion, openness to experience,
agreeableness and conscientiousness (p < 0.05). Some parts of the results are not consistent with the literature on
Five-Factor Model of Personality. The differences in results are probably because of consideration of a wide range
of neuropsychological control variables.
Key Words: Five-factor model of personality (FFM), Gender, Asymmetry, Handedness, Eye Dominance.

This is a trial of the EHI_8, which has been available for example on ResearchGate and Academia.edu for about ten years and adopted for use in their research by numerous researchers (it has already received over twenty citations on Google Scholar). Some of the participants were paid, through Survey Monkey. The sample was a community one of all ages. Pre-processing of the completed responses indicated that all the 76 used were answered conscientiously. Thirteen of the 76 (17%) were not right-handed, seven classified left- and six mixed-handers. For several reasons nonparametric statistics are indicated. A principal component analysis confirms a single-factor solution, and in line with other findings pointing in the same direction finds Knife and Mouse to be outliers. Computer mouse, which is the new item, should be persisted with. Configuring a mouse for left-hand use will become more user-friendly and the item will improve over time, as scissors has done due to the easier availability of left-handed scissors. The EHI_8 has high internal reliability and is much better than the original EHI_10 for identifying “truly” inconsistent handedness. The trial was small in scale, but not so much as to distort the major findings.

A list has been prepared (appendix A) of 182 articles featuring the Edinburgh Handedness Inventory prominently, ordered by citations received. The article introducing the inventory has been cited an extreme number of times (over 26,000 on the specific date investigated). Another article confirming the relevance of left- and mixed-handedness to neurology has also attracted a great deal of attention. A core set of journals is identified that published many of these articles. Of numeric variables explored, only the age of the article had an influence on the citation counts: unsurprising but the modest degree of influence is more so. A secular trend is exposed of greater multi-authorship, particularly in the peripheral set of journals. It has little benefit in terms of citations. The more productive authors are identified. Evidence is presented that it is the neurological significance of handedness that interests researchers most.

Previous research has attempted to understand why countries with relatively favorable conditions and high estimated average IQs (such as Finland and Japan) have a relatively low per capita number of scientific Nobel prizes. In the present study, we examine whether there is a relationship between national schizophrenia and left-handedness prevalence, on the one hand, and per capita scientific and literary achievement, on the other hand, in countries with IQ estimates of at least 90. We found that per capita science and literature Nobel prizes and scientific publications are strongly negatively associated with schizophrenia and strongly positively correlated with left-handedness. There also was a very pronounced negative correlation between schizophrenia rate and left-handedness rate. These results suggest that genius can be regarded as a combination of very high IQ, aspects of high-functioning autism (specifically low empathy) plus relatively low impulse control, consistent with observations of intellectually outstanding individuals, and the fact that schizophrenia appears to constitute the opposite pole of these aspects of autism spectrum. We posit differences in androgen levels as a possible underlying explanation for these findings.

Men and women living in New Zealand and California completed five studies regarding human physique and sexual attractiveness. In Studies 1–3, women rated images of male stimuli and, in Studies 4–5, men rated female stimuli. In Study 1, women in both countries rated mesomorphic (muscular) and average male somatotypes as most attractive, followed by ectomorphic (slim) and endomorphic (heavily built) figures. In Study 2, amount and distribution of masculine trunk hair (chest and abdominal) was altered progressively in a series of front-posed male figures. In both countries, the image lacking any trunk hair was rated as the most attractive, with a steady decline in attractiveness as hirsutism became more pronounced. Study 3 assessed attractiveness of front-posed male figures that varied only in the length of the non-erect penis. Five lengths were presented: The smallest penile size was rated as less attractive than three intermediate sizes. The largest penile size was not the most attractive, but received higher scores than the unaltered and smallest penile size. In Study 4, men rated the attractiveness of back-posed female images varying in waist-to-hip ratio (WHR) (from 0.5 to 1.0). The 0.7 WHR figure was rated more attractive in New Zealand and the 0.6 WHR in California. Study 5 measured the attractiveness of female skin color; men expressed preferences for lighter skinned female figures in New Zealand and California. Results indicate very similar preferences for sexually dimorphic physical traits among men and women of European extraction, living in two culturally and geographically different environments.

Homo sapiens sapiens displays a species wide lateralised hand preference, with 85% of individuals in all populations being right-handed for most manual actions. In contrast, no other great ape species shows such strong and consistent population level biases, indicating that extremes of both direction and strength of manual laterality (i.e., species-wide right-handedness) may have emerged after divergence from the last common ancestor. To reconstruct the hand use patterns of early hominins, laterality is assessed in prehistoric artefacts. Group right side biases are well established from the Neanderthals onward, while patchy evidence from older fossils and artefacts indicates a preponderance of right- handed individuals. Individual hand preferences and group level biases can occur in chimpanzees and other apes for skilled tool use and food processing. Comparing these findings with human ethological data on spontaneous hand use reveals that the great ape clade (including humans) probably has a common effect at the individual level, such that a person can vary from ambidextrous to completely lateralised depending on the action. However, there is currently no theoretical model to explain this result. The degree of task complexity and bimanual complementarity have been proposed as factors affecting lateralisation strength. When primatology meets palaeoanthropology, the evidence suggests species-level right-handedness may have emerged through the social transmission of increasingly complex, bimanually differentiated, tool using activities.

Des origines de la latéralisation et des rapports entre latéralités manuelle et cérébrale Bulletin de psychologie, Tome XXXIII, n* 343 , Université de Paris, déc. 1979. Des origines de la latéralisation et des rapports entre latéralités manuelle et cérébrale Evolution. L'asymétrie dans la structure des organismes est un fait biologique bien connu qui se retrouve à tous les stades de l'évolution, même dans les formes animales les plus primitives (Monod, 1969). La signification de l'asymétrie, le problème de sa transmission génétique, enfin l'apparente contradiction entre asymétrie strucurale et symétrie comportementale sont autant d'énigmes pour le biologiste et pour le psychologue qui s'interroge sur la latéralité humaine. La symétrie que l'on observe tout au long du règne animal, — sphérique pour les créature primitives qui vivent en suspension dans l'eau, axiale pour celles qui vivent au fond de l'eau dans un milieu soumis à une force gravitationnelle, enfin bilatérale chez les organismes capables de mouvements dans une direction —, s'oppose toujours à quelques asymétries structurales, parfois grossières : coeur à gauche chez tous les vertébrés, asymétrie des pinces du crabe (Gardner, 1967), jusqu'à l'asymétrie des membres supérieurs et du visage humain (Gilbert et Bakan, 1973). Chez l'homme cependant l'asymétrie fonctionnelle, (c'est-à-dire la latéralité manuelle et cérébrale, est considérée comme récente dans l'évolution. T Comparés à l'homme, qui présente des signes de latéralisation corporelle systématique dès la naissance, les animaux sont répartis également entre gauchers et droitiers en ce qui concerne l'utilisation préférentielle de l'une des pattes. Il existe cependant quelques rares exceptions, notamment chez les oiseaux. Chaque animal tend à se latéraliser avec l'expérience. Lehman, 1978, par exemple, trouve un effet de l'âge sur la stabilité de la latérallsation chez le singe rhésus : il n'observe pas de préférence manuelle initiale chez les jeunes animaux, tandis que les singes plus âgés montrent une préférence manuelle spontanée qui reste stable aux essais suivants. En répétant la tâche de prendre une pièce de nourriture (l'observation s'étend sur 600 gestes par animal), les singes, jeunes et vieux, parviennent a une préférence manuelle d'environ 85 %. Au niveau de l'asymétrie cérébrale, Nottebohm, 1971, 1972, a montré que le chant des oiseaux est handicapé après section du nerf hypoglosse gauche et non pas après celle du droit. Chez le singe, plusieurs auteurs ont montré une asymétrie des lobes temporaux (démontrée précédemment chez les humains). Par conséquent, bien que la latéralité maluelle et cérébrale caractérise fortement les comportements humains, on ne peut pas affirmer qu'elle fasse la différence entre les animaux et les hommes. L'avantage d'une latéralisation manuelle et cérébrale pour l'homme est sujet de spéculations très controversées. Il semble que, dans l'histoire des hommes, l'asymétrie comportementale fût déjà présente, sinon apparût, à époque de la prolifération des outils fabriqués. De plus, la latéralisation cérébrale représente, au moins pour Brown, 1976, la continuation du processus non seulement phylogénétique d'encéphalisation, mais également ontogénétique, résultant dans l'émergence de territoires focalisés qui deviendront les zones du langage humain. L'homme hériterait un gradient de latéralisation Chez l'homme, on ne peut expliquer le fait que toutes les civilisations soient droitières qu'en postulant l'existence d'un gradient qui guide la maturation selon un ensemble de lois concernant la spécialisation de la gauche et de la droite du corps et en particulier du

The discipline of Paleoneurology goes beyond the determination of biological characteristics and morphologies; it can also be used to infer behaviour in extinct species. In Paleocognition, the cognitive capacities of extinct humans can be examined through their fossil remains and the tools they left behind. This chapter examines some inferences that can be made about the origins of language based on paleoneurological and archaeological evidence. It focuses on laterality as a case study for the many behaviours that can be inferred from archaeology, and which are relevant to the origins and evolution of language. First is a review of the ontogeny of human hand preference, handedness in humans, and the hand preferences of non-human apes. Human handedness begins before birth, and develops into adulthood. All human populations have a majority of right-handers; explanations for the maintenance of a minority of left-handers are discussed. Next, the data for hand preferences and asymmetries in extinct fossil hominins are summarised. These show that species-level right-handedness has existed since Homo heidelbergensis, but there is only evidence for left-handed minorities in Neanderthals and Homo sapiens. Finally, links between language, hand skill, ancient stone tool-making, and other cultural behaviours are discussed to propose a tentative date for the origins of language.

In the history of jazz, only a very few bassists have played ‘left-handed’ on a ‘righthanded’ instrument. This ‘idiodextrous’ approach is an embodied phenomenon that affects the body-instrument interface, giving rise to unique physical and sonic consequences. Each idiodextrous bassist studied here was mostly self-taught and ‘intuitively’ applied this unconventional handedness approach to a conventional instrument. Studying this rare practice raises questions that challenge traditions of string instrument playing and expose arbitrary prejudices against unconventional handedness approaches. Since its defining trait is the ‘reversed’ order of the strings in relation to the body, idiodexterity challenges assumptions about the ideal stringings for different musical contexts. The malleability of identities and cultures in jazz is arguably more receptive to unusual handedness approaches than is the classical tradition. In the context of jazz improvisation, idiodexterity may even facilitate the development of a ‘uniquely idiodextrous’ vocabulary of musical phrases and techniques. This paper is an attempt to succinctly encompass the issues central to idiodextrous double bass in jazz, within the scope of a one-year MA by Research programme, and to make recommendations for future studies. Four main areas of research have been investigated: Instrument, Body, Identity and Vocabulary. Interviews with bassists of varying handedness approaches, with luthiers and with body experts have been employed to address this unique subject, compensating for the effective non-existence of any previous academic literature. The insights of these expert practitioners contribute new knowledge on this rare and intriguing practice.

The Tyrolean Iceman, a 5,300-year-old glacier mummy recovered at the Tisenjoch (South Tyrol, Italy) together with his clothes and personal equipment, represents a unique opportunity for prehistoric research. The present work examines the Iceman’s tools which are made from chert or are related to chert working ‑ dagger, two arrowheads, endscraper, borer, small flake and antler retoucher ‑ and considers also the arrowhead still embedded in the shoulder of the mummy. The interdisciplinary results achieved by study of the lithic raw material, technology, use-wear analysis, CT analysis and typology all add new information to Ötzi‘s individual history and his last days, and allow insights into the way of life of Alpine Copper Age communities. The chert raw material of the small assemblage originates from at least three different areas of provenance in the Southalpine region. One, or possibly two, sources derive from outcrops in the Trentino, specifically the Non Valley. Such variability s...

In an earlier essay a discussion was presented of left- and right-handedness in writing-painting contexts on painted, incised, and carved Classic Maya ceramic containers. In an opening section entitled “Visualizing the Hand”, I referred in short to a series of hieroglyphic signs that depict or include the human hand. Hermann Beyer (1934) was the first researcher to describe the “hand” in Maya hieroglyphs, but the corpus with which he worked was much smaller than currently available. The present essay describes 45 common as well as rare and unique hieroglyphic signs that depict or include the human hand. The different signs are presented and described in alphabetical order according to their currently accepted syllabic or logographic value within the international epigraphic community.

Right-handedness dominates among all human populations but the question is if and how the
Aegean artists depicted it in their art, or whether they compromised between reality and artistic concepts.
In order to find answers to those questions, this paper examines wall and vase paintings, stone and metal
vases, ivories, bronzes and terracottas, larnakes, stelae, daggers (seals and sealings are excluded because
of the seal/sealing problem). These are examined according to the categorisation of skilled and unskilled,
bi- and unimanual activities. The results suggest a domination of right-handedness in the Aegean iconography with some exceptions resulting mainly from the symmetry of specific compositions. It is also
notable that the Aegean artists tended to represent right hands as the near ones and they preferred to show
shoulders supporting long objects like spears as the near ones regardless of the orientation of depicted
subjects.

Directional preferences in moving images are primarily theorized as deriving from 'cultural' factors, principally the dominant language's reading/writing direction. This study examines the origins of this notion and positions it within recent analytical thinking. In order to expand the context of analysis it draws in research from neurology and practical knowledge of typical production tools. Two manifestations of directionality-camera panning movements (pans) and soundbite gaze direction-are compared, data is drawn from two countries, Japan and the UK, where directional conventions may differ. Results suggest there is a limited degree of support for the hypothesis that reading/writing direction is linked to directional preferences in television news image creation, but the processes involved may be subconscious rather than conscious and analysts should therefore be wary of attibuting semiotic significance to these variations, of 'over-reading' manifestations of directionality in news images.

According to Greimas, the semiotic square is far more than a heuristic for semantic and literary analysis. It represents the generative "deep structure" of human culture and cognition which "define the fundamental mode of existence of an individual or of a society, and subsequently the conditions of existence of semiotic objects". The veracity of this bold hypothesis has received little attention in the literature. In response, this paper traces the history and development of the square of opposition from Aristotle to Greimas and beyond, to propose that the relations modeled in these diagrams are rooted in gestalt memories of kinesthesia and proprioception from which we derive basic structural awareness of opposition and contrast-including verticality, bilaterality, transversality, markedness and analogy. The paper draws on findings in the phenomenology of movement, recent developments in the analysis of logical opposition, recent scholarship in (post)Greimasian semiotics and prescient insights from Greimas himself. The argument is further tested via multimodal content analyses of a popular music video-highlighting relationships the semiotic square shares with mundane cultural ideologies and showing how these relationships might be traced to memory structures of bodily movement. The paper highlights the neglected relevance of embodied chiasmus and illustrates the enduring relevance of Greimasean thought.

Recent studies show that in the sport of fencing left-handers have an advantage over right-handers. This was recognised by fencing masters as early as the sixteenth century. They also agreed that the advantage was due to left-handers’ numbers—that being a minority gave them more opportunities to compete against right-handers than right-handers had against them. Fencing masters today have reached the same conclusion, as have laterality researchers, who see the advantage as an example of what is now called a “frequency-dependent” effect. However, some researchers have also suggested other possibilities that relate the advantage to natural differences in ability. This article presents a sampling of views of fencing masters from the past, along with a summary and analysis of explanations, old and new.

A number of paradoxical illusions occur when two streams of sound emanate simultaneously from different regions of space. Right-handers and left-handers differ statistically in terms of the illusory percepts obtained. The bases for these illusions are examined, and their implications are discussed.

To understand the evolution of lateralized motor biases and cognitive functions, we rely on archeological methods to give us a window onto the past. Currently, the overwhelming majority of prehistoric data on asymmetry and laterality concern only the hominin lineage, spanning the time period from the presumed evolutionary split with the other great apes around 6–8 million years ago until the present day. We present an overview of these data from paleontology and archeology. Lateralized motor biases and anatomical asymmetries are evident throughout prehistory, showing increases in the predominance of right-handedness over time. Laterality was a key feature of the motor-cognitive development of extinct human ancestors. However, further research in living humans is needed to resolve the extent of colateralization of functions in the human brain, so we urge caution when inferring functional cognitive laterality from behavioral markers of handedness.