ArticlePDF Available

Handedness frequency over more than ten thousand years


Abstract and Figures

Although there are quite important geographical variations in the frequency of left-handers around the world, nothing is known about its temporal evolution. During the upper Palaeolithic (ca. 35,000-10,000 YBP), humans painted 'negative hands' by blowing pigments with a tube onto one hand applied on the rock in caves in Western Europe, by blowing pigments on their own hand through a tube held in the other hand. The frequency of left-handers prevailing during this period could thus be assessed. For comparison, the handedness of French university students has been observed for the same task. No difference was detected between the two proportions of left-handers, separated by more than 10,000 years. Implications for the evolution of the polymorphism of handedness are discussed.
Content may be subject to copyright.
doi: 10.1098/rsbl.2003.0092
, S43-S45271 2004 Proc. R. Soc. Lond. B
Charlotte Faurie and Michel Raymond
Handedness frequency over more than ten thousand years
Article cited in:
Email alerting service
hereright-hand corner of the article or click
Receive free email alerts when new articles cite this article - sign up in the box at the top go to: Proc. R. Soc. Lond. BTo subscribe to
This journal is © 2004 The Royal Society
on October 17, 2011rspb.royalsocietypublishing.orgDownloaded from
Handedness frequency
over more than ten
thousand years
Charlotte Faurie
and Michel Raymond
tique et Environnement, Institut des Sciences de l’Evolution de
Montpellier (UMR CNRS 5554), Universite
Montpellier II CC 065,
Place Euge
ne Bataillon, F-34095 Montpellier cedex 5, France
Author for correspondence (
Recd 02.06.03; Accptd 04.08.03; Online 25.09.03
Although there are quite important geographical
variations in the frequency of left-handers around
the world, nothing is known about its temporal evol-
ution. During the upper Palaeolithic (ca. 35 000–
10 000 YBP), humans painted ‘negative hands’ by
blowing pigments with a tube onto one hand applied
on the rock in caves in Western Europe, by blowing
pigments on their own hand through a tube held in
the other hand. The frequency of left-handers pre-
vailing during this period could thus be assessed.
For comparison, the handedness of French univer-
sity students has been observed for the same task.
No difference was detected between the two pro-
portions of left-handers, separated by more than
10 000 years. Implications for the evolution of the
polymorphism of handedness are discussed.
Keywords: Homo; polymorphism; stabilizing selection;
asymmetry; laterality; Palaeolithic
Several studies indicate that the coexistence of both right-
and left-handed individuals has been maintained for a long
time in hominids. The oldest undisputed evidence is from
the middle (ca. 425 000–180 000 YBP) and early upper
Pleistocene (upper Pleistocene was 180 000–10 000
YBP), where marking on incisors indicates the existence
of Homo neanderthalensis individuals who were right- or
left-handed for sharp tool manipulation, while slicing meat
held between the front teeth and the other hand
dez de Castro et al. 1988; Lalueza & Frayer 1997).
In the Homo sapiens taxon, indications of handedness poly-
morphism come from studies of stone artefacts, hole-
making rotation movements in wood and wear marks on
spoons (e.g. Palaeolithic: Keeley (1977); Cornford (1986)
and Westergaard & Suomi (1996); Neolithic: Bocquet
(1978)). The oldest known evidence is from the upper
Palaeolithic, with the negative hand paintings in caves in
France and Spain (Groe
nen 1997).
There is still today a polymorphism of handedness in
humans, in all populations so far investigated (e.g.
Connolly & Bishop 1992; Carrie
re & Raymond 2000).
The evolutionary significance of this polymorphism is
unclear. However, the heritability of this trait is clearly
established (e.g. Sicotte et al. 1999; McKeever 2000;
Francks et al. 2002). It is known that the frequency of left-
handers is variable across geographical areas (Raymond &
Pontier 2004), but nothing is known about its temporal
Proc. R. Soc. Lond. B (Suppl.) 271, S43–S45 (2004) S43 2003 The Royal Society
DOI 10.1098/rsbl.2003.0092
evolution. We propose to compare the proportion of left-
handers among the people who painted the negative hands
in the Palaeolithic with the current proportion.
Detailed studies suggest that negative hands were prob-
ably made by blowing paint onto the back of one hand
applied on the rock surface, the other hand holding a
blowing tube (Groe
nen 1988). Thus a right negative hand
corresponds to a left-hander for the task of holding a tube
for paint blowing. These negative hands have different
sizes and are located at different heights, suggesting the
existence of different painters. Moreover, the caves are
often far apart in space, and the paintings were done over
a long period of time (30 000 to 10 000 YBP; Valladas et
al. 2001). They can thus be used to estimate the pro-
portion of left-handers in this period. Although we cannot
rule out the possibility that some individuals painted their
own hand more than once, the ratios should remain simi-
lar (all things being equal). In the following work, we use
experimentation to compare this proportion with the cur-
rent proportion.
(a) Palaeolithic record
There are 507 known negative hands from the upper Palaeolithic
of France and Spain (10 000 to 30 000 YBP). Laterality can be
unambiguously determined for 343 of them (Groe
nen 1997). There
are 79 right negative hands; this provides an estimate of 23% of
(b) Experiment
We placed our experimental subjects in hand-painting conditions
that were similar to the original situations. For comparison, we also
observed handedness for more usual tasks: throwing and writing
handedness were measured on the basis of performance.
(i) Subjects
The subjects were university students, attending the first and
second year in the University of Montpellier, France. They were
recruited on a voluntary basis, and were not told the purpose of the
study. They came one by one to the experimental room, so that they
did not have any opportunity to influence each other. The tests
were anonymous.
(ii) Throwing handedness
The subject was asked to pick up a ball placed on the middle of
a table in front of him and to throw it as close as possible to the
centre of a target 3.5 m distant. This way, the choice of the throwing
hand is not influenced by the configuration of the experiment. The
presence of the target increases the precision of the tasks, which
ameliorates the determination of the handedness of the individual
(Hopkins 1997).
(iii) Negative hand painting
The subjects were given a special pen that projects ink at one
extremity when they blow at the other (see for
details). Each subject was instructed to paint a negative hand on a
blank paper. The technique is thus very similar to the pigment tube-
blowing technique attributed to the Palaeolithic artists.
(iv) Questionnaire
Subjects were asked to give the following information: age, sex and
writing hand.
(c) Data analysis
Three handedness variables were thus recorded: throwing hand-
edness, hand painted while holding the tube with the other hand,
and writing handedness. These qualitative variables have two possible
values: left or right.
The frequency of left and right negative hands obtained in our
experiment and as recorded in the caves were compared using a Fish-
er’s exact test. We tested with the same method the independence
between the three handedness variables. Non-parametric statistics
) were used to measure the correlations between vari-
ables. These analyses were performed with the SAS software, v. V8.
on October 17, 2011rspb.royalsocietypublishing.orgDownloaded from
S44 C. Faurie and M. Raymond Handedness frequency in the Palaeolithic
Figure 1. (a) Right negative hand from the cave of Le Pech-Merle (Lot, France; photograph by J. Vertut). (b) Left negative
hand made by a subject in our experiment.
Table 1. Number of right and left negative hands recorded in
the caves and from university students.
negative hands
left right
264 (77.0%) 79 (23.0%)
Present 138 (77.1%) 41 (22.9%)
Data from Groe
nen (1997).
One hundred and seventy-nine students participated in
the study (58 males and 121 females, aged 19.8 ± 1.1
years). Figure 1 shows a Palaeolithic negative hand, and
one made by one of the students. The percentage of them
that made a right negative hand was 22.9%. No effect of
sex was observed (Fishers exact test, p = 0.85). The
results of the experiment are compared with the Palaeo-
lithic record in table 1. There is no significant difference
between the frequency of right negative hands in our sam-
ple and in the Palaeolithic sample (Fishers exact test,
p = 0.99).
Left-handed writers and throwers were 8.9% and 7.8%,
respectively. The three measures of handedness are highly
dependent (Fishers exact test, p 0.0001). No effect of
sex was observed (Fishers exact test, p = 0.78 and
p = 0.77 respectively). The handedness for holding the
tube while making the negative hand is positively corre-
lated with writing (Kendalls
= 0.48, p 0.0001) and
throwing (
= 0.49, p 0.0001) handedness. Among sub-
jects who made a left negative hand, almost all (99.3%)
are right-handers for throwing. Among subjects who made
a right negative hand, however, only 31.7% are left-
handed for throwing.
The proportion of right and left negative hands in our
latterday experiment is not different from the proportion
recorded by Groe
nen in the European caves. The absence
of significant variation in the frequency of left-handers (for
the task of holding a tube to paint the other hand) over
more than 10 000 years is surprising. It suggests that
Proc. R. Soc. Lond. B (Suppl.)
handedness is a trait under some functional constraint that
has not substantially changed since the upper Palaeolithic.
This is the first information, to our knowledge, on the
temporal variations of the frequency of left-handers for
one particular task. The only exception concerns the twen-
tieth century increase of left-handed writers in western
societies, probably explained by the relaxing of social
pressures (Porac et al. 1980). Studies based on human
subjects depicted in artworks sampled over 50 centuries
(Coren & Porac 1977) are irrelevant, because the conven-
tionaland often religiousrepresentation of a lateralized
human has no necessary link, in this respect, with a real
individual (Needham 1973).
To our knowledge, handedness for painting negative
hands has never before been measured in a contemporary
population. In the present sample, it is significantly corre-
lated with writing and throwing handedness. Surprisingly,
the correlation found is not as strong as the correlation
linking writing and throwing handedness: a substantial
proportion (17%) of right-handed throwers hold the tube
with the left hand. Inference on the frequency of left-
handed throwers during the upper Palaeolithic requires
the assumption that the level of the observed positive cor-
relation was already present at that time, which is difficult
to establish.
Negative hands are described in several locations
(Australia, South America, Indonesia). They all date from
Neolithic to contemporary times. The negative hands of
Western Europe are the most ancient (upper Palaeolithic;
Leroi-Gourhan et al. 1995).
The significance of the negative hands painted in caves
or shelters has long been a mystery. In some cultures (e.g.
in South Africa), traditional rock painting is still practised
(or was still practised very recently). The hand prints are
made by shamans and have a sacred meaning (Lewis-
Williams 1983). A comparative analysis indicated that the
negative hands from the upper Palaeolithic probably have
the same interpretation (Lewis-Williams & Dowson 1988;
Clottes & Lewis-Williams 1998). A more adequate sample
to estimate the present handedness would then be the
shamans themselves. A comparison of the frequency of
right and left negative hands from these locations would
be useful to know if the stability of the proportion of left-
handers over more than 10 000 years in Western Europe
is also found elsewhere.
on October 17, 2011rspb.royalsocietypublishing.orgDownloaded from
Handedness frequency in the Palaeolithic C. Faurie and M. Raymond S45
We thank J. Dumant for her help with the experiment, V. Durand
for bibliographic help and the students of Montpellier for their par-
ticipation. Contribution 2003.064 of the Institut des Sciences de
lEvolution de Montpellier (UMR CNRS 5554).
dez de Castro, J. M., Bromage, T. G. & Ferna
ndez Jalvo, Y.
1988 Buccal striations on fossil human anterior teeth: evidence of
handedness in the middle and early Upper Pleistocene. J. Hum.
Evol. 17, 403412.
Bocquet, A. 1978 Ils vivaient il y a 5000 ans a
Charavines (Ise
Grenoble: Centre de Documentation de la Pre
histoire Alpine.
re, S. & Raymond, M. 2000 Handedness and aggressive
behavior in a Ntumu village in southern Cameroon. Acta Ethol. 2,
Clottes, J. & Lewis-Williams, D. 1998 The Shamans of prehistory:
trance and magic in the painted caves. New York: Abrams.
Connolly, K. J. & Bishop, D. V. M. 1992 The measurement of hand-
edness: a cross-cultural comparison of samples from England and
Papua New Guinea. Neuropsychology 30,1326.
Coren, S. & Porac, C. 1977 Fifty centuries of right-handedness: the
historical record. Science 198, 631632.
Cornford, J. M. 1986 Specialized resharpening techniques and evi-
dence of handedness. In La Cotte de St. Brelade 1961–1978 (ed.
P. Callow & J. M. Cornford), pp. 337351. Norwich: Geo Books.
Francks, C., Fisher, S. E., MacPhie, I. L., Richardson, A. J., Marlow,
A. J., Stein, J. F. & Monaco, A. P. 2002 A genomewide linkage
screen for relative hand skill in sibling pairs. Am. J. Hum. Genet.
70, 800805.
nen, M. 1988 Les repre
sentations de mains ne
gatives dans les
grottes de Gargas et de Tibiran. Bull. Socie
Royale Belge d’Anthro-
pologie et de Pre
histoire 99,81113.
nen, M. 1997 Ombre et lumie
res dans l’art des grottes. U.L.B. Cah-
iers de
tudes VI. Bruxelles: U.L.B.
Proc. R. Soc. Lond. B (Suppl.)
Hopkins, W. D. 1997 Manual specialisation and tool use in captive
chimpanzees (Pan troglodytes): the effect of unimanual and biman-
ual strategies on hand preference. Laterality 2, 267277.
Keeley, L. H. 1977 The functions of paleolithic flint tools. Scient.
Am. 237, 108126.
Lalueza, C. & Frayer, D. W. 1997 Non-dietary marks in the anterior
dentition of the Krapina neanderthals. Int. J. Osteoarchaeol. 7,
Leroi-Gourhan, A., Coppens, Y., Delluc, B. & Delluc, G. 1995 Pre
histoire de L’art occidental.Lart et les grandes civilisations: Cita-
delles et Mazenod.
Lewis-Williams, J. D. 1983 The rock art of southern Africa. Cambridge
University Press.
Lewis-Williams, J. D. & Dowson, T. A. 1988 The signs of all times.
Entoptic phenomena in Upper Palaolithic art. Curr. Anthropol. 29,
McKeever, W. F. 2000 A new family handedness sample with find-
ings consistent with X-linked transmission. Br. J. Psychol. 91,
Needham, R. (ed.) 1973 Essay on dual symbolic classification. Right
and left. The University of Chicago Press.
Porac, C., Coren, S. & Duncan, P. 1980 Lifespan age trends in lat-
erality. J. Gerontol. 35, 715721.
Raymond, M. & Pontier, D. 2004 Is there a geographical variation
of human handedness? Laterality 9. (In the press.)
Sicotte, N. L., Woods, R. P. & Mazziotta, J. P. 1999 Handedness in
twins: a meta-analysis. Laterality 4, 265286.
Valladas, H., Clottes, J., Geneste, J. M., Garcia, M. A., Arnold, M.,
Cachier, H. & Tisne
rat-Laborde, N. 2001 Evolution of prehistoric
cave art. Nature 413, 479.
Westergaard, G. C. & Suomi, S. J. 1996 Hand preference for stone
artefact production and tool-use by monkeys: possible implications
for the evolution of right-handedness in hominids. J. Hum. Evol.
30, 291298.
on October 17, 2011rspb.royalsocietypublishing.orgDownloaded from
... Left-handed individuals comprise approximately 10% of the population (Faurie and Raymond, 2004). This rare event in the population is believed to be due to the development of language lateralization in the left hemisphere, giving rise to a primarily right-handed population (Corballis, 2003). ...
... Future studies that include a large number of left-handed individuals may need to control for handedness in a similar manner as other covariates, such as sex. One caveat might be that left-handed individuals are relatively rare (around 10% of the population (Faurie and Raymond, 2004)). Many functional connectivity studies may not have a sufficiently large sample of left-handed individuals to properly estimate these effects. ...
Full-text available
Handedness influences differences in lateralization of language areas as well as dominance of motor and somatosensory cortices. However, differences in whole-brain functional connectivity (i.e., functional connectomes) due to handedness have been relatively understudied beyond pre-specified networks of interest. Here, we compared functional connectomes of left- and right-handed individuals at the whole brain level. We explored differences in functional connectivity of previously established regions of interest, and showed differences between primarily left- and primarily right-handed individuals in the motor, somatosensory, and language areas using functional connectivity. We then proceeded to investigate these differences in the whole brain and found that the functional connectivity of left- and right-handed individuals are not specific to networks of interest, but extend across every region of the brain. In particular, we found that connections between and within the cerebellum show distinct patterns of connectivity. To put these effects into context, we show that the effect sizes associated with handedness differences account for a similar amount of individual differences in the connectome as sex differences. Together these results shed light on regions of the brain beyond those traditionally explored that contribute to differences in the functional organization of left- and right-handed individuals and underscore that handedness effects are neurobiologically meaningful in addition to being statistically significant.
... The prevalence of left-handedness in the general population is in the range of 10-13% (Faurie & Raymond, 2004), a higher proportion of left-handers was found mainly in some interactive sports (boxing, ice hockey, tennis). In tennis, the proportion of left-handers is higher among the world's elite tennis players (Holtzen, 2000). ...
Full-text available
The term laterality refers to the preference or dominance of the lateral asymmetry of the human body. The prevalence of left-handedness is reported to be 10–13%, but in some sports (e.g. boxing, ice hockey, tennis), the proportion of left-handers is higher. The left-handedness is considered an advantage in tennis; however, the one-sided load can cause muscular dysbalances leading to injuries. The research aim was to assess bilateral differences in handgrip strength in top Czech female tennis players U12 as to injury prevention. The participants were tennis players (n = 165) aged 11.0–12.9 years taking part in the regular testing by the Czech Tennis Association using the TENDIAG1 test battery between 2000 and 2018. 87.3% of all players were right-handed (RH) and only 12.7% left-handed (LH). Bilateral differences between the right- and left-hand strength of all players were medium significant in favor of the right hand. The assessment of differences between RH and LH players showed only small differences in favor of LH players. There was a medium significant difference between RH and LH players in favor of the dominant hand (DH) over the non-dominant one (NDH). As to injury prevention, it is surprising that a difference between DH and NDH strength >15% was found in 40.91% of RH players and even in 40.06% of LH players. This predicts an increased risk of injury, so it is desirable to pay attention to both sides of the training load and to include compensatory or strengthening exercises.
... Handedness, irrespective of whether it is environmental or genetic in origin, is a stable polymorphism, the proportions of right-and left-handedness seeming to be stable over long periods of historical time, in the past century or two [384], the last five millennia [385], since the upper palaeolithic [386], or half a million years ago [387,388]. Going back further than that is difficult, but there does seem to be evidence that the majority of humans were right-handed perhaps two to three million years ago [389]. ...
Full-text available
Recent fMRI and fTCD studies have found that functional modules for aspects of language, praxis, and visuo-spatial functioning, while typically left, left and right hemispheric respectively, frequently show atypical lateralisation. Studies with increasing numbers of modules and participants are finding increasing numbers of module combinations, which here are termed cerebral polymorphisms—qualitatively different lateral organisations of cognitive functions. Polymorphisms are more frequent in left-handers than right-handers, but it is far from the case that right-handers all show the lateral organisation of modules described in introductory textbooks. In computational terms, this paper extends the original, monogenic McManus DC (dextral-chance) model of handedness and language dominance to multiple functional modules, and to a polygenic DC model compatible with the molecular genetics of handedness, and with the biology of visceral asymmetries found in primary ciliary dyskinesia. Distributions of cerebral polymorphisms are calculated for families and twins, and consequences and implications of cerebral polymorphisms are explored for explaining aphasia due to cerebral damage, as well as possible talents and deficits arising from atypical inter- and intra-hemispheric modular connections. The model is set in the broader context of the testing of psychological theories, of issues of laterality measurement, of mutation-selection balance, and the evolution of brain and visceral asymmetries.
... Stencilled and imprinted hands are some of the most useful archaeological evidences to be able to approach Upper Palaeolithic artists physicality and, therefore, their study from a palaeodemographic perspective is essential for understanding holistically past societies. Based on the size and shape of hand imprints in the archaeological record, different biometric methods have been proposed to estimate the age and sex (Groenen, 1988;Manhire, 1998;Ripoll et al., 1999a;Guthrie, 2005;Gunn, 2006;Bednarik, 2008;Snow, 2006Snow, , 2013Pettitt et al., 2014;Mackie, 2015;Carden and Blanco, 2016;Rabazo-Rodriguez et al., 2017, Chazine et al., 2021.), height (Manhire, 1998) and laterality (Faurie and Raymond, 2004;Gunn, 2007;Cashmore et al., 2008;Uomini, 2009) of the corresponding individuals ( Fig. 1). ...
Full-text available
This paper presents rock art as a collective action in which different strata of society took part, including children and subadults. Until recent decades archaeology of childhood has not been in the main focus of the archaeological research, much less the participation of those children in the artistic activity. The present study approaches the palaeodemography of artists in the decorated caves through the paleolithic rock art itself. The approximate age of these individuals has been calculated through the biometric analysis of hand stencils in the caves of Fuente del Salín, Castillo, La Garma, Maltravieso and Fuente del Trucho, using 3D photogrammetric models as reference. The results have been compared with a modern reference population in order to assign the Palaeolithic hands to certain age groups. It has been demonstrated the presence of hand stencil motifs belongs to infants, children and juveniles, revealing this stratum's importance in the artistic activity.
... A recent meta-analysis estimated that the prevalence of lefthanded preference lies between 9.3% and 18.1%, with the best overall estimate being 10.6%, the prevalence of mixedhandedness lies between 6.7% and 12.0% (best overall estimate, 9.3%), and the prevalence of non-right-handedness lies between 13.9% and 22.3% (best overall estimate, 18.1%) (Papadatou-Pastou et al., 2020a). Importantly, several factors have been shown to affect the chances of being a lefthander, such as sex (Papadatou-Pastou et al., 2008), geographical location (Raymond & Pontier, 2004), year of birth (Faurie & Raymond, 2004), breastfeeding (Hujoel, 2019), and birthweight (de Kovel et al., 2019). ...
Full-text available
Meta-analyses have shown that several neurodevelopmental and psychiatric disorders, such as autism spectrum disorder and schizophrenia, are associated with a higher prevalence of atypical (left-, non-right-, or mixed-) handedness. One neurodevelopmental disorder for which this association is unclear is attention deficit hyperactivity disorder (ADHD). Here, some empirical studies have found evidence for a higher prevalence of atypical handedness in individuals with ADHD compared to neurotypical individuals. However, other studies failed to establish such an association. Therefore, meta-analytic integration is critical to estimate whether or not there is an association between handedness and ADHD. We report the results of three meta-analyses (left-, mixed-, and non-right-handedness) comparing handedness in individuals with ADHD to controls (typically developing individuals). The results show evidence of a trend towards elevated levels of atypical handedness when it comes to differences in left- and mixed-handedness (p = 0.09 and p = 0.07, respectively), but do show clear evidence of elevated levels of non-right-handedness between individuals with ADHD and controls (p = 0.02). These findings are discussed in the context of the hypothesis that ADHD is a disorder in which mostly right-hemispheric brain networks are affected. Since right-handedness represents a dominance of the left motor cortex for fine motor behavior, such as writing, as well as a left-hemispheric dominance for language functions, and about 90% of individuals are right-handers, this hypothesis might explain why there is not stronger evidence for an association of left-handedness with ADHD. We suggest that the mechanisms involved in the pathogenesis of ADHD might show an overlap with the mechanisms involved in handedness strength, but not handedness direction.
... brain asymmetry j left-handedness j cerebral cortex j gene-brain-behavior j polygenic scores R oughly 90% of the human population is right-handed and 10% left-handed, and this strong bias is broadly consistent across cultures, ethnicities, and history (1)(2)(3)(4)(5). Hand motor control is performed primarily by the contralateral brain hemisphere, such that right-handedness reflects left-hemisphere dominance for hand articulation, and vice versa (6). ...
Full-text available
Significance Left-handedness occurs in roughly 10% of people, but whether it involves altered brain anatomy has remained unclear. We measured left to right asymmetry of the cerebral cortex in 28,802 right-handers and 3,062 left-handers. There were small average differences between the two handedness groups in brain regions important for hand control, language, vision, and working memory. Genetic influences on handedness were associated with some of these brain asymmetries, especially of language-related regions. This suggests links between handedness and language during human development and evolution. One implicated gene is NME7 , which also affects placement of the visceral organs (heart, liver, etc.) on the left to right body axis—a possible connection between brain and body asymmetries in embryonic development.
The left and right hemispheres of our brains differ subtly in structure, and each is dominant in processing specific cognitive tasks. Our species has a unique system of distributing behavior and cognition between each cerebral hemisphere, with a preponderance of pronounced side biases and lateralized functions. This hemisphere-dependent relationship between cognitive, sensory or motor function and a set of brain structures is called hemispheric specialization. Hemispheric specialization has led to the emergence of model systems to link anatomical asymmetries to brain function and behavior. Scientific research on hemispheric specialization and lateralized functions in living humans focuses on three major domains: (1) hand preferences, (2) language, and (3) visuospatial skills and attention. In this chapter we present an overview of this research with a specific focus on living humans and the applications of this research in the context of hominin brain evolution. Our objective is to put into perspective what we know about brain-behavior relationships in living humans and how we can apply the same methods to investigate this relationship in fossil hominin species, and thus improve our understanding of the emergence and development of complex cognitive abilities.
Full-text available
Giriş ve Amaç: Bu araştırmada, İstanbul ilinde spor eğitimi veren yükseköğretim kurumlarındaki akademisyenlerin karanlık kişilik ve kişi-örgüt uyumları arasındaki ilişkinin incelenmesi amaçlanmıştır. Yöntem: Araştırmanın çalışma grubunu İstanbul ilinde bulunan üniversitelerin Beden Eğitimi ve Spor Yüksek Okulları ile Spor Bilimleri Fakültelerinde görev yapan 39 kadın 51 Erkek toplamda 90 akademisyen oluşturmaktadır. Araştırmada veri toplama aracı olarak araştırmacılar tarafından hazırlanmış “Kişisel Bilgi Formu”, akademisyenlerin karanlık üçlü özelliklerinin belirlenmesi amacıyla Jones ve Paulhus (2014) tarafından geliştirilen, Şahin, Ağralı Ermiş ve Demirus (2018) tarafından uyarlaması gerçekleştirilen “Kısa Karanlık Üçlü Ölçeği (SD3)” ve Netemeyer vd., (1997) tarafından geliştirilen, Turunç ve Çelik (2012) tarafından uyarlaması yapılan “Kişi-Örgüt Uyumu Ölçeği” kullanılmıştır. Elde edilen veriler SPSS-24 Paket Programı ile analiz edilmiştir. Aynı zamanda verilerin çözüm ve yorumlanmasında Pearson ve Spearman korelasyon analizleri, bağımsız örneklemler (Independent-Samples) t-testi analizi, One-Way ANOVA (Tek Yönlü Varyans Analizi), Mann-Whitney U Testi ve Kruskal-Wallis H Testi kullanılmıştır. Bulgular: Ölçeklere ait puan dağılımlarının homojen dağılıp dağılmadığına yönelik Levene istatistiği sonuçlarına bakıldığında kısa karanlık üçlü ölçeği toplamı ve psikopati alt boyutunun normal dağılım göstermediği, kısa karanlık üçlü ölçeği diğer alt boyutları olan makyavelizm ve narsizm ve kişi örgüt uyumu ölçeğinin normal dağılım gösterdiği tespit edilmiştir. Akademisyenlerin cinsiyetlerine göre kişi-örgüt uyumları arasında anlamlı farklılık bulunurken, kısa karanlık üçlü ölçeği toplamı ve alt boyutları arasında anlamlı bir farklılık bulunmamaktadır. Medeni durumlarına göre kişi örgüt uyumu, kısa karanlık üçlü ölçeği toplamı ve alt boyutları olan psikopati ve narsizm arasında anlamlı farklılık bulunmazken, kısa karanlık üçlü ölçeği diğer alt boyutu olan makyavelizm arasında anlamlı farklılık bulunmaktadır. Unvan, bölüm, üniversite türü ve idari göre olma durumuna göre kişi örgüt uyumu, kısa karanlık üçlü ölçeği toplamı ve alt boyutları arasında anlamlı bir farklılık bulunmadığı tespit edilmiştir. Anahtar Kelimeler: Kişilik, Karanlık Kişilik, Kişi-Örgüt Uyumu
Full-text available
Presentation d'un modele neuropsychologique permettant d'interpreter les signes dans l'art paleolithique comme des formes resultant de phenomenes entoptiques. Mise en parallele avec differents arts chamanistes. Six categories de phenomenes entoptiques sont ainsi mises en evidence
Full-text available
A samole of 82 anterior teeth from Krapina (Croatia) was studied using a light binocular microscope and a scanning electron microscope to document the presence of non-dietary dental scratches. The patterns of distribution, location and orientation of these marks suggest two different aetiologies: scratches on the labial-occlusal enamel border appear to be related to the action of clenching abrasive materials between teeth, while the scratches primarily in the centre of the labial face correspond to cutmarks as described by other researchers. These scratches may have been produced when flake tools involved in processing materials held between the anterior teeth came into contact with the labial enamel face. Alternatively, they may simply reflect some consistent operation which pulled hard objects across the labial surfaces of the anterior teeth. In either case, the marks on the central face of the labial surface provide evidence for manual dexterity in the Neanderthals. Of the seven Krapina individuals which show a predominant pattern, one shows a pattern of left oblique marks, while six provide evidence of right-handedness. Coupled with other Neanderthal or Upper Pleistocene individuals with these patterns, right-handedness is the dominant pattern in 90 per cent of the documented cases. One complication factor in the analysis of these scratches in the Krapina hominids is that marks of a similar morphology are found in several anterior teeth of Ursus spelaeus from the site. While resembling the marks on the hominid incisors, the scratches on the bears lack a dominant orientation on the labial face and appear to be more variable in their widths. Despite the occurence of some similarities in the enamel scratches between ursids and hominids at Karpina, the study of anterior dental marks provided information about manipulative activities which are unique to ancient humans.
Full-text available
Handedness in humans is possibly maintained by a frequency-dependent advantage during aggressive interactions. To contribute to relevant data related to this idea, functional handedness has been measured in a traditional ethnic group (Ntumu) from southern Cameroon, and confronted to the level of aggressive behavior. Functional handedness was measured by the hand holding the machete, an asymmetric tool used every day. Aggressive behavior was assessed by the frequency of occurrence of the traditional tribunal for solving internal conflicts. There was a low percentage of left-handers (8.1%), with no significant sex differences, although females below 50 year old displayed a significant increase of left-handedness with age. The level of aggressive behavior was low, as the traditional tribunal took place only seven times during the last five years. Results are discussed in the context of the evolution of handedness and the possible recent societal changes following European colonisation.
This research examined hand preference for stone artefact production and tool-use in monkeys. We presented capuchins (Cebus apella) with stones and an apparatus that accommodated the use of stones as cutting tools. The monkeys were preferentially right-handed for striking stones against hard surfaces and for using stones as cutting tools. These results further demonstrate that primates exhibit lateral bias for tool-related activities, and indicate that handedness for the production and use of stone tools may have pre-dated the earliest known occurrence of lateral bias in hominids.
In the largest meta-analysis of twins and singletons conducted to date we have found a higher incidence of left-handedness in twins compared to singletons. Our analysis revealed no difference in the frequency of left-handedness among monozygotic versus dizygotic twins. However, identical twins were more likely to be concordant for hand preference than non-identical twins, which is consistent with a genetic model of handedness. Prior analyses have not revealed these findings consistently, and this has led to a number of conflicting models of handedness.