Why are some people left-handed? An evolutionary perspective

Abstract

Since prehistoric times, left-handed individuals have been ubiquitous in human populations, exhibiting geographical frequency variations. Evolutionary explanations have been proposed for the persistence of the handedness polymorphism. Left-handedness could be favoured by negative frequency-dependent selection. Data have suggested that left-handedness, as the rare hand preference, could represent an important strategic advantage in fighting interactions. However, the fact that left-handedness occurs at a low frequency indicates that some evolutionary costs could be associated with left-handedness. Overall, the evolutionary dynamics of this polymorphism are not fully understood. Here, we review the abundant literature available regarding the possible mechanisms and consequences of left-handedness. We point out that hand preference is heritable, and report how hand preference is influenced by genetic, hormonal, developmental and cultural factors. We review the available information on potential fitness costs and benefits acting as selective forces on the proportion of left-handers. Thus, evolutionary perspectives on the persistence of this polymorphism in humans are gathered for the first time, highlighting the necessity for an assessment of fitness differences between right-and left-handers.

Impact of right‐handedness on anaesthetic sensitivity, intra‐operative awareness and postoperative mortality

“…It is currently unknown whether there is a 'pathological' subgroup of left-handers who may be predisposed to morbidity and mortality [32]. Furthermore, right-handedness is highly correlated with left cerebral hemisphere dominance, whereas hemispheric dominance is less consistent in left-handed individuals.…”

“…Left-handedness has been tentatively linked with numerous pathological conditions [25][26][27][28][29][30] including hypertension and, in some studies, with decreased longevity [31][32][33][34][35]. Several mechanisms have been proposed to explain the shorter lifespan observed in left-handers [29][30][31][32][33][34][35]; hypotheses have included abnormal developmental factors in utero, increased birth stress and increased risk of lethal accidents among left-handers.…”

“…Several mechanisms have been proposed to explain the shorter lifespan observed in left-handers [29][30][31][32][33][34][35]; hypotheses have included abnormal developmental factors in utero, increased birth stress and increased risk of lethal accidents among left-handers.…”

Endless forms: human behavioural diversity and evolved universals

“…While the real world is far more complex than simple models such as Hawk -Dove, these do provide insight into some of the conditions that probably help generate empirical complexity. One possible empirical example is the equilibrium between right-handedness (common) and left-handedness (rare), an equilibrium that might be maintained by advantages in hand-tohand fighting [23,24], by cultural preferences [25] or by a combination of factors favouring and disfavouring left-handedness [26].…”

Innovative mechatronic system for testing laterality

“…The mathematical models designed to explain the laterality prove to be narrowed, because a lot of empirical factors and coefficients were considered [8,9].Predilections for left hand and its consequences have been the subject of research [10]. Some authors have attempted to discover the gene responsible for the dominance of cerebral hemispheres [11,12], others have tried to reveal if there is a connection between laterality and cognitive development [13], while others were concerned about the advantages and of asymmetry [14,15].…”