Behavioral Asymmetries Research Articles

History, development and current advances concerning the evolutionary roots of human right‐handedness and language: Brain lateralisation and manual laterality in non‐human primates

AbstractThis review highlights the scientific advances concerning the origins of human right‐handedness and language (speech and gestures). The comparative approach we adopted provides evidence that research on human and non‐human animals’ behavioural asymmetries helps understand the processes that lead to the strong human left‐hemisphere specialisation. We review four major non‐mutually exclusive environmental factors that are likely to have shaped the evolution of human and non‐human primates’ manual asymmetry: socioecological lifestyle, postural characteristics, task‐level complexity and tool use. We hypothesise the following scenario for the evolutionary origins of human right‐handedness: the right‐direction of modern humans’ manual laterality would have emerged from our ecological (terrestrial) and social (multilevel system) lifestyle; then, it would have been strengthened by the gradual adoption of the bipedal stance associated with bipedal locomotion, and the increasing level of complexity of our daily tasks including bimanual coordinated actions and tool use. Although hemispheric functional lateralisation has been shaped through evolution, reports indicate that many factors and their mutual intertwinement can modulate human and non‐human primates’ manual laterality throughout their life cycle: genetic and environmental factors, mainly individual sociodemographic characteristics (e.g., age, sex and rank), behavioural characteristics (e.g., gesture per se and gestural sensory modality) and context‐related characteristics (e.g., emotional context and position of target). These environmental (evolutionary and life cycle) factors could also have influenced primates’ manual asymmetry indirectly through epigenetic modifications. All these findings led us to propose the hypothesis of a multicausal origin of human right‐handedness.

Deformation mechanisms and scaling relations in the mechanical response of nano-porous Au

We report a series of atomistic virtual mechanical tests on digitally created samples of nanoporous gold with 60% porosity, and average ligament diameters varying from 5.5 nm to 14.4 nm. Corresponding tests were also conducted for nanowires of equivalent surface to volume ratio and crystalline orientation. The validity of the Gibson-Ashby (G-A) scaling relations for the elastic and plastic behavior of the NP-Au structures is discussed. Tension/compression asymmetry in the plastic behavior was observed in both the nanoporous samples as well as the nanowires. Consistent with previous experimental and computational studies, the asymmetry becomes increasingly evident for the smaller ligament diameters, clearly pointing to capillary effects for large surface to volume ratios. Based on the present simulation results, a simple analytical model is presented for predicting the tension/compression asymmetry. The effects of internal ligament stresses on the deformation mechanisms and dislocation activity in the NP-Au structures are also discussed.

Asymmetries in the phonological behaviour of Dagbani place features: Implications for markedness

It has been observed in phonological studies that phonological processes often apply to place features in asymmetrical ways. Certain processes may affect only one of the place features, others may affect all but one place feature. This paper analyses various asymmetrical phonological patterns in Dagbani, a Gur language of Ghana. It shows that while the dorsal place is the target of most processes that lead to the loss of underlying place features, the labial and coronal places are targets of processes that enhance underlying place specifications. Labial-dorsals [kp, ɡb, ŋm] also surface in patterns of neutralisation with dorsals. Evidence from both diachronic and synchronic sound patterns suggest active sound changes in progress with the labial-dorsals being preferred to plain dorsals. The paper discusses the implication of these findings for the understanding of the theory of markedness and questions the widely held view of segmental complexity as a markedness diagnostic.

Asymmetries of the visual system and their influence on visual performance and oculomotor dynamics

Our representation of the visual field is not homogenous. There are differences in resolution not only between the fovea and regions eccentric to it, but also between the nasal and temporal hemiretinae, that can be traced to asymmetric distributions of photoreceptors and ganglion cells. We review evidence for differences in visual and attentional processing and oculomotor behaviour that can be traced to asymmetries of the visual system, mainly emphasising nasal-temporal asymmetries. Asymmetries in the visual system manifest in various measures, in basic psychophysical tests of visual performance, attentional processing, choice behaviour, saccadic peak velocity, and latencies. Nasal-temporal asymmetries on saccadic latency seem primarily to occur for express saccades. Neural asymmetries between the upper and lower hemifields are strong and cause corresponding differences in performance between the hemifields. There are interesting individual differences in asymmetric processing which seem to be related to the strength of eye dominance. These neurophysiological asymmetries and the corresponding asymmetries in visual performance and oculomotor behaviour can strongly influence experimental results in vision and must be considered during experimental design and the interpretation of results.

Power logics of consumers’ gendered (in)justices: reading reproductive health interventions through the transformative gender justice framework

ABSTRACTGlobal gender asymmetries in marketing and consumer behavior were recently exemplified by the Transformative Gender Justice Framework (TGJF). The TGJF, however, lacks an explicit reference to power – an aspect that becomes apparent when it is used to assess a consumer phenomenology. In this article we augment the TGJF by building out the power logics and by empirically testing it through an assessment of the reproductive market in Uganda. We capture macro-, meso-, and micro-level power asymmetries, and explore how bio-power and control over resources melds with local gender relations and agentic practices that (i) leave social marketing efforts misaligned with embodied realities, and (ii) result in dichotomies and tensions in the reproductive health market as the North–South strive to define the modern-traditional, medical-pleasurable, and women-men nature of contraceptives.

Correction: Asymmetries in mother-infant behaviour in Barbary macaques (Macaca sylvanus).

[This corrects the article DOI: 10.7717/peerj.4736.].

Charge Interactions Can Dominate Coupled Folding and Binding on the Ribosome

Interactions between emerging nascent polypeptide chains and the ribosome can modulate cotranslational protein folding. However, it has remained unclear how such interactions can affect the binding of nascent chains to their cellular targets. We thus investigated on the ribosome the interaction between two intrinsically disordered proteins of opposite charge, ACTR and NCBD, which form a high-affinity complex in a coupled folding-and-binding reaction. Using fluorescence correlation spectroscopy and arrest-peptide-mediated force measurements in vitro and in vivo, we find that the ACTR-NCBD complex can form cotranslationally but only with ACTR as the nascent chain and NCBD free in solution, not vice versa. We show that this surprising asymmetry in behavior is caused by pronounced charge interactions: attraction of the positively charged nascent chain of NCBD to the negatively charged ribosomal surface competes with complex formation and prevents ACTR binding. In contrast, the negatively charged nascent ACTR is repelled by the ribosomal surface and thus remains available for productively binding its partner. Electrostatic interactions may thus be more important for cotranslational folding and binding than previously thought.

Communication in Dogs.

Simple SummaryCommunication takes place between members of the same species, as well as between heterospecific individuals, such as the long co-habitation process and inter-dependent relationship present in domestic dogs and humans. Dogs engage in visual communication by modifying different parts of their body; in tactile communication; and also in auditory and olfactory communication, with vocalizations and body odours, respectively. The aim of this review is to provide an overview of the recent literature about dog communication, describing the different nature of the signals used in conspecific and heterospecific interactions and their communicative meaning. Lateralized dog brain patterns underlying basic neural mechanisms are also discussed, for both conspecific and heterospecific social communication.Dogs have a vast and flexible repertoire of visual, acoustic, and olfactory signals that allow an expressive and fine tuned conspecific and dog–human communication. Dogs use this behavioural repertoire when communicating with humans, employing the same signals used during conspecific interactions, some of which can acquire and carry a different meaning when directed toward humans. The aim of this review is to provide an overview of the latest progress made in the study of dog communication, describing the different nature of the signals used in conspecific (dog–dog) and heterospecific (dog–human) interactions and their communicative meaning. Finally, behavioural asymmetries that reflect lateralized neural patterns involved in both dog–dog and dog–human social communication are discussed.

Islamic finance and herding behavior: an application to Gulf Islamic stock markets

PurposeThe purpose of this paper is to examine the herding behavior in GCC Islamic stock markets.Design/methodology/approachThe authors followed the methodology developed by Chiang and Zheng (2010) to test herding behavior. Cross-sectional tests have been considered in this paper. The authors use both OLS and GARCH estimations to examine herding behavior by using a sample of GCC Islamic stock markets.FindingsBy applying monthly data for the period between January 2006 and February 2016 for five Islamic GCC stock returns (Bahrain, Kuwait, Qatar, Saudi Arabia and UAE), results suggest a significant evidence of herd behavior in Saudi and Qatari Islamic stock markets only. When the authors take into account the existence of asymmetry in herd behavior between down- and up-market periods, evidence of herding behavior during down market periods in the case of Qatar and Saudi Arabia was found. In addition, the authors found that Kuwaiti and Emirates Islamic stock markets herd with the local conventional stock market, showing the interdependencies between Islamic and conventional markets.Research limitations/implicationsIn this paper, the authors found an absence of herding behavior in some Islamic stock markets (Bahrain, Kuwait and Emirates). This is not the result of Shariah guidelines in these Islamic markets, but this is mainly due to the weak oscillations of returns which are very close to zero. In our future research, the authors could apply daily data and compare the results to those obtained in this paper by using monthly data.Originality/valueThis paper provides a practical framework in order to analyze the herding behavior concept for GCC Islamic stock markets. Its originality consists of linking the herding behavior to ethics and morality to verify whether the properties and guidelines of Islam are respected in Islamic stock markets. To the best of the authors’ knowledge, no other paper has treated the case of herding behavior in Islamic stock markets and taking into account the possible influence of the conventional market on the Islamic stock market that may impact herding behavior.

How emotion-cognition interactions drive affective bipolarity

Abstract
 Affective bipolarity is observed in a large group of people falling within the broad bipolar spectrum. Here, we propose a model of how emotion-cognition cycles drive affective bipolarity in the general case, and when these cycles may spiral into excessive forms. Our account specifies how emotion-cognition interactions produce two distinct epistemic modes: A behaviorally engaged, externally oriented mode of phenomenal exploration and a behaviorally disengaged, internally oriented mode of conceptual rumination. Affective bipolarity is viewed as a ubiquitous phenomenon underlying epistemic progress, which explains why mood fluctuations can be observed in many psychiatric disorders. The model explains why individuals with bipolar tendencies exhibit polar asymmetries in emotion, cognition and behavior, and are at risk for excessive affective bipolarity when their epistemic activities are guided by immutable and stable core beliefs.

Asymmetries in mother-infant behaviour in Barbary macaques (Macaca sylvanus).

Asymmetries in the maternal behaviour and anatomy might play an important role in the development of primate manual lateralization. In particular, early life asymmetries in mother’s and infant’s behaviour have been suggested to be associated with the development of the hand preference of the offspring. The aim of this study was to investigate the presence of behavioural asymmetries in different behavioural categories of mother-infant dyads of zoo-living Barbary macaques (Macaca sylvanus). The study subjects were 14 Barbary macaques involved in seven mother-infant dyads housed in Parco Natura Viva, Italy. For the mothers, bouts of hand preference for maternal cradling and infant retrieval were collected. For the infants, we focused on nipple preference and hand preference for clinging on mother ventrum. Moreover, we collected bouts of hand preference for food reaching in both groups. No significant group-level bias was found for any of the behavioural categories in either mothers or infants. However, at the individual level, six out of seven mothers showed a significant cradling bias, three toward the right hand and three toward the left hand. Moreover, all infants showed a significant nipple preference, six toward the mother’s right nipple, one toward the left nipple. Furthermore, a significant correlation was found between the infant nipple preference and their hand preference for food reaching, suggesting that maternal environment rather than behaviour might affect the development of hand preference in Old World monkeys. Our findings seem partially to add to previous literature on perceptual lateralization in different species of non-primate mammals, reporting a lateral bias in mother-infant interactions. Given the incongruences between our study and previous research in great apes and humans, our results seem to suggest possible phylogenetic differences in the lateralization of mothers and infants within the Primates order.

Reapplying behavioral symmetry: public choice and choice architecture

New justifications for government intervention based on behavioral psychology rely on a behavioral asymmetry between expert policymakers and market participants. Public choice theory applied the behavioral symmetry assumption to policy making in order to illustrate how special interests corrupt the suppositions of benevolence on the part of policy makers. Cognitive problems associated with market choices have been used to argue for even more intervention. If behavioral symmetry is applied to the experts and not just to market participants, problems with this approach to public policy formation become clear. Manipulation, cognitive capture, and expert bias are among the problems associated with a behavioral theory of market failure. The application of behavioral symmetry to the expanding role of choice architecture will help to limit the bias in behavioral policy. Since experts are also subject to cognitive failures, policy must include an evaluation of expert error. Like the rent-seeking literature before it, a theory of cognitive capture points out the systematic problems with a theory of asymmetry between policy experts and citizens when it comes to policy making.

Intrastriatal administration of botulinum neurotoxin A normalizes striatal D2 R binding and reduces striatal D1 R binding in male hemiparkinsonian rats.

Cerebral administration of botulinum neurotoxin A (BoNT-A) has been shown to improve disease-specific motor behavior in a rat model of Parkinson disease (PD). Since the dopaminergic system of the basal ganglia fundamentally contributes to motor function, we investigated the impact of BoNT-A on striatal dopamine receptor expression using in vitro and in vivo imaging techniques (positron emission tomography and quantitative autoradiography, respectively). Seventeen male Wistar rats were unilaterally lesioned with 6-hydroxydopamine (6-OHDA) and assigned to two treatment groups 7 weeks later: 10 rats were treated ipsilaterally with an intrastriatal injection of 1 ng BoNT-A, while the others received vehicle (n = 7). All animals were tested for asymmetric motor behavior (apomorphine-induced rotations and forelimb usage) and for striatal expression of dopamine receptors and transporters (D1 R, D2 R, and DAT). The striatal D2 R availability was also quantified longitudinally (1.5, 3, and 5 months after intervention) in 5 animals per treatment group. The 6-OHDA lesion alone induced a unilateral PD-like phenotype and a 13% increase of striatal D2 R. BoNT-A treatment reduced the asymmetry in both apomorphine-induced rotational behavior and D2 R expression, with the latter returning to normal values 5 months after intervention. D1 R expression was significantly reduced, while DAT concentrations showed no alteration. Independent of the treatment, higher interhemispheric symmetry in raclopride binding to D2 R was generally associated with reduced forelimb akinesia. Our findings indicate that striatal BoNT-A treatment diminishes motor impairment and induces changes in D1 and D2 binding site density in the 6-OHDA rat model of PD.

Early uneven ear input induces long-lasting differences in left-right motor function.

How asymmetries in motor behavior become established normally or atypically in mammals remains unclear. An established model for motor asymmetry that is conserved across mammals can be obtained by experimentally inducing asymmetric striatal dopamine activity. However, the factors that can cause motor asymmetries in the absence of experimental manipulations to the brain remain unknown. Here, we show that mice with inner ear dysfunction display a robust left or right rotational preference, and this motor preference reflects an atypical asymmetry in cortico-striatal neurotransmission. By unilaterally targeting striatal activity with an antagonist of extracellular signal-regulated kinase (ERK), a downstream integrator of striatal neurotransmitter signaling, we can reverse or exaggerate rotational preference in these mice. By surgically biasing vestibular failure to one ear, we can dictate the direction of motor preference, illustrating the influence of uneven vestibular failure in establishing the outward asymmetries in motor preference. The inner ear–induced striatal asymmetries identified here intersect with non–ear-induced asymmetries previously linked to lateralized motor behavior across species and suggest that aspects of left–right brain function in mammals can be ontogenetically influenced by inner ear input. Consistent with inner ear input contributing to motor asymmetry, we also show that, in humans with normal ear function, the motor-dominant hemisphere, measured as handedness, is ipsilateral to the ear with weaker vestibular input.

Effects of elevated carbon dioxide on male and female behavioural lateralization in a temperate goby.

Behavioural abnormality in fishes has been proposed as a significant consequence of the increasing levels of carbon dioxide occurring in the oceans. Negative effects of elevated CO2 have been reported for behaviours such as predator–prey interactions, foraging, hearing and behavioural lateralization. Importantly, the effects vary greatly both within and between species, and some recent studies have shown minimal effects of CO2 on behaviour. Whether the effect of CO2 also varies between males and females is, however, virtually unexplored. According to resource allocation theory, females are expected to be more sensitive to elevated CO2, meaning that non-sex-specific studies may overlook ecologically important differences between the sexes. In this study, we investigated the possible differences between males and females in their response to elevated CO2 by performing behavioural lateralization tests in adult temperate two-spotted gobies, Gobiusculus flavescens. We found that the strength of the side bias (absolute lateralization) was unaffected by the CO2 treatment, and there was no difference between males and females. The control fish were slightly right-biased in their behavioural asymmetry (mean relative lateralization of 14). Exposure to high CO2 affected this pattern, such that treated fish were slightly left-biased (mean relative lateralization of −10), regardless of their sex. The same results were obtained yet again when the study was repeated during a second year. We discuss our results in light of the great variation in lateralization that has been reported to depend on variables such as species, ecological settings and environmental factors.

Male mate choice and the potential for complex mating dynamics in the tree lizard (Urosaurus ornatus)

AbstractA growing body of literature is recognizing that males may also play a role in the mating process by behaving non‐randomly toward potential female mates during courtship. In numerous species, discrete color polymorphisms in males are inferred to represent alternative mating tactics, which often correspond with concomitant asymmetries in ecology and behavior. In terms of their mating behavior, these ecological outcomes of a color polymorphism should affect a morph's likelihood and frequency of encountering females in a population, possibly favoring the evolution of morph‐specific mating preferences. Knowledge of how male morphs contribute to a species’ overall mating dynamics will improve our understanding of how sexual selection shapes phenotypic diversity in color polymorphic systems. We conducted a mate choice experiment to evaluate the extent and morph specificity of non‐random mating preferences by male ornate tree lizards, Urosaurus ornatus. We observed the behavior of blue and yellow males in an experimental arena in response to a choice between an orange or yellow female. We found that blue males preferred yellow females over orange females, and although yellow males visited females more often than blue males overall, their attention was not morph‐specific. Given male morph differences in choosiness, and their differences in social dominance, we conclude that female throat color may be partly under sexual selection in U. ornatus. However, a lack of concordance between male and female mating preferences (drawn from an earlier study) suggests that overall mating dynamics may serve to maintain, rather than enhance, color morph differences in this species.

Examining Spillovers between Long and Short Repeated Prisoner's Dilemma Games Played in the Laboratory.

We had participants play two sets of repeated Prisoner’s Dilemma (RPD) games, one with a large continuation probability and the other with a small continuation probability, as well as Dictator Games (DGs) before and after the RPDs. We find that, regardless of which is RPD set is played first, participants typically cooperate when the continuation probability is large and defect when the continuation probability is small. However, there is an asymmetry in behavior when transitioning from one continuation probability to the other. When switching from large to small, transient higher levels of cooperation are observed in the early games of the small continuation set. Conversely, when switching from small to large, cooperation is immediately high in the first game of the large continuation set. We also observe that response times increase when transitioning between sets of RPDs, except for altruistic participants transitioning into the set of RPDs with long continuation probabilities. These asymmetries suggest a bias in favor of cooperation. Finally, we examine the link between altruism and RPD play. We find that small continuation probability RPD play is correlated with giving in DGs played before and after the RPDs, whereas high continuation probability RPD play is not.

Lateralisation of visual function in yellow-eyed mullet (Aldrichetta forsteri) and its role in schooling behaviour

Lateralisation of cognitive function is a common phenomenon found throughout the animal kingdom. In fish, lateralisation is involved in visually mediated behaviours such as schooling, predator avoidance and foraging. This study sought to quantify visual laterality in yellow-eyed mullet (Aldrichetta forsteri), to determine visual asymmetries and the significance of lateralisation, and the factors which influence functional behaviours in schooling fish. Tank-based experiments investigated individual and population level lateralisation, schooling behaviour, and optic lobe asymmetry. Variation in direction and strength of lateralisation in individuals was found in juveniles, but at a population level significant bias was found in adults. Right eye biased fish had a larger right optic lobe than control fish. Strongly lateralised fish showed a tendency to occupy positions of safety within the school more frequently than control fish. In combination with observed differences in schooling behaviour, the possibility of ontogenetic plasticity in behavioural lateralisation and optic lobe morphology is suggested.

Distinct molecular mechanisms for development of brain asymmetries?

Brain and behavioral asymmetries are often associated with neurodevelopmental disorders, but have yet uncovered genetic and developmental mechanisms. A recent study (Vingerhoets et al., 2018), published in Brain Structure and Function, examined neural structural and functional asymmetries in a cohort of patients with situs inversus totalis, with and without primary ciliarly dyskinesia as a second diagnosis. The authors showed a potential for independent randomization of handedness, language dominance, and visceral laterality; this provides the first experimental hint that different mechanisms for symmetry breaking and molecular cascades may be involved in producing asymmetry of body and brain.

Behavioral Asymmetries among Mother-Infant Dyads of Syntopic Macaques (Macaca Assamensis and M. Mulatta) in Shivapuri-Nagarjun National Park, Nepal

Behavioral Asymmetries among Mother-Infant Dyads of Syntopic Macaques (Macaca Assamensis and M. Mulatta) in Shivapuri-Nagarjun National Park, Nepal