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Abstract

The division of labor by the two cerebral hemispheres—once thought to be uniquely human—predates us by half a billion years. Speech, right-handedness, facial recognition and the processing of spatial relations can be traced to brain asymmetries in early vertebrates

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... In animals, emotional states are usually recognized with the use of behavioral and physiological measurements [7,8]. Laterality is a frequently reported phenomenon studied both in humans and in various animal species [9][10][11][12]. ...
... As demonstrated by MacNeilage et al. [10], the right brain hemisphere is responsible for responses to strong emotions and stimulates an increase in cortisol release in the blood by controlling endocrine functions. In turn, the left hemisphere of the brain allows focusing on specific stimuli without distraction by signals that are not related to the performed task [10]. ...
... As demonstrated by MacNeilage et al. [10], the right brain hemisphere is responsible for responses to strong emotions and stimulates an increase in cortisol release in the blood by controlling endocrine functions. In turn, the left hemisphere of the brain allows focusing on specific stimuli without distraction by signals that are not related to the performed task [10]. Literature data indicate a possible relationship between motor laterality and the emotional state of dogs, although it is believed that dogs with left hemisphere predominance are usually calmer than left-pawed individuals [9,66,67]. ...
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It has been assumed that stroking relieves stress responses in dogs, and dogs with the activation of the left-brain hemisphere (right-pawed) may show better adaptation to stress conditions. The aim of the study was to determine whether the stroking stimulus induced changes in the level of selected neuroregulators in dogs’ blood and whether these changes depended on the sex and the predominance of the activity of one of the brain hemispheres. The study involved 40 dogs of various breeds and both sexes. The experimental animals were subjected to a behavioral tests (Kong test), and the levels of noradrenaline, serotonin, and cortisol were determined in their blood plasma. The results of the behavioral test revealed that most dogs exhibited increased activity of the left hemisphere. Furthermore, irrespective of the sex and paw preference, stroking the animal was found to alleviate the stress response, which was reflected in reduced cortisol levels and increased serotonin levels. It was found that the plasma noradrenaline, cortisol, and serotonin levels were lower in the female dogs than in the males. Additionally, the plasma noradrenaline and serotonin levels were higher in the right-pawed dogs than in the left-pawed dogs. The present results confirm the assumption that right-pawed dogs adapt to stressful conditions more readily.
... The left hemisphere engages mainly in processing positive stimuli and learnt routine tasks, and responding to food or prey; the right hemisphere is more associated with the responses to negative and unexpected stimuli or dangerous events (e.g. predators, conspecific aggression), and encoding the spatial relationships occurring in the surrounding environment (MacNeilage et al., 2009;Rogers et al., 2013). Substantial findings have shown benefits related to cerebral lateralization (Ferrari et al., 2017), such as specialization of certain cognitive or motor tasks by avoiding duplication of functions in the two hemispheres (Frasnelli, 2013;Vallortigara and Rogers, 2005), and processing several streams of information in parallel Vallortigara, 2006). ...
... Our results support both the 'valence theory', which presumes that the right hemisphere is mainly used to process negative stimuli (Prete et al., 2015;Siniscalchi et al., 2013), and the 'brain's right hemisphere' theory, which proposes that the right brain is preferentially used to process information concerning novel events in which the animal may be in an intense emotional state (e.g. aggression, fear and escape behavior) and should respond rapidly (MacNeilage et al., 2009;Rogers et al., 2013). ...
Article
Visual lateralization is widespread for prey and anti-predation in numerous taxa. However, it is still unknown how the brain governs this asymmetry. In this study, we conducted both behavioral and electrophysiological experiments to evaluate anti-predatory behaviors and dynamic brain activities in the Emei music frogs (Nidirana daunchina) in order to explore the potential eye bias for anti-predation and the underlying neural mechanism. To do this, the predator stimuli (the head of a snake model and leaf as control) were moved around the subjects in clockwise and anticlockwise at steady velocity, respectively. We counted the number of anti-predatory responses and measured electroencephalogram (EEG) power spectra for each band and each brain area (the telencephalon, diencephalon and mesencephalon). The results showed that: (1) no significant eye preferences could be found for the control (leaf), however, the laterality index was significantly lower than zero when the predator stimulus was moved anticlockwise, suggesting left-eye advantage exists in this species for anti-predation; (2) compared with no stimulus in the visual field, the power spectra of delta and alpha bands were significantly greater when the predator stimulus was moved into LVF anticlockwise; and (3) generally, the power spectra of each band in the right-hemisphere for LVF were higher than those in the left counterpart. These results support that the left-eye mediates monitoring of the predator in the music frogs and the lower frequency EEG oscillations govern this visual lateralization.
... Within a group, or population, there are equal numbers of left-hand and right-hand preferring marmosets [14][15][16], and each individual retains its hand preference throughout adulthood [17]. However, the same marmosets with either left-or righthand preference were found to show a strong population bias to use the right eye to view familiar, non-arousing stimuli, assessed by the eye preferred to view each stimulus through a peephole [18,19] Since viewing with the right eye shows initial and preferential use of the left hemisphere [19], the group preference is consistent with the known specialization of the left-hemisphere to process nonarousing stimuli and to categorize them [20], and this eye-hemisphere bias had no association with hand preference. ...
... Now we know that not only is this simple genetic model incorrect but also there are many different types of asymmetry in a broad range of vertebrate species. Indeed, there is evidence that functional lateralization of the brain evolved in early vertebrates [103] and that a basic plan of lateralized function can be found across vertebrate species [20,59]; viz., specialization of the left side of the brain, or hemisphere, to categorize stimuli and follow acquired rules, whereas the right side of the brain, or hemisphere, is specialized to respond to changes in the environment, including detection of novelty and predators, and to control social behavior [59,104,105]. The right hemisphere is also specialized to respond to negative emotional stimuli [106][107][108]. ...
Article
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By examining the development of lateralization in the sensory and motor systems of the human fetus and chick embryo, this paper debates which lateralized functions develop first and what interactions may occur between the different sensory and motor systems during development. It also discusses some known influences of inputs from the environment on the development of lateralization, particularly the effects of light exposure on the development of visual and motor lateralization in chicks. The effects of light on the human fetus are related in this context. Using the chick embryo as a model to elucidate the genetic and environmental factors involved in development of lateralization, some understanding has been gained about how these lateralized functions emerge. At the same time, the value of carrying out much more research on the development of the various types of lateralization has become apparent.
... Studies now suggest that cerebral functional asymmetry is not unique to humans but may be a fundamental feature of all vertebrate, and even some invertebrate, brains (for reviews [5][6][7][8][9][10][11]). What is less clear is whether non-human species exhibit lateralisation in their limb use in a manner that approximates human handedness or whether the preferred use of a specific hand, paw or similar appendage is related to other aspects of brain asymmetry (see reviews [12][13][14]). ...
... Research has shown that the two cerebral hemispheres control very different functions, one being emotional reactivity; however, the exact influence of each hemisphere in emotional processing is still debated (for a review see [53]). The left hemisphere is largely believed to dominate approach and exploratory behaviour, whilst inhibiting fear [6]. The right hemisphere, by contrast, is thought to control the processing of fear and stimulates withdrawal in novel situations [55]. ...
Article
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Cat breeds differ enormously in their behavioural disposition, a factor that can impact on the pet-owner relationship, with indirect consequences for animal welfare. This study examined whether lateral bias, in the form of paw preference, can be used as a tool for assessing breed differences in emotional reactivity in the cat. The paw preferences of 4 commonly owned breeds were tested using a food-reaching challenge. Cats were more likely to be paw-preferent than ambilateral. Maine Coons, Ragdolls and Bengals were more likely to be paw-preferent than ambilateral, although only the Bengals showed a consistent preference for using one paw (left) over the other. The strength of the cats’ paw use was related to cat breed, with Persians being more weakly lateralised. Direction of paw use was unrelated to feline breed, but strongly sex-related, with male cats showing a left paw preference and females displaying a right-sided bias. We propose that paw preference measurement could provide a useful method for assessing emotional reactivity in domestic cats. Such information would be of benefit to individuals considering the acquisition of a new cat, and, in the longer term, may help to foster more successful cat-owner relationships, leading to indirect benefits to feline welfare.
... It discriminates between categories and memorises patterns. It is the hemisphere used when attention is focussed on the task being performed and under relatively relaxed conditions [51]. The right hemisphere is used in emotionally charged situations, including detection of predators, in agonistic interactions and copulation and in escape responses [51]. ...
... It is the hemisphere used when attention is focussed on the task being performed and under relatively relaxed conditions [51]. The right hemisphere is used in emotionally charged situations, including detection of predators, in agonistic interactions and copulation and in escape responses [51]. This leads us to ask whether the same pattern is seen in wild-living avian species. ...
Article
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We know a good deal about brain lateralization in birds and a good deal about animal welfare, but relatively little about whether there is a noteworthy relationship between avian welfare and brain lateralization. In birds, the left hemisphere is specialised to categorise stimuli and to discriminate preferred categories from distracting stimuli (e.g., food from an array of inedible objects), whereas the right hemisphere responds to small differences between stimuli, controls social behaviour, detects predators and controls attack, fear and escape responses. In this paper, we concentrate on visual lateralization and the effect of light exposure of the avian embryo on the development of lateralization, and we consider its role in the welfare of birds after hatching. Findings suggest that light-exposure during incubation has a general positive effect on post-hatching behaviour, likely because it facilitates control of behaviour by the left hemisphere, which can suppress fear and other distress behaviour controlled by the right hemisphere. In this context, particular attention needs to be paid to the influence of corticosterone, a stress hormone, on lateralization. Welfare of animals in captivity, as is well known, has two cornerstones: enrichment and reduction of stress. What is less well-known is the link between the influence of experience on brain lateralization and its consequent positive or negative outcomes on behaviour. We conclude that the welfare of birds may be diminished by failure to expose the developing embryos to light but we also recognise that more research on the association between lateralization and welfare is needed.
... Understandably, summaries of functions controlled by each of the hemispheres may serve as a useful tool for explaining of the general understanding of brain and behavioural lateralization (e.g., Rogers 2002;MacNeilage et al. 2009). However, it appears to be more controversial when any simple distinction is considered as a universal concept and is used to predict the direction of lateralization in specific behavioural responses. ...
... Similarly, Australian magpies preferentially looked up with the left eye scanning for predators after the playback of a species-specific 'eagle' alarm call(Rogers Kaplan 2006). It is widely assumed that the right visual field (left hemisphere) is associated with processing routine responses and established patterns, whilst the left visual field (right hemisphere) is specialized for response in unexpected situations(MacNeilage et al. 2009). ...
Article
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The visual system and lifestyle characteristics make the even-toed ungulates an excellent model for the studies of behavioural lateralization. Recent research has focused on these mammals providing evidence of lateralization in a wide range of behaviours. This provides an opportunity for the collation of the current theoretical assumptions and the existing empirical evidence for visual lateralization in artiodactyls. In the present study, we aim first to gain a fuller picture of hemispheric specializations in saiga antelopes by investigating the lateralization of vigilance and novel object inspection in the wild. Second, we summarized the results of the research into visual lateralization in even-toed ungulates and attempted to assess the applicability of two popular hypotheses about the division of hemispheric roles. The results on saigas show a significant preference for head turns to the right visual field during vigilance which was more robust in individuals in larger groups. When an unfamiliar artificial object was placed in their natural setting, saigas preferentially viewed it predominantly with the right eye. These results, together with the cumulative evidence in artiodactyls, do not follow either the approach—withdrawal or positivity—negativity dichotomous patterns widely used to explain the division of functions between the hemispheres.
... In horses, the left forelimbs and their laterally placed eyes and ears are largely connected to the right brain hemisphere, and vice versa [28]. While the left hemisphere has been shown to be preferentially used for established learned responses, categorization of stimuli and approach behavior, the right hemisphere has been proposed as being dominant in information processing for emergency reactions, stress responses, novelty, and social interactions [29][30][31][32][33][34][35][36]. The motor laterality is assumed to be the result of brain hemispheric modulation through former experiences and training [27,37]. ...
Article
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Domesticated horses are constantly confronted with novel tasks. A recent study on anecdotal data indicates that some are innovative in dealing with such tasks. However, innovative behavior in horses has not previously been investigated under experimental conditions. In this study, we investigated whether 16 horses found an innovative solution when confronted with a novel feeder. Moreover, we investigated whether innovative behavior in horses may be affected by individual aspects such as: age, sex, size, motor and sensory laterality, fecal stress hormone concentrations (GCMs), and task-related behavior. Our study revealed evidence for 25% of the horses being capable of innovative problem solving for operating a novel feeder. Innovative horses of the present study were active, tenacious, and may be considered to have a higher inhibitory control, which was revealed by their task related behavior. Furthermore, they appeared to be emotional, reflected by high baseline GCM concentrations and a left sensory and motor laterality. These findings may contribute to the understanding of horses’ cognitive capacities to deal with their environment and calls for enriched environments in sports and leisure horse management.
... Associated with these neural changes there are related asymmetries in both fish and birds on a variety of visuallyguided responses (review in (Chiandetti, 2017)). In general terms, the literature consistently shows that the right hemisphere attends to novelty by responding to extraneous and unexpected aspects, whereas the left hemisphere chiefly sustains attention against distractors and mediates routine responses to invariant and familiar characteristics (Vallortigara et al., 1999;MacNeilage et al., 2009;Rogers, 2014). Thus, the neural pathway of the epigenetic asymmetries differs between fish and birds although the observed labor division of the two hemispheres is the same. ...
Article
Embryonic light exposure affects similarly functional lateralization in fish and birds. While the light acts on an asymmetric habenular system during the first post fertilization hours in zebrafish, in the domestic chicks it shapes the thalamofugal visual pathway affecting the right retinal photoreceptors in the last stages before hatching. However, recent evidence has shown that also in chicks a precocial embryonic time window seems open to light action. Here we addressed the issue of whether the light effect is comparable in the early and late sensitive periods of chicks' embryonic development by testing birds coming from early (EL) and late (LL) light stimulated eggs compared to dark maintained eggs (DK) under different conditions of vision in a gravel-grain task. The perseveration of pecks directed to irrelevant elements revealed that in all chicks the right hemisphere was heavily attracted by the novel elements when tested with the left eye. When using the right eye, instead, only DK chicks attended repeatedly to distractors whereas LL and EL chicks showed a left hemisphere advantage for fine discrimination and sustained attention; conversely, when tested binocularly, LL chicks perseverated significantly more than both DK and EL chicks, likely compensating the distraction with the analysis carried out by both hemispheres. For the first time, we unveiled a fine graded difference between the light modulation exerted during the two time windows, adding evidence to the idea that genes and environmental factors interplay in several separate routes to the modulation of the neurodevelopment of cerebral lateralization in vertebrates.
... The study of lateralization can, arguably, utilize this componential approach to the study of emotions because it has been shown that the cognitive, physiological and behavioural components of emotions are underlain by lateralized cerebral processes in many vertebrate taxa (Leliveld, Langbein, & Puppe, 2013;Rogers, 2010;Rogers, Vallortigara, & Andrew, 2013). Lateralization refers to the fact that the brain hemispheres can play different roles in many cerebral processes (MacNeilage, Rogers, & Vallortigara, 2009;Rogers & Vallortigara, 2015;Vallortigara & Versace, 2017), such as in emotional processing. The emotional valence hypothesis states that positive emotions are processed predominantly by the left (L) hemisphere while negative emotions are processed predominantly by the right (R) hemisphere (Demaree, Everhart, Youngstrom, & Harrison, 2005;Quaranta, Siniscalchi, & Vallortigara, 2007;Siniscalchi, Lusito, Vallortigara, & Quaranta, 2013) and seems to prevail over alternative hypotheses, for example the approach/ withdrawal hypothesis (Leliveld et al., 2013). ...
Article
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Understanding animal emotions is an important scientific and ethical question but assessing emotional valence is still considered challenging. As the observation of lateralization (hemispheric asymmetries in structure and/or function) can provide insight into the underlying processes of the cognitive, physiological and behavioural components of emotions, it is a promising approach for studying them. The emotional valence hypothesis states that positive emotions are mostly processed by the left hemisphere, while negative emotions are mostly processed by the right hemisphere. Support for this hypothesis is still not conclusive; therefore, our study tested it in the context of visual laterality for viewing positive or negative emotionally conditioned stimuli. Ninety male piglets were either positively (food-reward) or negatively (mild punishment) conditioned to an object. Afterwards, the object was presented without the reinforcer under three different treatments: patch on the left or right eye (reducing input to the contralateral hemisphere) or patch between the eyes (the control). Monocular viewing had no clear effects on the negatively conditioned subjects. In contrast, in the positively conditioned group, covering the right eye caused a longer interruption of vocalization, a longer latency to touch the object, a shorter duration of exploring the arena and an increased vagal activity compared to the control. This suggests that reduced processing in the left hemisphere leads to heightened attention that is accompanied by a general orienting response, possibly resulting from a reduced positive appraisal. These findings therefore partially support the emotional valence hypothesis and suggest an important role of the left hemisphere in the quick recognition of a positive stimulus. This study demonstrated that investigating the lateralized processing of emotions can provide insight into the mechanisms of positive appraisal in animals.
... Regarding body posture, the postural origin hypothesis states that (1) arboreal primates prefer using the right hand to support the body in trees and the left hand for manual tasks, whereas (2) more terrestrial primates prefer using the right hand during manual tasks (MacNeilage et al., 1987;MacNeilage, 1991). Increasing primate research lends support to the postural origin hypothesis (MacNeilage, 2007;MacNeilage et al., 2009). For example, with regard to spontaneous bimanual grooming and experimental tube tasks, chimpanzees (Pan troglodytes) show group-level right-hand preference (Hopkins, 2007;Hopkins et al., 2007), whereas Sichuan snub-nosed monkeys (Rhinopithecus roxellana) display group-level left-hand preference (Zhao et al., 2010(Zhao et al., , 2012. ...
Article
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Investigations on manual laterality in non-human primates can help clarify human evolutionary origins of hand preference and cerebral cognition. Although body posture can influence primate hand preference, investigations on how posture affects hylobatid manual laterality are still in their infancy. This study focused on how spontaneous bipedal behavioral tasks affect hand preference in Hylobatidae. Ten captive northern white-cheeked gibbons (Nomascus leucogenys) were chosen as focal subjects. Unimanual grooming during sitting posture and supported bipedal posture were applied as behavioral tasks. The gibbons displayed a modest tendency on left-hand preference during sitting posture and right-hand preference during supported bipedal posture, although no group-level hand preference was detected for either posture. From the sitting to supported bipedal posture, 70% of individuals displayed different degrees of right-side deviation trends. The strength of manual laterality in the supported bipedal posture was higher than that in the sitting posture. We found significant sex differences in manual laterality during supported bipedal posture but not during sitting posture. Thus, to a certain degree, bipedal posture in N. leucogenys facilitates stronger hand preference, elicits a rightward trend in manual laterality, and produces sex-specific hand preference.
... Research on humans and other animals has shown external ear temperature (e.g., dogs: Riemer et al., 2016) and within-ear temperature to reflect hemispheric temperature in the brain with high accuracy (humans: Brinnel & Cabanac, 1989;Cabanac, 1993;Mariak et al., 1994Mariak et al., , 2003Ogawa, 1994;rabbits: Tanabe & Takaori, 1964; pig-tailed macaques: Baker et al., 1972;cats: Mazzotti & Boere, 2009). In humans, left and right hemispheres are responsible for processing different emotional responses (Ahern & Schwartz, 1985;Altenmüller et al., 2002;Davidson & Fox, 1982;Jones & Fox, 1992;MacNeilage et al., 2009;Turhan et al., 1998) and the same is true for several species of domesticated animals (dogs, cats, horses, chickens, and goldfish: Leliveld et al., 2013). Frontal and temporal lobe activity appears responsible for generating the corresponding side's hemispheric activity, which alters as a function of the motivational state experienced (Propper & Brunyé, 2013). ...
... It was first described in the 19th century by M. Dax and P. Broca who showed that lesions in specific areas in the left hemisphere but not in the right one, were associated with deficits in producing language thus suggesting left hemisphere dominance for speech. For more than a century brain lateralization has been considered a human peculiarity linked to handedness, and complex cognitive functions, such as language (McManus, 1999;MacNeilage et al., 2009). This belief has been challenged in the 1970s by a series of independent discoveries. ...
Article
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It is widely acknowledged that the left and right hemispheres of human brains display both anatomical and functional asymmetries. For more than a century, brain and behavioral lateralization have been considered a uniquely human feature linked to language and handedness. However, over the past decades this idea has been challenged by an increasing number of studies describing structural asymmetries and lateralized behaviors in non-human species extending from primates to fish. Evidence suggesting that a similar pattern of brain lateralization occurs in all vertebrates, humans included, has allowed the emergence of different model systems to investigate the development of brain asymmetries and their impact on behavior. Among animal models, fish have contributed much to the research on lateralization as several fish species exhibit lateralized behaviors. For instance, behavioral studies have shown that the advantages of having an asymmetric brain, such as the ability of simultaneously processing different information and perform parallel tasks compensate the potential costs associated with poor integration of information between the two hemispheres thus helping to better understand the possible evolutionary significance of lateralization. However, these studies inferred how the two sides of the brains are differentially specialized by measuring the differences in the behavioral responses but did not allow to directly investigate the relation between anatomical and functional asymmetries. With respect to this issue, in recent years zebrafish has become a powerful model to address lateralization at different level of complexity, from genes to neural circuitry and behavior. The possibility of combining genetic manipulation of brain asymmetries with cutting-edge in vivo imaging technique and behavioral tests makes the zebrafish a valuable model to investigate the phylogeny and ontogeny of brain lateralization and its relevance for normal brain function and behavior.
... The study of lateralization can, arguably, utilize this componential approach to the study of emotions because it has been shown that the cognitive, physiological and behavioural components of emotions are underlain by lateralized cerebral processes in many vertebrate taxa (Leliveld, Langbein, & Puppe, 2013;Rogers, 2010;Rogers, Vallortigara, & Andrew, 2013). Lateralization refers to the fact that the brain hemispheres can play different roles in many cerebral processes (MacNeilage, Rogers, & Vallortigara, 2009;Rogers & Vallortigara, 2015;Vallortigara & Versace, 2017), such as in emotional processing. The emotional valence hypothesis states that positive emotions are processed predominantly by the left (L) hemisphere while negative emotions are processed predominantly by the right (R) hemisphere (Demaree, Everhart, Youngstrom, & Harrison, 2005;Quaranta, Siniscalchi, & Vallortigara, 2007;Siniscalchi, Lusito, Vallortigara, & Quaranta, 2013) and seems to prevail over alternative hypotheses, for example the approach/ withdrawal hypothesis (Leliveld et al., 2013). ...
Conference Paper
The observation of laterality –hemispheric asymmetries in structure and/or function– is a promising non-invasive approach to better understand animal affect since it can give insight into cerebral processes underlying the key components of emotions. The emotional valence hypothesis states that positive emotions are mostly processed by the left hemisphere, while negative emotions are mostly processed by the right hemisphere. Testing this hypothesis in farm animals could help to gain insight into their emotional valence which is relevant for animal welfare but challenging to assess. Whereas previous studies found evidence of opposite hemispheric dominances for perceiving food or a predator, a distinction between emotional arousal and valence is impossible when using such complex natural stimuli. The aim of this study was to test the emotional valence hypothesis in the context of visual laterality in pigs by using a paradigm of emotional conditioning. Ninety male piglets were either positively (using a food-reward, 45 subjects) or negatively (using a mild punishment, 45 subjects) conditioned to an object (a ball). Afterwards, the object was presented without the reinforcer. Each subject was tested 3 times under 3 different treatments: right or left eye covered with a patch causing a reduced visual input to the contralateral hemisphere; or binocular viewing as the control treatment for which a patch was fixed between the eyes. We measured the duration, frequency and latency of touching the object, latency to vocalise after the introduction of the object, duration of locomotion and of exploration in the arena and number of vocalisations. Using a heart rate measurement belt, we also analysed heart rate variability. All parameters were analysed by repeated measures analyses of variance and multiple pairwise Tukey-Kramer-tests. In the negatively conditioned group, covering the left eye caused increased vocalisation rates (t=-3.24; P=0.004) compared to seeing with both eyes . Due to the lack of other effects, this did not provide a clear support for the emotional valence hypothesis with regard to negative emotions. In contrast, in the positively conditioned group, covering the right eye (reduced input to the left hemisphere) caused longer latencies to touch the object (t=-2.96, P=0.010) and to vocalise after the introduction of the object (t=-3.24, P=0.004), a shorter duration of exploring the arena (t=2.71, P=0.020) and an increased vagal activity (t=-3.14, P=0.007) compared to binocular viewing. This suggests that reduced visual input to the left hemisphere possibly resulted in a reduced positive appraisal which supports the emotional valence hypothesis with regard to positive emotions. This study shows that investigating the lateralised processing of emotionally conditioned stimuli can provide insight into the mechanisms of positive appraisal in animals.
... For instance, the GMV of the R4 correlated with the GMV of the bilateral amygdala, bilateral hippocampal formation, and bilateral thalamus; however, the fMRI of R4 correlated primarily with the regions in the right hemisphere, especially in lateral prefrontal and lateral parietal cortex. This result suggests that human brain is functionally and anatomically asymmetric (Kimura, 1973;MacNeilage, Rogers, & Vallortigara, 2009); however, the functional asymmetry is much more striking. Moreover, the functional connectivity patterns of the anterior subregions (L1, R1, and R2) were primarily located at the anterior part of the default mode network (DMN), whereas the func- We demonstrated converging and similar structural covariance and functional connectivity patterns for each hippocampal subregion and bilaterally symmetric subregions, respectively. ...
Article
The hippocampus is a key brain region that participates in a range of cognitive and affective functions, and is involved in the etiopathogenesis of numerous neuropsychiatric disorders. The structural complexity and functional diversity of the hippocampus suggest the existence of structural and functional subdivisions within this structure. For the first time, we parcellated the human hippocampus with two independent data sets, each of which consisted of 198 T1‐weighted structural magnetic resonance imaging (sMRI) images of healthy young subjects. The method was based on gray matter volume (GMV) covariance, which was quantified by a bivariate voxel‐to‐voxel linear correlation approach, as well as a multivariate masked independent component analysis approach. We subsequently interrogated the relationship between the GMV covariance patterns and the functional connectivity patterns of the hippocampal subregions using sMRI and resting‐state functional MRI (fMRI) data from the same participants. Seven distinct GMV covariance‐based subregions were identified for bilateral hippocampi, with robust reproducibility across the two data sets. We further demonstrated that the structural covariance patterns of the hippocampal subregions had a correspondence with the intrinsic functional connectivity patterns of these subregions. Together, our results provide a topographical configuration of the hippocampus with converging structural and functional support. The resulting subregions may improve our understanding of the hippocampal connectivity and functions at a subregional level, which provides useful parcellations and masks for future neuroscience and clinical research on the structural and/or functional connectivity of the hippocampus.
... Reviews within the behavioural and neural approach (Goble & Brown, 2008;Sainburg, 2014) advanced in the field by moving towards a complementary dominance view of the phenomenon (each hemisphere is specialized in certain aspects of movement control), leaving the global dominance (preferred hand is better in all aspects) construct behind. This shift of perspective is supported by other experimental research (Woytowicz, Westlake, Whitall, & Sainburg, 2018), and backed up by an evolutionist approach, in which the neural development and increased processing efficiency verified in humans is closely related to lateralization of brain processes (MacNeilage, Rogers, & Vallortigara, 2009;Rogers, Zucca, & Vallortigara, 2004). Additionally, in the behavioural component, if we consider energy expenditure (metabolic) and movement efficiency, it would not be favourable to have two hemispheres specialized in manipulations, as most tasks require both components (stabilizing and manipulating) in a coordinated fashion. ...
Article
Handedness ontogenesis is still under debate in science. This systematic review analyzed articles regarding the theories and basis of handedness formation, highlighting the historical knowledge path that this literature underwent. Cochrane Library, LILACS, Web of Sciences, Science Direct and PubMed databases were searched. This review included review studies with handedness as the main topic. Only papers written in English with analyses exclusively in neurotypical humans (any age range) were included. Different approaches (genetic, neural, social, and behavioural) were reviewed in light of growing evidence, summarizing the current state of the art. Genetic and environmental/social impacts are common points in most of the reviews, each given more or less importance, depending on the author and theory proposed. Multifactorial, developmental approaches to handedness formation seem to be the most up to date view of the phenomenon. Different control mechanisms between hemisphere and neural asymmetries are also contributing factors to handedness formation.
... The present study also demonstrated that the occipital lobes were affected by LED lighting. High color temperature during the robot programming activity affected the left hemisphere, which is involved in solving problems logically and analytically more than right hemisphere [30][31][32]. ...
Article
The purpose of the present study was to analyze the effects of LED lighting with three different color temperature values on the stability, concentration, activation, and stress indices of electroencephalogram (EEG) during a robot programming activity. The EEG was measured in the presence and absence of LED lighting. Variations in EEG from bilateral prefrontal and occipital lobes were measured during a robot programming activity under color temperature values in the presence of LED lighting. Based on the measured EEG values, the stability, concentration, activation, and stress indices were calculated and analyzed. Subjects were classified into two groups based on the brain regions from which a stronger α-wave was generated (prefrontal or occipital lobes). LED lighting with a color temperature of 7000 K increased overall EEG indices during the robot programming activity; LED lighting with color temperature of 5000 K also increased several indices. These findings support previous results that high color temperatures over 5000 K may facilitate learning in mathematics and sciences, suggesting that color temperature may need to be adjusted according to the types of learning and personal characteristics of learners.
... One of his more recent publications (Andrew, 2009) considered the evolution of brain and behavioural asymmetry from left-right differences in habenulae of early tetrapods and, as well, discussed asymmetry in invertebrate species, the latter having by then been found in bees (Rogers & Vallortigara, 2008). In vertebrates he saw a common pattern of right eye use in sustained pursuit (as in catching prey) and left eye use to attend to valent stimuli and to promote intense response (as in escape response), later in evolution to be expressed as strong emotion (see MacNeilage, Rogers, & Vallortigara, 2009;Vallortigara & Versace, 2017). ...
... In a similar fashion, one can predict how intrinsic differences, resulting from the lateralization of the vertebrate brain (MacNeilage et al. 2009), should shift the optimal fraction of reuse. For anticipatory motor planning, studies support the notion of a left-hemispheric dominance: lefthemispheric damage severely impairs performance in anticipatory grasp planning (Mutsaarts et al. 2007;Crajé et al. 2009). ...
Article
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In sequential, repetitive tasks, we often partially reuse former motor plans. This causes a persistence of an earlier adopted posture (termed motor hysteresis). The cost-optimization hypothesis states that a partial reuse reduces the cognitive cost of a movement, while the persistence in a former posture increases its mechanical cost. An optimal fraction of reuse, which depends on the relative cognitive and mechanical cost, minimizes the total movement cost. Several studies postulate differences in mechanical or cognitive cost as a result of hemispheric lateralization. In the current study, we asked whether these differences would result in different fractions of motor plan reuse. To this end, left- and right-handed dominant participants executed a sequential motor task (opening a column of drawers) with their dominant and non-dominant hand. The size of the motor hysteresis effect was measured as a proxy for the fraction of plan reuse. Participants used similar postures and exhibited a similar hysteresis effect, irrespective of hand and handedness. This finding indicates that either the cognitive and mechanical costs of a motor task are unaffected by hemispheric differences or that their effect on motor planning is negligible.
... Rogers, Zucca, & Vallortigara, 2004). Whereas the left hemispherehence right visual fieldmainly controls routine and goal-directed action behaviour as, for example, singing in birds (Nottebohm, Stokes, & Leonard, 1976) or catching prey in toads (Vallortigara, Rogers, Bisazza, Lippolis, & Robins, 1998), the right hemisphere -hence left visual fieldis more activated when something unexpected happens, as for example, the appearance of a predator (MacNeilage, Rogers, & Vallortigara, 2009). For instance, it was found that toads only reacted to a snake rubber head by jumping away if the head was pushed towards them from the left but not when approaching from the right. ...
Article
Pseudoneglect represents the tendency in healthy people to show a slight bias in favour of stimuli appearing in the left visual field. Some studies have shown that this leftward bias can be annulled or reserved towards a rightward bisection bias when lateral attentional biases are assessed in far space. Using an immersive simulated, ecologically valid football task, we investigated whether possible attentional and perceptual asymmetries affect sport-specific decision making. Twenty-seven sport athletes were required to judge different game situations, which involved both perceptual and attentional skills to perceive player configurations in the visual periphery. We did not find any performance differences in accuracy rate between the left and right visual field side for stimuli presented close to the screen centre in an object-detection (perception-based) and feature-recognition (attention-based) task. This result is in line with previous findings showing an absence of a left- or rightward bisection bias in far space. However, accuracy was higher for stimuli being presented at visual angles wide away from the screen centre at the left side compared to the right side of visual field. This finding cannot be explained by literature focusing on pseudoneglect in far space, but rather by previous findings on landmark judgments often showing left bias both in near and in far space. Overall, the current findings provide new perspectives on attentional and perceptual asymmetries in real-world scenarios, and different interpretations of results are discussed.
... The left hemisphere specializes in categorizing stimuli (e.g., food vs. non-food items ( Rogers et al., 2013)) and controlling established behaviors with focused attention, while the right hemisphere specializes in responding to novel and threatening stimuli by eliciting rapid emotional and behavioral changes in emergency situations, such as heightened fear and aggression (Rogers et al., 2013). Indeed, most studied species appear to be more reactive to predators occurring in the left visual field, for which information is processed by the right (contralateral) hemisphere (MacNeilage, Rogers, & Vallortigara, 2009;Vallortigara, 2006). Although examples of lateralization have mostly been obtained in controlled laboratory conditions, striking similarities of hemispheric control have also been found in the wild ( Rogers et al., 2013). ...
Article
Brain and behavioral asymmetries (termed "lateralization"; e.g., preferential eye‐use) have been mostly described in controlled laboratory conditions, although striking similarities of hemispheric brain control for specific behaviors have also been shown in the wild. Visual lateralization may provide ecological advantages by allowing complementary roles played by the left–right lateral and frontal visual field in distant or close motion detection of predators or other threats. In this study, we tested for lateralization in aggressive behavior in wild king penguins (Aptenodytes patagonicus), seabirds breeding in a context of strong colonial aggressiveness, and subject to on‐land‐based predation of their egg or chick. We show that males initiated more agonistic interactions when a congener was located in their right frontal visual field and in their left lateral visual field. The results obtained in females were the exact opposite for each subdivision of their visual fields. Complementary lateralization in male and female penguins may be part of a more general phenomenon, allowing partners to coordinate their behavior during reproduction. This may be especially true during the period of courtship, during which these seasonally monogamous and monomorphic seabirds engage in mutual mate choice based on a complex and ritualized display of ornaments located on the left and right lateral sides of the head. Those results open exciting questions as to whether hemispheric control of aggression is a commonly selected phenotypic trait across colonial seabirds.
... Two prominent models have been proposed that describe lateralization across a large range of neurobehavioral domains, including language, cognition, and movement. Rogers and Andrew (2008) and MacNeilage et al. (2009), proposed a model based on empirical findings of lateralized behaviors across a range of neurobehavioral domains, and across a wide range of vertebrate species. According to this model, the left hemisphere is viewed as specialized for control of well-established patterns of behavior under predictable environmental conditions, while the right hemisphere is specialized for detecting and responding Communicated by John C. Rothwell. ...
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We have previously proposed a model of motor lateralization that attributes specialization for predictive control of intersegmental coordination to the dominant hemisphere/limb system, and control of limb impedance to the non-dominant system. This hypothesis was developed based on visually targeted discrete reaching movement made predominantly with the shoulder and elbow joints. The purpose of this experiment was to determine whether dominant arm advantages for multi-degree of freedom coordination also occur during continuous distal movements of the wrist that do not involve visual guidance. In other words, are the advantages of the dominant arm restricted to controlling intersegmental coordination during discrete visually targeted reaching movements, or are they more generally related to coordination of multiple degrees of freedom at other joints, regardless of whether the movements are discrete or invoke visual guidance? Eight right-handed participants were instructed to perform alternating wrist ulnar/radial deviation movements at two instructed speeds, slow and fast, with the dominant or the non-dominant arm, and were instructed not to rotate the forearm (pronation/supination) or move the wrist up and down (flexion/extension). This was explained by slowly and passively moving the wrist in each plane during the instructions. Because all the muscles that cross the wrist have moment arms with respect to more than one axis of rotation, intermuscular coordination is required to prevent motion about non-instructed axes of rotation. We included two conditions, a very slow condition, as a control condition, to demonstrate understanding of the task, and an as-fast-as-possible condition to challenge predictive aspect of control, which we hypothesize are specialized to the dominant controller. Our results indicated that during as-fast-as-possible conditions the non-dominant arm incorporated significantly more non-instructed motion, which resulted in greater circumduction at the non-dominant than the dominant wrist. These findings extend the dynamic dominance hypothesis, indicating that the dominant hemisphere-arm system is specialized for predictive control of multiple degrees of freedom, even in movements of the distal arm and made in the absence of visual guidance.
... However, it is more complicated than a simple binary left-right brain organization distinction. In other species, the strength of hemisphere biases and associated contralateral behaviors are positively associated with fitness (e.g., survival) of the organism (MacNeilage, Rogers, & Vallortigara, 2009). We do not know if this is still true in humans. ...
Article
The last decade of laterality research has been bolstered by a significant broadening in theoretical framing and investigative approaches. Comparative research contributions continue to strengthen the position that ancient functional and anatomical brain biases are preserved in modern humans. However, how they unfold over developmental time and contribute to cognitive abilities is still unclear. To make further advances, we must position human brains and behaviors within an evolutionary framework. This includes viewing motor-sensory behavior as an integral part of a developing cognitive system. In their review article "Laterality 2020: Entering the next decade", Ocklenberg and colleagues (2020) reflect on the significant progress achieved in laterality research over the last decade and anticipate the themes that may dominate the new decade. While "Bridging the gap between laterality research in human subjects and non-human model species" makes an appearance as point 7, the development of human brain and behavioral biases within an evolutionary framework is integral to a better understanding of how cognition emerges in modern humans. Specifically, understanding why ancient asymmetric brain characteristics are preserved in modern humans, how they unfold and whether or not they impact cognition over developmental time are matters of critical importance. In order to progress the field of laterality research, we must recognize that we do not simply exist and interact with the natural world, but as animals, our bodies and our brains are a result of evolutionary processes. Owing to comparative research, we acknowledge that the asymmetry patterns that exist across vertebrate species have been preserved throughout hominid evolution such that the majority of the population still possess a
... But there is also a negative side, as right hemisphere is the more specialized for aggressive behavior in several species, including anurans [55], lizards [56], chicks [57], baboons [58], and humans [59]. MacNeilage, Rogers and Vallortigara [60] suggest that brain asymmetry was already present when the vertebrates emerged some 500 million years ago, with the left hemisphere oriented more toward action, including feeding and aggression, and the right toward emotion and detection of predators. ...
Article
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We belong to a clade of species known as the bilateria, with a body plan that is essentially symmetrical with respect to left and right, an adaptation to the indifference of the natural world to mirror-reflection. Limbs and sense organs are in bilaterally symmetrical pairs, dictating a high degree of symmetry in the brain itself. Bilateral symmetry can be maladaptive, though, especially in the human world where it is important to distinguish between left and right sides, and between left-right mirror images, as in reading directional scripts. The brains of many animals have evolved asymmetries, often but not exclusively in functions not dependent on sensory input or immediate reaction to the environment. Brain asymmetries in humans have led to exaggerate notions of a duality between the sides of the brain. The tradeoff between symmetry and asymmetry results in individual differences in brain asymmetries and handedness, contributing to a diversity of aptitude and divisions of labor. Asymmetries may have their origin in fundamental molecular asymmetries going far back in biological evolution.
... Lateralization has been observed during preferential use of one hand/ paw over the other (Lonsdorf and Hopkins, 2005;Westergaard and Suomi, 1996;Wells and Millsopp, 2009), favored swimming direction (Blois-Heulin et al., 2012;Marino and Stowe, 1997a, b;Ridgway, 1972), frequented use of one eye (Delfour and Marten, 2006;Farmer et al., 2010;Thieltges et al., 2011) and even during tail wagging (Quaranta et al., 2007;Siniscalchi et al., 2013). Previously hemispherical lateralization was considered to be found exclusively in humans, however recent studies suggested its presence since 500 million years ago, when vertebrates emerged (MacNeilage et al., 2009). Experiments with non-human primates (McGrew and Marchant, 1997), birds (Franklin and Lima, 2001;Hunt et al., 2002), reptiles Robins et al., 2005), amphibians Robins et al., 1998) and fish (Bisazza et al., 2007;Takeuchi and Hori, 2008) confirmed general manifestation of lateralization in vertebrates. ...
Article
Perceptual and behavioral asymmetry has been observed in a wide range of vertebrate and invertebrate species with its origin estimated to go back over 500 million years. Previously, hemispheric lateralization in marine mammals has been recorded during foraging, parental care, preferred swimming direction as well as when solving cognitive challenges. Visual laterality has been demonstrated in preferred eye use and performance accuracy. A female Indo-Pacific bottlenose dolphin was trained to associate eight pairs of non-identical visual stimuli. Her performance was tested and compared under binocular and monocular conditions. No significant difference was found in accuracy, while a clear left eye advantage was demonstrated in reaction time. In addition, behavioral asymmetry was observed in movement pattern preference during the stimulus discrimination.
... It has been maintained for a long time that functional lateralization is a prerogative of human beings [1,2]. More recent studies, however, showed that asymmetries and functional lateralization are present in both vertebrates and invertebrates, related to different types of functions, such as foraging, prey recognition, visual discrimination [1,[3][4][5][6]. Certainly, the most important species for a possible comparison with human beings about functional lateralization are non-human primates. ...
Article
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To date, both in monkeys and humans, very few studies have addressed the issue of the lateralization of the cortical parietal and premotor areas involved in the organization of voluntary movements and in action understanding. In this review, we will first analyze studies in the monkey, describing the functional properties of neurons of the parieto-frontal circuits, involved in the organization of reaching-grasping actions, in terms of unilateral or bilateral control. We will concentrate, in particular, on the properties of the mirror neuron system (MNS). Then, we will consider the evidence about the mirror neuron mechanism in humans, describing studies in which action perception, as well as action execution, produces unilateral or bilateral brain activation. Finally, we will report some investigations demonstrating plastic changes of the MNS following specific unilateral brain damage, discussing how this plasticity can be related to the rehabilitation outcome.
... Brain lateralization was once thought to be a unique characteristic of humans and an attribute contributing to our cognitive superiority (Corballis, 2014) but that idea was overthrown by the discovery of lateralization in nonhuman species, the chick being one of three species in which this was first discovered (Rogers and Anson, 1979, and see summary in Rogers et al., 2013, andMacNeilage et al., 2009). Now we know that brain lateralization is present in a wide range of vertebrate species and it has even been found in some invertebrates (Frasnelli et al., 2012). ...
... [27] Moreover, this split in autonomic function seems to occur across all vertebrates, which implies that it arose during the Cambrian explosion over 500 million years ago. [28] When considered from an evolutionary perspective, the advantage of emotions is to generate behavior that maintains homeostasis. It seems plausible that an ancient lateralization in forebrain control of the ANS, with its central role in homeostasis, would be coopted and expanded by natural selection to also represent concordant emotional valencies. ...
Article
We propose that synesthetic cross‐activation between the primary auditory cortex and the anatomically adjacent insula may help explain two puzzling conditions—autonomous sensory meridian response (ASMR) and misophonia—in which quotidian sounds involuntarily trigger strong emotional responses. In ASMR the sounds engender relaxation, while in misophonia they trigger an aversive response. The insula both plays an important role in autonomic nervous system control and integrates multiple interoceptive maps representing the physiological state of the body to substantiate a dynamic representation of emotional wellbeing. We propose that in ASMR cross‐activation of the map for affective (sensual) touch leads to an increase in subjective wellbeing and parasympathetic activity. Conversely, in misophonia the effect of the cross‐activation is to decrease emotional wellbeing and increase sympathetic activity. Our hypothesis also illuminates the connection between hearing and wellbeing more broadly and helps explain why so many people experience decreased wellbeing from modern urban soundscapes.
... The left-hemisphere focuses on movement preparation, resulting almost entirely from the use of "routine" activities such as reaching actions. The function of the right hemisphere might be to detect and respond to unforeseen environmental stimuli [42]. Improvement of movement seen in group 2 with right hemisphere lesion is thought to represent improvements in predictive control intensified during TST. ...
Article
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Functional impairment of the upper limb (UL) after stroke is a great problem. Finding methods that can improve UL function after stroke is a major concern to all medical service providers. This study was intended to compare the effect of upper limb task specific training (TST) on brain excitability of the affected hemisphere and motor function improvements in patients with left and right stroke. Forty male patients with mild impairment of UL functions were divided into two equal groups; G1 consisted of patients with left hemisphere affection (right side stroke) while G2 consisted of patients with right hemisphere affection (left side stroke). All patients received TST for the affected UL for one hour, three sessions per week for six consecutive weeks. Evaluation was performed twice, pre-, and post-treatment. Outcome measures used were Wolf Motor Function Test (WMFT) and Box and Block Test (BBT) as measures of UL motor function and Quantitative Electroencephalogram (QEEG) of motor and sensory areas of the affected hemisphere as a measure of brain reorganization post-stroke. Both groups showed improvement in motor function of the affected UL measured by WMFT and BBT with reported significant difference between them. G1 showed greater improvement in motor function of the affected UL post-treatment compared to G2. Additionally, there was a significant increase in peak frequency of motor and sensory areas with higher and significant excitability in G1 only. These findings imply that brain reorganization in the left hemisphere responded more to TST compared to the right hemisphere. Based on findings of the current study, we can recommend adding TST to the physical therapy program in stroke patients with left hemisphere lesions.
... At first it has been argued that it was unique to humans and associated with language and higher cognitive abilities (for a historical account, see Corballis, 2020). Then, it was slowly recognized that asymmetry is quite widespread among vertebrates, even if they do not have anything equivalent to human language (e.g., MacNeilage, Rogers and Vallortigara, 2009;Rogers, Vallortigara and Andrew, 2013). Finally, more recently, it has become apparent that brain asymmetry is observed also in invertebrates (review in Frasnelli et al., 2012), most notably in insects like bees (Frasnelli et al., 2014) but also in C. elegans worms, who have only 300 neurons (Vidal and Hobert, 2017). ...
... Unfortunately, comparative cross-species laterality studies are still rare, but a small body of research has been gathered in recent years. For example, it has been shown that for detection of predators on the left side and visual discrimination on the right side, results are fairly consistent across a number of vertebrate species (MacNeilage, Rogers, & Vallortigara, 2009;Vallortigara & Rogers, 2005). However, for most fields of laterality, comparative crossspecies are still lacking. ...
Article
In the 2010s, significant progress has been made in several key areas of laterality research, including neuroimaging, genetics and comparative research. In the present article, we discuss which trends are likely to shape laterality research in the 2020s. These include, but are not limited to: (1) Finding laterality-specific solutions to the replication crisis. (2) Integrating non-W.E.I.R.D. (Western, Educated, Industrialized, Rich, and Democratic) samples into laterality research to a larger extent. (3). Combining meta-analysis and large-scale databank studies to come to unbiased conclusions about true effects. (4) Understanding altered laterality in different psychiatric and neurodevelopmental disorders. (5) Exploring the relevance of laterality research for the treatment of psychiatric and neurodevelopmental disorders. (6) Investigating the molecular correlates of environmental factors that affect laterality. (7) Bridging the gap between laterality research in human subjects and non-human model species. (8) Utilizing “next-generation” neuroimaging in laterality research. (9) Integrating graph-theory and machine learning into laterality research. (10) Enhancing ecological validity in laterality research using mobile EEG and smartphone-based data collection. These trends will likely shape the next decade of laterality research by opening the way for novel questions, enhancing collaborations and boosting the reliability and validity of research findings in our field.
... Left and right asymmetries in the brain and behaviour (i.e., lateralization) may help to enhance brain efficiency in cognitive tasks involving concurrent but different hemispheres (Rogers et al., 2004). Lateralization has been documented in all vertebrate classes (Bisazza et al., 1998;Vallortigara, 2000;Vallortigara et al., 1999Vallortigara et al., , 2010Rogers and Andrew, 2002;Ghirlanda and Vallortigara, 2004;Vallortigara and Rogers, 2005;MacNeilage et al., 2009;Rogers et al., 2013a). If compared to laterality research on vertebrates, our knowledge about the role and evolution of lateralized traits in invertebrates is still limited (Frasnelli et al., 2012;Frasnelli, 2013;Gaudry et al., 2013;Schnell et al., 2019;David Fernandes and Niven, 2020;Versace et al., 2020), especially in insects. ...
Article
The lesser grain borer, Rhyzopertha dominica (F.) (Coleoptera: Bostrychidae), is an important pest of stored grains globally. In this study, the impact of geographical origin on male mating success and lateralization in three strains of R. dominica (i.e., a Greek strain, a Romanian strain and a Turkish strain) was investigated. Concerning the Greek strain, even though most males showed a left-biased approach, males performing right-biased copulation attempts achieved the highest proportion of successful copulations. Males of the Romanian and Turkish strains exhibited right-biased approaches and copulation attempts, resulting in higher mating success over the males that approached and performed copulation attempts from the left or backside of females. Copula was significantly longer than mate recognition and precopula phases. Furthermore, copula duration was significantly longer in the Turkish strain over the Romanian strain, while copula duration differences between Greek and Romanian individuals, as well as between Greek and Turkish individuals, were not significant. Unsuccessful sexual interactions were characterized by a longer precopula in Greek and Romanian strains, but not in the Turkish strain. Our results add basic knowledge to the mating behaviour of R. dominica, with emphasis on impact of the geographical origin and laterality on male mating success, which may be helpful for optimizing mass-rearing techniques of stored-product pests needed for large-scale laboratory or semi-field experiments, as well as to contribute to the development of behaviour-based control tools.
... Other research suggests that left-right asymmetries are a fundamental property of all species (Rogers, 2017) and originate from the lateralization of brain function (MacNeilage, Rogers, & Vallortigara, 2009;Ocklenburg & Gunturkun, 2012;Rogers & Vallortigara, 2015). For example, a leftward bias in the allocation of attention, similar to pseudoneglect in humans, is present in two-week-old chicks and adult pigeons during food detection (Diekamp, Regolin, Güntürkün, & Vallortigara, 2005;Rugani, Vallortigara, & Regolin, 2016), and rhesus monkeys and domestic dogs show a left looking bias for human faces (Guo, Meints, Hall, Hall, & Mills, 2009). ...
Article
People are frequently biased to use left-side information more than right-side information to inform their perceptual judgements. This research examined whether the leftward bias also applied to preferences for the arrangement of everyday consumer items. Pairs of consumer items were created where one item was more attractive than the other item. Using a two-alternative forced choice task, Experiment 1 found a robust preference for arrangements with the more attractive consumer item on the left side rather than the right side of a pair. Experiment 2 reversed the judgement decision, with participants asked to choose the arrangement they least preferred, and a bias for arrangements with the more attractive item on the right side emerged. Experiment 3 failed to find an effect of the “attractive left” preference on participants’ purchasing intentions. The preference for attractive left arrangements has implications for the display of consumer products and for the aesthetic arrangement of objects in general. The findings are discussed in relation to hemispheric asymmetries in processing and the role of left to right scanning.
... Our findings support the hypothesis of a rightside preference in flamingos in feeding contexts. Similar biases during feeding have been extensively described in birds (e.g., Brown & Magat, 2011;Rogers, 2010;Ventolini et al., 2005) as well as in other taxa (for review see Rogers, 2009;Ströckens, Güntürkün, & Ocklenburg, 2013) and have been linked to the left-brain hemisphere involvement in controlling feeding behaviour such as prey/food discrimination and manipulation (MacNeilage, Rogers, & Vallortigara, 2009;Vallortigara & Rogers, 2005). Other possible explanations for the lateralization in foraging could be social synchronization and task complexity, as suggested by Vidal et al. (2018) for wild greater flamingos. ...
Article
Many studies have highlighted evidence of lateralized behaviours in vertebrates and invertebrates, indicating that cerebral lateralization might not be uniquely human. Flamingos, as highly social species, might represent an interesting model in the study of lateralization, as this trait appears to be useful in gregarious animals. This study aims to investigate the presence of lateralized behaviours in zoo flamingos. The subjects of this study were 41 greater flamingos (Phoenicopterus roseus) and 29 Chilean flamingos (Phoenicopterus chilensis). Ten 20-minute observation sessions per subject were carried out, using focal animal sampling method. Bouts of side preferences were recorded for foraging, neck resting and preening. Moreover, bouts and duration of leg use for postural support during unipedal standing (leg stance) were also collected. Results highlighted a group-level right-side preference for foraging in the whole sample as well as within each species. Within greater flamingos, group-level right-side preferences were also reported for neck resting and leg stance. Differences between the two flocks were found, with greater flamingos displaying right preferences to a greater extent than Chilean flamingos. Males showed a more pronounced right preference than females for some categories. This study adds to previous literature highlighting the presence of group-level behavioural lateralization in flamingos.
... Similarly, strong-lateralized common marmosets (Callithrix jacchus) also show better ability to perform foraging and predator detection simultaneously than weak-lateralized ones (Piddington & Rogers, 2013). It is now known that in vertebrates the right hemisphere is more likely to be involved in attending to novel stimuli (e.g., predation risk), expressing intense emotions, controlling social behavior, processing spatial information, and making decisions, while the left hemisphere is more specialized in focusing attention to perform learned tasks, following rules and categorizing stimuli (MacNeilage, Rogers, & Vallortigara, 2009;Rogers, 2002;Rogers & Vallortigara, 2017). ...
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Behavioral lateralization, which is associated with the functional lateralization of the two brain hemispheres, commonly exists in animals and can provide an individual with benefits such as enhanced cognition and dual tasking. Lateral bias in limb use, as a type of behavioral lateralization, occur in many species, but the reasons for the coexistence of left‐ and right‐biased individuals in a population remain poorly understood. We examined the footedness of male yellow‐bellied tits (Pardaliparus venustulus) when they used feet to clamp mealworms against a perch, and tested its association with other fitness‐related behavioral traits (i.e., feeding efficiency, exploration tendency, and escape performance). We expected differently footed individuals to have respective advantages in these behaviors and thereby coexist (“respective advantage” hypothesis). We found their footedness repeatable, and there was no population‐level bias. While no associations of feeding efficiency and exploration tendency with footedness were detected, the right‐footed individuals were found to be harder to catch than the other individuals. Future studies need to investigate the reasons for the right‐footed individuals' superior escape performance. Moreover, the escape advantage for being right‐footed and the lack of population‐level bias in footedness in male yellow‐bellied tits suggest that the benefits related to left footedness also remain to be explored.
... This could be linked to a potential hemispheric lateralization. In particular, lateralization effects are reported for emotional processes, but also during learning tasks 31,32 . For example, goats showed a right-hemisphere bias of processing of visuospatial cues in a maze before they had understood the rule 33 . ...
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Horses are capable of identifying individual conspecifics based on olfactory, auditory or visual cues. However, this raises the questions of their ability to recognize human beings and on the basis of what cues. This study investigated whether horses could differentiate between a familiar and unfamiliar human from photographs of faces. Eleven horses were trained on a discrimination task using a computer-controlled screen, on which two photographs were presented simultaneously (32 trials/session): touching one was rewarded (S+) and the other not (S−). In the training phase, the S+ faces were of four unfamiliar people which gradually became familiar over the trials. The S− faces were novel for each trial. After the training phase, the faces of the horses’ keepers were presented opposite novel faces to test whether the horses could identify the former spontaneously. A reward was given whichever face was touched to avoid any possible learning effect. Horses touched the faces of keepers significantly more than chance, whether it was their current keeper or one they had not seen for six months (t = 3.65; p < 0.004 and t = 6.24; p < 0.0001). Overall, these results show that horses have advanced human face-recognition abilities and a long-term memory of those human faces.
... The origin of these many perceptual, cognitive, and motoric biases can be found in the fundamental features of a perceptual system driven by global/local processing mechanisms. A left-hemisphere predominance in discrimination between targets that are similar in local features (grains vs. grit), distinguishable through detailed comparison, and a right-hemisphere superiority in discrimination based on larger changes (e.g., predators vs. conspecifics, [63,64]), which is distinguishable through a coarse comparison. Thus, a wide range of non-human species shows functional asymmetries resembling those present in humans with the right and left hemisphere specialized for holistic and analytic processing, respectively. ...
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To construct a coherent multi-modal percept, vertebrate brains extract low-level features (such as spatial and temporal frequencies) from incoming sensory signals. However, because frequency processing is lateralized with the right hemisphere favouring low frequencies while the left favours higher frequencies, this introduces asymmetries between the hemispheres. Here, we describe how this lateralization shapes the development of several cognitive domains, ranging from visuo-spatial and numerical cognition to language, social cognition, and even aesthetic appreciation, and leads to the emergence of asymmetries in behaviour. We discuss the neuropsychological and educational implications of these emergent asymmetries and suggest future research approaches.
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The contralateral organization of the forebrain and the crossing of the optic nerves in the optic chiasm represent a long-standing conundrum. According to the Axial Twist Hypothesis (ATH) the rostral head and the rest of the body are twisted with respect to each other to form a left-handed half turn. This twist is the result, mainly, of asymmetric, twisted growth in the early embryo. Evolutionary selection tends to restore bilateral symmetry. Since selective pressure will decrease as the organism approaches symmetry, we expected a small control error in the form of a small, residual right-handed twist. We found that the mouth-eyes-nose (rostral head) region shows a left-offset with respect to the ears (posterior head) by up to 0.8◦ (P < 0.01, Bonferroni-corrected). Moreover, this systematic aurofacial asymmetry was larger in young children (on average up to 3◦) and reduced with age. Finally, we predicted and found a right-sided bias for hugging (78%) and a left-sided bias for kissing (69%). Thus, all predictions were confirmed by the data. These results are all in support of the ATH, whereas the pattern of results is not (or only partly) explained by existing alternative theories. As of the present results, the ATH is the first theory for the contralateral forebrain and the optic chiasm whose predictions have been tested empirically. We conclude that humans (and all other vertebrates) are fundamentally asymmetric, both in their anatomy and their behavior. This supports the thesis that the approximate bilateral symmetry of vertebrates is a secondary feature, despite their being bilaterians.
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This chapter shifts gears from research with humans to animal research . It gives some findings for invertebrates and, through fossil evidence, indicates that lateralization processes were evident in the earliest life forms, well over 1 billion years ago. The chapter also examines laterality in extant species; the ubiquity of lateralization in species, such as bees, points to the evolutionary basis to the characteristic. The chapter also considers laterality in early hominins ; the evidence, for example, through tool use, also indicates an early presence of laterality in the lineage leading to modern humans . The best evidence in this regard concerns the study of lateralization in great apes/non-human primates, such as chimpanzees. Once methodological care is taken, these species also manifest a right-side lateralization for critical manual behaviors such as in the tube task and also in the wild. Even developing great apes/non-human primates exhibit this pattern. The evidence also indicates right hemispheric specialization in these species for its typical skills. At times, the evidence also reveals contradictory patterns of results related to great ape/non-human primate and human comparisons, including the brain areas involved (e.g., Broca) . As for evolutionary models on lateralization, some are very broad and refer to asymmetries stretching into the earliest species, while others focus on our more recent ancestry in the hominid line. The evidence does not uniquely support the primary hypotheses in the area, for example, a tool-use first or gestural communication first origin. Also, issue arises about the evolutionary continuity in lateralization and whether dextralization has arisen multiply and independently over the course of evolution. The chapter concludes on the relevance of the concept of activation-inhibition coordination as a common function in these different evolutionary models.
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In a previous study on hand selection in a sequential reaching task, the authors showed a shift of the point-of-change (POC) to the left of the midline. This implies that participants conducted a number of contralateral reaches with their dominant, right hand. Contralateral movements have longer planning and execution times and a lower precision. In the current study, we asked whether lower mechanical costs of motor execution or lower cognitive costs of motor planning compensated for these disadvantages. Theories on hemispheric differences postulate lower mechanical costs in the dominant hemisphere and lower cognitive costs in the left hemisphere (independent of handedness). In right-handed participants, both factors act agonistically to reduce the total cost of right-handed reaches. To distinguish between the cost factors, we had left- and right-hand-dominant participants execute a sequential, unimanual reaching task. Results showed a left-shift of the POC in the right-handed and a right-shift in the left-handed group. Both shifts were similar in magnitude. These findings indicate that only the mechanical cost of motor execution compensates for the disadvantages of the contralateral reaches, while the cognitive cost of motor planning is irrelevant for the POC shift.
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Behavioural lateralization, which reflects the functional specializations of the two brain hemispheres, is assumed to play an important role in cooperative intraspecific interactions. However, there are few studies focused on the lateralization in cooperative behaviours of individuals, especially in a natural setting. In the present study, we investigated lateralized spatial interactions between the partners in lifelong monogamous pairs. The male-female pairs of two geese species (barnacle, Branta leucopsis, and white-fronted, Anser albifrons geese), were observed during different stages of the annual cycle in a variety of conditions. In geese flocks, we recorded which visual hemifield (left/right) the following partner used to monitor the leading partner relevant to the type of behaviour and the disturbance factors. In a significant majority of pairs, the following bird viewed the leading partner with the left eye during routine behaviours such as resting and feeding in undisturbed conditions. This behavioural lateralization, implicating the right hemisphere processing, was consistent across the different aggregation sites and years of the study. In contrast, no significant bias was found in a variety of geese behaviours associated with enhanced disturbance (when alert on water, flying or fleeing away when disturbed, feeding during the hunting period, in urban area feeding and during moulting). We hypothesize that the increased demands for right hemisphere processing to deal with stressful and emergency situations may interfere with the manifestation of lateralization in social interactions.
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