Laterality Research Papers - Academia.edu (original) (raw)
Population-level right-handedness is a defining characteristic of humans. Despite extensive research, we still do not know the conditions or timing of its emergence in human evolution. We present a review of research into the origins of... more
Population-level right-handedness is a defining characteristic of humans. Despite extensive research, we still do not know the conditions or timing of its emergence in human evolution. We present a review of research into the origins of handedness, based on fossil and archaeological data for hand preference and great ape hand-use. The data show that skeletal asymmetries in arm and hand bones supporting a rightsided dominance were present at least in the genus Homo, although data are more robust for Neanderthals. The evidence from tool-use, production, and cave art confirms that right-hand preference was established in Neanderthals and was maintained until the present. The great apes can provide real-life models for testing the conditions that facilitate or enhance hand preference at both the individual and group levels. The database on great ape hand-use indicates that they do exhibit hand preferences, especially in complex tasks. However, their preferences vary between tasks, and w...
We examined two commonly used dichotic listening tests for measuring the degree of hemispheric specialization for language in individuals who had undergone cerebral hemispherectomy: the Consonant-Vowel (CV) nonsense syllables and the... more
We examined two commonly used dichotic listening tests for measuring the degree of hemispheric specialization for language in individuals who had undergone cerebral hemispherectomy: the Consonant-Vowel (CV) nonsense syllables and the Fused Words (FW) tests, using the common laterality indices f and λ. Hemispherectomy on either side resulted in a massive contralateral ear advantage, demonstrating nearly complete ipsilateral suppression of the left ear in the right hemispherectomy group but slightly less complete suppression of the right ear in the left hemispherectomy group. The results are consistent with the anatomical model of the ear advantage . Most syllables or words are reported for the ear contralateral to the remaining hemisphere, while few or none are reported for the ear ipsilateral to the remaining hemisphere. In the presence of competing inputs to the two ears, the stronger contralateral ear-hemisphere connection dominates/suppresses the weaker ipsilateral ear-hemisphere connection. The λ index was similar in the two tests but the index f was higher in the CV than the FW test. Both indices of the CV test were sensitive to side of resection, higher in the right hemispherectomy than in the left hemispherectomy groups.
Perceptual asymmetries for tasks involving aesthetic preference or line bisection can be affected by asymmetrical neurological mechanisms or left/right reading habits. This study investigated the relative contribution of these mechanisms... more
Perceptual asymmetries for tasks involving aesthetic preference or line bisection can be affected by asymmetrical neurological mechanisms or left/right reading habits. This study investigated the relative contribution of these mechanisms in 100 readers of Japanese and English. Participants made aesthetic judgments between pairs of mirror-reversed pictures showing: (a) static objects, (b) moving objects and (c) landscapes. A line bisection task
Surface electromyographic (EMG) amplitude and mean power frequency (MPF) were used to study the isometric muscular activity of the right versus the left upper trapezius muscles in 14 healthy right-handed women. The EMG activity was... more
Surface electromyographic (EMG) amplitude and mean power frequency (MPF) were used to study the isometric muscular activity of the right versus the left upper trapezius muscles in 14 healthy right-handed women. The EMG activity was recorded simultaneously with force signals during a 10-15 s gradually increasing exertion of force, up to maximal force. Only one side at a time was tested. On both sides there was a significant increase in EMG amplitude (~tV) during the gradually increasing force from 0% to 100% maximal voluntary contraction (MVC). The right trapezius muscle showed significantly less steep slopes for regression of EMG amplitude versus force at low force levels (0%-40% MVC) compared intra-individually with l)igh force levels (60%-100% MVC). This was not found for the left trapezius muscle. At 40% MVC a significantly lower MPF value was found for the right trapezius muscle intra-individually compared with the left. An increase in MPF between 5% and 40% MVC was statistically significant when both sides were included in the test. The differences in EMG activity between the two sides at low force levels could be due to more slow-twitch (type I fibres) motor unit activity in the right trapezius muscles. It is suggested that this is related to right-handed activity.
The study investigated performance on pantomime and imitation of transitive and intransitive gestures in 80 stroke patients, 42 with left (LHD) and 38 with right (RHD) hemisphere damage. Patients were also categorized in two groups based... more
The study investigated performance on pantomime and imitation of transitive and intransitive gestures in 80 stroke patients, 42 with left (LHD) and 38 with right (RHD) hemisphere damage. Patients were also categorized in two groups based on the time that has elapsed between their stroke and the apraxia assessment: acute-subacute (n = 42) and chronic (n = 38). In addition, patterns of performance in apraxia were examined. We expected that acute-subacute patients would be more impaired than chronic patients and that LHD patients would be more impaired than RHD patients, relative to controls. The hemisphere prediction was confirmed, replicating previous findings. The frequency of apraxia was also higher in all LHD time post-stroke groups. The most common impairment after LHD was impairment in both pantomime and imitation in both transitive and intransitive gestures. Selective deficits in imitation were more frequent after RHD for transitive gestures but for intransitive gestures they were more frequent after LHD. Patients were more impaired on imitation than pantomime, relative to controls. In addition, after looking at both gesture types concurrently, we have described cases of patients who suffered deficits in pantomime of intransitive gestures with preserved performance on transitive gestures. Such cases show that the right hemisphere may be in some cases critical for the successful pantomime of intransitive gestures and the neural networks subserving them may be distinct. Chronic patients were also less impaired than acute-subacute patients, even though the difference did not reach significance. A longitudinal study is needed to examine the recovery patterns in both LHD and RHD patients.
Young infants produce a variety of spontaneous arm and leg movements in the first few months of life. Coordination of leg joints has been extensively investigated, whereas arm joint coordination has mainly been investigated in the sitting... more
Young infants produce a variety of spontaneous arm and leg movements in the first few months of life. Coordination of leg joints has been extensively investigated, whereas arm joint coordination has mainly been investigated in the sitting position in the context of early reaching and grasping. The current study investigated arm and leg joint coordination of movements produced in the supine position in 10 fullterm infants aged 6, 12 and 18 weeks. Longitudinal comparisons within limbs (intralimb) as well as between limbs (interlimb, ipsilateral and contralateral) were made as well as an exploration of differences in the development for boys and girls. The relationship between the joint angles was examined by measuring pair-wise crosscorrelation functions for the angular displacement curves of the leg (hip, knee and ankle) and arm (shoulder, elbow and wrist) joints of both the right and left side. Both the arms and legs were found to follow a similar pattern of intralimb coordination, although the leg joints were more tightly coupled than the arm joints, particularly the proximal with the middle joint. In support of earlier findings, differences in the development of the right and left side were identified. In addition, gender differences in joint coordination were found for both intralimb and interlimb coordination. This contrasts with the view that gender differences in motor development may be primarily a result of environmental influences.
Evidence from a large-scale study of 11-year olds in Britain suggests that ambidextrous individuals may be disadvantaged in tests of verbal, nonverbal, reading, and mathematical skills relative to right-and left-handers, but this basic... more
Evidence from a large-scale study of 11-year olds in Britain suggests that ambidextrous individuals may be disadvantaged in tests of verbal, nonverbal, reading, and mathematical skills relative to right-and left-handers, but this basic finding was not replicated in another study of younger boys in Germany. Here, we present data based on a television show in which members of the public were given an IQ test. Some individuals were also asked to state whether they wrote with the left hand, right hand, or either hand. The data support the earlier finding that ambidextrous individuals perform more poorly than left-or right-handers, especially on subscales measuring arithmetic, memory, and reasoning, and extend that finding to adults.
This study tested whether male sexual orientation and gender nonconformity influenced functional cerebral lateralization for the processing of facial emotions. We also tested for the effects of sex of poser and emotion displayed on... more
This study tested whether male sexual orientation and gender nonconformity influenced functional cerebral lateralization for the processing of facial emotions. We also tested for the effects of sex of poser and emotion displayed on putative differences. Thirty heterosexual men, 30 heterosexual women, and 40 gay men completed measures of demographic variables, recalled childhood gender nonconformity (CGN), IQ, and the Chimeric Faces Test (CFT). The CFT depicts vertically split chimeric faces, formed with one half showing a neutral expression and the other half showing an emotional expression and performance is measured using a''laterality quotient''(LQ) score. We found that heterosexual men were significantly more right-lateralized when viewing female faces compared to heterosexual women and gay men, who did not differ significantly from each other. Heterosexual women and gay men were more left-lateralized for processing female faces. There were no significant group differences in lateralization for male faces. These results remained when controlling for age and IQ scores. There was no significant effect of CGN on LQ scores. These data suggest that gay men are feminized in some aspects of functional cerebral lateralization for facial emotion. The results were discussed in relation to the selectivity of functional lateralization and putative brain mechanisms underlying sexual attraction towards opposite-sex and same-sex targets.
A recent article in the Journal of Deaf Studies and Deaf Education (Leigh, Brice, & Meadow-Orlans, 2004) explored attachment between deaf mothers and their 18-month-old children and reported relationship patterns similar to those for... more
A recent article in the Journal of Deaf Studies and Deaf Education (Leigh, Brice, & Meadow-Orlans, 2004) explored attachment between deaf mothers and their 18-month-old children and reported relationship patterns similar to those for hearing dyads. The study reported here explores a marker of early mother-child relationships: cradling laterality. Results indicated that, overall, the cradling bias of deaf mothers is similar to that of hearing mothers, but that there are significant differences among deaf mothers related to the hearing status of their own parents and, in a complex way, to the hearing status of their children. Deaf mothers of deaf parents showed a strong leftward cradling bias with both hearing and deaf children, whereas deaf mothers of hearing parents showed a leftward cradling bias with hearing children and a rightward cradling bias with deaf children. Possible explanations for these patterns of behavior are discussed.
Objectives: This study investigated differences in intrahemispheric and interhemispheric electroencephalographic (EEG) coherences between attention-deficit/hyperactivity disorder (ADHD) and control children, and between children with the... more
Objectives: This study investigated differences in intrahemispheric and interhemispheric electroencephalographic (EEG) coherences between attention-deficit/hyperactivity disorder (ADHD) and control children, and between children with the Combined (ADHDcom) and Inattentive (ADHDin) types of ADHD. Methods: Three age-and sex-matched groups of 40 children, aged 8-12 years, diagnosed with ADHDcom, ADHDin, and normal control children, participated in this study. EEG was recorded from 21 sites during an eyes-closed resting condition and Fourier transformed. Waveshape coherence was calculated for 8 intrahemispheric electrode pairs (4 in each hemisphere), and 8 interhemispheric electrode pairs, within each of the delta, theta, alpha and beta bands. Results: At shorter inter-electrode distances, ADHD children had elevated intrahemispheric coherences in the theta band and reduced lateral differences in the theta and alpha bands. At longer inter-electrode distances, ADHD children had lower intrahemispheric alpha coherences than controls. Frontally, ADHD children had interhemispheric coherences elevated in the delta and theta bands, and reduced in the alpha band. An alpha coherence reduction in temporal regions, and a theta coherence enhancement in central/parietal/occipital regions, were also apparent. ADHDcom had greater intrahemispheric theta and beta coherences than ADHDin. Frontally, ADHDcom had higher levels of interhemispheric coherences than ADHDin for the delta and theta bands. In central/parietal/occipital regions, beta coherences were elevated in ADHDcom. Conclusions: EEG coherences suggest reduced cortical differentiation and specialisation in ADHD, particularly in cortico-cortical circuits involving theta activity. Generally, ADHDcom children displayed greater anomalies than ADHDin children.
Differences in abilities and preferences exist between left-handers who both write and throw with their left hands (consistent lefthanders) and those who write with their left hand but prefer to throw with their right (inconsistent... more
Differences in abilities and preferences exist between left-handers who both write and throw with their left hands (consistent lefthanders) and those who write with their left hand but prefer to throw with their right (inconsistent left-handers). It is also known that many left-handers are pressured to switch to right-hand writing, and that these pressures can lead to a right shift attempt. The present study is the first to explore the joint effects of the consistent/inconsistent left-handedness dichotomy, right shift attempt history, and lateral preference profiles. Testing 379 Canadian adults between the ages of 18 and 94 indicated that, while both types of left-handers were equally likely to experience a right shift attempt, the inconsistent left-handers were more likely to successfully switch to right-hand writing. Further analyses revealed that throwing hand was more associated than writing hand with the direction of sidedness for a lateral preference index based upon eye, foot, and ear preferences. More specifically, right-hand throwers were much more likely to have a rightward lateral preference score than were left-hand throwers, regardless of current preferred writing hand. Overall, the results support an hypothesis that the left-handers who are least likely to submit to rightward switch pressures are those with the strongest, most consistent left-sided lateral preference profile.
It is commonly accepted that phonology is the exclusive domain of the left hemisphere. However, this pattern of lateralization, which posits a right visual field advantage, has been questioned by several studies. In fact, certain factors... more
It is commonly accepted that phonology is the exclusive domain of the left hemisphere. However, this pattern of lateralization, which posits a right visual field advantage, has been questioned by several studies. In fact, certain factors such as characteristics of the stimuli and subjectsÕ handedness can modulate the right visual field advantage. Thus, the goal of this study was to compare the hemispheric dynamics of right-handers and left-handers during a divided visual field presentation of words that varied in terms of their phonological transparency. For non-transparent words, the left hemisphere seems more competent in both handedness groups. With regard to transparent words, the right hemisphere of both groups also appears competent. Surprisingly, left-handers achieved optimal processing with a functionally isolated left hemisphere, whereas right-handers needed the participation of both hemispheres. The pattern of performance cannot be fully explained by either the callosal or the direct access model.
Schizophrenia is present in all human populations with approximately the same incidence. Why does such illness persist given that it is associated with a reproductive disadvantage? What is the balancing advantage? A possible explanation... more
Schizophrenia is present in all human populations with approximately the same incidence. Why does such illness persist given that it is associated with a reproductive disadvantage? What is the balancing advantage? A possible explanation is linked to human language. According to this hypothesis schizophrenia occurs as a manifestation of genetic diversity associated with language-the function by which Homo sapiens has separated from other primate species. Language originated by a genetic mutation that allowed the cerebral hemispheres to develop with a degree of specialization (or lateralization) reflected in cerebral asymmetries. Individuals with schizophrenia show lesser structural and functional brain asymmetries than the population as a whole, and this finding can be interpreted as a delay, or failure in, establishing hemispheric dominance for language. We review recent evidence supporting this theory.
This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sublicensing, systematic supply, or distribution in any form to anyone is expressly... more
This article may be used for research, teaching, and private study purposes. Any substantial or systematic reproduction, redistribution, reselling, loan, sublicensing, systematic supply, or distribution in any form to anyone is expressly forbidden.
- by Iris Sommer and +1
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- Genetics, Schizophrenia, Metabolism, Magnetic Resonance Imaging
Male (n = 48) and female (n = 54) left-handed writers were subdivided according to familial sioistrality (FS+ vs. FS-) and strength of handedness (Consistent (C) vs. Non-Consistent (NC) left-handedness). Performance in computerized... more
Male (n = 48) and female (n = 54) left-handed writers were subdivided according to familial sioistrality (FS+ vs. FS-) and strength of handedness (Consistent (C) vs. Non-Consistent (NC) left-handedness). Performance in computerized reaction time (RT) and maze tests was assessed by skill, solving-strategy and laterality indices. Verbal ability was assessed by a vocabulary test. The main findings demonstrated that sex, but not FS or C/NC affected RT. Females were slower, particularly for left-sided stimuli, and made fewer errors in choice RT tasks. C subjects, of which a majority were females, were inferior in maze performance, in spite of using a speed-preferring solving strategy, which is assumed to reflect right-hemisphere processing. When controlling for factors of FS and C/NC, expected sex differences in maze performance were markedly attenuated. The findings underscore the importance of analyzing not only skill, but also strategy and laterality indices in studies of left-handers, and of considering factors of FS and C/NC particularly when studying cognitive sex differences. J Financial support was obtained by grants to D. Schalling from the Bank of Sweden Tercentenary Foundation, and the Swedish Medical Research Council.
Introduction: Laterality is the preference of using one half of the body over the other, and takes into account the dominance of hand, eye, ear and foot. A defined laterality refers to the correct communication between the brain... more
Introduction: Laterality is the preference of using one half of the body over the other, and takes into account the dominance of hand, eye, ear and foot. A defined laterality refers to the correct communication between the brain hemispheres; the lack of consolidation of affirmation of itself, is related to disorders in language learning and literacy skills. The Harris test identifies laterality in children and allows them to create teaching strategies to achieve an affirmation in the child, while the Peabody test shows the level of receptive language from the age of 2. Objective: To determine the prevalence of laterality and receptive language in 5 and 6 year old children. Method: Quantitative, transversal, descriptive and observational study, carried out with kindergarten and elementary children of the municipality of Corregidora, Querétaro, México. The Harris and Peabody tests were applied to 229 students. Results: Through descriptive statistics, 52% were preschoolers, and 48% were from first grade, 53.3% are boys and 46.7% girls. The 95.6% has poorly stated laterality, and 4.4% were right-handed, besides there weren’t students with cross-laterality or left-handedness. The level of receptive language in preschoolers was from high to higher in 56.1% of the population, while low to lower levels were only 43.8%, while in elementary the receptive language showed that 66.6% of students have levels from high to higher and only 32.4% from low to moderately low level. Conclusion: A lack of laterality consolidation is shown because a high percentage of students demonstrate poorly asserted laterality, while receptive language is properly acquired within the age.
The assumptions tested were that the relative contribution of each hemisphere to reading alters with experience and that experience increases suppression of the simultaneous use of identical strategies by the non-dominant hemisphere.... more
The assumptions tested were that the relative contribution of each hemisphere to reading alters with experience and that experience increases suppression of the simultaneous use of identical strategies by the non-dominant hemisphere. Males that were reading disabled and phonologically impaired, reading disabled and phonologically normal, or with no reading disability were presented familiar words, orthographically correct pseudowords, and orthographically incorrect non-words for lexical decision. Accuracy and response times in all groups showed a shift from no asymmetry in processing non-words to a stable left hemisphere advantage and clear suppression of the right hemisphere in processing words. In the pseudoword condition, accuracy scores were higher when both hemispheres were free to engage, especially in those with a reading disability and responses slowed in the phonologically impaired group but not the phonologically normal groups when the right hemisphere was disengaged. As familiar words typically invoke lexical processing by both hemispheres while pseudowords invoke lexical processing by the right and non-lexical processing by the left hemisphere, and as non-lexical processing is weak in the phonologically impaired, the results support the assumptions that were tested.
Vulnerability to depression and non-response to Selective Serotonin Reuptake Inhibitors (SSRIs) are associated with specific neurophysiological characteristics including greater right hemisphere (RH) relative to left hemisphere (LH)... more
Vulnerability to depression and non-response to Selective Serotonin Reuptake Inhibitors (SSRIs) are associated with specific neurophysiological characteristics including greater right hemisphere (RH) relative to left hemisphere (LH) activity. The present study investigated the relationship between hemispheric specialization and processing of emotional words using a divided visual field paradigm administered to never-depressed and previously-depressed individuals, who were subdivided into SSRI responders and non-responders. SSRI responders and never-depressed participants were similar in their left hemispheric lateralization for evaluating emotional words. In contrast, SSRI non-responders showed a relative shift towards RH processing of negative words, and a strong bias toward negative evaluation of words presented to the RH. The results are discussed within the context of a biological-cognitive model of vulnerability to depression.
- by Amy Walsh and +1
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- Physiology, Psychology, Cognitive Science, Neurology
This is a trial of the EHI_8, which has been available for example on ResearchGate and Academia.edu for about ten years and adopted for use in their research by numerous researchers (it has already received over twenty citations on Google... more
This is a trial of the EHI_8, which has been available for example on ResearchGate and Academia.edu for about ten years and adopted for use in their research by numerous researchers (it has already received over twenty citations on Google Scholar). Some of the participants were paid, through Survey Monkey. The sample was a community one of all ages. Pre-processing of the completed responses indicated that all the 76 used were answered conscientiously. Thirteen of the 76 (17%) were not right-handed, seven classified left- and six mixed-handers. For several reasons nonparametric statistics are indicated. A principal component analysis confirms a single-factor solution, and in line with other findings pointing in the same direction finds Knife and Mouse to be outliers. Computer mouse, which is the new item, should be persisted with. Configuring a mouse for left-hand use will become more user-friendly and the item will improve over time, as scissors has done due to the easier availability of left-handed scissors. The EHI_8 has high internal reliability and is much better than the original EHI_10 for identifying “truly” inconsistent handedness. The trial was small in scale, but not so much as to distort the major findings.
The impact of bilingualism on lateralized brain functions such as praxis – the control of skilled actions – and language representations themselves, particularly in the auditory domain, is still largely unknown. Recent studies suggest... more
The impact of bilingualism on lateralized brain functions such as praxis – the control of skilled actions – and language representations themselves, particularly in the auditory domain, is still largely unknown. Recent studies suggest that bilingualism affects both basic (fundamental frequency) sound and action-related speech processing. Whether it can impact non-verbal action sound processing is a question of debate. Here we examined twenty bilinguals using a dichotic listening paradigm, in which in addition to repeating the just heard action words, participants named – in Polish or English – one of two simultaneously presented tool sounds from attended ears. The results were compared with data from these same participants tested with reading the same words in a visual-half field paradigm. In contrast to typical outcomes from monolinguals, the laterality indices of action-related sound processing (verbal and non-verbal) were not left lateralized but hemispherically balanced. Notably, despite similar organization of tool- and action-word sound processing, their auditory (balanced) and visual-language (left-lateralized) representations might be independent because there were no significant correlations between any of their laterality indices. This indicates that bilingualism might involve reshuffling/reorganization of typically lateralized brain functions and such plasticity will have consequences for second language learning strategies, as well as for neurorehabilitation.
Early severe stress and maltreatment produces a cascade of neurobiological events that have the potential to cause enduring changes in brain development. These changes occur on multiple levels, from neurohumoral (especially the... more
Early severe stress and maltreatment produces a cascade of neurobiological events that have the potential to cause enduring changes in brain development. These changes occur on multiple levels, from neurohumoral (especially the hypothalamic-pituitary-adrenal {HPA} axis) to structural and functional. The major structural consequences of early stress include reduced size of the mid-portions of the corpus callosum and attenuated development of the left neocortex, hippocampus, and amygdala. Major functional consequences include increased electrical irritability in limbic structures and reduced functional activity of the cerebellar vermis. There are also gender differences in vulnerability and functional consequences. The neurobiological sequelae of early stress and maltreatment may play a significant role in the emergence of psychiatric disorders during development.
This study investigated the relationship between handedness, gender and behavioural approach and inhibition using Carver and White's (1994) BIS/BAS Scale. 112 participants took part: 46 left-handers and 66 right-handers. All participants... more
This study investigated the relationship between handedness, gender and behavioural approach and inhibition using Carver and White's (1994) BIS/BAS Scale. 112 participants took part: 46 left-handers and 66 right-handers. All participants completed Peters' (1998) handedness questionnaire followed by the self-report BIS/BAS Scale. Significant effects of both handedness and gender on the BIS scores were found, with left-handers and females scoring significantly higher on inhibition. BIS scores were re-examined to include FFFS scores, which showed a significant effect of gender. Revised BIS scores replicated the original BIS findings.
Unlike the aphasic syndromes, the organization of affective prosody in brain has remained controversial because affective-prosodic deficits may occur after left or right brain damage. However, different patterns of deficits are observed... more
Unlike the aphasic syndromes, the organization of affective prosody in brain has remained controversial because affective-prosodic deficits may occur after left or right brain damage. However, different patterns of deficits are observed following left and right brain damage that suggest affective prosody is a dominant and lateralized function of the right hemisphere. Using the Aprosodia Battery, which was developed to differentiate left and right hemisphere patterns of affective-prosodic deficits, functional-anatomic evidence is presented in patients with focal ischemic strokes to support the concepts that (1) affective prosody is a dominant and lateralized function of the right hemisphere, (2) the intrahemispheric organization of affective prosody in the right hemisphere, with the partial exception of Repetition, is analogous to the organization of propositional language in the left hemisphere and (3) the aprosodic syndromes are cortically based as part of evolutionary adaptations underlying human language and communication.
Adult volunteers (8 males and 13 females) aged 20 Á56 years, both right-and lefthanded, were asked to train their non-preferred hand to write two standard sentences by practising daily over a 28-day period. At the end of this period their... more
Adult volunteers (8 males and 13 females) aged 20 Á56 years, both right-and lefthanded, were asked to train their non-preferred hand to write two standard sentences by practising daily over a 28-day period. At the end of this period their non-preferred handwriting was of good quality and participants felt quite comfortable performing this task. The quality of non-preferred handwriting achieved was unrelated to age. We postulate that handedness, in terms of actual performance, may be less pronounced than is suggested by studies of hand preference.
Homo sapiens sapiens displays a species wide lateralised hand preference, with 85% of individuals in all populations being right-handed for most manual actions. In contrast, no other great ape species shows such strong and consistent... more
Homo sapiens sapiens displays a species wide lateralised hand preference, with 85% of individuals in all populations being right-handed for most manual actions. In contrast, no other great ape species shows such strong and consistent population level biases, indicating that extremes of both direction and strength of manual laterality (i.e., species-wide right-handedness) may have emerged after divergence from the last common ancestor. To reconstruct the hand use patterns of early hominins, laterality is assessed in prehistoric artefacts. Group right side biases are well established from the Neanderthals onward, while patchy evidence from older fossils and artefacts indicates a preponderance of right- handed individuals. Individual hand preferences and group level biases can occur in chimpanzees and other apes for skilled tool use and food processing. Comparing these findings with human ethological data on spontaneous hand use reveals that the great ape clade (including humans) probably has a common effect at the individual level, such that a person can vary from ambidextrous to completely lateralised depending on the action. However, there is currently no theoretical model to explain this result. The degree of task complexity and bimanual complementarity have been proposed as factors affecting lateralisation strength. When primatology meets palaeoanthropology, the evidence suggests species-level right-handedness may have emerged through the social transmission of increasingly complex, bimanually differentiated, tool using activities.
Psittacines are generally considered to possess cognitive abilities comparable to those of primates. Most psittacine research has evaluated performance on standardized complex cognition tasks, but studies of basic cognitive processes are... more
Psittacines are generally considered to possess cognitive abilities comparable to those of primates. Most psittacine research has evaluated performance on standardized complex cognition tasks, but studies of basic cognitive processes are limited. We tested orange-winged Amazon parrots (Amazona amazonica) on a spatial foraging assessment, the Hamilton search task. This task is a standardized test used in human and non-human primate studies. It has multiple phases, which require trial and error learning, learning set breaking, and spatial memory. We investigated search strategies used to complete the task, cognitive flexibility, and long-term memory for the task. We also assessed the effects of individual strength of motor lateralization (foot preference) and sex on task performance. Almost all (92 %) of the parrots acquired the task. All had significant foot preferences, with 69 % preferring their left foot, and showed side preferences contralateral to their preferred limb during location selection. The parrots were able to alter their search strategies when reward contingencies changed, demonstrating cognitive flexibility. They were also able to remember the task over a 6-month period. Lateralization had a significant influence on learning set acquisition but no effect on cognitive flexibility. There were no sex differences. To our knowledge, this is the first cognitive study using this particular species and one of the few studies of cognitive abilities in any Neotropical parrot species.
Wo von Verkörperung die Rede ist, gilt es Körper nicht nur als Stichwortgeber sondern auch als einen zentralen und systematischen Ausgangspunkt der Konzeptbildungen in die Theorie mitaufzunehmen. Mit MERLEAU-PONTY ist hierbei in der... more
Wo von Verkörperung die Rede ist, gilt es Körper nicht nur als Stichwortgeber sondern auch als einen zentralen und systematischen Ausgangspunkt der Konzeptbildungen in die Theorie mitaufzunehmen. Mit MERLEAU-PONTY ist hierbei in der post-phänomenologischen Philosophie eine Perspektive eingeführt, in der Körperlichkeit als eine strategische Doppelfigur gedacht ist, die den Körper zum einen als lebendige, empirische Struktur und zum anderen als Kontext oder Milieu verschiedener (kognitiver, sozialer, sprachlicher etc.) Mechanismen und Zusammenhänge umfaßt.
In einer entsprechend angesetzten Lektüre weisen so scheinbar verschiedene Denker wie MERLEAU-PONTY, MCLUHAN und BENJAMIN eine interessante Familienähnlichkeit auf, deren gemeinsames, sozusagen »virtuelles«, Zentrum ein raffiniertes und komplexes Konzept des Körperlichen darstellt, welches den Körper auch nach einer analytisch Durchdringung nicht als wesentliche Integrationsgröße der Theoriebildung aus dem Blick verliert. MERLEAU-PONTYs Konzeption einer gleichsam individuellen wie anonymen, quasi-ontologischen Leiblichkeit steht hierbei in Resonanz mit Beschreibungen, die sich für die in diesem Zusammenhang wirksame Eigenwertigkeit verschiedener medialer Vermittlungszusammenhänge interessier(t)en.
Inauguriert wird in einer so gearteten Zusammenschau auch eine eigenständige Idee des Medialen, nach der Körper gleichsam natürliche wie kulturelle »Rahmen« für implizit wie explizit wirkender Effektivitäten bilden, welche jeweils zusätzliche Handlungs- und Erfahrungs- und Sinn-Strukturen einführen. Eine solche Sicht, die an nicht-semiotischen Struktur-Effekten und -Schemata im Sinne einer nicht-signifikativen Bedeutungsbildung festhält,verspricht nicht nur einen Theorie-Boden für die notwendige Bestimmung der Unterscheidungen (wie der Zusammenhänge) von Zeichen und Medium, Semiotizität und Medialität, sondern auch für die Auslotung von unterschiedlichen Formen (»Grammatiken«) von Medialität (MCLUHAN) und Signifikation (HAYLES).
In zwei Kontexten kann diese Unterscheidung in ihrer Relevanz exemplifiziert werden: 1) der an Inszenierung und Performativität interessierten Kulturtheorie (GUMBRECHT/FISCHER-LICHTE u.a.); 2) der an virtuellen Realitäten und Telepräsenz-Effekten interessierten Techniktheorie (BIOCCA, HAYLES u.a.).
The discipline of Paleoneurology goes beyond the determination of biological characteristics and morphologies; it can also be used to infer behaviour in extinct species. In Paleocognition, the cognitive capacities of extinct humans can be... more
The discipline of Paleoneurology goes beyond the determination of biological characteristics and morphologies; it can also be used to infer behaviour in extinct species. In Paleocognition, the cognitive capacities of extinct humans can be examined through their fossil remains and the tools they left behind. This chapter examines some inferences that can be made about the origins of language based on paleoneurological and archaeological evidence. It focuses on laterality as a case study for the many behaviours that can be inferred from archaeology, and which are relevant to the origins and evolution of language. First is a review of the ontogeny of human hand preference, handedness in humans, and the hand preferences of non-human apes. Human handedness begins before birth, and develops into adulthood. All human populations have a majority of right-handers; explanations for the maintenance of a minority of left-handers are discussed. Next, the data for hand preferences and asymmetries in extinct fossil hominins are summarised. These show that species-level right-handedness has existed since Homo heidelbergensis, but there is only evidence for left-handed minorities in Neanderthals and Homo sapiens. Finally, links between language, hand skill, ancient stone tool-making, and other cultural behaviours are discussed to propose a tentative date for the origins of language.
Gordon's Cognitive Laterality Battery (1986) was used to test the hypothesis that light-eyed individuals are less cognitively able than the dark-eyed, following the theories of Gary and Glover (1976) and more recent reaction time studies... more
Gordon's Cognitive Laterality Battery (1986) was used to test the hypothesis that light-eyed individuals are less cognitively able than the dark-eyed, following the theories of Gary and Glover (1976) and more recent reaction time studies (Fallone, 1993). The hypothesis was supported: in this sample light-eyed University students were significantly (p<.02) less able than dark-eyed students on a battery of cognitive tests. If eye colour is a hitherto largely unconsidered but significant variable in cognitive testing this casts some doubt on previous research which has disregarded such a potentially influential confounding characteristic.
Introdução: A lateralidade é a diferença na capacidade de controlo entre os dois lados do corpo. Os métodos utilizados para avaliar a lateralidade manual incluem a observação efetiva do uso do membro dominante ou a aplicação de... more
Introdução: A lateralidade é a diferença na capacidade de controlo entre os dois lados do corpo. Os métodos utilizados para avaliar a lateralidade manual incluem a observação efetiva do uso do membro dominante ou a aplicação de inventários respondidos pelo próprio indivíduo avaliado. O Inventário de Lateralidade de Edinburgh (EHI) é o instrumento mais utilizado para avaliar a lateralidade manual.
Apesar do seu uso amplo, em Portugal não existem estudos que avaliem a sua validade e fidedignidade.
Objetivos: Estudar as propriedades psicométricas do Inventário de Lateralidade de Edinburgh numa amostra da população portuguesa.
Métodos: A amostra é constituída por 290 pessoas (135 homens e 155 mulheres), com idades compreendidas entre os 18 e os 65 anos. Todos os participantes preencheram uma declaração de consentimento informado e uma bateria de testes neuropsicológicos
Resultados: A média no EHI foi de 62,36 (DP = 38,00). Os resultados demonstraram que das seis variáveis sociodemográficas (idade, sexo, escolaridade, zona de residência, regiões e profissão) três apresentaram ter influência significativa nas pontuações do EHI: idade, zona de residência e regiões. A confiabilidade e a
estabilidade temporal do EHI apresentaram resultados adequados. A análise fatorial confirmatória mostrou que o modelo não é melhor explicado por um fator. Para dois fatores o modelo continua a não ser adequado.
Conclusão: Apesar de termos obtido uma boa consistência interna não nos é possível considerar este teste como o mais adequado para medir o constructo da lateralidade. / Introduction: The handedness is the difference in the control capacity between the two sides of the body. The methods used to evaluate the manual handedness include the effective observation of the use of dominant member or application of inventories answered by the person assessed. The Edinburgh Handedness Inventory (EHI) is the most used to evaluate manual handedness. Even though being widely used, in Portugal there are no studies that measure its validity and reliability.
Objective: To study the psychometric properties of Edinburgh Handedness Inventory in a Portuguese sample.
Methods: The sample consists of 290 people (135 men and 155 women), aged between 18 and 65 years. All participants filled an informed consent form and a battery of neuropsychological tests.
Results: The average in EHI was 62.36 (SD = 38.00). The results showed that 3 of 6 sociodemographic variables showed significant influence in EHI scores. The reliability and temporal stability of EHI were adequate. Confirmatory factor analysis showed that the model is not better explained by one factor. A two-factor model was not also suitable.
Conclusion: Even though we got a good internal consistency we cannot consider this test as the most appropriate for measuring the handedness construct.
- by Helena Espirito-Santo and +1
- •
- Neuropsychology, Laterality, Handedness
Two experiments tested the hypothesis that social perception recruits distinct limited-capacity processing resources that are distinguished by the cerebral hemispheres. To test this hypothesis, social perception efficiency was assessed... more
Two experiments tested the hypothesis that social perception recruits distinct limited-capacity processing resources that are distinguished by the cerebral hemispheres. To test this hypothesis, social perception efficiency was assessed after relevant hemispheric processing resources were depleted. In Experiment 1 prime faces were unilaterally presented for 30 ms, after which centrally presented target faces were categorised by sex. In Experiment 2 prime faces were unilaterally presented for 80 ms after which centrally presented target faces were categorised by fame. Results showed that sex categorisation was slower after primes were presented in the right versus left visual field, and that fame categorisation was slower after familiar primes were presented in the left versus right visual field. The results support a multiple resource account of social perception in which the availability of resources distributed across the cerebral hemispheres influences social perception.
Dès les origines de l’héraldique, la composition des armoiries valorise le côté gauche de l’écu par l’orientation des figures et le sens de lecture. Celui-ci est bientôt désigné sous le nom de dextre, à l’opposé du sens usuel. Cette... more
Dès les origines de l’héraldique, la composition des armoiries valorise le côté gauche de l’écu par l’orientation des
figures et le sens de lecture. Celui-ci est bientôt désigné sous le nom de dextre, à l’opposé du sens usuel. Cette inversion
de latéralité contribue à faire exister le porteur du bouclier derrière son écu, principe qui amplifie considérablement
la performativité de l’image héraldique et ses fonctions. Cet usage s’inspire peut-être des pratiques sigillaires. Mais
une telle inversion spatiale se retrouve ailleurs dans la culture médiévale, au sujet de l’autel situé au coeur de l’édifice
ecclésial. Véritable incarnation du Christ contemplant ses fidèles, cet objet-lieu voit lui aussi son côté gauche considéré
comme la droite de Dieu et, de ce fait, organise et hiérarchise la distribution du décor dans l’espace sacré. Fruits d’une
même effervescence intellectuelle, théologique et iconographique concentrée au XIIe s., l’église corps du Christ et
l’armoirie-incarnation chevaleresque semblent bien avoir bénéficié des mêmes symboliques conceptuelles que l’on
retrouvera bientôt appliquées aux portraits de la fin du Moyen Âge
We investigated hemispheric differences in image-specific and abstractive immediate repetition priming of famous faces. Participants performed speeded familiarity decisions for centrally presented famous and unfamiliar target faces.... more
We investigated hemispheric differences in image-specific and abstractive immediate repetition priming of famous faces. Participants performed speeded familiarity decisions for centrally presented famous and unfamiliar target faces. Target faces were preceded by lateralized primes (150 ms), presented either in the left or right visual field (LVF or RVF). Primes were either an identical photograph of the famous target face (image-specific priming), a different image of the famous target face (abstractive priming) or a different familiar face (unprimed condition). Reaction times (RTs) revealed significant effects of priming for both image-specific and abstractive priming overall. In addition, image-specific priming was more than twice the magnitude for targets following LVF primes as compared to RVF primes. By contrast, no hemispheric differences emerged for abstractive face priming across different images. Whereas ERPs revealed no evidence that priming affected the N170 component, both imagespecific and abstractive priming significantly modulated the amplitudes of a right temporal N250r and a parietal N400 component. Behavioural and electrophysiological evidence for hemispheric differences in image-specific and abstractive face priming are discussed with respect to current theories of how the human left and right ventral temporal cortices represent abstractive and form-specific visual information.
Most of our knowledge about the neurobiological bases of language comes from studies of spoken languages. By studying signed languages, we can determine whether what we have learnt so far is characteristic of language per se or whether it... more
Most of our knowledge about the neurobiological bases of language comes from studies of spoken languages. By studying signed languages, we can determine whether what we have learnt so far is characteristic of language per se or whether it is specific to languages that are spoken and heard. Overwhelmingly, lesion and neuroimaging studies indicate that the neural systems supporting signed and spoken language are very similar: both involve a predominantly left-lateralised perisylvian network. Recent studies have also highlighted processing differences between languages in these different modalities. These studies provide rich insights into language and communication processes in deaf and hearing people.
- by Cheryl Capek and +2
- •
- Sign Language, Cognition, Magnetic Resonance Imaging, Laterality
Humans are considered unique in their extreme population-level right handedness, seen in no other species to date. Certain behavioral asymmetries have been shown in other animals, especially in nonhuman primates, and these asymmetries are... more
Humans are considered unique in their extreme population-level right handedness, seen in no other species to date. Certain behavioral asymmetries have been shown in other animals, especially in nonhuman primates, and these asymmetries are suspected to be closely tied to anatomical asymmetries in the brain and possibly correlated with language and complex thought. Studies of primate hand preference have searched for evidence of population-level handedness for certain tasks as a proxy for brain asymmetries and their potential intellectual correlates. My study examines the hand preference during feeding of 34 chimpanzees living at the Chimpanzee Project Area (CPA) at Chimfunshi Wildlife Orphanage in Zambia. Results indicate that 30 of the 34 subjects exhibit a significant hand preference for unimanual feeding, refuting the commonly held conception that less complex, everyday tasks will not be lateralized. Additionally, data indicate that age, sex, and the presence of family members at the sanctuary all have some effect on the handedness of the subject, though the direction of this effect could not be determined. While many of the chimpanzees at the CPA have diverse and unique backgrounds before entering the sanctuary, this did not appear to have an effect on the handedness of the subject, though a number of unique individuals and potentially influential factors had to be excluded from analyses. Additionally, I suggest standardizing and correcting methodological inconsistencies in studies of handedness by using statistical methods more appropriate to the type of data gathered in such studies. Finally, I review current findings in the field of primate handedness and revisit the significance of such findings in light of the current study.
book is a:vailabic lroru ther Natiunal and Llniv*rsify Library in Zagreb under ths nurtrber 7771fr5 ISBN: 978-95 3 -3t7 -027 -5 'I-he statements and viervs expressed in the contributions are those of their authors and clo not necessarily... more
book is a:vailabic lroru ther Natiunal and Llniv*rsify Library in Zagreb under ths nurtrber 7771fr5 ISBN: 978-95 3 -3t7 -027 -5 'I-he statements and viervs expressed in the contributions are those of their authors and clo not necessarily represent those of the Editorial Board ancl the publisher. This i)roceeclings tsook inclucles all the conference contmunications (invitecl, oral and poster) receivecl before the e4iting deraclline. "Ihose received iater are not published in the book.
According to Greimas, the semiotic square is far more than a heuristic for semantic and literary analysis. It represents the generative "deep structure" of human culture and cognition which "define the fundamental mode of existence of an... more
According to Greimas, the semiotic square is far more than a heuristic for semantic and literary analysis. It represents the generative "deep structure" of human culture and cognition which "define the fundamental mode of existence of an individual or of a society, and subsequently the conditions of existence of semiotic objects". The veracity of this bold hypothesis has received little attention in the literature. In response, this paper traces the history and development of the square of opposition from Aristotle to Greimas and beyond, to propose that the relations modeled in these diagrams are rooted in gestalt memories of kinesthesia and proprioception from which we derive basic structural awareness of opposition and contrast-including verticality, bilaterality, transversality, markedness and analogy. The paper draws on findings in the phenomenology of movement, recent developments in the analysis of logical opposition, recent scholarship in (post)Greimasian semiotics and prescient insights from Greimas himself. The argument is further tested via multimodal content analyses of a popular music video-highlighting relationships the semiotic square shares with mundane cultural ideologies and showing how these relationships might be traced to memory structures of bodily movement. The paper highlights the neglected relevance of embodied chiasmus and illustrates the enduring relevance of Greimasean thought.
Speech sound perception is one of the most fascinating tasks performed by the human brain. It involves a mapping from continuous acoustic waveforms onto the discrete phonological units computed to store words in the mental lexicon. In... more
Speech sound perception is one of the most fascinating tasks performed by the human brain. It involves a mapping from continuous acoustic waveforms onto the discrete phonological units computed to store words in the mental lexicon. In this article, we review the magnetoencephalographic studies that have explored the timing and morphology of the N1m component to investigate how vowels and consonants are computed and represented within the auditory cortex. The neurons that are involved in the N1m act to construct a sensory memory of the stimulus due to spatially and temporally distributed activation patterns within the auditory cortex. Indeed, localization of auditory fields maps in animals and humans suggested two levels of sound coding, a tonotopy dimension for spectral properties and a tonochrony dimension for temporal properties of sounds. When the stimulus is a complex speech sound, tonotopy and tonochrony data may give important information to assess whether the speech sound parsing and decoding are generated by pure bottom-up reflection of acoustic differences or whether they are additionally affected by top-down processes related to phonological categories. Hints supporting pure bottom-up processing coexist with hints supporting top-down abstract phoneme representation. Actually, N1m data (amplitude, latency, source generators, and hemispheric distribution) are limited and do not help to disentangle the issue. The nature of these limitations is discussed. Moreover, neurophysiological studies on animals and neuroimaging studies on humans have been taken into consideration. We compare also the N1m findings with the investigation of the magnetic mismatch negativity (MMNm) component and with the analogous electrical components, the N1 and the MMN. We conclude that N1 seems more sensitive to capture lateralization and hierarchical processes than N1m, although the data are very preliminary. Finally, we suggest that MEG data should be integrated with EEG data in the light of the neural oscillations framework and we propose some concerns that should be addressed by future investigations if we want to closely line up language research with issues at the core of the functional brain mechanisms.
Dichotic listening performance is considered a reliable and valid procedure for the assessment of language lateralisation in the brain. However, the documentation of a relationship between language functions and dichotic listening... more
Dichotic listening performance is considered a reliable and valid procedure for the assessment of language lateralisation in the brain. However, the documentation of a relationship between language functions and dichotic listening performance is sparse, although it is accepted that dichotic listening measures language perception. In particular, language comprehension should show close correspondence to perception of language stimuli. In the present study, we tested samples of reading-impaired and normally achieving children between 10 and 13 years of age with tests of reading skills, language comprehension, and dichotic listening to consonant-vowel (CV) syllables. A high correlation between the language scores and the dichotic listening performance was expected. However, since the left ear score is believed to be an error when assessing language laterality, covariation was expected for the right ear scores only. In addition, directing attention to one ear input was believed to reduce the influence of random factors, and thus show a more concise estimate of left hemisphere language capacity. Thus, a stronger correlation between language comprehension skills and the dichotic listening performance when attending to the right ear was expected. The analyses yielded a positive correlation between the right ear score in DL and language comprehension, an effect that was stronger when attending to the right ear. The present results confirm the assumption that dichotic listening with CV syllables measures an aspect of language perception and language skills that is related to general language comprehension.