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Takeuchi Y. Developmental Process of a Pronounced Laterality in the Scale-eating Cichlid Fish Perissodus microlepis in Lake Tanganyika. Zoolog Sci 2023; 40:160-167. [PMID: 37042695 DOI: 10.2108/zs220078] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/13/2022] [Accepted: 02/19/2023] [Indexed: 04/09/2023]
Abstract
Lateral preference in behaviors has been widely documented in many vertebrates and invertebrates. Such preferences are strange, puzzling, and on the surface, not adaptive. However, behavioral laterality may increase an individual's fitness as well as foraging accuracy and speed. There is little experimental evidence regarding the developmental process of laterality, and unsolved questions have perplexed researchers for several decades. Related to these issues, here, I review that the scale-eating cichlid Perissodus microlepis found in Lake Tanganyika is a valuable model to address the developmental mechanism of animal laterality. The scale-eating cichlid has pronounced behavioral laterality and uses its asymmetric mouth during feeding events. Recent studies have shown that behavioral laterality in this fish depends on both genetic factors and past experience. The attack-side preference of scale eaters is an acquired trait in an early developmental stage. Juvenile fish empirically learn which side of the prey is more effective for tearing scales and gradually select the dominant side for attacking. However, the superior kinetics of body flexion during the dominant side attack has innate characteristics. Additionally, left-right differences in scale-eater mandibles also develop during ontogeny. Further progress toward understanding the comprehensive mechanisms of laterality should address the following persistent barriers: (1) the effects of phylogenetic constraints and ecological factors on the level of laterality; and (2) the neuronal and molecular mechanisms that produce left-right behavioral differences.
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Affiliation(s)
- Yuichi Takeuchi
- Department of Anatomy and Neuroscience, Faculty of Medicine, University of Toyama, Sugitani, Toyama 434-7207, Japan
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2
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Stetter L, Sattler JB, Marquardt C, Hermsdörfer J. Handwriting kinematics during learning to write with the dominant left hand in converted left-handers. Sci Rep 2023; 13:2171. [PMID: 36750597 PMCID: PMC9905490 DOI: 10.1038/s41598-023-28911-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/22/2022] [Accepted: 01/27/2023] [Indexed: 02/09/2023] Open
Abstract
Converting left-handers to their non-dominant right hand was previously widespread, particularly for handwriting. The present study aimed to explore the extent to which adult, converted left-handers can learn writing with their dominant left hand during a 2-year training program. Eleven converted left-handers participated in the training. Handwriting kinematics were assessed at regular intervals (seven sessions) and compared to those of 11 innate left-handed controls matched for age, gender, and overall handedness score for basic (Finger, Wrist, Circle) and complex (Sentence, Copy) handwriting tasks. Regarding basic tasks in the training group, we found rapid increases in left and right-hand frequency and no significant differences between both hands at any time point, indicating successful hand transfer. After 24 months, training participants significantly surpassed controls for writing frequency in basic tasks with their left hand. For complex tasks, we identified significant increases in the training groups' left-hand writing frequency and duration between the first and last session. While training participants' left-hand writing remained significantly slower than their right-hand writing, statistics confirmed final differences between hands only for the duration of the Sentence task. Importantly, left-hand writing in the training group was characterized by lower frequency, lower automaticity, and prolonged duration after 24 months compared to innate left-handers. With training participants' left-hand writing skills significantly increasing for complex tasks and no final statistically significant differences between hands for frequency and automaticity, the program was considered effective. Nevertheless, within 2 years, training participants did not reach innate left-handers handwriting proficiency for complex tasks. Underlying reasons may be various, such as a non-optimal training program, a sensitive period for learning to write, irreversible neural changes during conversion in childhood, age-related decline of motor learning capacity, or retrograde interference between right- and left-hand writing.
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Affiliation(s)
- Laura Stetter
- Chair of Human Movement Science, Department of Sport and Health Sciences, Technical University of Munich, Georg-Brauchle-Ring 60/62, 80992, Munich, Germany
| | - Johanna Barbara Sattler
- First German Consulting and Information Center for Left-Handers and Converted Left-Handers, Sendlinger Straße 17, 80331, Munich, Germany
| | | | - Joachim Hermsdörfer
- Chair of Human Movement Science, Department of Sport and Health Sciences, Technical University of Munich, Georg-Brauchle-Ring 60/62, 80992, Munich, Germany.
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Takeuchi Y, Higuchi Y, Ikeya K, Tagami M, Oda Y. Experience-dependent learning of behavioral laterality in the scale-eating cichlid Perissodus microlepis occurs during the early developmental stage. Sci Rep 2022; 12:723. [PMID: 35031653 PMCID: PMC8760303 DOI: 10.1038/s41598-021-04588-8] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 11/07/2021] [Accepted: 12/28/2021] [Indexed: 11/28/2022] Open
Abstract
Behavioral laterality-typically represented by human handedness-is widely observed among animals. However, how laterality is acquired during development remains largely unknown. Here, we examined the effect of behavioral experience on the acquisition of lateralized predation at different developmental stages of the scale-eating cichlid fish Perissodus microlepis. Naïve juvenile fish without previous scale-eating experience showed motivated attacks on prey goldfish and an innate attack side preference. Following short-term predation experience, naïve juveniles learned a pronounced lateralized attack using their slightly skewed mouth morphology, and improved the velocity and amplitude of body flexion to succeed in foraging scales during dominant-side attack. Naïve young fish, however, did not improve the dynamics of flexion movement, but progressively developed attack side preference and speed to approach the prey through predation experience. Thus, the cichlid learns different aspects of predation behavior at different developmental stages. In contrast, naïve adults lost the inherent laterality, and they neither developed the lateralized motions nor increased their success rate of predation, indicating that they missed appropriate learning opportunities for scale-eating skills. Therefore, we conclude that behavioral laterality of the cichlid fish requires the integration of genetic basis and behavioral experiences during early developmental stages, immediately after they start scale-eating.
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Affiliation(s)
- Yuichi Takeuchi
- Department of Anatomy and Neuroscience, Faculty of Medicine, University of Toyama, Toyama, Japan.
| | - Yuna Higuchi
- Department of Anatomy and Neuroscience, Faculty of Medicine, University of Toyama, Toyama, Japan
| | - Koki Ikeya
- World Freshwater Aquarium Aquatotto Gifu, Kakamigahara, Japan
| | - Masataka Tagami
- World Freshwater Aquarium Aquatotto Gifu, Kakamigahara, Japan
| | - Yoichi Oda
- Graduate School of Science, Nagoya University, Nagoya, Japan
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Handedness, intelligence, visual-perceptual and motor functions in young adults. CURRENT PSYCHOLOGY 2021. [DOI: 10.1007/s12144-021-01651-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
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Simões EN, Carvalho ALN, Schmidt SL. What does handedness reveal about ADHD? An analysis based on CPT performance. RESEARCH IN DEVELOPMENTAL DISABILITIES 2017; 65:46-56. [PMID: 28433793 DOI: 10.1016/j.ridd.2017.04.009] [Citation(s) in RCA: 16] [Impact Index Per Article: 2.3] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/06/2016] [Revised: 03/19/2017] [Accepted: 04/11/2017] [Indexed: 06/07/2023]
Abstract
BACKGROUND Attention-deficit/hyperactivity disorder (ADHD) is a developmental disorder. Continuous performance Tests (CPTs) aid the diagnosis. Handedness is linked to disabilities. OBJECTIVES 1-To study the association between handedness and ADHD; 2-To verify the usefulness of the CPT in school settings; 3-To exam the relationship between handedness and CPT performance. METHOD Each child was classified as right-consistent, left-consistent, or non-consistent. From the sample, 171 controls and 68 ADHDs fulfilled the inclusion criteria. The effect of handedness on the CPT was studied using a paired-sample that matched handedness by age, grade, gender, and ADHD. RESULTS Left-handed students had a probability of suffering from ADHD 2.88 greater than right-handers. ANOVAs on standardized scores indicated that the ADHD students exhibited higher number of errors and higher variability of reaction times as compared to the controls. Discriminant analysis indicated that these CPT parameters could discriminate ADHD from controls. Repeated ANOVAs showed a significant effect of handedness on commission errors (CE) because left-handers made more CEs than right-handers. CONCLUSIONS 1-The association between ADHD and handedness reflects that left-handers are less lateralized and have decreased interhemispheric connections; 2-The CPT can be used to measure different attention domains in school settings; 3- Left-handers have problems in the impulsive/hyperactivity domain.
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Affiliation(s)
- Eunice N Simões
- Neurology Department, Federal University of the State of Rio de Janeiro, Brazil
| | | | - Sergio L Schmidt
- Neurology Department, Federal University of the State of Rio de Janeiro, Brazil; Federal University of Juiz de Fora, Brazil; State University of Rio de Janeiro, Brazil.
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Drilling Simulated Temporal Bones with Left-Handed Tools: A Left-Hander's Right? Ann Otol Rhinol Laryngol 2016; 116:819-26. [DOI: 10.1177/000348940711601105] [Citation(s) in RCA: 10] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Objectives: Left-handed trainees can be at a disadvantage in the surgical environment because of a right-handed bias. The effectiveness of teaching left-handed trainees to use an otologic drill designed for their dominant hand versus the conventional right-handed drill was examined. Methods: Novice medical students were recruited from the university community. Twenty-four subjects were left-handed, and 12 were right-handed. Eight left-handed surgeons also participated. A randomized controlled trial was conducted to compare the performance of left-handed trainees using novel left-handed drills to that of left-handed trainees using right-handed tools and to that of right-handed trainees using right-handed tools. The evaluation consisted of 3 phases: Pretest, skill acquisition, and 2 post-tests. The measurement tools included expert assessment of performance, and subjective and objective final product analyses. Results: An initial construct validity phase was conducted in which validity of the assessment tools was ensured. Both the left-handers using left-handed tools and the right-handers using right-handed tools significantly outperformed the left-handers using right-handed tools at pretest, immediate posttest, and delayed posttest. All participants improved their performance as a function of practice. Conclusions: The left-handed trainees learned bone drilling better with tools designed for the left hand. These tools may be incorporated into residency training programs for the development of surgical technical skills. Future studies should assess skill transfer between the left-handed and right-handed drills.
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Left in a Right-Handed World. Laterality 2016. [DOI: 10.1016/b978-0-12-801239-0.00007-7] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
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Left to Die. Laterality 2016. [DOI: 10.1016/b978-0-12-801239-0.00006-5] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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9
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Porac C. Disorders, Diseases, and Life on the Left. Laterality 2016. [DOI: 10.1016/b978-0-12-801239-0.00009-0] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
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Gonzalez CLR, Flindall JW, Stone KD. Hand preference across the lifespan: effects of end-goal, task nature, and object location. Front Psychol 2015; 5:1579. [PMID: 25653633 PMCID: PMC4299429 DOI: 10.3389/fpsyg.2014.01579] [Citation(s) in RCA: 20] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 10/08/2014] [Accepted: 12/20/2014] [Indexed: 01/12/2023] Open
Abstract
In the present study we investigate age-related changes in hand preference for grasping and the influence of task demands on such preference. Children (2–11), young-adults (17–28) and older-adults (57–90) were examined in a grasp-to-eat and a grasp-to-construct task. The end-goal of these tasks was different (eat vs. construct) as was the nature of the task (unimanual vs. bimanual). In both tasks, ipsilateral and contralateral grasps were analyzed. Results showed a right-hand preference that did not change with age. Across the three age groups, a more robust right-hand preference was observed for the unimanual, grasp-to-eat task. To disentangle if the nature (unimanual) or the end-goal (grasp-to-eat) was the driver of the robust right-hand preference, a follow up experiment was conducted. Young-adult participants completed a unimanual grasp-to-place task. This was contrasted with the unimanual grasp-to-eat task and the bimanual grasp-to-construct task. Rates of hand preference for the grasp-to-eat task remained the highest when compared to the other two grasping tasks. Together, the results demonstrate that hand preference remains stable from childhood to older adulthood, and they suggest that a left hemisphere specialization exists for grasping, particularly when bringing food to the mouth.
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Affiliation(s)
- Claudia L R Gonzalez
- The Brain in Action Laboratory, Department of Kinesiology, University of Lethbridge Lethbridge, AB, Canada
| | - Jason W Flindall
- The Brain in Action Laboratory, Department of Kinesiology, University of Lethbridge Lethbridge, AB, Canada
| | - Kayla D Stone
- The Brain in Action Laboratory, Department of Kinesiology, University of Lethbridge Lethbridge, AB, Canada
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Abstract
Hand preference has been associated with psychological and physical well-being, risk of injury, pathological irregularities, longevity, and cognitive function. To determine hand preference, individuals are often asked what hand they use to write with, or what hand is used more frequently in activities of daily living. However, relying only on one source of information may be misleading, given the strong evidence to support a disassociation between self-reported hand preference and outcomes of hand performance assessments. This brief communication is intended to highlight the various methods used to determine hand preference, to discuss the relationship between hand preference inventories and performance measures and to present some recent findings associated with hand preference and musculoskeletal disorders.
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Affiliation(s)
- Diane E. Adamo
- Eugene Applebaum College of Pharmacy and Health Sciences, Physical Therapy Department, Wayne State University, 259 Mack Ave., Detroit, MI USA
| | - Anam Taufiq
- Eugene Applebaum College of Pharmacy and Health Sciences, Physical Therapy Department, Wayne State University, 259 Mack Ave., Detroit, MI USA
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Van der Elst W, Wassenberg R, Meijs C, Hurks P, Van Boxtel M, Jolles J. On the mediating effects of pregnancy and birth stress events on the relation between lateral preferences and cognitive functioning in healthy school-aged children. J Clin Exp Neuropsychol 2011; 33:548-58. [DOI: 10.1080/13803395.2010.537647] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/18/2022]
Affiliation(s)
- Wim Van der Elst
- a Faculty of Medicine and Life Sciences , Maastricht University , Maastricht, The Netherlands
| | - Renske Wassenberg
- b Maastricht University Medical Centre , Maastricht, The Netherlands
| | - Celeste Meijs
- a Faculty of Medicine and Life Sciences , Maastricht University , Maastricht, The Netherlands
| | - Petra Hurks
- c Faculty of Psychology and Neuroscience, Department of Neuropsychology & Psychopharmacology , Maastricht University , Maastricht, The Netherlands
| | - Martin Van Boxtel
- a Faculty of Medicine and Life Sciences , Maastricht University , Maastricht, The Netherlands
| | - Jelle Jolles
- d AZIRE Research Institute and Faculty of Psychology & Education , VU Universiteit Amsterdam , Amsterdam, The Netherlands
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Beratis IN, Rabavilas A, Papadimitriou GN, Papageorgiou C. Effect of handedness on the Stroop Colour Word Task. Laterality 2009; 15:597-609. [PMID: 19626538 DOI: 10.1080/13576500903071104] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
Handedness is associated with cerebral organisation, but its relationship with cognition remains unclear. Since the Stroop task is believed to measure aspects of executive control, this study aims to investigate the effect of handedness on Stroop interference. We used the Stroop task with 90 young adults with university education, of whom 47 (23 males) were right-handed and 43 (21 males) were left-handed. Main dependent variables were Stroop baseline (SB), Stroop incongruent (SI), and the proportional derivative Stroop reduction (SR) [SR=(SB - SI)/SB×100%] (Bugg, Delosh, Davalos, & Davis, 2007; Graf, Uttl, &Tuokko, 1995) scores. The analysis revealed that SI is significantly affected by both handedness and the interaction of sex×handedness, whereas SR is only affected by handedness. After controlling for the effect of SB on SI, only the effect of handedness remained statistically significant [F(1, 83) = 6.44, p=.013]. Post-hoc comparisons showed that left-handed females performed significantly better than right-handed females on both SI (p=.003) and SR (p=.007). The data suggest that handedness is associated with cognitive function alterations, which lead to a smaller Stroop interference of left-handers irrespectively of sex, an effect that is more pronounced in the female subpopulation.
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Karev GB. Comparative assessment of 13 of the widely used hand preference items in a Bulgarian sample. Int J Neurosci 2009; 119:953-74. [PMID: 19466632 DOI: 10.1080/00207450802324366] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/20/2022]
Abstract
The hand preference items included into Chapman and Chapman's (1987) inventory were comparatively assessed concerning the frequencies of the answers given by Bulgarian right, mixed, and left handers, concerning the correlation of each item with the remaining 12, with eyedness and footedness scores. Relationships between writing hand, throwing hand, eyedness, and footedness were studied. Application of a cumulative index of familial sinistrality evidenced the biological significance of the main findings. All the results showed the inferiority of the writing hand as compared to the remaining items and evidenced the full inappropriateness of this item as a single predictor of handedness.
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Affiliation(s)
- George B Karev
- Bulgarian Academy of Sciences, Institute of Experimental Morphology and Anthropology with Museum, Sofia, Bulgaria.
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Siengthai B, Kritz-Silverstein D, Barrett-Connor E. Handedness and cognitive function in older men and women: a comparison of methods. J Nutr Health Aging 2008; 12:641-7. [PMID: 18953462 PMCID: PMC2645079 DOI: 10.1007/bf03008275] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 09/29/2022]
Abstract
OBJECTIVE Previous studies of handedness and cognitive function rely on self-classification and yield inconsistent results. This study examines the associations of self-reported versus grip-strength-based handedness with cognitive function in healthy older men and women. DESIGN Cross-sectional study. SETTING 1988-91 follow-up clinic visit and 1991 mailed survey. PARTICIPANTS 684 men and 985 women aged 55-95 who were community dwelling. MEASUREMENTS Cognitive function was assessed with 12 tests and grip strength was measured by hand-held dynamometer. Self-reported handedness was obtained with a mailed survey. RESULTS By self-report, 92.1% of men and women were right-handed; 2.0% were left handed. By grip strength, in men, 64.3% were right-handed, 22.5% left-handed, and 13.2% ambidextrous. In women, 61.3% were right-handed, 17.3% left-handed, and 21.4% ambidextrous. No cognitive function differences were found by self-reported handedness in either sex (p's>0.10). However, based on grip strength, left-handed women scored poorer than right-handed or ambidextrous women in immediate and delayed memory, attention, and verbal fluency (p's<0.05). Using categorical definitions, left-handed or ambidextrous individuals based on grip strength were more likely to show poor cognitive function on 4 of 5 tests. CONCLUSION Grip strength is a useful alternative to self-reports for classifying handedness. Left-handedness by grip-strength, may be related to poorer cognitive function; this association may vary by gender.
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Affiliation(s)
- Boonclaire Siengthai
- University of California, San Diego, School of Medicine, Department of Family & Preventive Medicine, 9500 Gilman Drive, La Jolla, CA 92093
| | - Donna Kritz-Silverstein
- University of California, San Diego, School of Medicine, Department of Family & Preventive Medicine, 9500 Gilman Drive, La Jolla, CA 92093
| | - Elizabeth Barrett-Connor
- University of California, San Diego, School of Medicine, Department of Family & Preventive Medicine, 9500 Gilman Drive, La Jolla, CA 92093
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Porac C. Hand preference and skilled hand performance among individuals with successful rightward conversions of the writing hand. Laterality 2008; 14:105-21. [PMID: 18720207 DOI: 10.1080/13576500802299418] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/21/2022]
Abstract
Searleman and Porac (2001) studied lateral preference patterns among successfully switched left-hand writers, left-hand writers with no switch pressure history, and left-hand writers who did not switch when pressured. They concluded that left-handers who successfully shift to right-hand writing are following an inherent right-sided lateralisation pattern that they already possess. Searleman and Porac suggested that the neural mechanisms that control lateralisation in the successfully switched individuals are systematically different from those of other groups of left-handers. I examined patterns of skilled and less-skilled hand preference and skilled hand performance in a sample of 394 adults (ages 18-94 years). The sample contained successfully switched left-hand writers, left-handers pressured to shift who remained left-hand writers, left-handers who did not experience shift pressures, and right-handers. Both skilled hand preference and skilled hand performance were shifted towards the right side in successfully switched left-hand writers. This group also displayed mixed patterns of hand preference and skilled hand performance in that they were not as right-sided as "natural" right-handers nor were they as left-sided as the two left-hand writing groups, which did not differ from each other. The experience of being pressured to switch to right-hand writing was not sufficient to shift lateralisation patterns; the pressures must be experienced in the context of an underlying neural control mechanism that is amenable to change as a result of these external influences.
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Affiliation(s)
- Clare Porac
- Pennsylvania State University, 4951 College Drive, Erie, PA 16563, USA.
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Van der Elst W, Van Boxtel MPJ, Van Breukelen GJP, Jolles J. Is left-handedness associated with a more pronounced age-related cognitive decline? Laterality 2008; 13:234-54. [PMID: 18449840 DOI: 10.1080/13576500701825693] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/22/2022]
Abstract
The effect of handedness on cognitive functioning has been the subject of much controversy. The influential "pathological left-handedness theory" posited by Coren and Halpern (1991) claims that left-handedness is probabilistically related to deviations from the neurological and cognitive norm. Many studies have failed to find negative effects of left-handedness on cognitive functioning, but most of these studies related handedness to cognition at one moment in time. Such studies do not exclude the possibility that sinistrality may be related to a more pronounced age-related longitudinal decline in cognitive functions. This hypothesis was tested in the present study. In a longitudinal study involving a large population sample of cognitively intact people aged at least 50 years at baseline, we evaluated the effect of handedness on age-related decline in four major cognitive domains: speed of information processing, verbal learning, long-term verbal memory, and executive functioning. The results failed to provide support for the hypothesis that sinistrality is associated with a more pronounced age-related cognitive decline. Recommendations for future studies are provided.
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Abstract
To emote literally means to move or prepare for action. A large body of research indicates that flexor and extensor movements are conditionally associated with approach- and avoidance-related motivations. It has also been widely argued that approach and avoidant motivations are asymmetrically instantiated in the left and right hemispheres, respectively. Nevertheless, to date, these literatures remain largely separate. In the present investigation, flexor and extensor movements that were visuospatially contextualized as being directed toward the self and away from the self were observed to be asymmetrically represented in the "approach" and "avoidance" hemispheres. Moreover, this pattern of hemispheric specialization was manifested to a greater degree the higher participants' self-reported level of daily positive affect and the lower their self-reported level of dispositional anxiety. Collectively, these findings have direct implications for models of embodied emotional and perceptual processing, as well as for investigations of individual differences in emotional disposition.
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Abstract
The rate of handedness conversion was 2.7% to 11.8% in prior studies based on the total population including innately right-handed people. However, the conversion rate of innately left-handed people has not been reported. The purpose of this study was to investigate the percentage of handedness conversion in children who are innately left-handed. The data in the present study showed that 59.3% (121/211) of left-handed children had been forced to convert to right-handedness. Current handedness was also reported by 114 of the 121 informants, and the rates of right-, left-, and mixed-handedness were 56.1% (64/114), 26.3% (30/114), and 17.5% (20/114) respectively. More than half had successfully changed from left to right. Some variables, especially the educational level of the parents and the child's grade level, were related to this conversion intention. The children whose parents had less education were more likely to be forced to change handedness. Additionally, the rate of handedness conversion in younger children was lower than in older children. However, even for the children whose parents had higher education, or for the children who were younger, there was a high percentage (45.7% and 41.8% respectively) who had changed their handedness. Therefore, preventing the possible side effects for children who have undergone hand conversion should be emphasised in the future.
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Affiliation(s)
- Ling-fu Meng
- Department of Occupational Therapy, Institute of Clinical Behavioral Science, Chang Gung University, Tao-Yuan, Taiwan.
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Porac C, Searleman A. The relationship between hand preference consistency, health, and accidents in a sample of adults over the age of 65 years. Laterality 2006; 11:405-14. [PMID: 16882554 DOI: 10.1080/13576500600677823] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022]
Abstract
As a result of the Coren and Halpern (1991) hypothesis that left hand preference may be associated with decreased survival fitness, there has been interest in exploring the relationship between hand preference and indices of health status. In a series of studies of university-aged adults, Hicks and his colleagues found a higher prevalence of accidental injuries, falls, and sleep problems among individuals with mixed, rather than left, hand preference. They argued that hand preference consistency, not side, may be a marker for possible reduction in health and well-being. We looked at the relationship between hand preference consistency and the prevalence of sleep problems, accidental injuries, falls, injuries from falls, and the prevalence of autoimmune and other illnesses in a sample of 1277 adults between the ages of 65 and 100 years. Of those participants who reported a recent fall, mixed-handers were more likely to report a higher number of injuries from these falls when compared to the reports of consistent-handers. In contrast to the previous findings of Hicks et al., and highlighting the value of including broader age ranges, all other comparisons showed no differences between the two hand preference types.
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Affiliation(s)
- Clare Porac
- School of Humanities and Social Sciences, Pennsylvania State University, Erie, PA 16563-1501, USA.
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Porac C, Searleman A, Karagiannakis K. Pseudoneglect: Evidence for both perceptual and attentional factors. Brain Cogn 2006; 61:305-11. [PMID: 16527384 DOI: 10.1016/j.bandc.2006.01.003] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/30/2005] [Revised: 01/13/2006] [Accepted: 01/17/2006] [Indexed: 11/28/2022]
Abstract
When neurologically normal individuals bisect a horizontal line as accurately as possible, they reliably show a slight leftward error. This leftward inaccuracy is called pseudoneglect because errors made by neurologically normal individuals are directionally opposite to those made by persons with visuospatial neglect (Jewell & McCourt, 2000). In the current study, normal right-handed observers bisected horizontal lines that were altered to bias line length judgments either toward the right or the left side of the line. Non-target dots were placed on or near the line stimuli using principles derived from a theory of visual illusions of length called centroid extraction (Morgan, Hole, & Glennerster, 1990). This theory argues that the position of a visual target is calculated as the mean position of all stimuli in close proximity to the target stimulus. We predicted that perceptual alterations that shifted the direction of centroid extraction would also shift the direction of line bisection errors. Our findings confirmed this prediction and support the idea that both perceptual and attentional factors contribute to the pseudoneglect effect.
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Affiliation(s)
- Clare Porac
- School of Humanities and Social Sciences, Pennsylvania State University, Erie, Station Road, 16563-1501, USA.
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Mohr C, Thut G, Landis T, Brugger P. Arm folding, hand clasping, and Luria's concept of "latent left-handedness". Laterality 2006; 11:15-32. [PMID: 16414912 DOI: 10.1080/13576500500199795] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/25/2022]
Abstract
Luria (1947/1970) proposed left-top positions in arm folding (AF) and hand clasping (HC) to be signs of "latent left-handedness". However, research since has revealed that (1) left-top positions are canonical for European right-handers and (2) combined AF/HC measures may provide more information about cerebral laterality than either measure considered alone. We tested whether AF and HC or AF/HC combinations predicted diminished right-handedness for 12 handedness items. Results from 509 healthy participants showed that (1) left-top positions in AF and HC were dominant across participants, as was right-handedness, and a right-top position in HC was associated with attenuated right-handedness, (2) right-hand preference was more frequently associated with congruent AF/HC combinations, especially of the LL type (AF: left-top / HC: left-top), and (3) non-right-hand preference was associated with non-congruent, predominantly LR combinations. We conjecture that the LL type combination indicates left hemispheric dominance for motor actions, whereas the LR combination, in which HC as the distally innervated posture deviates from the canonical pattern, indicates attenuated hemispheric asymmetry. Our data support Luria's proposition that a left-top preference in AF points to "latent" left-handedness, but only if associated with a right-top preference in HC. Consistent left-top preference for the combined AF/HC measure appears to predict right-handedness.
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Abstract
Hemispheric specialization for language is one of the most robust findings of cognitive neuroscience. In this review, we first present the main hypotheses about the origins of this important aspect of brain organization. These theories are based in part on the main approaches to hemispheric specialization: studies of aphasia, anatomical asymmetries and, nowadays, neuroimaging. All these approaches uncovered a large inter-individual variability which became the bulk of research on hemispheric specialization. This is why, in a second part of the review, we present the main facts about inter-individual variability, trying to relate findings to the theories presented in the first part. This review focuses on neuroimaging as it has recently given important results, thanks to investigations of both anatomical and functional asymmetries in healthy subjects. Such investigations have confirmed that left-handers, especially "familial left-handers", are more likely to have an atypical pattern of hemispheric specialization for language. Differences between men and women seem less evident although a less marked hemispheric specialization for language was depicted in women. As for the supposed relationship between anatomical and functional asymmetries, it has been shown that the size of the left (not the right) planum temporale could explain part of the variability of left hemispheric specialization for language comprehension. Taken as a whole, findings seem to vary with language tasks and brain regions, therefore showing that hemispheric specialization for language is multi-dimensional. This is not accounted for in the existing models of hemispheric specialization.
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Affiliation(s)
- Goulven Josse
- Groupe d'Imagerie Neurofonctionnelle, UMR 6095, CNRS, CEA, Université de Caen and Université Paris V., France
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Searleman A, Porac C. Lateral preference profiles and right shift attempt histories of consistent and inconsistent left-handers. Brain Cogn 2003; 52:175-80. [PMID: 12821099 DOI: 10.1016/s0278-2626(03)00053-8] [Citation(s) in RCA: 18] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
Differences in abilities and preferences exist between left-handers who both write and throw with their left hands (consistent left-handers) 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.
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Affiliation(s)
- Alan Searleman
- Department of Psychology, St. Lawrence University, Canton, NY 13617-1475, USA
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