Laterality最新文献

Lateralization has been observed across the animal kingdom. In mammals, this is often associated with complex or precise motor tasks, such as paw and hand use. A recent study reported that cats prefer a leftward (clockwise) sleeping position, suggestive of lateralization. However, limitations in the design and execution of that work raise questions about this finding. The aim of the present study was to further investigate this effect and establish if there is a lateralized preference in the sleeping position of domestic cats. Three activities were performed (1) assessment of YouTube videos of unique cats' sleeping positions; (2) assessment of images from Reddit of unique cats' sleeping positions and (3) assessment of images from Instagram to quantify the leftwards: rightwards preference of specific cats. Compared to a 50:50 ratio, no significant difference was found in lying position from videos (χ² = 0.074, p = 0.786), images of unique cats (χ² = 0.522, p = 0.470) or from cats with multiple images (t = 0.836, p = 0.407). Given the full range of evidence available, it cannot be concluded that there is any population bias, preference or lateralization in the sleeping position of domestic cats. Results to the contrary can be explained by methodological issues.

Pseudoneglect is a spatial bias favoring the left side of space observed in healthy individuals, typically shown by a leftward deviation when bisecting horizontal lines. Although environmental and individual factors are known to modulate this bias, findings remain inconsistent. This study aimed to provide new insights into the influence of four environmental factors on pseudoneglect: Distance (near, far), Environment (real, immersive Virtual Reality (iVR)), Tool (pen, laser pointer), Stimulus (line, object), while controlling handedness. Fifty-five participants (M = 20.6 years, SD = 2.3, 35 right-handed) completed three line bisection tasks in a real environment (paper-and-pencil at near distance, laser at near and far distances) and three in iVR: (laser at near and far distances, French baguette bisection at near distance). A significant Tool effect emerged: pseudoneglect appeared only in the paper-and-pencil bisection task, while a rightward bias observed with a laser pointer. Stimulus also had a significant effect, with a more rightward bias for the baguette than for lines. No main effects of Distance, Environment, or Handedness were found. Several interpretations are discussed, such as inter-individual variability, coding of peripersonal and extrapersonal spaces, and interaction between semantic and attentional networks. Our results emphasize the need to homogenize methodologies across studies.

Long-standing debate concerns the lateralization of emotion. Four competing views prevail: The Right-Hemisphere Model claims that all emotions are right lateralized; the Valence Model, that negative and positively-valanced emotions are right- and left-lateralized, respectively; the Approach-Avoidance Model, that approach- and avoidance-type emotions are right- and left lateralized, respectively; and the Emotion-Type Model, that all primary emotions are right-lateralized and all others are left lateralized and socially constructed. A focused review finds four basic emotions - sadness, fear, anticipation, and acceptance - to be predominantly right lateralized; their opposites - happiness, anger, surprise, and disgust - left lateralized. All four models fail to explain the lateralization of these eight emotions. A new conceptualization, the Feeling-Function Model, hypothesizes that the right-lateralized emotions significantly involves global feeling states, or states of awareness of physiological changes in mind, body, and self that are partially unconscious processes; the left-hemisphere-based emotions, in contrast, are goal-oriented and functional; they enable the individual to act to address problems and opportunities in the world. The Function-Feeling Model correctly classifies the eight basic emotions: The right-lateralized basic emotions (sadness, fear, anticipation, acceptance) emphasize feelings; the opposite left-lateralized basic emotions (joy-happiness, anger, surprise, and disgust) are action-oriented and emphasize functions.

ABSTRACTPrevious studies examining the connections between the Eysenckian dimensions of personality and handedness have often been limited by small samples and by the failure to take sex differences recorded on the personality scales into account. Addressing these limitations, the present study draws on data provided by a sample of 26,730 13- to 15-year-old adolescents who completed the abbreviated form of the Junior Eysenck Personality Questionnaire, together with a measure of handedness. Binary logistic regression demonstrated that non-right-handedness was significantly associated with toughmindedness (higher psychoticism scores), introversion (lower extraversion scores) and emotional stability (lower neuroticism scores). The fitted logistic model was then calculated to predict probabilities for handedness.

The age at which leg preference becomes clearly established in children remains debated, possibly due to inconsistent expression across task types. Leg preference was assessed in 34 right-handed 7-year-olds (53% girls) using a battery of 10 age-appropriate tasks, each performed 10 times with trial independence. Tasks were categorized by bilateral vs. unilateral, movement-leading vs. stabilization, object manipulation, task starting and ending points, and body position. Leg preference was quantified by direction and degree across participants, tasks, and categories, and a general index was computed. Results indicate that 86% of children exhibited a strong right-leg preference. Stronger and more consistent preferences were found in bilateral, movement-leading, and object-manipulation tasks, whereas unilateral stabilization tasks showed weaker, more variable patterns. Significant differences emerged across task categories, but none between sitting and standing. These findings demonstrate that leg preference is well established by age seven in right-handed children, yet its expression remains dynamic and task-dependent. Stronger preferences tend to align with tasks demanding higher coordination and attentional engagement. Findings underscore the importance of using diverse tasks when assessing leg preference. This study offers a rigorous protocol for leg preference assessment and provides a baseline for studies of children with typical development and developmental disorders.

Non-right-handed individuals appear to face greater risks for some psychiatric disorders than those right-handed. Whether an analogous association exists in the general child population and for whom (non-right-handed, left-handed, or mixed-handed children) is unclear. To fill these gaps, we used data from 7,951 children (49.48% girls) of the UK's Millennium Cohort Study. The parent-reported Strengths and Difficulties Questionnaire (SDQ) subscales measured mental health difficulties: emotional, conduct, hyperactivity/inattention, peer difficulties, and prosocial behaviour, at ages 3, 5, 7, 11, and 14 years. Handedness (writing hand preference: right/left/either hand) was self-reported at 14 (a retrospective measure). Adjusted growth curve models explored the association between children's handedness and SDQ trajectories across 3-14. Non-right-handed (left-handed and mixed-handed) children exhibited elevated hyperactivity/inattention symptoms compared to those right-handed, with the association becoming nonsignificant after excluding the mixed-handed. Sex-stratified models did not show any association for girls. Among boys, the non-right-handed, compared to the right-handed, had higher hyperactivity/inattention and peer difficulties scores, though not after excluding the mixed-handed group. All effects were very small. Results suggest that left-handedness is not conferring risk for mental health in the general child population. Mixed-handed children, particularly boys, may face greater risks for social difficulties and hyperactivity/inattention, but effects were very small.

Pseudoneglect refers to the tendency for neurologically normal individuals to overattend to the left side of near space, which shifts to the right in far space. Such attentional asymmetries affect daily activities, such as navigation, where individuals have been found to deviate to the right when passing through an aperture. Interestingly, a representational form of pseudoneglect exists for briefly presented stimuli that need to be held in memory, whereby attention is shifted to the left. The current study examined whether representational pseudoneglect exists in a simulated navigation environment. Participants navigated through the centre of a computer-generated doorway or line. On perceptual trials, the doorway/line would remain on screen, while for representational trials, the doorway/line would disappear from the screen. Significant rightward biases were found for both the perceptual and representational trials of the line and doorway conditions, with the biases being exacerbated on representational trials. Results indicate that the significant load involved with holding a representation of the stimulus in memory may best explain the exacerbation of rightward shifts of attention in the present study.

Faces have been shown to be primarily processed by the right hemisphere, such that there is an advantage in their processing when they are presented in the left portion of the visual field. In the present research, we explore face lateralization in the context of faces in paintings. While prior research in art perception has explored hemispheric asymmetries, the role of a right-hemispheric advantage is still debated. Using a hemifield paradigm, we explored the accuracy of face identification in photographs of real faces, as well as in paintings with different art styles, differing in the extent to which they are realistic (renaissance) or distorted (cubism). Performance for photographs was higher when presented in the left half of the visual field, displaying a right hemisphere lateralization; similarly, a right hemisphere advantage in face processing was found for faces in paintings, regardless of how realistic the art style was. All in all, we found evidence of a right hemisphere advantage across stimuli categories. We consider these in relation to other phenomena in face processing literature (e.g., pareidolia), and discuss implications based on these parallels, namely regarding the time course of face perception.

Early studies separate verbal working memory (VWM) in the left hemisphere from visuospatial working memory (SWM) in the right hemisphere, but later studies found inconsistent results. Functional transcranial Doppler sonography (fTCD) offers a cost-effective and portable alternative, measuring changes in cerebral blood flow velocity as an index of lateralized brain activity. This study aimed to investigate how material type influences hemispheric lateralization in WM. We used fTCD to measure blood flow velocity in the bilateral middle cerebral arteries of 39 healthy, right-handed volunteers (aged 17-28 years, M = 19.10; 6 male, 33 female) during two item-recognition WM tasks. In the VWM task, participants memorized four pseudowords and judged whether a probe word matched one of them. In the SWM task, participants memorized the locations of four black dots and judged whether a probe dot matched a prior location. Our findings revealed that the VWM task showed a significant left-hemisphere lateralization, whereas the SWM task exhibited a bilateral pattern at the group level, but with notable individual differences in laterality.

Several cognitive systems in the human brain, such as language and face processing, are organized asymmetrically. One of the primary neuroscientific methods to assess such functional hemispheric asymmetries is electroencephalography (EEG). The two major forms of analyzing asymmetries in the EEG signal are event-related potentials (ERPs), such as the N1, and oscillations, such as the alpha band. However, the relationships between these two forms of EEG asymmetries are not well understood. Therefore, it was the aim of the present study to (1) replicate previous results on N1 and alpha band asymmetries and (2) assess whether they show a negative correlation with each other, as could be expected from the hypothesis that alpha represents an absence of cognition. To this end, we tested n = 100 left-, mixed-, and right-handed participants with EEG Resting-State, as well as task-based EEG with words, faces, emotional faces, and houses as stimuli. Replication of previous EEG asymmetry findings showed mixed results. Interestingly, we found strong positive associations between individual ERP and alpha band asymmetries. This finding highlights the need to reassess the functional role of alpha asymmetries and suggests that they do not only reflect the absence of cognition but also reflect active neuronal processing asymmetries.