Individual differences in personality as a function of degree of handedness: consistent-handers are less sensation seeking, more authoritarian, and more sensitive to disgust

State Resident Handedness, Ideology, and Political Party Preference: U.S. Presidential Election Outcomes Over the Past 60 Years

Pearson correlation, partial correlation, and multiple regression strategies determined the degree to which estimates of the level of left-handedness in each of the 48 contiguous American states related to citizen political ideology and to Democratic-Republican presidential popular vote over the past 60 years. Higher state levels of left-handedness were associated significantly with liberal ideology in each of the presidential election years from 1964 to 2016. Comparable ideology data were not available for 2020. Higher state levels of left-handedness also were associated with a greater degree of Democratic candidate popular vote support in each of the presidential election years from 1964 to 2020 except for 1976. The mean size of these 28 significant Pearson correlations involving the two political criteria was .62 (SD = .12) with a range of .38-.80, indicating handedness alone could account for a mean of 40.1% (SD = 14.9) of the variance in the two political preference variables. Corresponding multiple regressions showed that when state-level Big Five personality, White population percent, urbanization, and income variables were given the opportunity to enter the equations, handedness still emerged with a significant regression coefficient in 26 of the 28 equations. The two exceptions occurred for 1968 with either political preference criterion. It is speculated that such relations are grounded in hypothesized but poorly understood genetic links between handedness, personality, and political beliefs and attitudes, and, that a foundational genetic predisposition to left-handedness in a population may have much greater impact on correlates than overt levels of left-handedness.

Righty-tighty, lefty-loosey: relation between societal tightness scores, left-handedness rates, and COVID-19 outcomes in US states

As the percentage of right-handers increases in a state, the tightness of that state's culture, as measured, also increases. The relations between handedness, tightness, and various COVID measures (cases per 100,000, vaccination rates, hospitalization rates, death rates, and mask wearing adherence) were examined. Left-handedness rates and tightness both marginally predicted COVID cases and significantly predicted vaccination rates (more right-handers and more tightness associated with higher COVID rates and lower vaccination rates), only left-handedness rates predicted mask wearing adherence (more left-handers associated with increased adherence), only tightness predicted death rates (more tightness associated with higher death rates), and neither handedness or tightness predicted hospitalizations. Results are discussed in terms of the connection between consistent right-handedness and decreased cognitive flexibility and its implication for sociopolitical outcomes, and implications for the framing of public health messaging are presented.

The Handedness Index Practical Task (HI20): An economic behavioural measure for assessing manual preference

ABSTRACTBecause self-report hand preference measures are limited to investigating cognitive aspects of manual laterality, valid, easy-to-administer and economic behavioural methods are needed for capturing the motoric component of handedness. Therefore, this study introduces the Handedness Index Practical Task (HI₂₀) and tests it in a sample of 206 students (M_age = 23.79 years, SD_age = 3.01 years), half of whom were self-specified left-handers. After confirming good reliabilities at the subscale and total scale levels, k-means cluster analysis allowed an empirically based partitioning of test subjects into left- (n = 72), mixed- (n = 23) and right-handers (n = 111). To validate this categorization and the HI₂₀ index, data were compared with the Edinburgh Handedness Inventory (EHI), EHI-short, HI₂₂ and hand grip strength. The congruency between the HI₂₀ clusters and alternative categorizations ranged from 95.6% to 84.0%, while the clusters explained large portions of variance in grip strength differences. The HI₂₀ sub- and total scores showed strong correlations with other measures of lateral preference. Altogether, the freely available HI₂₀ emerges as a reliable and valid alternative for behavioural handedness assessment, whose power lies in explaining differential hand use patterns and enabling fine-grained examinations of handedness.

Asymmetry of Muscle Mass Distribution and Grip Strength in Professional Handball Players

Handball is among the disciplines that impose a significant degree of asymmetry on the body movement. The aim of the study is to assess the influence of physical effort on the occurrence of asymmetry in body musculature and in isometric strength of handball players. The study examined 36 professional handball players. Players' height and body mass were measured as to calculate their body mass indexes (BMIs). Segmental bioelectrical impedance analysis (SBIA) was used to assess: the percentage of fat mass, total muscle mass (MM), musculature of the right and left side of the body, and body segments (trunk, upper and lower limbs). Moreover, grip strength was also measured. The assessment confirmed the existence of discrepancies in the right and left sides of players' bodies for the majority of the parameters. Cross-asymmetry and significant bilateral discrepancies in trunk musculature were also observed. Morphological asymmetry may impact performance in sports since it can cause unfavorable functional changes, which in turn increase the risk of injury and conditions caused by overexertion. Therefore, we believe it is important to emphasize the importance of individualized symmetrization during sports practice and consistent monitoring of the asymmetries occurring in different body parts; this should both improve one's sports results and minimize the risk of injury.

Authoritarianism, Conspiracy Beliefs, Gender and COVID-19: Links Between Individual Differences and Concern About COVID-19, Mask Wearing Behaviors, and the Tendency to Blame China for the Virus

The present study investigated variables potentially associated with a lack of concern about COVID-19 and belief in the conspiracy theory that China is responsible for the virus. In particular, the study looked at Authoritarianism, Conspiracy Beliefs, gender, and consistency of handedness as predictors of nine Likert-type items gauging attitudes, behavior, and beliefs regarding the virus. Initial analyses showed that Authoritarianism predicted less concern about the impact of the virus on health, less mask wearing, and a stronger belief in China's responsibility for the illness. Conspiracy Beliefs were associated with a stronger belief in China's responsibility. Women expressed greater degrees of concern about their own and others' health and about the financial wellbeing of others. In order to reduce the number of dimensions, and thus the number of tests that could yield a type one error, the nine items were then submitted to a principal components analysis which yielded a "Concern about COVID" factor and a "Blame for China" factor. Authoritarianism is generally associated with less concern about the virus. In addition, men showed less concern about the virus overall than women. Both Authoritarianism and Conspiracy Beliefs accounted for unique variance in blame on China for the virus.

Handedness and the 2016 U.S. Primaries: consistent handedness predicts support for Donald Trump among republicans, but gender predicts support for Hillary Clinton among democrats

A growing number of studies demonstrate that consistent handers, people who use their dominant hand for all or most manual tasks, are less cognitively flexible than inconsistent handers, people who use their non-dominant hands at least some of the time. A recent hypothesis suggests that differences in handedness emerged evolutionarily because populations benefited from a balance between cognitively rigid and cognitively flexible people. One expectation is that cognitively rigid consistent handers would support more authoritarian policies or candidates. To test this idea, we looked at handedness, gender, and political affiliation as predictors of support for Donald Trump, a candidate whose supporters self-report being more authoritarian, in the 2016 primary. Our data show that in the Republican Primary, consistent handers report more support than inconsistent for Donald Trump. When authoritarianism was added as a covariate, the handedness effect disappeared. Further analyses showed that authoritarianism mediates the relationship between handedness and support for Donald Trump. In the Democratic Primary, there was a main effect of gender. Women reported more support than men for Hillary Clinton.

Why are consistently-handed individuals more authoritarian? The role of need for cognitive closure

Recent studies indicate that individuals with consistent hand preference are more authoritarian than individuals whose preference is relatively inconsistent. We explored the role of epistemic needs in the handedness-authoritarianism relationship. Based on findings that consistent individuals are less cognitively flexible than inconsistent individuals, we hypothesized that consistent-handers would report greater need for definite knowledge. To measure this, we administered the revised Need for Cognitive Closure scale to a sample of undergraduates (N = 235), along with measures of handedness consistency and authoritarian submission. Consistent individuals scored significantly higher on authoritarian submission and need for closure. Need for closure fully mediated the relationship between consistency and submission. Consistent individuals also expressed greater prejudice against authoritarian out-groups such as immigrants and liberals. This effect was partially mediated by authoritarian submission. We theorize that consistent-handers' cognitive inflexibility leads them to covet definite knowledge. These individuals turn to authoritarianism because it promises to stifle dissent and protect existing (conventional) knowledge.

Brief, prior, exposure to red decreases categorical and coordinate spatial task performance

Location information is processed through two types of spatial processing; categorical and coordinate processing. Categorical spatial relations indicate where an object is relative to another object, without regard to the metric distance between the two objects. Coordinate spatial relations indicate metric distance without regard to relative location. In human behavioral studies, the magnocellular pathway of the lateral geniculate nucleus has been implicated in coordinate spatial processing abilities. Magnocellular pathway cells (type IV) have a center surround organization, such that red light inhibits neuronal firing. In these behavioral studies, red stimuli decreases coordinate spatial processing accuracy. Prior studies also show that there is a lag between the time of visual stimulus presentation and the time of observing a neural response in the magnocellular pathway. We sought to understand whether prior presentation of red stimuli decreases coordinate spatial performance, and also examined its effects on categorical spatial performance. The results indicate that prior presentation of red stimuli decreases accuracy and perceived confidence on both the categorical and coordinate tasks. These results confirm prior findings of the association between magnocellular pathway function and coordinate spatial processing. Implications for categorical task results and associated neural pathways are discussed.

Individual differences in apology acceptance and forgiveness: the influence of handedness

The purpose of the current study was to determine if the relationship between interhemispheric interaction and cognitive flexibility extends to explanations of forgiveness and apology acceptance. A growing body of research indicates that consistency of handedness may be reflective of an individual's degree of interhemispheric interaction and access to processes of the right hemisphere. As such, individual differences in processing that require interhemispheric interaction, such as belief updating, are associated with consistency of handedness. Participants completed the Edinburgh Handedness Inventory (EHI) and read descriptions of interpersonal transgressions, then rated their willingness to forgive before and after an apology was offered. There was a main effect such that the presence of apology increased forgiveness. However, inconsistent handedness was associated with greater forgiveness prior to apology compared to consistent handedness. A second study was conducted to determine if the individual differences in forgiveness were mediated by different dimensions of empathy (personal distress, perspective taking, empathic concern and fantasy). Participants completed the Interpersonal Reactivity Index, the Forgiveness Scale and the EHI. Results revealed those with inconsistent handedness who scored lower on personal distress reported decreased negative thoughts about transgressors compared to those with consistent handedness.

Handedness predicts Conservative-Republican preference and eliminates relations of Big Five personality to political orientation using the 48 contiguous American states as analytical units

The two present nomothetic studies focused on the period from 1996 to 2012 to determine relations between handedness and political orientation using the 48 contiguous American states as analytical units. The estimated percentage of left-handers in each state operationally defined handedness. A composite measure of Conservative-Republican preference was created from CBS/New York Times/Gallup polls of state resident conservatism and the percent in each state voting Republican in each presidential election from 1996 to 2012. Study 1 showed that state levels of left-handedness correlated to an extremely high degree with Conservative-Republican preference (r = -.80). As well, with common demographic differences between states reflected in socioeconomic status, White population percent, and urban population percent controlled through multiple regression, handedness still accounted for an additional 37.2% of the variance in Conservative-Republican preference. Study 2 found that each of the Big Five personality variables correlated significantly with handedness and with Conservative-Republican preference, but in the opposite direction. Furthermore, Study 2 demonstrated quite surprisingly that all Big Five personality relations to Conservative-Republican preference were eliminated when handedness was controlled in multiple regression equations. For all regression equations, the global Moran's I test specifically developed for detecting residual spatial autocorrelation indicated no significant spatial autocorrelation.

The association between inconsistent handedness and psychopathy does not extend to the domain of moral reasoning

A recent study [Shobe, E., & Desimone, K. (2016). Inconsistent handers show higher psychopathy than consistent handers. Laterality: Asymmetries of Body, Brain and Cognition, 21(2), 143-160. doi:10.1080/1357650X.2015.1089879] found an association between inconsistent handedness (the use of one's non-dominant hand for some tasks) and psychopathy. Because this provides evidence for an association between an individual difference and a trait that is perceived negatively, the present study set out to (1) attempt to replicate the finding and (2) determine whether inconsistent handedness and psychopathy predict similar patterns of moral reasoning. An Mturk sample of 344 adults took the Edinburgh Handedness Inventory, the Short Dark Triad Questionnaire, and the Moral Foundations Questionnaire. The finding of a modest association between handedness and psychopathy was replicated. However, handedness and psychopathy predicted totally different response patterns on the Moral Foundations Questionnaire, with psychopathy predicting less concern for others and fairness and inconsistent handedness predicting less respect for authority and less in group loyalty.

Handedness and the neurocognitive foundations of public attitudes about international laws and norms

Whether Geneva Conventions (GC) rights should apply to terrorists is a contentious question that has received little attention in public opinion research. Both personality and contextual factors may be important. We queried participants' support for applying the GC to alleged terrorists, but first we measured participants' authoritarianism and presented them with a scenario concerning an alleged terrorist. We manipulated whether (1) the scenario contained examples of GC rights and (2) the alleged terrorist's religious affiliation was Muslim or non-Muslim. Support for applying the GC to alleged terrorists was high and unaffected by providing examples of GC provisions, but it was negatively related to authoritarianism. Support was reduced by priming with a Muslim terrorist, but only among participants exhibiting a behavioral marker for limited interhemispheric interaction - consistent-handedness. Consistent-handers in our sample expressed greater authoritarianism, suggesting that limited interhemispheric interaction promotes greater authoritarianism, which decreases support for applying the GC to alleged terrorists.

In praise of ambidexterity: How a continuum of handedness predicts social adjustment

This paper estimates the relationship between handedness and social adjustment in children. In addition to binary measures of hand preference, we also use a continuous measure of relative hand skill. Outcomes at ages 7, 11 and 16 are studied. The data used is the British 1958 Birth. Using a partially linear semi-parametric regression estimator, it is shown that non-right-handedness (as hand preference) is associated with poorer social adjustment but this effect weakens as individuals age into their teens. The continuous measure of hand skill has a non-monotonic effect on social adjustment with poorer social adjustment in the tails of the continuum. The results are consistent with a growing body of evidence which shows that it is the consistency or degree of laterality (rather than direction) that is important for many outcomes.

The Clock'N Test as a Possible Measure of Emotions: Normative Data Collected on a Non-clinical Population

Objective: At present emotional experience and implicit emotion regulation (IER) abilities are mainly assessed though self-reports, which are subjected to several biases. The aim of the present studies was to validate the Clock’N test, a recently developed time estimation task employing emotional priming to assess implicitly emotional reactivity and IER.

Methods: In Study 1, the Clock’N test was administered to 150 healthy participants with different age, laterality and gender, in order to ascertain whether these factors affected the test results. In phase 1 participant were asked to judge the duration of seven sounds. In phase 2, before judging the duration of the same sounds, participants were presented with short arousing video-clip used as emotional priming stimuli. Time warp was calculated as the difference in time estimation between phase 2 and phase 1, and used to assess how emotions affected subjective time estimations. In study 2, a representative sample was selected to provide normative scores to be employed to assess emotional reactivity (Score 1) and IER (Score 2), and to calculate statistical cutoffs, based on the 10th and 90th score distribution percentiles.

Results: Converging with previous findings, the results of study 1 suggested that the Clock’N test can be employed to assess both emotional reactivity, as indexed by an initial time underestimation, and IER, as indexed by a progressive shift to time overestimation. No effects of gender, age and laterality were found.

Conclusions: These results suggest that the Clock’N test is adapted to assess emotional reactivity and IER. After collection of data on the test discriminant and convergent validity, this test may be employed to assess deficits in these abilities in different clinical populations.

Handedness and social anxiety: Using Bryden's research as a catalyst to explore the influence of familial sinistrality and degree of handedness

Phil Bryden's work has impacted on many areas of laterality, including degree and measurement of hand preference, as well as influences of familial sinistrality (FS). For example, Bryden[(1977). Measuring handedness with questionnaires. Neuropsychologia, 15, 617-624] is a well-cited and influential paper that remains relevant to this day. Inspired by this we extended our analysis of the relationship between handedness and anxiety in a number of ways. We used familial handedness and strength of handedness to examine their potential influences on anxiety, and extended our research by exploring their relationship to social anxiety, using the Social Phobia Inventory (SPIN). Inconsistent left-handers (ILH) were found to be more socially anxious. In all categories of SPIN except avoidance, ILH were significantly more anxious than consistent right- and left-handers. There were FS differences between ILH with a first degree left-handed relative (FS+) compared to ILH with no first degree left-handed relative (FS-) on all categories of anxiety scores. Within FS+ participants, ILH had significantly higher anxiety scores, compared with consistent handers across all categories. This suggests that ILH's social anxiety may be influenced by a close left-handed relative. Inspired by examining Bryden's work for this special issue, we will continue to add both strength of preference and familial handedness to our work.

Factor analysis of the Edinburgh Handedness Inventory: Inconsistent handedness yields a two-factor solution

While neuropsychology has long focused on direction (left versus right) of handedness, a growing body of evidence indicates that degree (inconsistent versus consistent) of handedness is at least as important. A promising feature of this new emphasis on degree of handedness is its greater concordance with extant genetic models of handedness, which posit a continuum from inconsistent-handedness to consistent right-handedness, not a continuum from left- to right-handedness. Specifically, departures away from consistent-right-handedness are thought to reflect the action of a neutral genetic factor that leaves handedness up to random environmental influences. To test whether handedness in inconsistent-handers reflects the presence of multiple factors (compared to the presence of a single factor only in consistent-right-handers), factor analyses of handedness inventory scores were conducted on data from 987 right-handers, divided into consistent- versus inconsistent-handers. Consistent with predictions, analyses of inconsistent- versus consistent-handers yielded two versus one factor solutions, respectively. Results are discussed in terms of their potential implications for genetic models of handedness and for researchers interested in consistency of handedness as a neuropsychological variable.