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

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.

Senatorial signatures Absence of male-female differences in left-handedness

A greater frequency of left-handedness among males than females has been observed in general populations. Past studies have explained this difference with reference to males' greater susceptibility to adverse birth events, while more recent studies have identified other contributing factors. On January 16, 2020, U.S. senators signed an oath to act impartially during the president's impeachment trial. This televised event allowed direct comparison of the proportion of right-handedness and left-handedness in a professionally accomplished sample of males and females. As expected, no sex difference in the proportion of left-handed senators was found, although the small sample size offered low statistical power. Replicating this finding with a larger sample would support the view that left-handedness among select groups of males is linked to genetic factors.