Different laterality indexes are poorly correlated with one another but consistently show the tendency of males and females to be more left- and right- lateralised, respectively

Abstract

Handedness is assessed primarily as a binary trait on the basis of the preferred hand for writing. At population level, about 90% people prefer using the right. Handedness can also be assessed as a continuous trait with laterality indexes, but these are not time and cost effective, and are not routinely collected. Here, we assessed the relationship of writing hand preference with four laterality indexes derived from measures of dexterity (pegboard task, marking squares and sorting matches) and strength (grip strength) available in a range of N = 6664-8069 children from the ALSPAC cohort.Although all indexes identified a higher proportion of individuals performing better with their right hand, they showed low correlation with each other (0.08-0.3). Analysis of sex effects on the laterality indexes showed that males and females tend to be, on all measures, more right-and the leftlateralised, respectively. Males also had a higher tendency to be poorly lateralised. This study shows that different handedness measures tap into different dimensions of laterality and cannot be used interchangeably. The similar trends for males and females observed across indexes suggest that sex effects should be taken into account in handedness and laterality studies.

Prevalence and heritability of handedness in a Hong Kong Chinese twin and singleton sample

“…This is consistent with the overall correlation of .40~.50, indicating that the two measures do not map exactly on to each other. These results also concur with the aforementioned recent study conducted on UK children showing poor correlations across different handedness measures [53]. Our bivariate genetic modelling analysis further revealed that a model with one latent genetic factor did not fit the data.…”

“…Our results also found a discrepancy between boys and girls in the singleton sample on their pegboard performance scores, continuous or categorical. Though our sample is too small for the detection of significant sex effect, the pattern is consistent with a recent study in UK which found females tend to be more right lateralized and males are more left lateralized for PegQ [53].…”

“…Our results show that these two tasks have the lowest item-total correlation among all items on the inventory. Furthermore, we used only one laterality index (the PegQ), and it should be noted that handedness performance is not a one-dimensional trait, but rather a multi-dimensional one that includes different aspects such as dexterity, skill, and strength [53]. There has been evidence that using a single hand performance does not always correctly classify an individual who has a left-or right-handed preference, and a combination of different measures might be more effective [62].…”

Human handedness: A meta-analysis.

“…Nevertheless, preference is correlated with measures of relative hand skill with an estimated correlation of magnitude of .62 to .73 (Todor & Doane, 1977) or more recent estimates of .50 to .57 (Triggs et al, 2000), while Corey, Hurley, and Foundas (2001) found that in more than 90% of cases preference-based groups corresponded to groups based on relative hand skill. A recent study also showed that the correlation between hand preference and relative hand skill highly depends on which test is used to assess relative hand skill (Buenaventura Castillo, Lynch, & Paracchini, 2019, preprint). The authors assessed the relationship of hand preference with measures of relative hand skill (pegboard task, marking squares, and sorting matches) and relative hand strength (grip strength).…”

A deep phenotyping approach to assess the association of handedness, early life factors and mental health

“…Ideally, to come to a preferably differentiated picture of an individual’s lateralization, studies may combine different measures of self-reported hand preference and measures of hand skill as well as measures of other forms of functional asymmetries (e.g., language lateralization). This notion may be especially relevant considering that different performance measures of handedness (the Pegboard task amongst them) have been revealed to show only small correlations among each other and may reflect distinct dimensions of asymmetries 47 . Undoubtedly, a comprehensive assessment of functional asymmetries—which we refer to as deep phenotyping—may not be applicable for larger-scale studies.…”