Consistency of hand use and sleep problems.

In this study, we measured the relationship between the consistency of hand use and three symptoms of insomnia, i.e., delayed sleep onset, frequent awakenings during sleep, and trouble returning to sleep after an awakening. For each of these insomnia-related symptoms, university students who were classified as inconsistent in the use of their hands (n = 30) were significantly more likely to report problems than their consistent hand-use peers (n = 30). These data were discussed both in relation to the literature on handedness classification and sleep problems and the emerging literature on consistency of hand use and health-related problems.

Consistency of hand use and frequent falls.

We examined relationships between consistency of hand use and falling in groups of right-handed university undergraduates who were either consistent (n = 45) or inconsistent (n = 32) in the use of their hands. A scoring procedure developed for the Briggs-Nebes Handedness Scale permitted us to classify individuals as consistent or inconsistent in the use of their hands. The inconsistent group was 2.81 times more likely to have experienced frequent falls during the last 12-mo. period and was 1.64 times more likely to rate themselves higher on proneness to falling. These data suggest that inconsistent hand use may be a sign of a developmental inconsistency in motor coordination.

Consistency of hand use, exercise, and sports-related injuries.

In this study, we examined the relationships between the consistency of hand use, exercise, and sports-related injuries as an indirect test of the hypothesis that the consistency of hand use is a reflection of general motor coordination. As we predicted, the consistent hand-use group (n = 23) exercised more, were more likely to follow a regular exercise schedule, and reported having experienced more sports-related accidents than their inconsistent hand-use peers (n = 23).

Consistency of hand use and accidents with injury.

In this study, we examined the relationship between the consistency of hand use and the self-reported incidence of accidents with injuries which required medical care in groups of university students (n = 23 for each group). To do this, we adopted a scoring procedure for the Briggs-Nebes Handedness Scale that permitted us to classify individuals as consistent or inconsistent in the use of their hands. We observed that the inconsistent group was 6.12 times more likely to have experienced accidents with injury that required medical care than the consistent group. These data have implications for the literature on handedness classification and accidents. Collectively, these limited data underscore the need to pay attention to the consistency of hand use in research on handedness, health, and longevity.

Do right-handers live longer? An updated assessment of baseball player data.

In support of the argument that left-handedness is a marker for decreased survival fitness, in 1991 Coren and Halpern gave considerable weight to the results of their 1988 study in which right-handed baseball players were described as having lived about eight months longer than their left-handed peers. In their 1993 unsuccessful attempt to replicate this study, Fudin and colleagues cited certain difficulties with the sources of these data that led them to recommend a comprehensive third study which included only reliable data from the two current editions of the major sources of information on Major League baseball players, i.e., the 1993 editions of The Baseball Encyclopedia and Total Baseball. Following this suggestion, we measured the life spans of all baseball players, i.e., right-, left-, and mixed-handed players, for whom reliable data were available (N = 5441) and found that the relationship between handedness and longevity was not significant. Unlike Halpern and Coren we noted that right-handed players could be described as having lived about eight months less than their left-handed peers.