Pick a hand, any hand: mixed-handedness and night-sky watching in a college student sample.(Report)

This study explored the relationship between handedness and interest in night-sky watching. University students (N=128) completed the Edinburgh Handedness Inventory (Oldfield, 1971) and the Noctcaelador Inventory (Kelly, 2004). The findings indicated that mixed-handed participants scored highest on noctcaelador relative to those classified as either left or right-handed. The results and suggestions for future research are discussed.

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Broca's (1861) case-report indicating that damage to an area in the lower, left frontal lobe of the brain (Broca's Area) is associated with impaired speech production spurred scientists to further explore behaviors and mental processes associated with localized brain functioning. Continued research in this area led to findings that the cerebral cortex of the brain is split into two hemispheres, left and right (Sperry, 1968). Moreover, studies intimated that cortical functioning is generally asymmetrical; that is, one hemisphere is usually dominant in specific functions (of., Omstein, 1997).

One of the largest literatures related to hemisphericity (the lateralization of brain cortical functioning) is the research on handedness, the hand that humans prefer to use across various tasks (Annett, 1985). Handedness has been reported as an adequate indicator of hemispheric dominance (Coulson & Lovett, 2004; Knecht et al., 2000). The stronger an individual's left-hemispheric dominance, the more right-handed the individual; the more right hemisphere dominant, the more left-handed an individual.

Findings from handedness research indicated that left-handed individuals (relative to right-handed individuals) had more divergent thought processes (Coren, 1995) and were more emotionally expressive (Jackson, 2005). Hemisphere functioning has also been related to affective style. For example, left-handers have been found to be more vulnerable to experiencing negative affective reactions, such as stress. Right-handers, conversely, were more likely to experience positive affective states (Tomarken, Davidson, & Henriques, 1990; Wheeler, Davidson, & Tomarken, 1993).

Although most handedness research has investigated left versus right-handedness, some studies have found that mixed-handedness, defined as being comfortable using either the left or right hand depending upon the task, also reflects important individual differences. Mixed-handedness likely would be an indicator of mixed-hemisphericity, what Crow, Crow, Done, and Leask (1998) called the point of "hemispheric indecision." Essentially, at this point hemispheric dominance is not asymmetrical, but rather the right and left hemispheres both provide strong input into experiences and judgments. In other words, the more fantasy-prone, creative, and negative emotional right-hemisphere and the logical, linear-thinking left-hemisphere functionally "mix" together to influence the individual's experiences and thinking (Leonhard & Brugger, 1998).

The effects of this "mixed" hemisphericity can manifest in several ways. For example, studies have found that mixed-handedness was higher among individuals diagnosed with schizophrenia (Dragovic, Hammond, Badcock, & Jablensky, 2005) and with schizotypal traits, such as magical ideation (Barnett & Corballis, 2002). Perhaps related to the unconventional thinking-style involved with schizotypy, mixed-handedness has also been associated with creativity (Weinstein & Graves, 2001).