Abstract
Animals turn away from the hemisphere with the more active dopamine (DA) system. For humans, a similar relationship has been assumed, albeit that side preferences obtained from different measures are inconsistent. Given the important role of DA on human behaviour and cognition, a stable human turning measure is of significant experimental value. We assessed the stability (test and retest 4 weeks apart) of veering behaviour (lateral deviations during blindfolded straight ahead walking) in 20 healthy right-handers, 20 mixed-handers, and 20 left-handers. Veering behaviour did not differ between groups, and did not reveal any particular side preference in any group. Relationships of side preferences between testing sessions for the different handedness groups was low for right-handers, and showed some minor consistency for the mixed-handed group. Neither handedness nor footedness was significantly related to preferred veering side. These findings, if not related meaningfully to DA-mediated conditions (e.g., clinical populations, pharmacological studies, personality) in the future, suggests that veering behaviour is an inappropriate alternative to the animal turning model. These findings challenge the reliability of human turning measures, and invite more broadly for a critical evaluation of turning measures as an indicator of hemispheric DA asymmetries in human populations.
Acknowledgments
This research was supported by the British Academy (#SG-39550). We are grateful to Dr Angela Rowe (Bristol) for her editorial assistance.
Notes
1Mead and Hampson (1996, 1997) reported sex-mediated differences in turning behaviour (see also Bracha et al., 1987a, but see Mohr & Bracha, 2004; Mohr et al., 2003c). When including sex as an additional between-subject measure in the present ANOVA, we did not observe any sex-related significant findings (all F values <1.29, all p values >.28). Since population sizes became small when adding sex as an additional variable, and we did not assess for contraceptive use (Mead & Hampson, 1996) or menstrual cycle (Mead & Hampson, 1997), sex will not be considered further.