<|endoftext|> of variability which emerged in this survey is related to the relative order of finger counting within a single hand. In particular, while Western populations reported to start counting on the thumb and to continue sequentially until the pinkie, Middle-Eastern individuals usually counted following the opposite order (i.e., from the pinkie to the thumb; Lindemann et al., 2011). Currently, the causal link between the relative direction in counting fingers within a hand (i.e., starting from the thumb or from the pinkie) and the starting-hand preference (i.e., starting from the left or right-hand) remains to be clarified due to the still limited evidence emerging from counting practice in Middle-Eastern populations. If the conventional scanning habit is a determinant of finger counting direction, intra-cultural differences should be minimal or absent. In contrast, this practice is not homogeneous even within the same Western sample, since the left-hand starting preference is marked in Anglo-Saxon countries (i.e., UK, USA, and Canada), but not in Belgians and Italians. This evidence partially confirms the role of cultural effects but minimizes the influence of the writing system direction in predicting starting preference.
For example, a large-scale questionnaire used to investigate finger counting patterns in a Scottish sample reported a preference (66%) to start counting on the left-hand (Fischer, 2008). On the contrary, a direct test of hand preference in Italian (Di Luca et al., 2006; Sato et al., 2007) and French (Sato and Lalain, 2008) populations revealed that most individuals preferred to start counting on their right-hand (82% overall, 100 and 69% respectively). These contradictory results may well be attributed to the different methods adopted to assess finger counting, that is via written questionnaire or via direct observation. Aware of this difference, Lindemann et al. (2011) ran a control experiment comparing the two modalities within a group of participants on the basis of which they denied a modulation effect of the response mode. However, they considered only a homogeneous subgroup of individuals (English speakers of unknown handedness) different from those tested by enacting the finger count (Di Luca et al., 2006; Sato et al., 2007; Sato and Lalain, 2008). Yet, since the focus of our attention is a motor routine, a spontaneous and overlearned practice, the possible gap between enacting and reporting is expected to be significant. While the former procedural task involved an obvious implicit component, the latter requires explicit access to finger counting representations. For these reasons, we believe that task specific effects on finger counting deserve further attention in future research.
In conclusion, all data collected thus far clearly indicate that finger counting habits may vary substantially both within and between cultures, suggesting that reading–writing system direction is not the only factor that modulates the starting-hand preference during finger counting execution. Individual differences within the same population could be explained by taking handedness into consideration, since handedness indeed shapes many other motor activities.
Is Left- and Right- Starting a Dominance Matter?
In principle, at least in Western cultures whose counting system involves two hands, finger counting practice is expected to be shaped, as any other bimanual action, by the lateral asymmetry determining hand dominance. For this reason, most studies adopt right-handedness as a recruiting criterion (Di Luca et al., 2006; Sato et al., 2007; Brozzoli et al., 2008) preventing any conclusive remarks on the role of hand dominance in finger counting direction. Indeed, when right-handed participants were recruited they showed a preference to start counting with their right-hand (Di Luca et al., 2006; Sato et al., 2007). Although a cultural effect might not be excluded (i.e., in both studies participants were Italians), homogeneous right-handedness may well be a confounding factor. Moreover, regardless of handedness, assessment of finger counting direction has thus far not been systematic even in studies focused on embodied numerosities (Domahs et al., 2010).
The first study to directly investigate the link between handedness and direction of finger counting in adulthood did not find any association between the two (Fischer, 2008); the proportion of the left- and right-hand starters (i.e., participants who started to count with the left- and the right-hand respectively) was the same among left- (70 and 30% respectively) and right- handed (66 and 34% respectively) Scottish individuals. This pattern would suggest that finger counting direction is unrelated to hand preference (p > 0.05), although in this case the testing modality, i.e., written questionnaire, might have favored a left-to-right mapping, consistent with the Scottish reading habit direction.
In contrast, a more pronounced left-starting preference among left-handers has also been observed (Sato and Lalain, 2008; Previtali and G