Finger Counting Habits in Middle-Eastern and Western Individuals: An Online Survey

146 words; Main text: 4,724 words Finger Counting Habits 3 Our ability to precisely quantify arbitrarily large sets of objects is a key cultural achievement. At the root of this ability may be an evolutionarily inherited “number sense” that allows us to tell rapidly and effortlessly the precise numerosity of small sets. But this basic sense of quantity is assisted by acquired counting skills as we deal with larger sets (for discussion see the review by Göbel, Shaki, & Fischer, this issue). Counting involves the repetitive establishing of a one-to-one correspondence between an ordered series of count words and the available objects. Once all objects have been counted the last count word gives the cardinality of the set. Counting is a cultural technique that is acquired in the first four years of life by most children, and it universally relies on the use of body parts, most often the fingers. Finger counting has been documented in almost all cultures present and past, making the hand the “earliest calculating machine” (Ifrah, 1981, chapter 3; Pika, Nicolandis, & Marentette, 2009). The use of fingers is also the origin of the base 10 of our number system, and the term “digit” for numerals was already introduced from the Latin into English in the 14th century (Richardson, 1916, p. 7). Anthropological studies show that, in several languages, the word “five” has common ancestors with the words “fist” or “hand” (Menninger, 1969). All counting techniques must solve the fundamental problem of where to start – i.e. which finger is assigned to the first number? As we will show below, this problem has recently become a matter of renewed interest for numerical cognition researchers. Finger Counting Habits 4 The Romans, whose hand shapes during finger counting provided the inspiration for their number symbols (Cushing, 1892), were familiar with counting from 1 to 99 on the left hand alone (Bechtel, 1909). Consistent with this historical information, Bede’s influential medieval finger counting guide prescribed use of the left hand to depict numbers up to 100, but older sources such as Greek poems frequently reported the use of the right hand (e.g., Richardson, 1916). Could this inconsistency be due to different hand preferences of those individuals whose behaviors were reported? In agreement with this speculation, Cushing (1892, p. 292) postulated that, due to “...the universality of right handedness and of the tendency to number with the fingers, [...] the right hand has ever been the counter, the fingers of the left hand the ones counted”. This proposal was reiterated by Dantzig (1930/1954), who further argued that “... primitive man rarely goes about unarmed. If he wants to count he tucks his weapon under his arm, the left arm as a rule, and counts on his left hands, using his right hand as a check-off.” (1954, p. 13). However, Dantzig dropped the further claim of Cushing that this style of counting would involve facing the palm, thus making the little finger the most convenient starting point. The little finger may also become a starting point due to its small size, thus conveniently marking the smallest numerosity (what may be called the “smallest finger heuristic”). Conant (1896/1960, p. 437f.) stated that almost all of 206 investigated children (aged 4–8 years) from public schools in Worcester/Massachusetts began to count with their left hand, and that this left-preference remained in an older cohort. He also reported that the starting finger was initially arbitrary but then a preference for a palm-down posture and starting with the little finger (known as “pinkie”) emerged. Conant (1896/1960) argued that this developmental change possibly reflects a combination of the smallest finger heuristic and the acquisition of reading Finger Counting Habits 5 habits, because in a palm down posture the little finger of the left hand is on the left side, which corresponds to the starting position of reading in Western languages. Summarizing this brief review, there seems to be a clear trend towards starting to count on the left side. In addition to hand preference, the tendency to map small numbers with the left side of space could also reflect the influence of the writing system, which is from left to right in the predominantly Western populations that have been investigated by numerical cognition researchers so far (for further discussion see Gıbel et al., this issue). Little information seems to exist about finger counting preferences in contemporary cultures that use right to left writing systems, and hardly any data seem to address the issue of whether the left start preference reverses in left-handers, although this prediction was made by several scholars. Recently, these issues have been systematically re-addressed in the study of numerical cognition. Specifically, the claim has been investigated that our cognitive representation of numerical magnitude information has a spatial component (the SNARC effect; Dehaene, Bossini & Giraux, 1993; for a recent review see Wood & Fischer, 2008). The SNARC effect is one of several empirical observations that have led numerical cognition researchers to postulate a “mental number line”, i.e., a cognitive representation of numerical magnitude information in the form of a linear arrangement with small numbers to the left of larger numbers. While it was originally proposed that reading habits were the cause for the left-to-right arrangements of numbers along the mental number line, more recent work suggested that such habits were not as powerful as previously thought, and that this spatial bias is already present in Western children before reading acquisition (Opfer & Furlong, this issue; Gıbel et al., this issue). As an alternative proposal to explain the left bias for small numbers, an influence of finger counting habits on the SNARC effect was reported by Fischer (2008). The author Finger Counting Habits 6 measured start preferences for finger counting, as well as general hand preference in 445 Scottish adults. It emerged that 66% of respondents preferred to start counting on the left hand (so-called “left-starters”). This outcome supported the hypothesis that the association between small numbers and left space could well be a result of habitual finger counting. Importantly, the percentage of left-starters was similar for left-handed and for right-handed participants, thus suggesting that hand preference does not affect the starting hand in finger counting. Another result of this questionnaire study was that the thumb was most often assigned to the number 1. A follow-up experiment investigated whether finger counting habits modulated the spatial mapping of numbers. Although the SNARC effect was not reversed for rightcompared to left-starters, left-starters as a group had a stronger and more consistent spatial-numerical mapping (Fischer, 2008, Experiment 2). The notion that finger representations are crucially involved in the acquisition of number processing strategies received support from research indicating that children’s finger gnosis is a good predictor of their later numerical skills (Noel, 2005). Additional evidence for a coupling between hand motor circuits and representations of numerical magnitude has been provided by behavioral and neuroimaging studies with adults (e.g., Lindemann, Abolafia, Girardi, & Bekkering, 2007; Andres, Seron, & Olivier, 2007; Fischer & Campens, 2008). Taken together, these results suggest that finger counting habits affect numerical cognition throughout life. The present study followed up on this recent work by comparing finger counting preferences in different countries. Although we did not systematically dissociate national, cultural, and language-related influences on finger counting, we compared counting patterns between respondents who are familiar with a left-to right orthography and respondents who are familiar with a right-to-left orthography. Cross-cultural comparisons suggest that the direction of Finger Counting Habits 7 writing affects several aspects of cognitive processing (Vaid & Singh, 1989; Chokron & Imbert, 1993). It might therefore be speculated that generalized scanning habits also have an impact on the development of finger counting strategies. However, research into the acquisition of spatial aspects of counting is still very limited (e.g., Opfer & Furlong, this issue). First empirical evidence supporting the notion of culturally mediated developmental changes comes from a recent study of Shaki, Göbel and Fischer (2010) demonstrating that Israeli children initially start counting on their left side but when they learn to read and write Hebrew they prefer starting on their right side. To document the role of cultural effects in adults’ finger counting, we performed an online survey and compared finger counting habits in Western and Middle-Eastern cultures. All languages common in the Middle East except Hebrew have an Arabic alphabet and use Eastern Arabic digits. Importantly, the directionality of writing is opposite to that from Western languages [Footnote 1]. One of the most spoken Middle Eastern languages is Persian or Farsi, the official language of Iran. We asked Iranian as well as European and American participants of an internet-based questionnaire study in Persian or English language how they map the numbers 1 to 10 onto the fingers of their hands [Footnote 2].