Embodied numerosity: Implicit hand-based representations influence symbolic number processing across cultures

The role of vision in the development of finger–number interactions: Finger-counting and finger-montring in blind children

“…As suggested by previous research (Raz, Striem, Pundak, Orlov, & Zohary, 2007;Röder, Rösler, & Neville, 2001;Siegel & Ryan, 1989;Stankov & Spilsbury, 1978) and by their better span scores at the pseudo-word repetition task (see ''Working memory'' section above), it is possible that blind children rely much more on their auditory working memory than sighted children to manipulate numbers (see Cornoldi, Tinti, Mammarella, Re, & Varotto, 2009, for similar results with adults in a mental imagery task). In the same way as traces of the finger-counting behavior have been found in sighted adults' numerical cognition (Andres et al, 2007;Badets et al, 2010;Di Luca et al, 2006;Domahs et al, 2010), traces of the working memory use have been found in blind adults' numerical cognition. Indeed, although the behavioral data of a recent electroencephalogram (EEG) study demonstrated that blind and sighted adults represent numbers through a similar spatial code, different neurophysiological correlates have been found to underlie number manipulation in the two groups (Sallilas, Granà, El-Yagoubi, & Semenza, 2009).…”

“…Conversely, according to the redeployment hypothesis, individuals who do not have finger agnosia but who did not use the finger-counting and finger-montring strategies during infancy should nevertheless show traces of a numerical finger-based representation while performing numerical tasks during adulthood. So, although blind adults did not use their fingers to process numbers during infancy, they should show (a) activation of the left angular gyrus while performing arithmetic tasks (e.g., Pesenti et al, 2000), (b) greater reaction times while comparing a pair of digits that contains at least one number larger than 5 (Domahs et al, 2010), and (c) increased corticospinal activity of hand muscles while performing a parity judgment task (e.g., Sato et al, 2007). Therefore, we argue that further investigation of numerical processing in blind adults may help to disentangle the functionalist and redeployment hypotheses, which might not be two mutually exclusive theories.…”

“…First, traces of the base-5 finger-counting system (i.e., numbers larger than 5 always include a full hand representation) were witnessed by a disproportionate number of split five errors (i.e., errors deviating by the correct result by exactly ±5) while children performed complex mental calculation (Domahs, Krinzinger, & Willmes, 2008) and by larger reaction times when adults compare a pair of digits containing at least one number larger than 5 (Domahs, Moeller, Huber, Willmes, & Nuerk, 2010). Second, increased corticospinal activity of hand muscles was found when adults were required to put items in correspondence with elements of an ordered series (Andres, Seron, & Olivier, 2007;see Sato, Cattaneo, Rizzolatti, & Gallese, 2007, for similar results in a parity judgment task).…”

The Organization of Spatial Reference Frames Involved in the Snarc Effect

“…For example, the SNARC effect can be influenced by counting habits (Fischer, 2008), or canonical hand representation of numbers between cultures (Domahs, Moeller, Huber, Willmes, & Nuerk, 2010). Moreover, a recent study showed that a fingerbased reference frame could interact with the SNARC effect.…”

Number-space associations in synaesthesia are not influenced by finger-counting habits

“…the Babylonian counting system; Bender & Beller, 2012), or some numbers may be represented symbolically (e.g. the Chinese counting system; Domahs, Moeller, Huber, Willmes, & Nuerk, 2010). In the most widely studied variant of finger-counting, each finger represents one number, meaning that the total quantity that can be counted on the fingers is ten.…”