Intuitions for Multiplication in Amazonian Adults and in U.S. Adults and Children

International audienceSuccess at non-symbolic addition and subtraction has been documentedwith diverse populations: preschool children, occidental adults (in conditionspreventing counting), and also an indigene group from the Amazon, theMundurucu, who speak a language with a restricted number lexicon (Barth et al.,2005; Pica et al., 2004). In all these populations, performance shows acharacteristic ratio effect: the sums and differences that participants estimate areapproximate, and the range of uncertainty increases for larger numbers.Studies of brain-damaged patients (Lemer et al, 2003), brain imaging (Dehaene etal., 2003), or task interference (Lee & Kang, 2002) suggest that multiplicationand division, on the contrary, may be mediated by language and rotelearnedtables. Nevertheless, the existence of a universal capacity fornonsymbolic multiplication has not been investigated directly.Here, we investigated whether multiplication is part of humans’ universalknowledge about numbers. We presented computer animations illustrating nonsymbolicmultiplication problems to three different populations: US adults,Amazonian Adults, and US children at two ages, before and during the first years oflearning multiplication (respectively Preschool-1st grade, and 3rd-5th grade)