Human Infants' Preference for Left-to-Right Oriented Increasing Numerical Sequences

Abstract

While associations between number and space, in the form of a spatially oriented numerical representation, have been extensively reported in human adults, the origins of this phenomenon are still poorly understood. The commonly accepted view is that this number-space association is a product of human invention, with accounts proposing that culture, symbolic knowledge, and mathematics education are at the roots of this phenomenon. Here we show that preverbal infants aged 7 months, who lack symbolic knowledge and mathematics education, show a preference for increasing magnitude displayed in a left-to-right spatial orientation. Infants habituated to left-to-right oriented increasing or decreasing numerical sequences showed an overall higher looking time to new left-to-right oriented increasing numerical sequences at test (Experiment 1). This pattern did not hold when infants were presented with the same ordinal numerical information displayed from right to left (Experiment 2). The different pattern of results was congruent with the presence of a malleable, context-dependent baseline preference for increasing, left-to-right oriented, numerosities (Experiment 3). These findings are suggestive of an early predisposition in humans to link numerical order with a left-to-right spatial orientation, which precedes the acquisition of symbolic abilities, mathematics education, and the acquisition of reading and writing skills.

Development of spatial preferences for counting and picture naming

“…While this predisposition is consistent with neuroscientific theorizing such as A Theory Of Magnitude (ATOM: Bueti & Walsh, 2009;Dehaene & Brannon, 2011;Walsh, 2003), according to which common cortical substrate is allocated to the representation of magnitudes across domains, it merely supports non-directional associations between space and number (but see de Hevia et al, 2014). A second, culturespecific process builds on this predisposition of children to establish directional habits.…”

“…Moreover, the majority of children also counted objects left-to-right. More recently, de Hevia, Girelli, Addabbo, and Macchi Cassia (2014) applied the habituation paradigm to show that preverbal 7-monthold Italian infants already prefer a left-to-right increase of numerosity over a right-to-left increase. These and other recent studies raise the question about the origins of SNARC.…”

Operational momentum during ordering operations for size and number in 4-month-old infants

“…This evidence has been recently extended to preverbal infants, who, at 7 months, can extract and learn rule-like patterns (i.e., ABB or ABA) specified by items' order in spatio-temporal visual sequences presented along a left-to-right orientation, but not along a right-to-left orientation (Bulf, de Hevia, Gariboldi, & Macchi Cassia, 2017). This finding extends earlier demonstrations that 7-month-olds can extract and learn a numerical ordinal (increasing vs. decreasing) rule when sequences of numerical displays are presented from left to right, but not when presented from right to left (de Hevia, Girelli, Addabbo, & Macchi Cassia, 2014), and 8-month-olds relate an increase in number to an increase in spatial extent (de Hevia & Spelke, 2010). Together, these findings show that space is involved in order processing from the earliest stages of development, when infants lack symbolic knowledge and formal education, and that, at least from the age of 7 months, infants are prone to represent ordered information along a left-to-right spatial continuum.…”

Playing Reading, Using Hands: Which Activities are Linked to Number-Space Processing in Preschool Children?

“…Knowledge about the spatial organization of words and sentences within a text is not necessarily required to form culture-consistent associations, at least not in the case of counting direction. Some authors also postulate that number-space coding is at least partially hardwired and determined by biological factors (de Hevia et al, 2014;Rugani, Vallortigara, Priftis, & Regolin, 2015).…”