A left visual advantage for quantity processing in neonates

Abstract

Forty-eight newborn infants were tested in one of three multimodal stimulus conditions, in which auditory quantities were presented alongside visual object arrays in two test trials. These tests varied with respect to which side (either left or right) numerically matched the auditory number. The infants looked longer to the test trials in which the left side of the visual display exhibited a quantity that matched the presented auditory quantity. This study provides the first evidence for an untrained, innate bias for humans to preferentially process quantity information presented in the left field of vision.

How the Human Mind Grounds Numerical Quantities on Space

“…Nevertheless, in Western adults, the left‐to‐right directionality emerged in spontaneous circumstances and was hard to reverse completely (e.g., Pitt & Casasanto, 2020). Also, adults with opposite reading and writing directions showed the same association of more, and addition, with the right, and less, and subtraction, with the left side of space (e.g., Masson, Andres, Alsamour, Bollen, & Pesenti, 2020), underscoring the key role of biological factors and early biases at birth (McCrink, Veggiotti, & de Hevia, 2020).…”

“…When the focus is not on the individuals but on the set as a whole, one could select the larger set and link it to the right hemifield. This is a purely speculative idea that needs to be fully explored in research, particularly whether functional specialization for visuospatial processing is lateralized to the right hemisphere at birth (McCrink et al, 2020). For now, the available evidence of an advantage in processing and modulation of spatial attention toward the left when processing a small number and to the right when processing a large number is congruent with the idea that these might constitute only side effects with no specific function.…”

Abstract representations of small sets in newborns

“…abilities found success only with large sets, and only when the set numerosities differed by a 1:3 ratio (Coubart et al, 2014;de Hevia et al, 2014;Izard et al, 2009;McCrink et al, 2020). Other studies found that newborns are sensitive to repetitions (Gervain et al, 2008) or that they can discriminate between sets of numerosity 2 vs. 3 (Antell & Keating, 1983;Bijeljac-Babic et al, 1993;Turati et al, 2013), but these abilities were only tested within the auditory or visual modalities.…”

“…Hence, since the pioneer studies of the 1980s, we know that newborns react specifically when the sounds they hear and the images they see are temporally synchronous or emanate from the same place ( Butterworth, 1983 ; Filippetti, Johnson, Lloyd-Fox, Dragovic, & Farroni, 2013 ; Lewkowicz, Leo, & Simion, 2010 ; Morrongiello, Fenwick, & Chance, 1998 ; Slater, Brown, & Badenoch, 1997 ; Slater, Quinn, Brown, & Hayes, 1999 ), an indication that they perhaps project visual and auditory information onto an amodal sense of time and space. While this evidence is only suggestive (and may simply reflect the existence of special detectors for temporal and spatial synchrony), several studies have now unambiguously demonstrated that newborns can recognize some amodal properties across senses: for example, direction of movement ( Orioli, Bremner, & Farroni, 2018 ), shape ( Sann & Streri, 2007 ; Streri & Gentaz, 2004 ), texture ( Kaye & Bower, 1994 ; Sann & Streri, 2007 ), or approximate numerosity ( Coubart, Izard, Spelke, Marie, & Streri, 2014 ; Izard, Sann, Spelke, & Streri, 2009 ; McCrink, Veggiotti, & de Hevia, 2020 ). In other experiments, newborns were even found to react to correspondences between dimensions of different nature, thus accessing even more abstract invariants.…”

“…As part of a larger project looking for amodal representations in newborns ( Bonn, Netskou, Streri, & de Hevia, 2019 ; Coubart et al, 2014 ; de Hevia et al, 2014 ; de Hevia et al, 2017 ; Izard et al, 2009 ; Streri et al, 2013 ), here we tested whether they possess abstract representations that apply to small sets. Indeed, in all the studies that demonstrated abstraction of magnitudes in newborns ( Coubart et al, 2014 ; de Hevia et al, 2014 ; de Hevia et al, 2017 ; Di Giorgio et al, 2019 ; Izard et al, 2009 ; McCrink et al, 2020 ), participants were exclusively presented with large sets. Older infants however use two different systems to process the numerosity of small and large sets, at least from the age of 5 months.…”