Newborn infants perceive abstract numbers

Abstract

Although infants and animals respond to the approximate number of elements in visual, auditory, and tactile arrays, only human children and adults have been shown to possess abstract numerical representations that apply to entities of all kinds (e.g., 7 samurai, seas, or sins). Do abstract numerical concepts depend on language or culture, or do they form a part of humans' innate, core knowledge? Here we show that newborn infants spontaneously associate stationary, visual-spatial arrays of 4 -18 objects with auditory sequences of events on the basis of number. Their performance provides evidence for abstract numerical representations at the start of postnatal experience.development ͉ numerical cognition ͉ cognitive A re humans endowed with abstract representations of the surrounding world? In the domain of number, animals and preverbal infants have been shown to react to the cardinal values of sets presented in a variety of different stimulus formats, and this core number sense is thought to guide learning of numeric symbols and arithmetic in human children and adults (1-5). For example, by the age of 4.5 to 6 months, infants are able to discriminate between numbers differing in a 1:2 ratio (e.g., 16 vs. 32, 8 vs. 16, 4 vs. 8), when presented with arrays of dots (6, 7), sequences of sounds (8), or sequences of actions (9). In each of these experiments, however, infants were tested with only 1 type of stimulus, raising the question of the level of abstraction of these numeric representations.From the early 1980s to present, several investigations have tested for numeric cross-modal matching in infants with mixed results. Although infants initially were reported to look longer at a set of objects that matched a sequence of sounds played simultaneously (10, 11), subsequent experiments yielded either no such preference (12) or a reversed preference (13). Failures to match sounds and objects on the basis of number have been documented until 3-4 years of age, eventually resolving as children start to master verbal counting (14). By using more natural stimuli, later research showed unequivocally that infants and animals could detect the numerical correspondence between 2 or 3 items in different modalities (15)(16)(17)(18). In all of these studies, however, matching was elicited either by drawing on cross-modal correspondences that were familiar [faces and voices (15, 16) or objects with similar features presented across the visual and tactile modalities (18)], or by presenting a familiarization phase in which events in different modalities occurred in synchrony (17). In these situations, cross-modal matching might be achieved by calling on amodal representations of objects rather than amodal representations of abstract, cardinal values. For example, presentation of a voice may elicit an image of a face; when 3 distinct voices are played, therefore, infants may represent 3 correspondingly distinct faces that then can be quantified and compared to a matching or nonmatching visual stimulus. Indeed, the numbers tested in t...

Numerosity representation is encoded in human subcortex

“…As development proceeds, however, the system becomes more finely tuned to smaller differences in quantities. Consistent with this, infants as young as 48 h are able to differentiate ratios of 3:1 but not 2:1 (20), and, as they age, children show increasingly precise abilities: at 6 mo, they can distinguish ratios of 2:1, and by 9 mo, ratios of 3:2 (21,22). They eventually reach competencies for ratios 4:3 by 3 y, 6:5 by 6 y, and 8:7 and more difficult ratios by adulthood (23)(24)(25)(26).…”

“…Specifically, we expect the subcortical mechanism to respond selectively to nonsymbolic quantities (here, dot arrays) given that symbolic manipulation of quantities is uniquely human and likely requires cortical contributions. Moreover, we predict that subcortical contributions to number processing will be ratio dependent as young children evince numerical abilities that are themselves ratio dependent (20)(21)(22).…”

Evidence of the impact of visuo-spatial processing on magnitude representation in 22q11.2 microdeletion syndrome

“…The ANS is believed to be shared by many species and would allow the discrimination, the comparison, the addition, and the subtraction of numerosities presented in and across different formats and modalities (i.e. comparing the number of objects seen or touched, the number of tones or voices, the number of perceived events; Féron, Gentaz, & Streri, 2006;Izard, Sann, Spelke, & Streri, 2009;Kobayashi, Hiraki, & Hasegawa, 2005). The resulting approximate number representation is therefore considered to be independent of the modality (Barth, Kanwisher, & Spelke, 2003;Barth et al, 2006;Meck & Church, 1983).…”

Nonsymbolic number and cumulative area representations contribute shared and unique variance to symbolic math competence

“…Also known as the approximate number system (ANS), this nonsymbolic sense of numerical magnitude is shared with nonhuman animals (6) and is widespread across cultures (7). Unlike the acquisition of symbolic number (e.g., Arabic digits) and formal math concepts, which are learned via explicit instruction and allow for exact quantification, the ANS may be innate (8) and is characteristically "noisy," with variance increasing linearly as a function of the absolute numerical value (9). This imprecision can be modeled as overlapping Gaussian distributions along an internal continuum (10) and is captured by Weber's law, which holds that subjective differences in intensity are proportional to the objective ratios between values.…”