Parallels in Stimulus-Driven Oscillatory Brain Responses to Numerosity Changes in Adults and Seven-Month-Old Infants

Abstract

Previous studies provide indirect evidence for an ontogenetically continuous Approximate-Number System. We employed a rapid steady-state visual-presentation paradigm combined with electroencephalography to measure stimulus-driven neural oscillatory responses to numerosities in infants and adults. Steady-state repetition of the same numerosity across a 2.4-sec time block yielded an increase in the stimulus-locked neural entrainment in both groups. Entrainment changes following a numerosity switch varied by the ratio of the numerosities, consistent with Weber’s Law. These similarities thus provide direct evidence for an ontogenetically continuous Approximate-Number System. Moreover, the degree of neural entrainment significantly predicted infants’ number discrimination measured behaviorally two months later.

Numerical approximation abilities correlate with and predict informal but not formal mathematics abilities

“…Therefore, we used average accuracy (percent correct) across all trials as a measure of children’s ANS precision at each time point. We used accuracy instead of Weber fraction because estimates of individual Weber fractions, especially at the youngest ages, are quite volatile and noisy (Libertus, Feigenson, et al, 2011). Data from two children at Time 3 and two other children at Time 4 were excluded because their average accuracies were more than three standard deviations below the group average.…”

“…Eighty-five children (39 females, average age at Time 1 = 4.15 years, SD = 0.66) who were recruited as part of a larger, longitudinal study on children’s mathematics and language development contributed data to this study (see Libertus, Feigenson, et al, 2011; Libertus et al, 2013, for results from other aspects of the study). Data from eight of these children were not included in the analyses of performance from Time 1 due to inability to complete the task (n = 3), external interference (n = 2), language problems (n = 1), or absence from the preschool at the assigned day of testing (n = 2).…”

“…To measure the precision of children’s Approximate Number System (ANS) for visual arrays at each time point, we administered a version of Panamath (the Psychophysical Assessment of Number-sense Acuity; Halberda & Ly, in preparation) – a non-symbolic numerical comparison task (Halberda et al, 2008; Libertus, Feigenson, et al, 2011). Children were told that the cartoon character Grover had a box of blue balls and the character Big Bird had a box of yellow balls, and then were shown arrays of spatially separated blue and yellow dots on a 13-inch laptop screen.…”

“…Even so, there are large differences in ANS precision between individuals of similar age. These individual differences are already present and stable in infancy (Libertus & Brannon, 2010; Libertus, Brannon, & Woldorff, 2011) and can be found across the entire lifespan (Halberda et al, 2012). …”

“…Importantly, this relationship remained robust even when controlling for other cognitive abilities such as general intelligence, visuo-spatial skills, and working memory, thereby suggesting a fairly specific relationship between the ANS and mathematics ability. Furthermore, recent studies showed that ANS precision and mathematics performance are already linked in preschool-aged children, before the onset of rigorous mathematics instruction (Libertus, Feigenson, & Halberda, 2011), and that ANS precision measured in preschool predicts later mathematics performance (Libertus, Feigenson, & Halberda, 2013; Mazzocco, Feigenson, & Halberda, 2011). Finally, this link appears to persist even into adulthood (Halberda et al, 2012; Libertus, Odic, & Halberda, 2012).…”