[2] The ANS plays a crucial role in development of other numerical abilities, such as the concept of exact number and simple arithmetic.
The work of Rochel Gelman and C. Randy Gallistel among others in the 1970s suggested that preschoolers have intuitive understanding of the quantity of a set and its conservation under non cardinality-related changes, expressing surprise when objects disappear without an apparent cause.
[2] Beginning as infants, people have an innate sense of approximate number that depends on the ratio between sets of objects.
[11] Specifically within this lobe is the intraparietal sulcus which is "active whenever we think about a number, whether spoken or written, as a word or as an Arabic digit, or even when we inspect a set of objects and think about its cardinality".
Parietal lobe brain activity seen in adults is also observed during infancy during non-verbal numerical tasks, suggesting that the ANS is present very early in life.
[6] A neuroimaging technique, functional Near-Infrared Spectroscopy, was performed on infants revealing that the parietal lobe is specialized for number representation before the development of language.
[6] This indicates that numerical cognition may be initially reserved to the right hemisphere of the brain and becomes bilateral through experience and the development of complex number representation.
[5] Symptoms vary based the location of damage, but can include the inability to perform simple calculations or to decide that one number is larger than another.
[13] This syndrome can manifest in several different ways from the inability to assign a quantity to Arabic numerals to difficulty with times tables.
[13] Brain imaging in children exhibiting symptoms of dyscalculia show less gray matter or less activation in the intraparietal regions stimulated normally during mathematical tasks.
[2] Additionally, impaired ANS acuity has been shown to differentiate children with dyscalculia from their normally-developing peers with low maths achievement.
The difficulty results in underestimation of the magnitude present in the set or a longer amount of time needed to perform an estimate.
Although the ANS is present in infancy before any numerical education, research has shown a link between people's mathematical abilities and the accuracy in which they approximate the magnitude of a set.
A study involving 3- to 5-year-old children revealed that ANS acuity corresponds to better mathematical cognition while remaining independent of factors that may interfere, such as reading ability and the use of Arabic numerals.