linked to a spatial representation. Dehaene and other researchers believe this effect is caused by the presence of a “mental number line” in which small numbers appear on the left and increase as you move right. The SNARC effect indicates that the ANS works more effectively and accurately if the larger set of objects is on the right and the smaller on the left. Development and mathematical performance 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. This correlation is supported by several studies in which school-aged children's ANS abilities are compared to their mathematical achievements. At this point the children have received training in other mathematical concepts, such as exact number and arithmetic. More surprisingly, ANS precision before any formal education accurately predicts better math performance. 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. ANS in animals Many species of animals exhibit the ability to assess and compare magnitude. This skill is believed to be a product of the ANS. Research has revealed this capability in both vertebrate and non-vertebrate animals including birds, mammals, fish, and even insects. In primates, implications of the ANS have been steadily observed through research. One study involving lemurs showed that they were able to distinguish groups of objects based only on numerical differences, suggesting that humans and other primates utilize a similar numerical processing mechanism. In a study comparing students to guppies, both the fish and students performed the numerical task almost identically. The ability for the test groups to distinguish large numbers was dependent on the ratio between them, suggesting the ANS was involved. Such results seen when testing guppies indicate that the ANS may have been evolutionarily passed down through many species. Applications in society Implications for the classroom Understanding how the ANS affects students' learning could be beneficial for teachers and parents. The following tactics have been suggested by neuroscientists to utilize the ANS in school: Counting or abacus games Simple board games Computer-based number association games Teacher sensitivity and different teaching methods for different learners Such tools are most helpful in training the number system when the child is at