Number-space mapping in the newborn chick resembles humans’ mental number line

Even chicks may count from left to right For the most part, humans represent numbers across a mental number line, with smaller numbers on the left and larger numbers on the right. Some have argued that this is due to culture rather than being innate. Rugani et al. , however, show that 3-day-old chicks share this representation of numbers, consistently seeking lower numbers to the left of a target and larger numbers to the right (see the Perspective by Brugger). These results suggest that there may be an innate spatial representation of numerical values that we share with other animals. Science , this issue p. 534 ; see also p. 477