Scientists have found that chicks seem to count upwards moving from left to right - they put smaller numbers on the left and larger numbers on the right, the same mental representation of the number line that humans use. Most people learned about number lines in math class, with smaller numbers coming from the left and increasing as they go right, researchers said. That same way of thinking about numbers seems to be embedded in people's mental representations of numbers, researchers added. However, the reason for this is not known.