The innateness view says that the ability to acquire a human language is part of the biologically innate equipment of the human being, and that an infant is born with this ability just as it is born with two arms, two legs, and a beating heart. It also claims that this built-in ability is linked in some manner to physiological maturation, that it is the strongest in the very small child, and that some degree of decay in its function begins around the time of puberty. Evidence for the innateness hypothesis is very strong. For example, there is no formal instruction in first language acquisition. Children become competent speakers of a language at a comparatively early age before they are ready for other cognitively complex tasks such as learning mathematics, physics or chemistry. It has also been observed that children all over the world go through the same stages in language acquisition regardless of their linguistic environment. Children do not choose their first language; they can learn any language equally well as long as they are in the right linguistic environment.