Such changes are all but invisible over the short time scale of modern observations, and, it is argued, they are usually obscured by innumerable gaps in the imperfect fossil record.

As expected, the memory circuit in the brains of older monkeys didn't sustain activity as well as in younger monkeys, even though they still performed accurately at this short time scale.

However, it was a solution that we knew we could at least scale in the short term.