Abstract

“The clocks throughout the city, Began to whirr and chime, Oh, let not Time deceive you, You cannot conquer Time”.

W.H. Auden “As I walked out one evening”

Abstract—In old age, the speed with which we can make simple decisions is one of the best predictors of how long we have left to live and so how slowly our mental abilities are changing. Because speed is one of the only two mental performance characteristics we can measure, there has been much research on how our brains, and so our decisions, slow as we grow old. It is unsurprising that the most influential idea of how all our mental abilities change as we age has been that age affects the speed at which our nerve cells can transmit information and that this reduces the efficiency of our memories and our ability to solve problems quickly. When explored more closely these ideas turn out to be useful when we study how gross changes in our brains affect our competence at dealing with the world.