"A thing belonging or appropriate to a period other than that in which it exists, especially a thing that is conspicuously old-fashioned"

"Because of the rapid change in the world around us since our birth, we humans are living anachronisms. Our world has changed dramatically in the past 150 years.
Human physiology, in contrast, took millions of years to create and has not changed much in 150.000 years. Your body - even if it is in mint condition - is designed for succes in the past. It is an antique biological machine that evolved in response to a world that no longer exists.
Although we live in a world in which computer processing speed doubles roughly every twenty-four months, human information processing has not expanded substantially over the past 150.000 years. Our physiology is clearly behind with the times.

We are hertz machines in a megahertz world.
For an average human, simple reaction time is about 250 milliseconds. Simple reaction time is the time that it takes to react to a stimulus, such as a light going on when a button is pushed. Therefore, each "cycle" of light input and button depression response takes a quarter second. Four complete cycles can take place each second. Thus, a typical human has a processing speed of about four hertz. In comparison, modern desktop computers have central processing unit (CPU - the brain of a computer) clock speeds of over three gigahertz; they are roughly 750.000.000 times faster than we are.

This relatively slow processing speed has two important implications. First, it means that all of us live more than 250 milliseconds in the past. Our bodies take approximately that long to register things going on around us, such as light turning on. We take even longer to perceive sound, because the speed of sound is much slower than the speed of light.

Second, because our mental CPU runs slowly, we humans have to be careful about how much time we spend thinking about any one thing. We save, protect, and conserve our mental thought cycles, much as a miser guards his money. Psychologists have actually coined a term for this tendency, calling humans "coginitive misers".
In daily life, when faced with routine decisions, people conserve their thought cycles and rely instead on mental heuristics - simple, practical rules of thumb that we learn through trial and error. We save our judgement and decision-making skills for thinking about the novel, unpredictable, and dangerous forces in our lives: indeed, for predicting the future. Unfortunately, what has worked in the past may not work well in the immediate present, especially if now differs from then. Furthermore, our past successes are not automatically reproduced in the future, as much as we wish they were."

The Time Paradox - Philip Zimbardo & John Boyd