"Your biological age is the number of days you've lived.

Your psychological age is the number of thoughts you've entertained.

Your sociological age is the number of contributions you've made."

He cites research by Harvard social psychologist Ellen Langer in her 2009 book Counterclockwise , that suggests that by creating a “reminiscence bump” for residents of their own past college experiences, university-based communities may even help to “reverse” ageing. “You are as young as you feel. If you put people in their past environments,” he s... See more