1. Throw out nonessential numbers. This includes age, weight and height. Let the doctors worry about them. That is why you pay them.

2. Keep only cheerful friends. The grouches pull you down.

3. Keep learning. Learn more about the computer, crafts, gardening, whatever. Never let the brain idle. 'An idle mind is the devil's workshop.'

Sherry Turkle is a Professor of the Social Studies of Science and Technology at the Massachusetts Institute of Technology.

Having obtained her undergraduate degree of BA of Social Studies and later her Ph.D. in Sociology and Personality Psychology at Harvard University, she now focuses her research on psychoanalysis and human-technology interaction.