The distinguished behaviorist B.F. Skinner was addressing the Nova University 1978 Conference on Aging. He was explaining how, at age 74, he made allowances for his impaired vision and hearing.
Skinner recalled a time when he was having a Chinese meal in a busy senior-center living room, and someone sitting near him pointed out the food in the middle of the table. Skinner decided he was expected to eat some. As he took a piece, he admired its thin, pale-brown crust. Eating the crunchy delicacy, he wondered how the Chinese were able to produce such a fragile, yet crispy, crust. Then he noticed that his neighbor was eating the same thing. She was peeling hers.
It was a hard-boiled egg.