When a society undergoes slow change, its younger members find great value in the advice of its older members  But when a society undergoes rapid change, young people think that little in the experience of their elders is relevant to them, and so do not value their advice
Thus, we may measure the rate at which a society is changing by measuring the amount of deference its younger members show to their elders
The faster a society changes, the less relevant the experience of older members of the society is to younger members.