Christopher Swann– Christopher Swann is a Reuters columnist. The views expressed are his own –

This recession is introducing many Americans to a novel experience — the pay cut.

Fifteen percent of employers surveyed by the Society of Human Resource Management reduced pay in the past six months — a threefold increase from earlier this year. Companies like Hewlett-Packard, Caterpillar and the New York Times have taken the pruning shears to wages.

Real pay cuts — when wages fail to keep pace with inflation — are commonplace in recessions, but you would have to look back to the 1930s for the last example of widespread cuts in nominal wages in the United States.

Since Keynes, many economists have treated nominal wage cuts as a virtual impossibility. In 1999, Yale economist Truman Bewley wrote the optimistically titled “Why Wages Don’t Fall During a Recession.”