Much of history is the tale of luxuries becoming necessities. I remember my surprise when I read that the discovery of America was partly caused by a desire to reach the Spice Islands, to get those luxuries for wealthy Europeans without having to use the existing trading systems.

But can things go the other way?

The Pew Research Center is out with a poll today that seems to say they can. Whether this is a brief, recession-induced pause, or a real change, is not easy to say.

The response that most impressed me was to the question of whether home air conditioning was a necessity. In 2006, 70 percent deemed it a necessity. This year the figure was down to 54 percent. Dishwashers, clothes dryers, microwave ovens and television sets are also seen as necessities by fewer people now than in 2006.

Overall, 52 percent think a television is a necessity. That is the lowest figure since that question was first asked in 1973.

The television breakdown is interesting. The older you are, the more likely you are to view it as a necessity. Among those over 65, 68 percent think a set is a necessity, compared to 38 percent of those age 18 to 29. But both those figures are down from three years ago.

Similarly, the young are more likely to view a cellphone as a necessity, and less likely to see a need for a landline.

There’s been no significant change in the number deeming a computer for home use to be a necessity (50 percent this year, 51 percent in 2006). But I am surprised it did not grow. The proportion who deem high-speed Internet service to be a necessity also showed no significant change (31 percent this year, 29 percent in 2006).

And appearances to the contrary, only 4 percent of Americans think an iPod is a necessity.