"When news periodicals begin forecasting a recession…"

[OliviaP316]

From: MGMAT Guide 6, Critical Reasoning (6th ed.), p. 101:

"When news periodicals begin forecasting a recession, people tend to spend less money on nonessential purchases. Therefore, the perceived threat of a future recession decreases the willingness of people to purchase products that they regard as optional or luxury goods.

Which of the following is an assumption on which the argument depends?

A) People do not always agree as to which goods should be considered luxury goods.
B) Many more people read news periodicals today than five years ago.
C) Most people do not regularly read news periodicals.
D) Decreased spending on nonessential goods does not prompt news periodicals to forecast a recession.
E) At least some of the biggest spending consumers prior to the recession were among those who curtailed their spending after the recession began."

My problem: I don't understand the reasoning, on page 102, for answer D as the right choice. As the book states on that page: "This choice is saying that the drop in spending is not itself causing the forecasts. That's good, because the argument is that the causality runs the other way: the forecasts cause the drop in spending." Why does the argument necessarily depend on this statement? Can you explain to me in a different way, or simpler terms?

Thanks!

[tim]

Try this:

"Whenever it is December, people tend to put up holiday decorations. Therefore, the arrival of December causes people to put up holiday decorations."

The conclusion here depends on the assumption that people putting up holiday decorations doesn't cause it to become December. See, the first sentence is pointing out a correlation, two things that happen at the same time. If A and B happen at the same time, we can't conclude that A causes B unless we're sure it's not the other way around, in other words, unless we're sure that B didn't cause A. Now my example is silly of course, because we know that putting up holiday decorations doesn't cause December to arrive. But THAT'S exactly what we need in order to reach the conclusion that the arrival of December is what causes people to put up holiday decorations.

[OliviaP316]

Thanks, Tim!

[cgentry]

Glad you found Tim's response helpful!