Back in 1931, for example, The New York Times attributed the emerging economic cataclysm to a “mood of pessimism which had been carried to grotesque extremes.” In 1932, it compared reckless talk about “depression” to shouting “fire” in a crowded theater.

President Roosevelt is widely remembered for saying, in 1933, that “the only thing we have to fear is fear itself.” But he was only repeating an oft-told message.

It wasn’t until 1948 that the Columbia University sociologist Robert K. Merton wrote an article in The Antioch Review titled “The Self-Fulfilling Prophecy,” using the Great Depression as his first example. He is often credited with having invented the “self-fulfilling prophesy” phrase, but by the 1930s the idea was already as commonplace as the breakfast toast made with modern electric toasters. (Interestingly, the same Robert Merton documented the tendency for important ideas to be falsely attributed to celebrities.)

In fact, in 1937, “Think and Grow Rich,” a book by Napoleon Hill, urged readers to adopt a positive mental attitude and to channel the power of the subconscious mind so that real wealth would follow. It became a runaway best seller. Faddish interest had already emerged not only in Freud’s theory of the unconscious mind, but also in the theories of the psychologist Émile Coué, who urged people to recite that “every day in every way I’m getting better and better.” He said this “autosuggestion” would bolster the unconscious self.

In important ways, we are still using that 1930s pattern of thinking. We are instinctively fearful of reckless talk about depressions, and we try to support one another’s confidence. We like the idea that modern scientific economics seems to show that all recessions end in due course.

For now, our common efforts at building confidence appear to be working somewhat. But the economy has still not recovered, by any means.

COUÉISM has been discredited generally, as has much of the old business-cycle theory, but they live on in our popular notions about recessions. We may hope that our resorting to euphemism and belief in timetables of business-cycle recoveries work better to restore confidence than they did in the ’30s.

The problem might be put this way: There is still a nagging doubt afloat that the current event is really just another example in that long sequence of recessions. In which mental category does the current contraction belong: recession or depression? We may still be at a tipping point. To the extent that the theory of the self-fulfilling prophecy is correct, there is a case for continued vigilance, to ensure that adverse events don’t encourage widespread talk of the second category.