I do not know what the common man thought about the causes Great Depression. What I can tell you, is that Hoover was counseled by his economic advisers to do nothing. John Maynard Keynes' book, "The General Theory of Employment, Interest and Money" wasn't published until 1936, well after the depression was well under way.

Hoover himself blamed WWI. With the effective destruction of an industrial powerhouse, introduction of unemployed soldiers into the economy, his theory wasn't terrible. Especially considering at the time, few people if any knew what the causes were.

Policies under the Hoover administration showed that those in charge really didn't know how to fix it. Andrew Mellon, Hoover's treasury secretary said,

"Liquidate labor, liquidate stocks, liquidate farmers, liquidate real estate... it will purge the rottenness out of the system. High costs of living and high living will come down. People will work harder, live a more moral life. Values will be adjusted, and enterprising people will pick up from less competent people."

Add in the fact that the US government started a trade war with Europe, with the Smoot-Hawley tariff, refused to leave the gold standard (unlike Britain) and it's clear that no one in power knew (at least early on) what really caused it, and how to fix it.

At the risk of speculating, I would think most Americans would be worried about their next meal or getting a job, not what ultimately caused the mess in the first place.

Hello, though I may not be able to provide a specific answer to this question, I feel as though I can answer at least a part, or offer some evidence in support of others' write ups. I do not claim to fully understand or know what the causes of the Great Depression even are however, I feel as though I command a basic understanding of it. I'm currently reading from "Words of a Century" by Stephen E. Lucas and will be referring to speeches within.

The first speech I use is Roosevelt's First Inaugural Address given March 4th, 1933. This is the famous speech with the "...the only thing we have to fear is fear itself" line. Seriously, check it out.

Finally, in our progress toward a resumption of work we require two safeguards against a return of the evils of the old order; there must be a strict supervision of all banking and credits and investments; there must be an end to speculation with other people’s money, and there must be provision for an adequate but sound currency.

As evident in this speech, I think it is safe to say that the President knew, or at least believed, unregulated investing and speculation was a contributing factor the the Great Collapse and by extension the Great Depression. These speeches were highly publicized and broadcast throughout the nation. As Brown puts it here on page 14

"Roosevelt's "fireside chats" were the only occasion in broadcasting in which all national and regional networks would drop prior commitments and link together into "one huge chain," giving the president to the largest audience ever assembled for a single speech."

As you may well know, President Roosevelt loved his fireside chats. On March 12th, 1933 he gave one entitled "The Banking Crisis" which looks to educate the common American on just what is all going on.

It starts with:

"I want to talk for a few minutes with the people of the United States about banking... "

Roosevelt goes on to explain how banks work and how the money is invested with a small amount actually available for withdrawal. ( would encourage to simply read the speech to be honest.

What, then, happened during the last few days of February and the first few days of March? Because of undermined confidence on the part of the public, there was a general rush by a large portion of our population to turn bank deposits into currency or gold. A rush so great that the soundest banks could not get enough currency to meet the demand. The reason for this was that on the spur of the moment it was, of course, impossible to sell perfectly sound assets of a bank and convert them into cash except at panic prices far below their real value.

By the afternoon of March 3 scarcely a bank in the country was open to do business. Proclamations temporarily closing them in whole or in part had been issued by the Governors in almost all the states.

I would encourage a reading of this if you are interested in what the layman thought. Roosevelt sought to educate people on these things and if anything my grandfather said was true, people really put their trust in him and what he had to say during these fireside chats.

Somewhat of a follow-up question, somewhat of an attempt to give an answer from a different angle: other answers so far seem to focus on government policies, and how they show the people in charge didn't know what they were doing, hence the people on the street probably didn't understand what was going on either.

However, couldn't we get insights from works from the time that did not focus on the government's role in economics, but still referenced the Great Depression in other ways?

For example, in "The Arts" (1937) by Van Loon there's the following passage early on in the section on Egyptian art (emphasis mine):

[The Egyptian temple contained a] dark little room which served as a sort of town residence to the God who happened to be worshipped on that particular spot. I say "town residence" because the Gods, of course, were supposed to dwell in a realm of their own, situated far beyond the distand mountain ranges. But this idea was too vague, too remote, for the needs of the ordinary citizen. He needed something a little more concrete, something a little more tangible or at least visible. Even if he himself was never allowed to behold the Deity, he felt happy in the knowledge that the Deity sometimes visited a spot where a few highly privileged personages could behold his countenance.

Perhaps I can make this attitude clear to you by giving you a modern parallel. Take that mysterious yellowish metal which has become the great object of veneration of the people of today, the gold supply of the nation upon which (as most citizens seem to believe) the safety of their country depends. Except for a few guards, nobody has ever seen it. Like an old Egyptian God it lies hidden in a dark cave, and even the President of the United States or the Secretary of the Treasury is not allowed to enter this holy of holies which contains the basis for our national credit.

Nobody so far has hit upon the idea of connecting this modern golden calf with some new form of ceremonial worship. But such a thing is not out of the sphere of what one might call "spiritual possibilities," for stranger things than that have happened before and may easily happen again.

If however, such a veneration of our gold supply should be elevated to the dignity of a regular national form of worship, then we would have a parallel to the religion of ancient Egypt. We merely need to substitute an invisible Deity for an invisible barrel of gold stones. And we must thereupon convert Wall Street and Broad Street and William Street into a series of great courts in which the populace will stand and wait, while way down in the dark and invisible interior of the Sub-Treasury some assistant Secretary of the Treasury intones, "One billion and ninety-seven cents - two billion and forty-eight dollars." Whereupon the congregation, reassured as to the actual presence of the object of its devotion, returns happily to its daily tasks and duties, for all is still well with the world.

Of course, I wouldn't call a highly educated, famous historian and writer of popular history books representative of the average man, but insofar as this is a reliable source, Van Loon suggests that many people did seem to believe the gold standard was important somehow, as the emphasized passage shows.

(For the record: I'm just someone who found this book while studying art and finds it a very interesting historical artifact of the perception of art of one well-learned individual from the 1930s; it always struck me as interesting that in an attempt to make the writing more accessible Van Loon makes a lot of comparisons to his "present time", meaning the 1930s. So the book ends up being as much an impression of his experience of those days and how it colours his view of history, as being an art history book.)

Many of the causes were reasonably clear in hindsight, and the best account of these is JK Galbraith's The Crash of 1929 which is perhaps the one economics book everyone should read, it's short, funny and direct.

The deeper problem was how to re-start a stalled economy, especially in the US context where economic orthodoxy demanded minimal government interference. Then as now, there was little consensus about the best course, and although Keynesianism as we know it was yet to be espoused, similar arguments were made in 1933 and 2009.