As well as the idea of it being related to the social mood, there is a theory linking the degree of social reactivity to the sunspot cycle. Here is one link to a discussion of Chijevsky's theory. 
http://www.carolmoore.net/articles/sunspot-cycle.html 
 
Study of sunspots and skirt fashions going back to 1700 here 
http://www.montgomerycap.com/universal_economics.html 
 
The Dow adjusted for inflation peaked at the beginning of 1966 and did not bottom till 1982 - a 74% decline in real terms. So I would not be inclined to lump 66-73 in with 47-66. The experience of the period that followed its peak was very different to the preceding era in terms of unemployment and inflation and Prechter and others have done some interesting work on how this manifested in popular music and other aspects of culture.

Robert Prechter has written about this extensively. 
 
http://www.socionomics.net/whatis/social-mood.aspx#socialmood 
 
"Social mood waxes and wanes positively and negatively. A positive social mood is associated with a host of social phenomena, such as bull markets, bright colors, short skirts, re-election of incumbents, peace, and deregulation. A negative social mood is also associated with a host of social phenomena, such as bear markets, dark colors, falling hemlines, rejection of incumbents, discord, and regulation." 
 
http://futurejacked.blogspot.com/2008/12/socionomic-trendspotting-for-2009.html