I wonder if the post on generosity could be expanded by some information from the Pew "Inside the Middle Class" poll. This paragraph I think tells us a great deal:

Some two-thirds (68%) of middle class respondents say that "having enough free time to do the things you want" is a very important priority in their lives. That's more than say the same about any other priority we asked about in this survey including: having children (62% said that is very important), being successful in a career (59%), being married (55%), living a religious life (53%), doing volunteer work/donating to charity (52%); and being wealthy (12%). Upper and lower class respondents give essentially the same answers. The demographic groups most inclined to say they highly value free time are the ones least likely to have it -- such as the employed, the middle-aged, and mothers of young children. In recent years, a number of public opinion surveys have documented Americans' growing sense of feeling rushed, and this perception tracks with the growth in the number of mothers who are employed outside the home and in the number of two-earner couples. However, recent research on whether Americans in fact have less leisure time has produced mixed findings. At least one major report, which relied on five decades of time use logs kept by different groups of survey respondents, found that no matter what most people may perceive, Americans today have more leisure time now than they did several decades ago. Other reports find that many middle class families have maintained their lifestyle only by becoming two-earner households, with all the attendant time stresses.

Notice where charity and volunteering rank on that list, relative to being wealthy. People jealously guard their time, perhaps due to the perceived stresses of having both parents work outside the home.

In short, what we are contemplating are long-run changes in labor supply. Real wages having been roughly constant, what else can be causing the labor-leisure tradeoff to change as it has. The intensive margin -- the number of hours worked per employee -- hasn't changed greatly in the US since 1980, but the extensive margin -- the share of the active population working -- has increased. So fewer people have time for volunteering, but everyone has the same (or actually a little more) time than before. (See this recent paper about aggregate hours across the OECD.) Perhaps we need models that involve joint optimization for two-adult households that choose to give volunteer time as well as work. I don't know any of those; sounds like a good thesis.

Labels: economics