Grow the economy - drink a beer with a colleague.

From Bar Talk: Informal Social Interactions, Alcohol Prohibition, and Invention by Michael Andrews. From the Abstract.

To understand the importance of informal social interactions for invention, I examine a massive and involuntary disruption of informal social networks from U.S. history: alcohol prohibition. The enactment of state-level prohibition laws differentially treated counties depending on whether those counties were wet or dry prior to prohibition. After the imposition of state-level prohibition, previously wet counties had 8-18% fewer patents per year relative to consistently dry counties. The effect was largest in the first three years after the imposition of prohibition and rebounds thereafter. The effect was smaller for groups that were less likely to frequent saloons, namely women and particular ethnic groups. Next, I use the imposition of prohibition to show that the social network exhibited path dependence in the sense that as individuals rebuilt their networks following prohibition, they connected with new individuals and patented in new technology classes. Thus, while prohibition had only a temporary effect on the rate of invention, it had a lasting effect on the direction of inventive activity. Additionally, I exploit the imposition of prohibition to show that networks increase invention by exposing individuals to others’ ideas in addition to simply facilitating collaboration and that informal and formal interactions are complements in the invention production function.

It is certainly a conceivable hypothesis that more forums for social exchange of knowledge and best cultural practice might increase innovation and productivity, both locally and nationally. I have always been struck by the correlation between the proliferation of taverns and coffee shops and the emergence of the Industrial Revolution in England in general and London in particular. At this remove, it is hard to prove causal flow but there seems merit in the argument that increased convivial exchange of knowledge and information might lead to improved rates of innovation and economic growth.

Rather than trying to prove the earlier, coffee house, hypothesis, Andrews is using a much more recent and better documented natural experiment - prohibition.

Andrews' new evidence does not move the conceivable process to the proven hypothesis column. But it certainly moves it to plausible, if not even probable.