To the point:

• Drunk hypothesis. Scholars have long suggested that alcohol played a significant role in promoting large-scale cooperation and the development of complex hierarchical societies.
• Cross-cultural test. An analysis of 186 non-industrial societies found a positive relationship between the presence of traditional fermented beverages (such as mead, wine and beer) and higher levels of political complexity.
• One of many factors. The effect of alcohol was, however, rather small, suggesting that other factors, such as agriculture, were more important for the rise of complex societies.