The first is the economic surplus hypothesis. This hypothesis states that an economic surplus leads to more leisure time in the individuals, which nurtures more cultural complexity. This theory is tested through the beginning of the article by looking at hunter gatherers and agriculturalist around the world. The second theory is the time scarcity theory. The theory hypothesizes that with the more cultural complexity the culture has, the less leisure time the individuals have.
Chick gives reasons that raises doubt in the reader.
Thirdly, the U-shaped curve hypothesis states the previous theories are over simplified. The theory states that the amount of leisure time is greater at the hunter gatherer level which is considered not a very complex culture. The amount of leisure time then begins to lower as you get towards agricultural societies who have a complex culture, and then leisure begins to rise as you get closer to post-industrial cultures which are very complex. Therefore, at the bottom of the curve are the agricultural cultures who have the least amount of leisure time. The final theory considered is the null hypothesis.