What are some chief mechanisms through which social behavior is shaped and social outcomes are caused? Ideally the best answer to this question would result from a survey or inventory of many explanations. But consider some high level possibilities that could serve as a causal mechanism bringing about a social phenomenon of interest.
Selection mechanisms. Why are passengers on commercial aircraft better educated than the general population? Because most airline passengers are business travelers, and high-level and mid-level business employees tend to have a higher level of education than the general population.
Evolutionary explanations. Why does the level of firm efficiency tend to rise over time? Because the net efficiency of a firm is the product of many small factors. These small factors sometimes change, with an effect on the efficiency of the firm. Low efficiency firms tend ultimately to lose market share and decline into bankruptcy. Surviving firms will have features that produce higher efficiency.
Imitation mechanisms. Why did the no-huddle offense become so common in the NFL in the 1980s? Because it was successful for a few teams, and others copied the offense in the hope that they too would win more games.
Rational-intentional explanations. Why do rebellions often fizzle out? Because participants are rational agents with private goals, and they make calculating decisions about participation.
Aggregative explanations (aggregate consequences of individual-level strategies). Why does technological innovation occur continuously within a market-based society? Because manufacturers are constantly looking for lower-cost and higher-value-added methods of manufacturing, and this search leads them to innovations in products and technologies.
Conspiracy explanations (covert strategems of the powerful). Why did the United States move away from passenger railroads as the primary form of intercity transportation? Because powerful interests took political actions to assure that private automobiles would be encouraged as the primary form of transport.
Mentality explanations (behavior is changed by changing beliefs and attitudes). Why were so many Quaker men conscientious objectors at great personal cost during World War II? Because their religious beliefs categorically rejected the violence in war and they refused to participate in this immoral activity.
Historical / path-dependency explanations. Why do we still use the very inefficient QWERTY keyboard arrangement that was devised in 1874? Because this arrangement, designed to keep typists from typing faster than the mechanical keyboard would permit, was so deeply embodied in the typing skills of a large population and the existing typewriter inventory by 1940 that no other keyboard arrangement could be introduced without incurring massive marketing and training costs.