Convergence theory presumes that as nations move from the early stages of industrialization toward becoming fully industrialized, they begin to resemble other industrialized societies in terms of societal norms and technology.
The characteristics of these nations effectively converge. Ultimately, this could lead to a unified global culture if nothing impeded the process.
Convergence theory has its roots in the functionalist perspective of economics which assumes that societies have certain requirements that must be met if they are to survive and operate effectively.
Convergence theory became popular in the 1960s when it was formulated by the University of California, Berkeley Professor of Economics Clark Kerr.
Some theorists have since expounded upon Kerr's original premise. They say industrialized nations may become more alike in some ways than in others.
Convergence theory is not an across-the-board transformation. Although technologies may be shared, it's not as likely that more fundamental aspects of life such as religion and politics would necessarily converge—though they may.
Convergence theory is also sometimes referred to as the "catch-up effect."
When technology is introduced to nations still in the early stages of industrialization, money from other nations may pour in to develop and take advantage of this opportunity. These nations may become more accessible and susceptible to international markets. This allows them to "catch up" with more advanced nations.
If capital is not invested in these countries, however, and if international markets do not take notice or find that opportunity is viable there, no catch-up can occur. The country is then said to have diverged rather than converged.
Unstable nations are more likely to diverge because they are unable to converge due to political or social-structural factors, such as lack of educational or job-training resources. Convergence theory, therefore, would not apply to them.
Convergence theory also allows that the economies of developing nations will grow more rapidly than those of industrialized countries under these circumstances. Therefore, all should reach an equal footing eventually.
Some examples of convergence theory include Russia and Vietnam, formerly purely communist countries that have eased away from strict communist doctrines as the economies in other countries, such as the United States, have burgeoned.
State-controlled socialism is less the norm in these countries now than is market socialism, which allows for economic fluctuations and, in some cases, private businesses as well. Russia and Vietnam have both experienced economic growth as their socialistic rules and politics have changed and relaxed to some degree.
Former World War II Axis nations including Italy, Germany, and Japan rebuilt their economic bases into economies not dissimilar to those that existed among the Allied Powers of the United States, the Soviet Union, and Great Britain.