Causes of inequality
There are many reasons for economic inequality within societies. These causes are often inter-related, non-linear, and complex. Acknowledged factors that impact economic inequality include the labour market, innate ability, education, race, gender, culture, preference for earning income or enjoying leisure, willingness to take risks, wealth condensation, and development patterns.
The labor market
A major cause of economic inequality within modern market economies is the determination of wages by the market, provided, that this market is a free market ruled only by the law of supply and demand. In this view, inequality is caused by the differences in the supply and demand for different types of work.
A job where there are many willing workers (high supply) but only a small number of positions (low demand) will result in a low wage for that job. This is because competition between workers drives down the wage. An example of this would be low-skill jobs such as dish-washing or customer service. Because of the persistence of unemployment in market economies and the fact that these jobs require very little skill results in a very high supply of willing workers. Competition amongst workers tend to drive down the wage since if any one worker demands a higher wage the employer can simply hire another employee at an equally low wage.
A job where there are few willing workers (low supply) but a large demand for the skills these workers have will results in high wages for that job. This is because competition between employers will drive up the wage. An example of this would be high-skill jobs such as engineers, professional athletes, or capable CEOs. Competition amongst employers tends to drive up wages since if any one employer demands a low wage, the worker can simply quit and easily find a new job at a higher wage.
While the above examples tend to identify skill with high demand and wages, this is not necessarily the case. For example, highly skilled computer programmers in western countries have seen their wages suppressed by competition from computer programmers in Developing Countries who are willing to accept a lower wage.
The final results amongst these supply and demand interactions is a gradation of different wages representing income inequality within society.
Innate ability
Many people believe that there is a correlation between differences in innate ability, such as intelligence, strength, or charisma, and an individual's wealth. Relating these innate abilities back to the labor market suggests that such abilities are in high demand relative to their supply and hence play a large role in increasing the wage of those who have them. Contrariwise, such innate abilities might also affect an individuals ability to operate within society in general, regardless of the labor market.
Various studies have been conducted on the correlation between IQ scores and wealth/income. The book titled "IQ and the Wealth of Nations", written by Dr. Richard Lynn, examines this relationship with limited success; other peer-reviewed research papers have also been criticised harshly. Without further research on the topic, incorporating statistical models that are universally accepted, it is fairly difficult to come towards an objective conclusion regarding any relationship between intelligence and wealth or income.
Education
One important factor in the creation of inequality is variation in individuals' access to education. Education, especially in an area where there is a high demand for workers, creates high wages for those with this education. As a result, those who are unable to afford an education, or choose not to pursue optional education, generally receive much lower wages. Many economists believe that a major reason the world has experienced increasing levels of inequality since the 1980s is an increase in the demand for highly skilled workers in high-tech industries. They believe that this has resulted in an increase in wages for those with an education, but has not increased the wages of those without an education, leading to greater inequality.
Gender, race, and culture
The existence of different genders, races and cultures within a society is also thought to contribute to economic inequality. Some psychologists such as Richard Lynn argue that there are innate group differences in ability that are partially responsible for producing race and gender group differences in wealth (see also race and intelligence, sex and intelligence) though this assertion is highly controversial.
The idea of the gender gap tries to explain differences in income between genders. Culture and religion are thought to play a role in creating inequality by either encouraging or discouraging wealth-acquiring behavior, and by providing a basis for discrimination. In many countries individuals belonging to certain racial and ethnic minorities are more likely to be poor. Proposed causes include cultural differences amongst different races, an educational achievement gap, and racism.