Social (in)equality

For most of our evolutionary history, we humans have been living in small groups, with no more than a few hundered people. Any life in groups brings with it the potential for conflict and the challenge of how to distribute resources or how to make decisions. We have evolved social behaviors that allow us to regulate social life in such small groups, including social emotions, social preferences, moral intuitions such as a sense of fairness and a sense of liberty and autonomy, and a so-called norm-psychology - a tendency to learn and imitate the behaviors of the people around us, considering these behaviors as "normal" and being angered if someone behaves in a way that doesn't follow the group's norms. 

Today's hunter gatherers give us some clues about the social organization that our species lived in throughout most of our history. Hunter-gatherers tend to live in egalitarian groups, meaning that there is no strong hierarchy and an equal distribution of resources. Attempts by individuals to dominate the group or hord resources are discouraged and punished by everyone else in the group. 

However, with agriculture, the ability to store and accumulate valuable resources, division of labor, the first cities, our group sizes started to grow, from a few thousand to many thousands and finally millions of people. How can life in such groups be regulated? It seems that with the increase in group sizes, the leveling mechanisms that worked well in small hunter-gatherer groups did not work sufficiently anymore in such larger group, and with increasing group size came an increasing inequality in power and wealth. 

Scientists are trying to better understand the factors that have lead to this departure from egalitarian hunter-gatherer origins and the spread of inequality throughout our history. One such factor seems to be the ability to store, accumulate, and defend valuable resources, which became possible and important with the beginning of a sedentary lifestyle and agriculture. Another factor seems to be the inheritance or transmission of these resources to children (instead of redistributing them equally to everyone in the next generation). Whether or not wealth is inherited or redistributed in the population, and to what extend, is governed by more or less formal social norms and institutions (such as property rights, tax regulations for different sources of wealth, existence or absence of social welfare programs such as funding equal access to education and health care for all citizens).

These factors together led to a transition to greater inequality in the neolithic period, and to an increase in inequality over time, through a feedback loop - the more wealth someone has, the more access to power and education they have, and the more wealth they can accumulate (and transmit to their offspring) (see also: Corruption). Over time, the rich get richer, and the poor get poorer.

However, in the last two centuries, there is also a decrease in inequality observable.

When we try to compare two countries, or two time periods, by their level of inequality within their population, we have to find a common measure. 

One measure that scientists use to do this is called Gini coefficient.  The higher the Gini coefficient, the higher the economic inequality in a population. A Gini coefficient of 1 (or: 100%) means that one person has all of the wealth and everybody else has nothing. A Gini coefficient of 0 means that everybody has exactly the same wealth. In reality, the Gini of a population is somewhere between these values. 

The Gini coefficient does not really tell us exactly how income in a population is distributed - two different distributions can have the same Gini coefficient.

Another type of measure to compare economic inequality between populations are shares of income held by certain groups of the population. 

An important effect of social inequality that scientists are trying to understand is its relationship to measures of well-being. 

For example, a number of studies have found that more unequal societies appear to have higher rates of obesity, mental illness, teenage births, homicides, imprisonment rates, lower levels of trust, lower life expectancy and lower student educational performance. 

But what mechanisms could in fact be causing such effects of inequality on a society? Some mechanisms that have been proposed include:

• People with low socio-economic status have less access to resources, including health care and education.

• People with low status experience more uncertainty and less control over their lives. This affects stress which affects health and longevity. This is true not just for humans but also for other animals that live in social groups where hierarchies tend to form, creating social and psychological stress, such as in baboons. 

• However, there also appear to be negative effects on society as a whole - not only those with a relatively low social status, but everyboy becomes more competitive, more worried, more uncertain and more stressed about one's social status.

Generally, due to our evolutionary history as a highly social species, human well-being is greatly dependend on factors of a healthy and safe social environment, such as social cohesion, high levels of trust, solidarity, a sense of belonging and community. The more unequal a society, the more there is social division, hierarchy, coercion, discrimination, prejudice, uncertainty and lack of trust in the social environment.

Furthermore, due to our evolutionary history as a highly social species, we humans have a hightened sense of fairness and other moral intuitions, such that we tend to compare ourselves to others in our social environment, and we care more about relative status and wealth than absolute wealth. The less we have compared to others within the group that we consider ourselves part of, the more frustrated we are. 

see also: Human evolution / Human needs, values, well-being

"Our society, like all previous complex societies, is on a rollercoaster. Impersonal social forces bring us to the top; then comes the inevitable plunge. But the descent is not inevitable. Ours is the first society that can perceive how those forces operate, even if dimly. This means that we can avoid the worst — perhaps by switching to a less harrowing track, perhaps by redesigning the rollercoaster altogether. "

Peter Turchin (2013)

(Under construction)

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