In 1881, F. Edgeworth defines the first principle of economics such that every agent is motivated only by self-interest. The idea of self-interest motivation is conceptualized with a hypothetical economic agent named as "homo-economicus" who behaves rationally and in accord with logical principles, thus seeks to maximize his/her own benefits. Even though the use of homo-economicus, or the "money-making animal" and "money-hungry monomaniac" in the words of John Kells Ingram, as a rational representative agent in economic modeling becomes the norm in economic studies, the presence of irrational and quasi-rational people in the society and the actuality of irrational behaviors (in economic sense) in rational people pose some question about the use of this constructed man to understand the people's economic behaviors.

Homo economicus

Pioneered by Adam Smith, one of the founders of capitalism, the idea of homo-economicus is used as a base to construct theories on consumption and investment. In his famous book The Wealth of Nations, Adam Smith emphasizes the importance of self interest in human behaviors and describes the self-interest as the key driver of social prosperity. An economic agent has been constructed as a representative one which typifies the economic behavior of a typical person in the society and it is assumed that this agent systematically behaves rationally when deciding on any issue, especially the economic issues. If we define rationality, from the economics standpoint, as an act that aims for the maximum possible degree of acquirements with given limited resources, this constructed agent will be rational by behaving in favor of his/her own self-interest, hence he/she will always be optimizing.

Are we really rational?

In fact, the core belief in the idea of homo-economicus that homo-sapiens, the wise man, acts selfishly is a realistic assumption as self-interest is an important part of the innate human nature and an important intrinsic motive. We always want the best for ourselves and this motive is not exactly greed, but an intrinsic motivation to behave on one's interest. But, it is also true that not everyone is rational in the society and not all behaviors are considered rational in an economic sense. To test whether the individuals make rational choices or not, Nobel Laureate Daniel Kahneman and Amos Tversky conducted numerous experiments to test the human rationality and they reached this conclusion that human behaviors are not as rational as predicted by the homo-economicus assumption, instead they found that depending on how the question is framed or how things are measured people can make different choices. Also, they observed that not all behaviors are utility maximizing, sometimes people act altruistically, and sometimes people have the tendency to stay in the status quo. An interesting result of their experiment is that, when people make decisions, they emotionally value losses twice as much as they value an equivalent gain. In an experiment, they ask the subjects the following question:

Would you accept this gamble?
- 50% chance to win $150
- 50% chance to lose $100

They realized that, even though the expected value of gain in the above gamble (50% x $150= $75) is higher than the expected value of loss (50% x $100= $50), there are fewer takers of the gamble. Instead of showing their other experiment results, we can easily look at some of the marketing tricks to have an idea about the irrational choices we make in our daily life.
In a marketing strategy called Decoy marketing, marketers observe a boost in their sales of an expensive offer when they offer a similar item that is inferior in quality but about the same price of the expensive item. In his book Predictably Irrational Don Areily conducts an experiment using magazine subscription offers where subjects were offered two alternative subscription choices to The Economist magazine, one print only subscription (the inferior option which serves to make the combined offer look like a better value) and one internet and print subscription and they observe huge jump in sales due to the decoying effect.

In another experiment in Predictably Irrational, the author shows that people would walk 15 minutes to save $7 on an $18 item but wouldn't take the same 15-minute trip to save the same amount on a $455 item. In fact, it is the same amount of savings, and a rational person is expected to behave consistently at each case.

The current financial turmoil is a typical example for how people can make irrational decisions. Currently, the world is experiencing a catastrophic financial and economic meltdown started at the subprime mortgage markets in United States and spread out to other financial markets. Some people claim that the irrational behavior of sophisticated investors was the root cause of the recent meltdown. To get a better understanding of the issue, we need to look at the balance of greed and fear in the investors' behavior. While greed leads to overconfidence in the economy and excessive risk taking, the fear in the market leads to inactivity in the market and excessive aversion to risk. When investors make a decision about whether buying a stock, bond or any sophisticated security, they are expected to evaluate the expected reward versus the risk of possible expected loss. As predicted in Kahneman and Tversky study, the wisdom in the Wall Street is that "Fear always trumps greed." Neuroscientists describe the situation when greed dominates the fear as a "moral meltdown," and this is the situation where human brain loses control of reward and loss comparison and completely ignores risks. Take the trading in collateralized debt obligations (CDOs) which was perceived as one of major problems that leads to the recent financial crises. Since the security was rated excellent by the rating agencies and all losses were insured by AIG insurance company, the investors observed too much reward opportunities while no weight was given to the risk of a collapse in the market. That is the point when greed dominates fear in the market and fear fails to balance greed in the normal investor's brain. In the aftermath of the financial collapse, what we see right now is just the opposite of what was the case in the buildup of the financial bubble. Now, both investors and bankers are in a mode of excessive fear where negative news significantly decrease the stock prices and instead of providing credit to the markets, investors sit on a huge pile of cash.

If the excessive greed and overconfidence in the economy results in catastrophic events, should we ask investors to be less greedy? According to the Adam Smith, all humans have sympathy for the rich and famous. We can even find this in Holy Scriptures as well. There is always a sympathy for, and envy of, the rich. Hence, asking people to act against their innate nature may not be a wise decision but we should also keep in mind that this inherent human tendency can lead to moral corruption in the society. What we need is the balance of fear and greed in our behaviors and if one dominates the other, there will be misery for the whole.

Devrim Bulut holds a PhD degree in economics. Having taught at several universities in the United States for the last 5 years, he conducts research on market irrationality.