The Decision Theory: From Intuition to Strategic Wisdom

Decision theory is often used in academic or corporate jargon, leading to representation that suggests only large institutions can use it. On the contrary, professionals can—and should—leverage its frameworks. I believe everyone should. This article explores decision theory and its vital subfields: social choice theory and game theory.

The Story

On a sunny summer day in the 90s, I sat watching election coverage on TV. Homeland elections were volatile; since no party secured a clear majority, they frequently formed coalitions. I watched a leader confidently claim his victory as the “will of the people.” But did his narrow margin truly represent the public’s desire? Social choice theory suggests otherwise. While politicians often use the “will of the majority” as justification, the reality is different.

I recall that specific coalition dissolved quickly due to conflicting interests. This led me to wonder: Is there a system that truly represents the collective will? How can we prevent the abuse of election systems or minority domination? The answers lie within decision theory.

The Definition

Simply put, decision theory is the study of rational decision-making. As Martin Peterson states in his book, the goal is

“to formulate hypotheses about rational decision making that are as accurate and precise as possible.”

It is not a single golden formula like E=mc²; rather, it is a distilled mix of interdisciplinary insights.

A Brief History

While the Greeks explored logic, they never developed a formal theory for rational choices. The first discovery arrived in 1654 when Blaise Pascal and Pierre de Fermat exchanged letters regarding a gambling problem, introducing probability and expected value—terms that later defined our understanding of uncertainty.

As humanity we waited until 1944 for a formal mathematical foundation: John von Neumann and Oskar Morgenstern’s Theory of Games and Economic Behavior. Their work shifted the focus toward utility—the idea that people act to maximize benefit, whether in the form of money or other values – not just money.

Collective Decisions and Game Theory

We often view decision-making as an individual act, yet our choices are frequently interdependent. If you open a shop, your success depends on the competitors nearby. If two rivals open similar stores, your project might fail regardless of your effort. This is the realm of Game Theory: the science of making optimal choices when outcomes depend on the actions of others.

Social Choice, Normative, and Descriptive Theories

Social choice theory establishes principles for collective decisions. As Kenneth Arrow famously noted:

“The ‘will of the majority’ is not a property of the preferences of the individuals who make up the majority, but a property of the method of combining them.“

Two final categories define the field:

• Descriptive Decision Theory: Explains and predicts how people actually make decisions.
• Normative Decision Theory: Defines what decision-makers are rationally required to do.

Takeaways for Tomorrow

• The aim of decision theory is to formulate hypotheses about rational decision making.
• Social Choice Theory seeks to establish principles for how decisions involving more than one decision maker ought to be made.
• Game Theory is the science of making optimal choices when your success depends not only on your own actions but also on the decisions of others (competitors, partners, or stakeholders).
• The ‘will of the majority’ is not a reflection of individual desires, but a byproduct of the mathematical method used to combine them.
• Descriptive decision theory research on explaining and predicting how people actually make decisions.
• Normative decision theory seeks to yield details about what decision makers are rationally required to do.

References

• Peterson, M. (2017). An Introduction to Decision Theory. 2nd ed. Cambridge: Cambridge University Press. 
• Mao, F. (2023). A brief history of decision theory. SGFER.
• Arrow, K. J. (1951). Social Choice and Individual Values. Yale University Press.

Disclaimer: The views and opinions expressed in this article are solely my own and do not reflect the official policy or position of any past, present, or future employer or affiliated organisation. This content is intended for informational and educational purposes only and does not constitute professional advice.

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