Behavioral Game Theory

decision making

Behavioral Game Theory looks at how people really make choices

It helps us understand two main things:

In regular Game Theory, we assume everyone is a math wizard who only cares about winning. But in the real world, people have emotions! They learn from mistakes and care about what others think.

The Ultimatum Game

Imagine two players: one proposes how to divide a sum of money, and the other can either accept or reject this proposal.

The proposer is told:

What would be a fair offer?

... think about it for a bit ...

Traditional Game Theory suggests offering the smallest amount to the other player...

fairness


But Behavioral Game Theory observes that people often reject unfair offers.

This shows a preference for fairness over pure monetary gain.

Example: The Trust Game

In this game, Player 1 can send money to Player 2. Any money sent is tripled. Then, Player 2 decides how much to send back.

  • If Player 1 sends $10, it turns into $30 for Player 2
  • Player 2 can then be nice and send $15 back, or be greedy and keep all $30

Logic says "Don't send any money, because Player 2 will just keep it." But Behavioral Game Theory shows that many people do trust each other, and it pays off!

Player 2
Returns $15
Keeps All
Player 1
Sends $10
$5, $15
$0, $30
Keeps All
$10, $0
$10, $0

happy
sad

Loss Aversion (we hate losing)

People hate losing more than they love winning. This is called Loss Aversion.

For example, losing $20 feels much worse than the "happy feeling" of finding $20. Because of this, players often pick a "safe" choice even if a "risky" choice might give them a huge prize.

Example: Playing It Safe

Imagine you must choose one of these options:

  • Safe choice: Get $5 for sure
  • Risky choice: 50% chance to win $15, 50% chance to lose $5

Even though the risky choice has a higher average payoff, many people choose the safe option because they really want to avoid the possibility of losing $5.

Loss aversion: The pain of losing $5 feels stronger than the pleasure of winning $15.

Example: A Game Show Decision

A contestant has already won $1,000. They are offered a final gamble:

  • 50% chance to win $2,000 total
  • 50% chance to drop back to $500

Many contestants refuse the gamble, even though it could double their money, because losing $500 feels worse than the joy of gaining another $1,000.

This is one reason companies keep existing production methods rather than inventing something new due to perceived risk.

Real World Use

Example: Habits and Safety

Sometimes people follow a "system" just because everyone else does. It feels safe.

  • Staying late at work to be seen, even when no extra work gets done
  • Teaching only to the test instead of building real understanding
  • Being "busy" as a sign of importance or success
  • Endlessly scrolling news feeds out of habit

Example: Selling Too Early

An investor buys a stock for $50.

  • If the price goes up to $60, they quickly sell to "lock in" the gain
  • If the price drops to $40, they often refuse to sell and keep hoping it will recover

People dislike the feeling of a realized loss more than they enjoy a realized gain, so they avoid selling at a loss even when it might be the smarter choice.

Loss aversion: Losing $10 feels worse than the pleasure of gaining $10.

Example: Keeping a Bad Plan

A company has already spent $1 million developing a product.

  • New information shows the product is unlikely to succeed
  • Stopping now would save money in the long run

Even so, managers often continue the project because stopping would mean "accepting the loss." They prefer to risk losing more money rather than admit the original loss.

Loss aversion: People work harder to avoid admitting losses than to achieve new gains.

This is often called throwing good money after bad.

In economics it is known as the sunk cost fallacy: money already spent is gone, so it should not affect future decisions.

Good decisions look forward, not backward.

When we know how humans actually act, we can build better ways to work together.

Conclusion

Behavioral Game Theory teaches us that being "smart" isn't just about math. It's about understanding people!