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Game Theory

Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

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Page 1: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

Game Theory

Page 2: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

Page 3: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

John von Neumann 1928 - Mathematical genius von Neumann,

25, plays poker, invents game theory. Sees someone bluff and realizes that the

best way to play the game is not to play the probabilities but to play according to what moves the competition makes.

Figures out mathematically what the optimal moves are when two rational people play a game.

Page 4: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

Game theory is about not making moves in a vacuum, but about making moves based on your evaluation of what your opponents’ most likely moves will be.

– And assuming that your opponent is rational and smart (able to think strategically).

– “Look forward and reason backward.” Game theory is the science of rational

behavior in interactive situations.

Page 5: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

1944 - von Neumann is a major force in inventing the atomic bomb and the modern computer.

1950 - Two Rand Corporation scientists invent the Prisoner’s Dilemma game.

Page 6: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

The Prisoner’s Dilemma In 1950 a conductor on a train to Kiev

rehearses for a Tchaikovsky concert. KGB arrests him for subversive activity. KGB arrests Boris Tchaikovsky, a worker,

on the streets of Kiev. KGB puts them in separate cells so they

can’t communicate. KGB offers them both a deal.

Page 7: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

The Prisoner’s Dilemma

If the conductor turns state evidence against Boris (rats) and Boris doesn’t, he gets one year in a gulag and Boris gets 25 years.

If the conductor doesn’t rat and Boris does, the conductor gets 25 years in a gulag and Boris gets only one year.

Page 8: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

The Prisoner’s Dilemma

If both rat, each gets 10 years. If neither rats, each get three years (for

doing nothing). The silent auction begins.

– Because they cannot communicate, they must each figure out what they other will rationally do, and act accordingly.

They are acting simultaneously.

Page 9: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

The Prisoner’s Dilemma Each serve 10 years, meet in the gulag,

begin talking, and discover they ratted on each other.

While talking they realize that if each had said nothing, they would only have been in for three years.

Page 10: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

Boris

Conductor

Rat Not Rat

Payoff Matrix

Rat

Not Rat

10, 10 * 1, 25

25, 1 3, 3

* Conductor, Boris

Page 11: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

A Modern Game KAAA-TV, on the West Coast, is

considering switching from its current prime time (8-11 p.m.) to early prime time (7-10 p.m.). KAAA is #2 in prime time, and because of KBBB’s very strong 10-11 p.m. lead-in to its late news, KAAA is #2 in late news even though its news product is competitive. KBBB is #1 in late fringe also.

Page 12: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

KBBB-TV is #1 in prime time and has excellent 10-11 p.m. network lead-ins to its 11 o’clock news, which puts it #1 in the late news race. KBBB is also #1 in late fringe.

KCCC-TV is a weak #3 in prime time and late news. It is a network-owned station and will not switch to early prime.

The solution of this problem requires looking forward and reasoning back.

Page 13: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

KAAA Decision Tree

KAAA

KAAA Go

KBBB Go

KBBB No Go

KAAA No Go KBBB Go

KBBB No Go

Page 14: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

Payoff Matrix

KBBB

KAAA

Go

No go

Go No Go

4, 2* 3, 4

1, 3 2, 1

Assigning weights is the most difficult decision.

* KAAA, KBBB

Page 15: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

KAAA’s Payoff Weights 4,2 = If KAAA switches (go) to early prime

and KBBB also switches (go), both gain more revenue from higher ratings for 10-10:30 p.m. late news. KBBB doesn’t gain as much as it would if KAAA switches and KBBB doesn’t (3,4).

Page 16: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

KAAA’s Payoff Weights 3,4 = If KAAA switches (go) and KBBB

doesn’t switch (no go) , KAAA gains revenue with its 10-10:30 p.m. news, but the news is up against KBBB’s strong prime and KBBB’s late news gets higher ratings than before because KAAA has dropped news from the time period.

Page 17: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

KAAA Payoff Weights 1,3 = If KAAA doesn’t switch (no go) and

KBBB switches (go), KAAA loses big because its weaker 10-11 p.m. prime is up against strong KBBB news which has strong lead-ins and strong late fringe.

2,1 = If KAAA doesn’t switch and KBBB doesn’t switch, nothing happens, but the outcome isn’t as bad as if KAAA doesn’t switch and KBBB switches (1,3)

Page 18: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

KAAA Strategies Adding KAAA go weights (4+3 = 7) shows

switching is the best strategy, because its no-go weights (1+2 = 3) are much worse.

KBBB’s assigned weights are the same with either decision (4+1 and 3+2 = 5).

Page 19: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

KAAA Strategies KAAA’s best strategy is to falsely

announce it’s staying with its current schedule, hoping KBBB will switch to gain an advantage and hurt KAAA (1,3).

Then, at the last moment, KAAA switches to early prime to gain its maximum outcome (4,2), assuming KBBB stays with its decision to switch.

Secrecy is an imperative.

Page 20: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

Strategic Moves

Secrecy Commitment (burning

the getaway boats) Threats and promises Deterrence and

compellence Warnings and

assurances

Trial balloons False announcements Preemptive strikes Tit-for-tat Bluffs

Page 21: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

Strategies

Tit-for-tit, while effective, leads to escalation in many situations.

– The dollar auction A dollar bill is put up for sale; minimum bid one cent. Proceeds as a regular auction. One exception: Auctioneer must be paid by highest bidder,

but also by the second highest bidder. – Winning bidders pay what they bid and receive a dollar. – Second-highest bidders pay what they bid and receive nothing.

Game introduced in 1971. Thousands of games, average paid was $3.41

Page 22: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

Strategies

Bluffing– Bluffers make statements, show behaviors, and

perform activities that would be perfectly all right if they were not completely unfounded.

– “Bluffing is like vitamins. It is essential in small amounts, but harmful if used excessively.” *

Laszlo Mero, Moral Calculations, Copernicus, 1998.

Page 23: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

Mixed Strategy

You can’t bluff all the time, no one will believe you.

If you never bluff, everyone will fold because they know you’re telling the truth.

You have to bluff occasionally.– A mixed strategy.– On a random basis: No identifiable pattern.

Page 24: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

Strategies

Strategies depend on the game.– Sequential or Simultaneous

Soccer goalie (sequential) Chicken (simultaneous) Gift of the Magi (simultaneous)

Page 25: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

Games

Zero-sum games– Assume a winner (+1), and a loser (-1)

Multi-player games– Marathon - 1000 racers, different niches (men-women),

several winners– Business – a marathon– Business strategies are about getting more than your

fair share (not necessarily winning as in a zero-sum game).

Profit Market share Dominate a niche

Page 26: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

The Prisoner’s Dilemma If the prisoners had been able to

communicate, what would have happened?

If they had been given a chance to play the game again and again, what would have happened?

Page 27: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

The Prisoner’s Dilemma The rules for the game changes when you

play repeatedly, as the Rand Corporation scientists discovered.

And if the other side gets greedy (which is inevitable), you must use tit-for-tat.

You must teach the other side cooperation (to accept three years in the gulag) – do what’s best for both.

Use game theory to force legal cooperation.

Page 28: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

Co-opetition *

Customers

Complementors

Suppliers

Competitors

Business Ecosystem

* Adam Brandenburger and Barry Nalebuff, Co-opetition, Currency Doubleday, 1996

Page 29: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

Co-opetition If you are Steve Jobs at Apple …

What is Google? What is Intel? What is Microsoft?

Remember, ecosystems co-evolve.– Wolves and caribou

Page 30: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

Co-opetition It might be a smart strategic move to

change the game and the players. In fact, it might be a smart strategic move

to pay someone to compete.– GE tried to get Time Warner to bid for NBC U

Page 31: Game Theory. Poker Do you play poker? Do you play the probabilities? What happens when someone bluffs?

Business Insanity

“Doing the same thing over and over and expecting different results.”

Brainstorm to find new and different solutions, think strategically, and use game theory.

– Look forward and reason backward.