List of games in Chapter 12 Incomplete Information

Using Comlabgames


Game title

 (right click on the game to download it)

Short description of the experiment

12.1: Armageddon in extensive form


The northern hemisphere is inhospitable for large mammals, because of radioactive deposits from previous nuclear conflicts, atmospheric pollution, debilitating viral diseases, and low fertility rates. The bulk of the world's human population of 400 million live in South America and Australasia. The game inspired by this bleak scenario of a future world has only two players, Australia and Brazil. Incomplete information arises because Brazil is aware that they will know if they chose military expedition at the beginning of the game but Australia cannot know this.

12.2: Armageddon in the strategic form

12.3: Armageddon perfect information in extensive form

12.4: Traffic in extensive form

Illegal trade is big business. The stakes, and the excitement, are high for those playing on both sides of the law. The following example show why random behavior is inherent part of drug traffic and also of law enforcement authorities' attempts to curtail it. In its war on drugs, the DEA seeks to imprison those who profit most from the drug trade, partly because it directly reduces the supply of drugs, and also because it reduces the incentives of those people who specialize in the trade to enter it in the first place. An important tool of the DEA is to bribe small operators into betraying larger dealers. At the initial node the dealer chooses between proposing a job to his drug ring boss, or first approaching the DEA about the possibility of a sting that could lead to his boss's arrest. If the dealer chooses the latter, one response of the DEA is to arrest and convict the dealer on relatively minor charges. Another is to order a sting in the hope of ensuring the boss. Thus when the boss is approached by the dealer, he understands that the plan to enter a new market might be genuine or a ruse.

12.5: Total quality management in extensive form

    Producers have the opportunity to compromise the versatility, strength and integrity of their products by using cheaper materials and tolerating poorer workmanship. The advantage of this strategy is that costs are reduced, the disadvantage is that consumers might shun the product, thus reducing its demand. Retailers play a role in the marketing process, preferring to sell brands that consumers are happy with. Because retailers play a monitoring role, producers also benefit from the promotion of their produce through the amount of shelf space and store advertising. In this game the producer chooses between manufacturing a defective or a flawless item, which is then delivered to a retailer. The retailer inspects its quality and decides whether to market the item or not. If the item is returned to the producer as defective, the producer incurs a loss. If the item is marketed by the retailer the producer gains regardless of whether the item sells or not, but would much prefer a sale.

12.6: TQM with partial refund in extensive form game

12.7: Starting a new business in the extensive form

When an entrepreneur or an innovator approaches a partner, there is often a question about how much each potential partner knows about the market opportunities. In this game entrepreneur knows if the opportunity exists or not when he invites a potential partner. The potential partners knows the probability weights for the possible opportunity when he is approached by the enterprenour.

12.8: Starting a new business, reduced form in the extensive form

12.9: Starting a new business in the strategic form

12.10: Mechanic in the extensive form

The problem of getting truthful professional advice is illustrated by the stereotypical experience that car and house owners face when dealing with tradesmen and mechanics. Suppose the owner detects a noise that never occurred before and occurs intermittently. Past experience with previous vehicles and those of her friends suggests that there is an even chance that this signals a severe problem that will grow worse if remedial action is not taken, versus a minor problem that can be ignored with any repercosion  If the problem is sever the car will break down and cost $2,000, in which case the mechanic has 20 percent chance of getting the job. If he does not get the job, he will be otherwise occupied with jobs from other clients. Her first choice is whether to visit the mechanic, a visit that would cost $200 for his diagnosis. For this price the mechanic can indeed tell what the nature of the problem is and how to fix it. At this point the car owner decides whether to have the car repaired or not.

12.11: Mechanic, reduced form in the extensive form

12.12: Mechanic in the strategic form

12.13: Espionage in the extensive form

When a country is planning to invade another, the tactical advantage of surprise partly compensates for the disadvantages confronting foreign troops seeking to overwhelm an army defending its own land. Consequently the defending force has a great incentive to neutralize the surprise element by infiltrating the intelligence network of the invaders, and communicating the invasion plans to the defenders. In this example the United States is planning to topple the current regime in Iraq and replace it with one which has interests that are more closely tied to North America's. At the initial node it chooses between two main strategies, a land assault undertaken by a large number of ground troops, versus air strikes that are coupled with the strategic use of a relatively small force whose goal is to orchestrate and coordinate internal rebellion by opposition groups within Iraq. A spy working for the Iraqis has infiltrated U.S. intelligence. After a decision has been reached about the form of the invasion, the spy sends a message to the government in Iraq, and the Iraqis prepare for a land or air attack.

In the game without a spy, the payoffs and the game structure is the same (i.e. neither Iraq not America sees each others move)

12.14: Retaliation without spies in the extensive form

12.15: Retaliation without spies in the strategic form

12.16: Product development race in the extensive form game

Often companies do not know precisely how much competition they will face before launching a new product. Consider two rival firms are competing with each other to discover and introduce a new product. Both players: Thomson and Smith have two strategies to advertise product or to charge low price. When they are making a decision they do not know if both developed the product or just by himself.

12.17: Product development race in the strategic form

12.18: Product development race with an industry newsletter in the extensive form

This game has only one difference from the previous product development race: a newsletter is produced to keep firms abreast of the latest developments and it announces who developed the product before Thomson and Smith decided between advertising and low price. This information changes the game to be a prisoner dilemma game.


12.19: Product development race with an industry newsletter in the strategic form

12.20: Medical malpractice in the extensive form

One problem health insurance providers face is fraudulent behavior by doctors who prescribe treatment for healthy clients. When a doctor inspects a client she knows if the client is sick or healthy. She prescribes a treatment or does not recommend it. Client does not know if he is sick or not and he has a choice to take the treatment, seeks another opinion or ignore it.

12.21: Medical malpractice in the strategic form

12.22: Medical malpractice with full information in the extensive form