Decision Experiment

Decision-Making Experiment: Choices between Gambles

This is a study of decision making in which you can gamble without risk and perhaps even win some money, if you are lucky. At the same time, your participation in this study can help scientists in the Decision Research Center learn more about how people make choices. Decide first if you want to participate. You must be over 18, and each person can participate only once. Scroll down and look over the questionnaire. It usually takes about 5-10 minutes.

Email address:
We will notify you by email if you are a winner.
Country:
Age: You must be over 18 years to participate.
Are you Male or Female?
          Female
      OR
          Male

Education (in years).  
  If you are a college graduate, put 16.
  If you have a Ph.D., put 20.
Education:  Years.

Now, look at the first choice, No. 1, below.   Would you rather play: 
        A: fifty-fifty chance of winning either $100 or $0 (nothing), 
OR
        B: fifty-fifty chance to win either $35 or $25.

Think of probability as the number of tickets in a bag containing 100 tickets, divided by 100. Gamble A has 50 tickets that say $100 and 50 that say $0, so the probability to win $100 is .50 and the probability to get $0 is .50. If someone reaches in bag A, half the time they might win $0 and half the time $100. But in this study, you only get to play a gamble once, so the prize will be either $0 or $100. Gamble B's bag has 100 tickets also, but 50 of them say $25 and 50 of them say $35. Bag B thus guarantees at least $25, but the most you can win is $35. Some will prefer A and others will prefer B. To mark your choice, click the button next to A or B. Notice that the dot next to No. 1 will empty and fill in the button next to your choice.

In this study, gambles with be described with decumulative probabilities. Decumulative probabilities are simply the chances of winning a certain amount or more. In the example, the choice between A and B will be written as follows:

A:  .50 probability to win $100 or more
   1.00 probability to win $0 or more
   
OR

B:  .50 probability to win $35 or more
   1.00 probability to win $25 or more

In gamble A, the probability to win $100 or more is .50, because the probability to win $100 is .50. Even though it says, "$100 or more", you should assume that the prizes will be the LEAST value that make the statement true. Thus, you should not assume that you might win more than $100. The probability is 1.00 (a sure thing) to win either $0 or more. In gamble B, the probability to win $35 or more is .50, and you are sure to win $25 or more, since you have a fifty-fifty chance to win either $35 or $25. Thus the choice as described above is the same as a choice between fifty-fifty to win $100 or $0 versus fifty-fifty to win $25 or $35.

To summarize: there are 50 tickets to win $100, so there are 50 tickets to win $100 or more; there are 50 tickets to win $0; by adding these to the 50 to win $100, there are a total of 100 tickets to win $0 or more. In B, there are 50 tickets to win $35, so there are 50 to win $35 or more; and there are 50 to win $25; adding these to the 50 to win $35, that makes 100 tickets to win $25 or more. A probability of 1.00 is a "sure thing", so you are sure to win at least $0 in A and you are sure to win at least $25 in B.

For each choice below, click the button beside the gamble you would rather play. On June 21, 2003, after people have finished their choices, three people will be selected randomly to play one gamble for real money. One trial will be selected randomly from the 20 trials, and if you were the lucky person, you will get to play the gamble you chose on the trial selected. You might win as much as $110. Any one of the 20 choices might be the one you get to play, so choose carefully. Winners will be notified by email. Offer void where prohibited by law.

1. Which do you choose? A: .50 probability to win $100 or more 1.00 probability to win $0 or more OR B: .50 probability to win $35 or more 1.00 probability to win $25 or more 2. Which do you choose? C: .50 probability to win $100 or more 1.00 probability to win $0 or more OR D: .50 probability to win $45 or more 1.00 probability to win $35 or more 3. Which do you choose? E: .20 probability to win $100 or more .50 probability to win $96 or more 1.00 probability to win $50 or more OR F: .20 probability to win $100 or more .50 probability to win $62 or more 1.00 probability to win $50 or more 4. Which do you choose? G: .10 probability to win $108 or more .60 probability to win $12 or more 1.00 probability to win $2 or more OR H: .10 probability to win $108 or more .60 probability to win $96 or more 1.00 probability to win $2 or more 5. Which do you choose? I: .90 probability to win $96 or more .95 probability to win $14 or more 1.00 probability to win $12 or more OR J: .85 probability to win $96 or more .90 probability to win $90 or more 1.00 probability to win $12 or more 6. Which do you choose? K: .10 probability to win $44 or more .20 probability to win $40 or more 1.00 probability to win $2 or more OR L: .10 probability to win $98 or more .20 probability to win $10 or more 1.00 probability to win $2 or more 7. Which do you choose? M: .91 probability to win $99 or more .94 probability to win $96 or more 1.00 probability to win $6 or more OR N: .94 probability to win $99 or more .97 probability to win $8 or more 1.00 probability to win $6 or more 8. Which do you choose? O: .20 probability to win $44 or more 1.00 probability to win $10 or more OR P: .10 probability to win $98 or more 1.00 probability to win $10 or more 9. Which do you choose? Q: .80 probability to win $98 or more 1.00 probability to win $40 or more OR R: .90 probability to win $98 or more 1.00 probability to win $10 or more 10. Which do you choose? S: .80 probability to win $110 or more .90 probability to win $44 or more 1.00 probability to win $40 or more OR T: .80 probability to win $110 or more .90 probability to win $98 or more 1.00 probability to win $10 or more 11. Which do you choose? U: .85 probability to win $96 or more .90 probability to win $96 or more .95 probability to win $14 or more 1.00 probability to win $12 or more OR V: .85 probability to win $96 or more .90 probability to win $90 or more .95 probability to win $12 or more 1.00 probability to win $12 or more 12. Which do you choose? W: .90 probability to win $106 or more .95 probability to win $96 or more 1.00 probability to win $12 or more OR X: .90 probability to win $106 or more .95 probability to win $52 or more 1.00 probability to win $48 or more 13. Which do you choose? Y: .91 probability to win $99 or more .94 probability to win $96 or more .97 probability to win $6 or more 1.00 probability to win $6 or more OR Z: .91 probability to win $99 or more .94 probability to win $99 or more .97 probability to win $8 or more 1.00 probability to win $6 or more 14. Which do you choose? a: .95 probability to win $96 or more 1.00 probability to win $12 or more OR b: .90 probability to win $96 or more 1.00 probability to win $48 or more 15. Which do you choose? c: $1 for sure OR d: .01 probability to win $100 or more 1.00 probability to win $0 or more 16. Which do you choose? e: $3 for sure OR f: .01 probability to win $100 or more 1.00 probability to win $0 or more 17. Which do you choose? g: .05 probability to win $96 or more .10 probability to win $12 or more 1.00 probability to win $3 or more OR h: .05 probability to win $52 or more .10 probability to win $48 or more 1.00 probability to win $3 or more 18. Which do you choose? i: $90 for sure OR j: .99 probability to win $100 or more 1.00 probability to win $0 or more 19. Which do you choose? k: $96 for sure OR l: .99 probability to win $100 or more 1.00 probability to win $0 or more 20. Which do you choose? m: .05 probability to win $96 or more 1.00 probability to win $12 or more OR n: .10 probability to win $52 or more 1.00 probability to win $12 or more ----------- 21. Have you ever read a scientific paper (i.e., a journal article or book) on the theory of decision making or on the psychology of decision making? No. Never. OR Yes, I have.

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