General rules

Welcome and thank you for participating in this HIT run by researchers at the University of Cambridge and the University of Oxford (UK).

There are 4 parts to the HIT:

• Instructions
• Quiz
• Experiment
• Final Questionnaire

You will earn $2 for sure only if you complete the Experiment and the Final Questionnaire. In addition, you can win points that will be converted into real earnings in dollars. We expect the average total earnings to be within the $5-8 range, but your actual earnings may vary considerably depending on your performance.

The expected duration of the HIT is about 45 minutes, and you need to fully dedicate your time to this HIT for the next 45 minutes. If you exit at any point before completion, you will not receive any earnings.

The aim of this HIT is to study how individuals make decisions in certain contexts. You will make decisions that will affect your earnings and the earnings of other Turkers.

All your decisions will remain completely confidential. We will not disclose your Turker ID or any other information that might allow others to identify you.

You will be asked to take a Quiz to ensure that you understand the Instructions. If you cannot pass the Quiz within 3 tries, you will not be able to participate in the Experiment.

The expected average time before you reach the Quiz is 10 minutes, and it is important that you read through the Instructions carefully.

Please click the "Next" link below to continue.

General information

In this HIT you are an Employee who has to decide how much effort to exert on two tasks. The Computer plays the role of an Employer. You will be compensated according to a contract which is randomly chosen by the Employer between two different contracts.

The experiment lasts for 15 rounds. In every round you choose efforts for each task under each contract, and you learn the points you have won after the random selection of contract by the Employer at the end of the round. You do not interact with any other Turker throughout this experiment. Your decisions in one round do not affect the random selection of contract by the Employer in the following rounds. No one is informed about your decisions.

In each round you and the Employer make the following decisions simultaneously:

• The Employer randomly selects either Contract L or Contract R. The selection is completely random, and therefore there is a 50% chance that you will be compensated according to Contract L and a 50% chance that you will be compensated according to Contract R. The contract specifies how the wage is determined by the costly efforts you choose for the green task and for the blue task.
• You choose efforts on the green task and on the blue task for Contract L, and on the green task and on the blue task for Contract R. Efforts are costly to you. You choose efforts for both Contract L and Contract R because at this stage you do not know the outcome of the random selection of contract by the Employer.

At the end of the round, you are given the following information: the contract randomly selected by the Employer, the efforts you have chosen for the contract randomly selected by the Employer, the points won by the Employer, and the points you won.

The next part of the Instructions explains the decision task in detail. Please click the 'Next' link below to continue.

Choice of efforts

You, as an Employee, choose the efforts on the green task and on the blue task for each of the two contracts.

The Employer selects which contract to offer you at random after you have chosen efforts on the green task and the blue task for both Contract L and Contract R, and therefore there is a 50% chance that you will be compensated according to Contract L and a 50% chance that you will be compensated according to Contract R. Note that the random selection of contract by the Employer is not influenced by your choice of efforts. At the end of a round, the Employer's contract selection and your choice of efforts for the contract the Employer has selected will be revealed to you.

We will now explain in detail what you will see and how you can choose the efforts.

Top row of the screen

The top row reminds you that you are in the "Choice of efforts" stage. It also shows a countdown timer that indicates the time you have left to make your decisions. In total, you have 90 seconds to complete the round.

Top of the screen

This is where you see the information on Contract L and Contract R, where the letters simply indicate the left and right parts of the screen where the contracts are displayed.

Upper-left of the screen

On the left side of the screen you will see the information for Contract L:

Under Contract L, you get paid a wage which depends on the outcome of a coin toss that happens after you have chosen the efforts on the green task and on the blue task.

There is a 50% probability that the coin toss yields "Heads", in which case you get paid the following wage: $$ \text{Wage} = 1.8 \times \begin{pmatrix} \color{#00CC66}{Green}\\ effort \end{pmatrix} + 1 $$

There is a 50% probability that the coin toss yields "Tails", in which case you get paid the following wage: $$ \text{Wage} = 1.8 \times \begin{pmatrix} \color{#3399FF}{Blue}\\ effort \end{pmatrix} + 1 $$

Upper-right of the screen

On the right side of the screen you will see the information for Contract R:

Under Contract R, you get paid the following wage: $$ \text{Wage} = 0.9 \times \begin{pmatrix} \color{#00CC66}{Green}\\ effort \end{pmatrix} + 0.9 \times \begin{pmatrix} \color{#3399FF}{Blue}\\ effort \end{pmatrix} + 1 $$

Middle of the screen

This is where you make your decisions in the round by choosing the efforts on the green task and on the blue task for Contract L, and the efforts on the green task and on the blue task for Contract R. The efforts are in percentages so the minimum effort is 0% and the maximum effort is 100%.

The difference between the green task and the blue task is that at the beginning of every round, one task is randomly picked by the Employer to be "easy" while the other task is "difficult". This random determination of "easy" and "difficult" is repeated every round for each Employee. In other words, in each round there is a 50% probability that the green task is easy while the blue task is difficult, and a 50% probability that the blue task is easy while the green task is difficult. Each unit of effort on the "difficult" task has double the cost of each unit of effort on the easy task. The overall cost of efforts is given by the following formula: $$ \text{Cost of efforts} = 0.5 \times \left[ \begin{pmatrix} Effort\\ easy\\ task \end{pmatrix} + 2 \times \begin{pmatrix} Effort\\ difficult\\ task \end{pmatrix} \right] ^{\Large{2}} $$

A row of text across the middle of the screen will inform you which tasks the computer has randomly picked as the easy and the difficult ones in this round.

If the computer has randomly picked the blue task as the easy task and the green task as the difficult task, then you will see the following:

Otherwise, if the computer has randomly picked the green task as the easy task and the blue task as the difficult task, then you will see the following:

Middle-left of the screen

This is where you choose efforts for the green task and the blue task for Contract L.

There are two sliders labelled "Effort green task" and "Effort blue task". You can choose a specific effort by pointing the mouse and clicking on the slider. Once you have clicked on the slider, a handle bar will appear. You can choose an effort level by clicking on the slider using your mouse and then drag it to the left/right by moving your mouse and keeping the left button of your mouse pressed down.

As an example, suppose the computer has randomly picked the green task as the easy task, and therefore the blue task as the difficult task. Using the sliders below, try to choose 45% effort on the green task and 30% effort on the blue task:

The "Cost of efforts" box updates to indicate the cost for you of this combination of efforts: $$ \begin{align} \text{Cost of efforts} &= 0.5 \times \left[ \begin{pmatrix} Effort\\ easy\\ task \end{pmatrix} + 2 \times \begin{pmatrix} Effort\\ difficult\\ task \end{pmatrix} \right] ^{\Large{2}} \\ &= 0.5 \times \left[ \frac{45}{100} + 2 \times \frac{30}{100} \right]^{\Large{2}} = 0.55 \end{align} $$

The two "Wage" boxes update to indicate the Wage you get from the Employer, depending on the outcome of the coin toss.

There is a 50% probability that the coin toss yields "Heads", in which case you get the following wage: $$ \begin{align} \text{Wage} &= 1.8 \times \begin{pmatrix} \color{#00CC66}{Green}\\ effort \end{pmatrix} + 1 \\ &= 1.8 \times \frac{45}{100} + 1 = 1.81 \end{align} $$

There is a 50% probability that the coin toss yields "Tails", in which case you get the following wage: $$ \begin{align} \text{Wage} &= 1.8 \times \begin{pmatrix} \color{#3399FF}{Blue}\\ effort \end{pmatrix} + 1 \\ &= 1.8 \times \frac{30}{100} + 1 = 1.54 \end{align} $$

For each outcome of the coin toss, there are two boxes labelled "Your points" and "Employer's points": they update to indicate the points you and the Employer would win, for each outcome of the coin toss, if the Employer selected Contract L and you chose this combination of efforts. We will explain on the next page how your and the Employer's point tally is computed.

Middle-right of the screen

This is where you choose efforts for the green task and the blue task for Contract R.

As an example, suppose the computer has randomly picked the blue task as the easy task, and therefore the green task as the difficult task. Using the sliders below, try to choose 37% effort on the blue task and 18% effort on the green task:

The "Cost of efforts" box updates to indicate the cost for you of this combination of efforts: $$ \begin{align} \text{Cost of efforts} &= 0.5 \times \left[ \begin{pmatrix} Effort\\ easy\\ task \end{pmatrix} + 2 \times \begin{pmatrix} Effort\\ difficult\\ task \end{pmatrix} \right] ^{\Large{2}} \\ &= 0.5 \times \left[ \frac{37}{100} + 2 \times \frac{18}{100} \right]^{\Large{2}} = 0.27 \end{align} $$

The "Wage" box updates to indicate that with Contract R the Wage you would get if you chose these efforts is equal to: $$ \begin{align} \text{Wage} &= \left( 0.9 \times \begin{pmatrix} \color{#00CC66}{Green}\\ effort \end{pmatrix} \right) + \left( 0.9 \times \begin{pmatrix} \color{#3399FF}{Blue}\\ effort \end{pmatrix} \right) + 1 \\ &= \left( 0.9 \times \frac{18}{100} \right) + \left( 0.9 \times \frac{37}{100} \right) + 1 = 1.49 \end{align} $$

The boxes labelled "Your points" and "Employer's points" update to indicate the points you and the Employer would win if the Employer randomly selected Contract R and you chose this combination of efforts. We will explain on the next page how your and the Employer's point tally is computed.

Bottom of the screen

This is where you confirm your decisions.

The left part of the screen reminds you of your choices of efforts for the green task and the blue task for Contract L.

The right part of the screen reminds you of your choices of efforts for the green task and the blue task for Contract R.

To confirm your choices, you click on the "Submit all efforts" button.

Please click the "Next" link below to continue.

How to win points

This page explains how you and the Employer win points in each round.

At the end of each round, you will a summary of the following form.

The summary shows the following information: the Employer's random selection of contract, your choice of efforts for the contract randomly selected by the Employer, the outcome of the coin toss if the Employer selected Contract L, and the number of points you and the Employer have won.

The Employer wins a number of points that depends on the efforts you chose for the green task and the blue task minus the Wage the Employer pays you: $$ \text{Points the Employer wins} = (32 \times \text{low effort task}) + (4 \times \text{high effort task}) - \text{Wage} $$

"Low effort task" means whichever of the efforts on the two tasks was lower. Likewise, "high effort task" means whichever of these two efforts was higher. For example, if you chose higher effort for the green task than for the blue task, the Employer wins: $$ \text{Points the Employer wins} = 32 \times \begin{pmatrix} \color{#3399FF}{Blue}\\ effort \end{pmatrix} + 4 \times \begin{pmatrix} \color{#00CC66}{Green}\\ effort \end{pmatrix} - \text{Wage} $$

You, the Employee, win a number of points equal to the Wage the Employer pays you minus the total cost of the efforts you chose on the green task and the blue task: $$ \text{Points you win} = \text{Wage} - 0.5 \times \left[ \begin{pmatrix} Effort\\ easy\\ task\\ \end{pmatrix} + 2 \times \begin{pmatrix} Effort\\ difficult\\ task \end{pmatrix} \right] ^{\Large{2}} $$

We will now go through two examples to make sure you understand how you and the Employer win points depending on your decisions.

Example 1

Suppose that in this round:

• The Employer randomly selects Contract L.
• The task randomly picked by the computer to be easy for you is the green task.
• You choose 55% effort on the green task and 12% on the blue task.

The cost to you of choosing 55% effort on the easy green task and 12% effort on the difficult blue task is: $$ \begin{align} \text{Cost of efforts} &= 0.5 \times \left[ \begin{pmatrix} Effort\\ easy\\ task \end{pmatrix} + 2 \times \begin{pmatrix} Effort\\ difficult\\ task \end{pmatrix} \right] ^{\Large{2}} \\ &= 0.5 \times \left[ \frac{55}{100} + 2 \times \frac{12}{100} \right]^{\Large{2}} = 0.31 \end{align} $$

During the experiment you will not need to compute this yourself: the total cost of efforts is automatically displayed in the "Cost of efforts" box as you move the sliders to choose the efforts. Using the sliders below, check that the cost to you of choosing 55% effort on the green task and 12% on the blue task is 0.31.

After you have chosen efforts, the Employer tosses a coin. For the purpose of this example, suppose that the outcome is "Heads".

According to Contract L, as you can see using the sliders above, when the outcome is "Heads" the Wage is equal to: $$ \text{Wage} = 1.8 \times \begin{pmatrix} \color{#00CC66}{Green}\\ effort \end{pmatrix} + 1 = \left(1.8 \times \frac{55}{100}\right) + 1 = 1.99 $$

We can now compute the total points you and the Employer win: $$ \text{Points you win} = \text{Wage} - (\text{Cost of efforts}) = 1.99 - 0.31 = 1.68 $$ $$ \begin{align} \text{Points the Employer wins} &= \left( 32 \times \begin{pmatrix} lower\\ effort \end{pmatrix} \right) + \left( 4 \times \begin{pmatrix} higher\\ effort \end{pmatrix} \right) - \text{Wage} \\ &= \left( 32 \times \begin{pmatrix} \color{#3399FF}{Blue}\\ effort \end{pmatrix} \right) + \left(4 \times \begin{pmatrix} \color{#00CC66}{Green}\\ effort \end{pmatrix} \right) - \text{Wage} \\ &= \left( 32 \times \frac{12}{100} \right) + \left( 4 \times \frac{55}{100} \right) - 1.99 = 4.05 \end{align} $$

When the outcome is "Tails" the Wage is equal to: $$ \text{Wage} = 1.8 \times \begin{pmatrix} \color{#3399FF}{Blue}\\ effort \end{pmatrix} + 1 = \left(1.8 \times \frac{12}{100}\right) + 1 = 1.22 $$

We can now compute the total points you and the Employer win: $$ \text{Points you win} = \text{Wage} - (\text{Cost of efforts}) = 1.22 - 0.31 = 0.91 $$ $$ \begin{align} \text{Points the Employer wins} &= \left( 32 \times \begin{pmatrix} lower\\ effort \end{pmatrix} \right) + \left( 4 \times \begin{pmatrix} higher\\ effort \end{pmatrix} \right) - \text{Wage} \\ &= \left( 32 \times \begin{pmatrix} \color{#3399FF}{Blue}\\ effort \end{pmatrix} \right) + \left(4 \times \begin{pmatrix} \color{#00CC66}{Green}\\ effort \end{pmatrix} \right) - \text{Wage} \\ &= \left( 32 \times \frac{12}{100} \right) + \left( 4 \times \frac{55}{100} \right) - 1.22 = 4.82 \end{align} $$

Example 2

Suppose that in this round:

• The Employer randomly selects Contract R.
• The task randomly picked by the computer to be easy for you is the blue task.
• You choose 34% effort on the easy blue task and 5% effort on the difficult green task.

The cost to you of choosing 34% effort on the easy blue task and 5% effort on the difficult green task is: $$ \begin{align} \text{Cost of efforts} &= 0.5 \times \left[ \begin{pmatrix} Effort\\ easy\\ task \end{pmatrix} + 2 \times \begin{pmatrix} Effort\\ difficult\\ task \end{pmatrix} \right] ^{\Large{2}} \\ &= 0.5 \times \left[ \frac{34}{100} + 2 \times \frac{5}{100} \right]^{\Large{2}} = 0.10 \end{align} $$

Using the sliders below, check that the cost to you of choosing 34% effort on the blue task and 5% effort on the green task is 0.10.

According to Contract R, as you can see using the sliders above, the Wage is equal to: $$ \begin{align} \text{Wage} &= 0.9 \times \begin{pmatrix} \color{#00CC66}{Green}\\ effort \end{pmatrix} + 0.9 \times \begin{pmatrix} \color{#3399FF}{Blue}\\ effort \end{pmatrix} + 1 \\ &= \left( 0.9 \times \frac{34}{100} \right) + \left( 0.5 \times \frac{5}{100} \right) + 1 = 1.35 \end{align} $$

We can now compute the total points you and the Employer win: $$ \text{Points you win} = \text{Wage} - (\text{Cost of efforts}) = 1.35 - 0.10 = 1.25 $$ $$ \begin{align} \text{Points the Employer wins} &= \left( 32 \times \begin{pmatrix} lower\\ effort \end{pmatrix} \right) + \left( 4 \times \begin{pmatrix} higher\\ effort \end{pmatrix} \right) - \text{Wage} \\ &= \left( 32 \times \begin{pmatrix} \color{#00CC66}{Green}\\ effort \end{pmatrix} \right) + \left(4 \times \begin{pmatrix} \color{#3399FF}{Blue}\\ effort \end{pmatrix} \right) - \text{Wage} \\ &= \left( 32 \times \frac{5}{100} \right) + \left( 4 \times \frac{34}{100} \right) - 1.35 = 1.61 \end{align} $$

Please click the "Next" link below to continue.

Your earnings

At the end of the experiment, 3 out of 15 rounds will be randomly selected by the computer, and the points won in these rounds will determine your earnings. The exchange rate from points to US dollars is: $$ \text{1 point} = \text{\$1} $$

Let V = number of points won in the 3 randomly drawn rounds, then your total bonus in addition to the $2 fixed participation fee will be equal to $V. For example, if V = 4 points, then at the end of the experiment you will earn a $4 bonus plus the $2 fixed participation fee.

You can also win an additional bonus payment in the Final Questionnaire. We will explain this when you are doing the Final Questionnaire.

Please click the "Next" link below to continue to an "interactive tour" of the interface.