The MTurk participants first practice the key-pressing task in a trial round for 10 seconds, then work on the bonus round for 5 minutes in which they may earn bonus payments.
Before they start to work on the key-pressing task, they receive different information on how they will earn bonus payments depending on their assigned treatments. Their instructions read as the follows:
"In this round, you will be randomly matched to another worker recruited for this study.
You and your paired other worker will independently work on the task for 5 minutes. The pair of you will earn a joint bonus reward of $2 for completing this task."
For participants assigned to the equal treatment, they will be paid by an equal bonus scheme, and read:
"You and the other worker will each earn $1, regardless of your scores."
For participants assigned to the tournament treatment, they will be paid by a tournament bonus scheme, and read:
"The worker with the higher score will earn $2, the other worker will not earn any bonus."
For participants assigned to the proportional treatment, they will be paid by a proportional bonus scheme, and read:
"You and the other worker will split the $2 bonus proportional to your scores."