Answer:
Self-report
Step-by-step explanation:
A self-report is a method of research in which a participant is asked about his feelings, attitudes, beliefs, etc. This means that the participant is the one who reports his own personal information. Most of the time, this is done through the use of documents such as questionnaires, interviews and surveys. In this example, the psychologist wants to employ self-report in order to find out which incentives cause workers to work harder.