Its main purpose is to measure whether a person's circadian rhythm (biological clock) produces peak alertness in the morning, in the evening, or in between.
Assume that you work a five-hour day (including breaks), your job is interesting, and you are paid based on your performance.
Responses to the questions are combined to form a composite score that indicates the degree to which the respondent favors morning versus evening.
[6] A study in 2000 showed that both "morningness" and "eveningness" participants performed poorly in the morning on the Multidimensional Aptitude Battery (MAB) tests.
It found a negative correlation in women, but not in men, suggesting that gender-related variables may be attributed to morningness and eveningness when looking at mood.