Why Do Interviewers Ask "why Are You Interested in This Position"?

Interviewers typically ask about a candidate's interest in a position to discern whether the candidate's motives and passion for the job align with what the interviewer expects. A hiring manager for a customer service job would like to know whether an applicant has a genuine desire to help people.

An additional reason the interviewer asks this question is to gauge whether a the candidate has researched or understands the nature of the position. If the candidate indicates the motive for the job is a paycheck or something unrelated to the actual work, this may signal that the work does not align with the candidate's interests and abilities.