The unintended effects of the researcher's presence on participants' behaviour are known as the Hawthorne effect.

• A. Hawthorne effect
• B. Interviewer effect
• C. Subjectivity
• D. Laboratory experiments

Answer: (A)

The idea being tested is reactivity: people change their behavior when they know they are being watched. The Hawthorne effect captures this by noting that participants may alter how they act simply because an observer is present or because they feel singled out for study. This is an unintended consequence of research because the researcher’s presence unintentionally influences what the participants do, which can affect the study’s results.

Why this is the best fit: it directly names the phenomenon—behavior changes due to the awareness of being observed by researchers—without tying it to a specific method or setting. The other terms describe different things: an interviewer effect focuses on how the person asking questions might shape responses during interviews; subjectivity refers to personal biases in interpreting data; laboratory experiments describe a research setting or method, not the unintended behavioral changes caused by being studied.