Deception in research refers to the deliberate withholding of information, providing incomplete information, or presenting false information to research participants so that their behavior remains natural and unbiased. It is generally used in situations where revealing the true purpose of the study would influence participants' responses and compromise the validity of the findings. Although deception is most common in psychological and social science research, it may also be employed in anthropology, sociology, communication studies, and behavioral research under carefully regulated ethical conditions. The primary purpose of deception is to eliminate response bias, demand characteristics, and the Hawthorne effect, where participants modify their behavior because they know they are being observed. By concealing the actual objective of the study, researchers can collect more authentic and reliable data. For example, in studies examining honesty, prejudice, conformity, or helping behavior, participants may act differently if they know the exact hypothesis being tested. In such cases, limited deception helps researchers observe genuine human behavior. Deception can take several forms. Direct deception occurs when participants are intentionally given false