Addressing demand artifacts in psychological research (and beyond)

Demand artifacts stem from participants' beliefs about treatment effects and motivations to respond in accordance with these beliefs. These artifacts typically build on subtle cues that exert extraneous influences unbeknownst to researchers, through processes that are not part of their stated theory. Demand artifacts threaten the internal and external validity of studies, and they have been supported across a wide range of psychological domains (e.g., clinical, cognitive, and social psychology, psychology of perception) and beyond (e.g., consumer research, experimental economics, psychosomatic medicine, neurosciences). This article reviews prominent methods used to address them. Our discussion is structured around Corneille and Lush's (2023) framework of demand effects, which distinguishes between participants' hypothesis formation, motivation, and implementation strategies. We conclude this review by discussing three fundamental questions of broad interest: when should we care about demand artifacts, what is the best approach for addressing them, and how can we usefully build on demand artifacts?