Deception has been used for many years in psychology, sociology, behavioral economics, and medicine. Although researchers and disciplines have defined deception differently, one common definition involves providing participants with false information about the purpose, content, or process of a study (Adair et al., 1983; Baumrind, 1985; Menges, 1973; Nicks et al., 1997). Deception can be used in different ways. Some of these involve hiding a study’s true purpose from the participants; giving false or incorrect information about the purpose, feedback (e.g., personality, test/task success), people involved in the research process, stimuli, or measurement tools; presenting the stages of the study to participants as different studies; or taking psychological or physiological measurements without the participants’ awareness.

Deception used in research can be active or passive, depending on the method (Kimmel, 2004). Active deception involves the participant being given false information about the purpose of the research, the identity of the researcher, and/or the materials. Meanwhile, passive deception entails the researcher intentionally hiding certain information from the participants and not sharing information about the purpose of the research or its processes with the participants (Gross & Fleeming, 1982; Kimmel et al., 2011). Deception has also been separated into the two categories of mild and severe deception based on the consequences. A low risk of harm to a participant characterizes mild deception, which occurs based on providing false information or concealing information about the purpose and/or contents of the research. Conversely, severe deception has a high probability of harming a participant and involves providing false information about important aspects of the participant’s self and/or personality. Severe deception may have negative consequences such as anxiety and trauma (Kimmel, 2004).

Deception raises questions about ethics, methodology, and the reputation of the science and the profession. Milgram’s (1974) obedience studies are an exemplary example of how deception can lead to ethical problems. In that study, participants who were uncomfortable giving electric shocks to another participant in the role of a student showed reactions of stress, fear, and anxiety. Moreover, the effects of these negative emotions did not disappear over a short time. Physical or psychological harm to research participants is one of the most important ethical concerns. Unfortunately, evaluating psychological harm in the research process is more complex than evaluating physical harm. In order to identify any possible harm, the participants are asked certain questions at the end of the experiment/research. However, whether or not the participants’ answers properly reveal the possible harm is disputable. For example, even if a participant has suffered psychological or emotional damage during a study, they may not express this due to cognitive dissonance (Baumrind, 1985).

Methodological concerns are also found regarding deception. The biggest concern here is the possibility of damaging the participant pool. A participant who learns that deception was used in one study may expect deception to be used in other studies in the future. This expectation may affect the participant’s preferences in subsequent studies (Epley & Huff, 1998). Kruglanski (1975) stated that participants are active actors who interpret and analyze experimental processes. The frequent use of deception can affect participants’ expectations. Suspicious participants may change their responses with respect to their expectations (Orne, 1962). This concern is more likely to be realized in studies conducted with student participants (Davis & Holt, 1992). Apart from individual participation, a general awareness that deception is being used in a study may also occur among participants by way of media or shared experiences (Lindsay & Holden, 1987). Confirming all these suspicions, Galang (2018) compared the reproducibility success of experiments with and without deception using data from the Open Science Movement (2015). Analyzing the data from approximately 100 studies, the researcher reported that the studies using deception encountered very small effect sizes during the replication stages. These findings point to concerns about the internal and external validity of studies that use deception.

Another concern about deception relates to the reputation of the profession and scientists. Deception is thought to be able to cause a loss of trust in both the profession and in scientific research (Baumrind, 1964; Kelman, 1967). Participants may stigmatize researchers, scientists, and psychologists as unreliable. However, some researchers argue the use of deception in research to be necessary in order to develop science. For this reason, methods that benefit from deception may be used to evaluate experimental findings more realistically and to prevent behavior change.

Researchers do not have an unlimited right to use deception. The American Psychological Association (APA, 2002, p.1071) has included specific criteria in its Standard 8.07 limiting the use of deception in research, stating that research must meet the following criteria in order to be able to use deception:

(a) Psychologists may only conduct a study involving deception if they have determined that deceptive techniques are justified by the study’s significant prospective scientific, educational, or applied value and that effective non-deceptive alternative procedures are not feasible. (b) Psychologists are not to deceive prospective participants about research that can be reasonably expected to cause physical pain or severe emotional distress. (c) Psychologists are to explain any deception that is an integral feature of the design and conduct of an experiment to participants as early as is feasible, preferably after their participation, but no later than after the data collection, and they are to permit participants to withdraw their data.

Despite these concerns and criticisms, deception is often used in psychology, with some fairly predictable reasons found for justifying its use. The main reason relates to the content and complexity of the topics being researched. Studying more complex processes such as attitudes, prosocial behavior, or motivations has required researchers to take more rigorous control measures, and deception may prevent participants from giving socially desirable answers. In addition, deception avoids demanding characteristics that might arise if a participant knew the study’s true purpose. Therefore, some studies need to use deception to achieve their purpose (Cook & Yamagashi, 2008). In social psychological research in particular, deception is frequently used to change and control behaviors (Nicks et al., 1997). For this reason, deception is often used in these types of studies. For example, Hertwig and Ortmann (2008) reported deception to have been used in 63 of 117 studies published in one social psychology journal (i.e., Journal of Experimental Social Psychology) they had reviewed in 2002.

Discussion

As outlined above, deception raises ethical and methodological concerns. These concerns do not have the same strength for every study in which deception is used. However, researchers should always be more careful and take precautions regarding any possible risks in deception studies. The researcher should ensure that participants’ right to autonomy are protected through informed consent (Pittenger, 2002). Informed consent forms should include information about the possibility of deception often being used in social science research. The researcher should also be alert to the possible risks of deception and should never support others’ participation in high-risk studies or in studies in which they would not want to participate. Researchers should share in their publications why and how they used deception and what was done to prevent possible harm to the participants, and reviewers and journal editors should pay attention to this issue. It should not be used as long as an alternative to deception exists, with deception only ever being used as a last resort (Kimmel et al., 2011). The use of deception in scientific research is inevitable, but it should be used effectively so as not to jeopardize the validity of a study. Kimmel et al. also stated that deception used in only one phase of a study might cause participants to be suspicious about the entire study. Therefore, using deception in multiple stages in a way that is difficult to detect and mild in severity is crucial. Deception can be successfully used in research by means of cover stories, fake material, fake feedback, and confederates/research actors (Olson & Raz, 2021). The use of deception is considered a laboratory tradition and implicit norm that has been passed down from generation to generation (Galang, 2018). Meanwhile, the preparation of more accessible and concrete guidelines for how deception can be used will be helpful for researchers.

Throughout the study, the focus has mainly been on social psychological research, with studies in subfields such as experimental and clinical psychology having been omitted. The ethical and methodological implications of the use of deception in all subfields of psychology, as well as comparisons between subfields, should be addressed in future studies. In addition, many of the explanations discussed throughout the article are primarily valid for laboratory studies and face-to-face data collection. Topics such as the advantages and disadvantages of deception in online studies, what kind of risks this may have, and what kind of solutions can be produced should be addressed in future studies.

This review presents ethical and methodological concerns and recommendations regarding the use of deception in psychological research. The article’s purpose is not to support or criticize deception in research. Deception has been used in studies for many years and is now considered a natural phase of scientific research. However, various risks are found to be associated with deception, and addressing these is not only relevant for participants’ well-being but also essential for conducting validity and reliability of a study. Being aware of these risks and taking necessary precautions will enable research to be conducted under ethical standards.