Informed consent is a basic ethical and legal requirement for human subjects research. The U.S. federal regulations governing research on human subjects stipulate general requirements for informed consent. Investigators are required to disclose to prospective subjects material information about the purpose, procedures, and likely consequences of the study, among other things. However, investigators sometimes employ deception for methodological reasons. In order to keep subjects’ responses unbiased, investigators deceive subjects about such things as the fact that they are taking part in research, the purpose of the research, the research interventions or interactions, or the likely consequences of those interventions or interactions. When investigators deceive subjects about such aspects of a study, the study fails to meet these general requirements for informed consent.