Informed Consent in Psychology

Informed consent is the process by which researchers ensure that individuals understand a study and voluntarily agree to participate.

In the context of psychology research, informed consent means that every participant consents freely and with full information before any data is collected​.

Informed Consent In Psychological Research

This involves providing potential participants with clear details about the study’s purpose, procedures, duration, potential benefits, and any risks or discomfort that might be involved​.

True informed consent also needs capacity, meaning the ability to understand the information and weigh the decision. Participants must be of sound mind or an appropriate age. Their agreement must be free of coercion or undue influence.

Why Informed Consent Matters

The importance of informed consent in ethical research cannot be overstated. It upholds the principle of respect for persons: honoring individuals’ autonomy, privacy, and dignity.

By being transparent about what participation entails, researchers build trust and protect participants from harm.

Modern ethical codes agree. From the Nuremberg Code to today’s professional guidelines, they insist on “sufficient knowledge and comprehension” before participants consent to research.

Five Elements of Informed Consent

Faden and Beauchamp (1986) argue that consent counts as informed only when five elements are all present.

• Competence: The person can reason about the decision at all.
• Disclosure: The researcher provides adequate information.
• Understanding: The person comprehends what was disclosed, not merely receives it.
• Voluntariness: The decision is free of coercion.
• Agreement: The person makes an affirmative act of consenting.

Disclosure alone is not enough. A person can receive every detail and still fail to understand it. A signed form records agreement, not understanding. That is why researchers treat consent as a process rather than a one-off event.

Informed consent therefore has two independent components: being adequately informed and choosing freely. A study can fail on either one while nominally satisfying the other.

Key Criteria for Informed Consent

Researchers must give participants enough information about the study so they can make an informed choice.

History of Informed Consent: Nuremberg to Milgram

Informed consent was written, clause by clause, in response to specific historical abuses.

The Nuremberg Code and Declaration of Helsinki

The Nuremberg Code (1947) was drafted by the judges of the Nuremberg Military Tribunal. Judges had just tried Nazi physicians in the “Doctors’ Trial.”

Those physicians had conducted lethal experiments on concentration-camp prisoners without their consent.

The Code’s first principle states flatly that “the voluntary consent of the human subject is absolutely essential” (Nuremberg Military Tribunal, 1947). It also required:

• Legal capacity: The person giving consent must be legally able to do so.
• Freedom from coercion: No “force, fraud, deceit, duress,” or any other form of coercion.
• Understanding: Sufficient knowledge and comprehension of the study to make an understanding and enlightened decision.

The Code had no enforcement mechanism. It was largely ignored in practice for two decades.

Even so, it established that consent is a precondition of ethical research, not an optional courtesy.

The World Medical Association adopted the Declaration of Helsinki in 1964 and has revised it repeatedly since (World Medical Association, 2013). It extended the Nuremberg principles to medical research.

It allowed legally authorized representatives to consent for people who cannot consent themselves. Nuremberg judged a past atrocity. Helsinki became a living professional standard.

Psychology’s professional bodies then translated these principles into codes for behavioral research.

The BPS issued its Ethical Principles for Conducting Research with Human Participants in 1978 and revised it in 1993. It replaced them with the Code of Human Research Ethics in 2010 (second edition, 2021).

Milgram’s Obedience Experiments (1963)

Milgram’s (1963) obedience experiments are the paradigm case of deception that rules out prior consent.

For consent, the key issue is deception. Participants could not know, and were actively misled about, the true nature of the procedure they agreed to.

Diana Baumrind (1964) argued that this deception, together with the distress it caused, made the study unjustifiable whatever its scientific value. Milgram (1964) replied that most participants later endorsed their participation and that a psychiatric follow-up found no lasting harm.

Stanford Prison Experiment and Tearoom Trade

The Stanford Prison Experiment posed a different problem. Participants were told the general procedure in advance (Haney, Banks, & Zimbardo, 1973): arrest, confinement, and role-play.

Nobody, including Zimbardo, could predict how far the roles would go. Consent given at intake could not anticipate an escalation that the study’s own design produced.

Humphreys’s (1970) Tearoom Trade shows two consent failures at once. Humphreys covertly observed encounters in public restrooms, so no consent was possible at the point of observation.

He then traced participants’ names and addresses from their licence-plate numbers and interviewed some of them at home without disclosing the connection.

Linking observations to identifiable personal records is the practice modern codes treat as needing the highest justification of any research technique.

How Researchers Obtain Informed Consent

Before You Begin: Familiarize yourself with the ethical guidelines relevant to your location and research area.

• United States: Psychologists adhere to the ethical standards outlined by the American Psychological Association (APA) when conducting research.
• United Kingdom: Researchers follow the British Psychological Society (BPS) ethical guidelines when obtaining informed consent.
• Australia: Psychologists adhere to the National Statement on Ethical Conduct in Human Research (2023), which took effect in January 2024.
• Canada: The Tri-Council Policy Statement: Ethical Conduct for Research Involving Humans (TCPS 2) .
• Your Institution’s Research Ethics Board (REB) or Institutional Review Board (IRB): They provide oversight and approval for research projects.

1. Information Sheet

This participant information sheet provides comprehensive details about the study. It should include:

• Title of the Study: Clearly state the title of the research project.
• Researcher’s Contact Information: Provide the names and affiliations of the researchers involved.
• Purpose of the Research: Explain in clear, concise language what the study is about and what the researchers hope to learn.
• Procedures: Detail what participants will be asked to do during the study. This includes the types of activities, the duration of each activity, and the overall time commitment.
• Location: Where will the research take place?
• Potential Risks and Discomforts: Describe any potential physical, psychological, social, or economic risks or discomforts that participants might experience. Be honest and upfront about any potential for harm, even if it is minimal.
• Potential Benefits: Explain any potential benefits of participating in the research. These benefits may be direct (e.g., receiving a treatment) or indirect (e.g., contributing to scientific knowledge). If there are no direct benefits to the participant, state that clearly.
• Confidentiality: Explain how you will protect participants’ data and privacy.
  • How data will be stored (e.g., securely, with identifying information removed).
  • Who will have access to the data.
  • How data will be used and reported (e.g., aggregated, anonymized).
  • If applicable, mention any legal limits to confidentiality (e.g., mandatory reporting of child abuse).
• Voluntary Participation and Withdrawal: Emphasize that participation is entirely voluntary, and they can withdraw at any time without penalty.
• Incentives: If offering any compensation or rewards, describe them clearly.
• Contact Information: Provide contact information for the researcher(s), including names, email addresses, and phone numbers. Provide contact information for the relevant ethics committee or Institutional Review Board (IRB).

Example Information Sheet

2. Consent Form

This is a separate document that participants sign to indicate their agreement. It should include:

• A statement confirming they have read and understood the information sheet.
• A statement confirming their voluntary consent to participate.
• Space for the participant’s signature and date.
• Space for the researcher’s (or witness’s) signature and date.

Example Consent Form

3. Obtaining Consent

• Provide Adequate Time: Give participants sufficient time to read the information sheet and ask questions.
• Explain and Clarify: Be prepared to answer questions and explain any aspect of the study in more detail.
• Ensure Comprehension: Make sure participants understand what they are agreeing to. The consent form should be written in clear, concise, and easy-to-understand language. Avoid jargon or technical terms.
• Respect Autonomy: Emphasize that participation is voluntary and there are no negative consequences for declining or withdrawing.
• Document Consent: Obtain written consent by having participants sign the consent form. Keep a copy for your records and provide a copy to the participant.

Ongoing Consent and Debriefing

• Re-Consent: If new information arises during the study that might affect a participant’s willingness to continue, re-consent them.
• Debriefing: At the end of the study, debrief participants, especially if deception was used. Explain the true purpose of the study, answer questions, and address any concerns.

Consent is not exhausted at recruitment. In multi-session or long-running studies, researchers check consent periodically rather than treating one signature as covering everything that follows.

Check again when recording is introduced partway through, when the study’s aims or methods change materially, or when a longitudinal design collects increasingly sensitive data.

Record Keeping

• Maintain Records: Keep records of all consent procedures, including dates, times, and any communication with participants.

• Store Consent Forms Securely: Protect participants’ privacy by storing consent forms in a safe and confidential manner, complying with data protection regulations.

Institutions typically require signed consent forms, and the information sheets that went with them, to be kept separately from the research data. That way, a participant’s identity cannot be casually linked to their responses.

Forms are stored securely for a defined period. This protects participants and provides an audit trail if the study’s ethical conduct is later questioned.

Special Considerations

Minors: Parental Consent and Child Assent

Obtain consent from parents or legal guardians, and assent from the minor. Assent is the child’s own age-appropriate agreement to take part, sought in addition to parental consent.

In the UK, people under 18 years old are considered minors who may not fully legally consent on their own. The rules then depend on the child’s age.

• Ages 16 to 17: The BPS guidelines indicate that young people aged 16-17 can potentially give consent for low-risk research if they are judged competent.
• Under 16: A parent or legal guardian must consent on the child’s behalf. The child should also assent, as far as they are able.
• Assent in practice: The study is explained in age-appropriate terms, and the child willingly agrees, even though the parent’s consent is legally required.
• Refusal: If a child does not want to take part, researchers respect that decision, even when a parent has consented. The child’s dissent “trumps” a parent’s wish to enroll them.
• School research: Researchers often seek the head teacher’s permission and notify parents (known as passive consent). They also seek the children’s active assent, depending on the activity.

Voluntariness needs special care with children. The BPS Code notes the power imbalance between adults and children. Children might feel they have to say yes, especially in schools, where obedience to adults is the norm.

To combat this, researchers can emphasize that saying “no” is okay. There will be no bad consequences for the child. They might offer several chances to decline (“It’s okay if you don’t want to: you can say no”) and watch for signs of discomfort.

Deception and Incomplete Disclosure

Researchers cannot deceive participants about research that is expected to cause pain or severe emotional distress. In other words, you cannot mislead someone into a study that will seriously harm them.

When deception or withholding of information does occur, the consent process is a bit different: participants give consent to participate without full knowledge of some details.

This is sometimes called consent to incomplete disclosure. Importantly, the BPS requires that the study protocol involving deception be approved by an ethics committee, and that there are plans to fully debrief participants afterwards​.

During debriefing, researchers reveal any withheld information or deception, explain why it was necessary, and address any of the participants’ questions or concerns.

Participants should leave the study without feeling harmed or betrayed.

The BPS code does not state this explicitly, but APA and other guidelines expect it. After debriefing, participants are given the chance to withdraw their data if they object to the deception.

In essence, even in studies that involve deception, informed consent is treated as an ongoing process.

Participants might not have all the facts at the start. They are informed at the earliest feasible time. Once the truth is revealed, they keep the right to decide what happens to their data.

Students, Clients, and Employees as Participants

Psychology researchers often recruit students (e.g. university participant pools) or even their own clients in some applied research.

Researchers should avoid putting people in a position where they feel pressured to consent because of a power relationship.

One safeguard is to have someone independent conduct the recruitment and consent process so participants don’t feel their academic or professional standing is at stake.

Course credit can add pressure. If participation is a course requirement or a way to earn credit in university psychology courses, researchers should offer alternatives. Students can then fulfill the requirement without feeling forced into a particular study.

Adults Who Cannot Give Consent

Not every adult can give valid consent. Some have an impairment that limits their capacity to understand and weigh the information.

Examples include an adult with a severe intellectual disability or someone temporarily incapacitated. UK researchers must then follow legal frameworks such as the Mental Capacity Act.

Typically, a legal representative or guardian provides consent. The individual is still involved in the decision as much as possible, as with assent for minors.

Proxy consent is an imperfect safeguard. A proxy’s judgment about what the person would have wanted is an inference, not a report of the person’s own preference.

The BPS emphasizes extra diligence in any dependent or unequal relationship. If participants depend on the researcher or others (for example, patients or prisoners), researchers must take extra care to ensure no coercion.

Consent in Intervention Research

If a psychology study is also a form of treatment or intervention (say, testing a new therapy), participants need extra information. They must be told:

• The experimental nature of the treatment.
• Whether the control group will receive some treatment or none.
• How participants will be assigned to groups (randomization, which allocates people by chance).
• What alternative treatments are available if they do not participate.
• Any compensation or costs involved.

This mirrors the consent given in a clinical trial. It ensures patients know what happens if they do not receive the experimental treatment.

Consent in Longitudinal Studies

Prolonged engagement studies involve researchers spending an extended period in the field, often immersed in the participants’ environment. They require continuous attention to informed consent. Good practice includes:

• Comprehensive initial consent: Explain the study’s evolving nature and ensure participants understand it.
• Ongoing consent: Hold regular check-ins and keep communication open, addressing any emerging questions or concerns.
• Re-consent: Ask participants again if the study design or procedures change significantly.
• Autonomy: Always allow participants to withdraw at any time.
• Power dynamics: Prioritize participants’ well-being, privacy, and confidentiality throughout the research process.

Consent for Audio and Video Recording

You may require separate informed consent for recordings (audio or video) unless an exception applies​.

This means if a study is video-taping or audio-recording participants (e.g. by interview), the consent form must explicitly mention this and participants should consent to being recorded.

Two exceptions apply.

• Naturalistic observation: The research is purely naturalistic observation in a public place, and the recordings won’t be used in a way that could harm or identify anyone.
• Deception: Participants are unaware of the recording at first. They must then be informed and consent to the use of their recording during the debrief (i.e., after the fact).

Imagine a researcher covertly videotapes behavior in a public park as part of an experiment. They would need to destroy any footage of anyone who later does not consent when debriefed.

Generally, U.S. researchers take care to get explicit consent for recordings upfront whenever possible (“Is it okay if we audio-record this interview? Please sign here if yes”).

Consent Form For Interviews

Critical Evaluation of Informed Consent

Informed consent is foundational, but a signed form does not guarantee that consent is informed.

Limits of Informed Consent

Four limits qualify the case for informed consent.

• Form versus understanding: A signed form can verify disclosure, documentation, and agreement. It cannot certify competence or genuine understanding, which arguably matter most (Faden & Beauchamp, 1986).
• Consent versus validity: Telling participants the true purpose can change the behavior being measured, a threat known as demand characteristics. This is why deception persists in obedience and conformity research.
• A matter of degree: No participant can fully anticipate an experience they have not had, and comprehension varies with age, education, and culture. Informed consent is therefore a spectrum, not a binary.
• Group-level harm: Consent from every individual cannot protect the wider group a study may stigmatize, as in race-and-cognition research. Ethics review now also asks how findings might be used or misused.

As Baumrind (1985) argued, deception corrodes trust and makes genuine consent structurally impossible at the moment it is meant to occur.

The APA and BPS codes take a different view. They conditionally permit minimal-risk deception followed by prompt debriefing. Their reasoning is that some scientific questions cannot be answered any other way.

The dispute is a real disagreement about weighing two goods, not a simple contest of ethics against methodology.

Alternatives When Full Consent Is Impossible

Full prior consent is sometimes impossible, most obviously when participants must not know what is being studied. Psychologists use four partial safeguards.

• Debriefing: Explains the true purpose afterwards, justifies any deception, and lets participants ask questions and withdraw their data. It repairs the breach only partly.
• Presumptive consent: Researchers describe the procedure to a separate sample from the same population and ask whether they would take part (Diener & Crandall, 1978). Approval is evidence, not proof, that actual participants would have consented.
• Retrospective consent: Participants are asked, after data collection, whether their data may be kept and used. It is increasingly common in secondary data analysis.
• Proxy consent: Another person’s judgment replaces the participant’s own, as with children and adults who lack capacity.

None of these equals genuine prior consent. Each manages a situation where that gold standard cannot be met.

Contemporary Research

Two developments have reshaped thinking about informed consent since 2015. Evidence shows that a signed form does not reliably indicate understanding. Digital research is also moving consent away from a single up-front event.

The strongest evidence on understanding comes from clinical trials, where consent is most heavily documented and studied. Newer work tests what helps. Meanwhile, data-intensive designs show why one signature at the start no longer fits much modern research.

Do Participants Understand What They Sign?

Tam and colleagues (2015) pooled the evidence on how well clinical-trial participants understand consent.

Understanding was also lower among critically ill patients and people with less education. A completed form is evidence of agreement, but a weak proxy for comprehension.

Simpler forms can help. Emanuel and colleagues (2026) randomized 334 healthy US adults to read one of three versions of the same stroke-prevention trial’s consent form.

The medium-length version, written at a lower reading level with shorter sentences and tables, scored highest (79.3% correct). The long form scored 65.7% and the short form 69.3%.

Grant, Hamilton, and Ormita (2025) ran two online experiments, with 510 adults and 293 psychology students. Form length made no difference to comprehension.

A fixed reading time and a required quiz improved instruction-following. Delivering the information live or as an audiovisual recording improved both comprehension and instruction-following. Even so, comprehension remained incomplete.

Dynamic Consent and Online Research

Much modern research no longer fits a single study with a bounded procedure. Kaye and colleagues (2015) point to large-scale data linkage, repeated reuse of stored data, and cross-border data sharing. A single signature at intake cannot cover all of these future uses.

Their alternative is dynamic consent. A persistent digital interface lets participants review what their data are used for and update their permissions at any time.

Platforms raise a related problem. In Facebook’s 2012 “emotional contagion” experiment, researchers covertly altered the News Feeds of hundreds of thousands of users for a week (Kramer, Guillory, & Hancock, 2014).

Facebook said users had already agreed through its Data Use Policy. Critics replied that a rarely read terms-of-service clause is not informed consent.

References

Baumrind, D. (1964). Some thoughts on ethics of research: After reading Milgram’s “Behavioral study of obedience.” American Psychologist, 19(6), 421–423. https://doi.org/10.1037/h0040128

Baumrind, D. (1985). Research using intentional deception: Ethical issues revisited. American Psychologist, 40(2), 165–174. https://doi.org/10.1037/0003-066X.40.2.165

Diener, E., & Crandall, R. (1978). Ethics in social and behavioral research. University of Chicago Press.

Emanuel, E. J., Lopez-Rico, S., Ozisik, M. L., & Silvert, E. (2026). A randomized control trial of re-designed and shorter research informed consent forms to improve comprehension. Clinical Trials, 23(4), 421–429. https://doi.org/10.1177/17407745261429936

Faden, R. R., & Beauchamp, T. L. (1986). A history and theory of informed consent. Oxford University Press.

Grant, N. K., Hamilton, L. K., & Ormita, J. M. (2025). Improving comprehension of consent forms in online research: An empirical test of four interventions. Journal of Empirical Research on Human Research Ethics, 20(1–2), 46–54. https://doi.org/10.1177/15562646251321132

Haney, C., Banks, W. C., & Zimbardo, P. G. (1973). A study of prisoners and guards in a simulated prison. Naval Research Reviews, 9, 1–17.

Humphreys, L. (1970). Tearoom trade: Impersonal sex in public places. Aldine.

Kaye, J., Whitley, E. A., Lund, D., Morrison, M., Teare, H., & Melham, K. (2015). Dynamic consent: A patient interface for twenty-first century research networks. European Journal of Human Genetics, 23(2), 141–146. https://doi.org/10.1038/ejhg.2014.71

Kramer, A. D. I., Guillory, J. E., & Hancock, J. T. (2014). Experimental evidence of massive-scale emotional contagion through social networks. Proceedings of the National Academy of Sciences, 111(24), 8788–8790. https://doi.org/10.1073/pnas.1320040111

Milgram, S. (1963). Behavioral study of obedience. Journal of Abnormal and Social Psychology, 67(4), 371–378. https://doi.org/10.1037/h0040525

Milgram, S. (1964). Issues in the study of obedience: A reply to Baumrind. American Psychologist, 19(11), 848–852. https://doi.org/10.1037/h0044954

Nuremberg Military Tribunal. (1947). The Nuremberg Code. In Trials of war criminals before the Nuremberg Military Tribunals under Control Council Law No. 10 (Vol. 2, pp. 181–182). US Government Printing Office.

Tam, N. T., Huy, N. T., Thoa, L. T. B., Long, N. P., Trang, N. T. H., Hirayama, K., & Karbwang, J. (2015). Participants’ understanding of informed consent in clinical trials over three decades: Systematic review and meta-analysis. Bulletin of the World Health Organization, 93(3), 186–198H. https://doi.org/10.2471/BLT.14.141390

World Medical Association. (2013). World Medical Association Declaration of Helsinki: Ethical principles for medical research involving human subjects. JAMA, 310(20), 2191–2194. https://doi.org/10.1001/jama.2013.281053