Suggestibility can cause us to make bad decisions, particularly if we receive false information that interferes with our memories and existing knowledge. This incorrect information can impact how we recall memories and make choices when dealing with similar instances. For example, we may recall a dentist visit as being uncomfortable yet manageable. Suppose another person describes how horrible they imagined our dentist appointment was. Based on this discussion, we may alter how we remember our experience at the dentist's and then later postpone a necessary appointment because of this warped memory.

Individuals with a vulnerability to suggestibility are also at risk of manipulation as they are more likely to believe and act on information given to them by another person. In mildly or overly manipulative contexts of seduction or coercion, an individual’s suggestibility increases in the same way as someone under the influence of hypnosis.²⁸ In these situations, a person’s confidence and trust in their own judgements is often slowly eroded, making them more likely to rely on external suggestions during decision-making. 

Suggestibility has practical educational, political, legal and commercial relevance in the modern world. Because suggestibility impacts people’s ability to make decisions and what information they accept, it can impact how we engage with and function within small and large systems. 

A typical example of the looming effect of suggestibility is seen in witness testimonies. When individuals give their initial statements, their memory of an event can be altered because of the initial interview process. During the interview process, attorneys or police may make suggestions, confusing and distorting the memory of the witness. This phenomenon has been extensively documented and observed and poses a real and threatening issue for legal decision-making.¹ 

Elizabeth Loftus, an American cognitive psychologist, was the first researcher to publish the highly influential series studying suggestibility in eyewitnesses in the 1970s. After her first series, a large amount of research was conducted on suggestibility to explore its impacts on memory and decision-making.⁷ Loftus’s research proved that suggestive interviews led individuals to make profound errors in their eyewitness testimony. Additionally, Loftus’s research highlighted fundamental questions regarding memory reliability regarding eyewitness testimony, opening the door to further research and investigation into this topic.

The research conducted by Loftus informs judicial systems and courts on best practices to avoid suggestibility and bring forth fair and just testimonies. Loftus’ work inspired debates and research on the nature of memory, memory performance, and the mechanisms of how we remember and forget.7 When memory recollection is critical to decision-making, problematic interview processes can lead to suggestibility and completely skew final decision-making. This is problematic across industries, be it the legal system, policy, or management.¹

Suggestibility can also impact the judicial process through false confessions and compliance. Otgaar et al. conducted a review of experimental data in which false confessions were experimentally evoked, and suggestibility and compliance were measured.²⁰ They found that high levels of suggestibility lead to individuals being more predisposed to making a false confession to a crime they did not commit. High levels of compliance also had the same effect, although not to the same extent. 

In medical research and clinical trials, suggestibility is a variable researchers must address and manage due to its influence on participants’ behaviors and responses. Clinical trials rely on participants giving truthful and objective accounts of how they are feeling or how they experienced an intervention. One ongoing question that looms over the sector is how technology can impact participant beliefs in these trials and whether this may alter responses to treatment by modulating suggestibility. Using online multi-media consent forms rather than traditional paper-based forms has been shown to enhance participants’ understanding of and engagement with clinical trials. Similarly, presenting an informational video during the consent phase can make patients more willing to participate in the research study and lead to better information retention.¹⁴

Though researchers are still attempting to fully understand what leads to certain people being more suggestible than others, academic research has determined that several characteristics and cognitive factors have some influence on our suggestibility.

People who experience intense or strong emotions are generally more receptive to suggestibility. This is because strong emotions, such as fear or excitement, can overwhelm the rational part of the brain (prefrontal cortex), which is responsible for critical thinking and logical analysis. When this happens, people are more likely to accept external suggestions to help them make decisions. Heuristic thinking, or the brain’s reliance on shortcuts to make quick decisions, may also influence suggestibility. When we are trying to make a decision, especially under pressure, cues or suggestions that are presented to us may be used as shortcuts by the brain. 

Age has been an identifier of how suggestible we are, with research indicating that suggestibility usually decreases as we get older.³ Researchers have also agreed that our personality and how we are raised as children impact our suggestibility levels. Children raised to be more skeptical are usually less suggestible in comparison to their less skeptical peers.⁴

Psychologists believe that people with lower levels of self-esteem and assertiveness are typically more suggestible. The relationship between low self-esteem, low assertiveness, and suggestibility stems from psychological traits and cognitive tendencies that influence how people respond to external suggestions. For example, individuals with low self-esteem and low assertiveness often experience an increased need for approval which can lead them to conform to others’ suggestions to feel more accepted. Similarly, while assertive individuals are better equipped to question and resist others’ suggestions, less assertive people may lack the skills or confidence to critically evaluate what they’re being told. Finally, an overall lack of confidence in one’s decisions can make individuals more dependent on external cues, instruction, or opinions. 

Finally, researchers have also attributed the variability to suggestibility to differences in attentional functioning. Attentional functioning is defined as our ability to filter irrelevant information and inhibit prepotent responses.⁵ Overall, several behavioral and social characteristics influence each individual’s tendency to take cues from others and change their beliefs based on those suggestions.

Understanding suggestibility and its processes is important because it influences how individuals and groups process information, make decisions, and form beliefs. Depending on the context, suggestibility can have either positive or negative outcomes. On the positive side, suggestibility can foster social cohesion, encourage learning, and drive constructive actions, such as adopting healthier habits or supporting community initiatives based on “trusted” suggestions. Many campaigns that attempt to influence people to positively change their behavior use celebrities and influencers to enhance the impact of their messaging. 

However, suggestibility can also lead to negative outcomes, such as people falling victim to manipulation, misinformation, or peer pressure, resulting in poor decisions or spreading false beliefs. Misinformation and disinformation, for example, can have a powerful effect on people’s beliefs and actions, particularly if they have high suggestibility. For example, a study by Mark Huff and Sharda Umanath looked at the effect of misinformation on suggestibility among younger and older adults.²⁷ They looked at two types of misinformation: additive, where misleading details were added to an original event, and contradictory, where errors changed the original details. The researchers found that suggestibility to additive misinformation was greater than contradictory, suggesting that we are good at detecting and rejecting misinformation when it contradicts what we were originally told. 

Our tendency to be swayed by external suggestions is further impacted by authority bias, which describes how we are more influenced by the opinions and judgments of authority figures. This bias isn’t problematic when the authority figure is giving suggestions that are grounded in evidence and facts (such as health recommendations from an expert) but can be very harmful if they are attempting to spread inaccurate information (such as when top US politicians suggested ingesting bleach could kill COVID-19). 

Suggestibility is a trait that individuals possess to varying degrees, and in a way, it’s part of who we are. Due to its basis in human cognition and social behavior, it may not be entirely possible to eliminate suggestibility. However, individuals can take steps to reduce the influence in various situations through strategies that enhance critical thinking, self-awareness, and emotional regulation. 

One study by Malwina Szpitalak and Romuald Polczyk looked at how reinforced self-affirmation, a technique that aims to boost self-confidence to increase someone’s tendency to rely on their own memory instead of external cues, can reduce interrogative suggestibility.²⁶ They found that a person’s tendency to change their answers during questioning could be reduced by giving them positive feedback relating to their memory and independent judgments. 

Being critical of the information we receive, even when it comes from reliable sources, is also an important step in reducing the effect of suggestibility. Rather than aligning beliefs and actions based on new suggestion, individuals can take a moment to find evidence that supports or refutes the information they have received. 

Elizabeth Loftus: American cognitive psychologist and expert in the field of human memory. Her research primarily focuses on memory and the brain’s malleability, specifically the ways it can be influenced by external factors. 

Franz Mesmer: German physician whose concept of  ‘animal magnetism’ went on to influence hypnotism. While his work was discredited during the course of his lifetime, his work contributed to the broader understanding of suggestion and the power of belief in therapeutic settings. 

James Braid: Scottish surgeon and pioneer of modern hypnotism. Braid is credited with shifting the practice of mesmerism (born out of Mesmer’s work) into a more scientific and clinical framework. 

Gísli Hannes Guðjónsson: Icelandic forensic psychologist who developed the Gudjonsson suggestibility scale. He is renowned for his work in suggestibility and false confessions, particularly false memory syndrome.

The history of suggestibility traces our evolving understanding of how external suggestions and cues influence individuals' thoughts, behaviors, and perceptions. Early interest in suggestibility emerged in the nineteenth century with research into hypnosis and mesmerism, two phenomena understood as suggestive practices because they rely on external cues and expectations altering individuals’ mental and physical states. During this time, pioneers such as German physician Franz Mesmer and Scottish surgeon James Braid explored the mind’s responsiveness to suggestion under altered states of consciousness. 

Mesmer, from whom we get the modern-day word ‘mesmerize,’ developed a theory of ‘animal magnetism’, which proposed that living organisms possess an invisible magnetic fluid which can be influenced to cure various illnesses.¹⁸ In his public experiments, Mesmer placed patients in a tub-like apparatus called a ‘baquet’ filled with water and iron filings and with rods extending outward to conduct the supposed magnetic energy. He would then pass magnets near the patient’s body in slow, sweeping motions to manipulate the ‘magnetic field.’ Mesmer’s theory was later debunked as no evidence of magnetic fluid was found in the human body, but it did highlight the power of suggestion in healing sick people, what we now call the placebo effect.

Braid rejected Mesmer’s mystical theories and instead focused on mental concentration and suggestion as the mechanisms for hypnosis. Braid is actually credited with coining the term ‘hypnotism’ in 1843, a word which is derived from the Greek word hypnos (sleep), although he later clarified that hypnosis is not a form of sleep but a focused state of mental concentration. By asking subjects to fix their gaze on a bright object while keeping their body relaxed, Braid realized that he could induce a trance-like condition in which the person became more responsive to his suggestions. Braid also used hypnosis for medical procedures such as minor surgeries to reduce the patient’s pain perception without anesthesia. The work of Mesmer and Braid, although not scientifically robust at the time, laid the groundwork for further scientific inquiry into suggestibility's psychological and physiological underpinnings. 

Central to many accounts of suggestibility is the idea of ideomotor action, a psychological phenomenon in which a person makes involuntary physical movements in response to mental processes, usually while unconscious.¹⁶ In the early 1840s, British physician and neurophysiologist Thomas Laycock conducted an experiment by observing participants with rabies (called ‘hydrophobia’ back then) to see how their visible symptoms were triggered. Laycock demonstrated that the visible symptoms of rabies, such as spasms of the respiratory muscles, gasping, and convulsions, were involuntary reflexes and could actually be triggered by a variety of stimuli, including mere imagination. In his write-up, Laycock describes how, in addition to touch, a slight current of air, or the sound of dipping water, the symptoms can be brought on by the idea of water, as when it is suggested to the patient that he should drink. Ideomotor action was studied by several psychologists and doctors in Europe during the nineteenth century and eventually consolidated in William James’ Principles of Psychology, published in 1890.¹⁷ The concept of ideomotor action underscores the interplay between suggest, thought, behavior, and action, highlighting how easily subconscious influences can manifest as physical actions. 

Finally, in 1983, former Icelandic detective turned psychologist Gísli Hannes Guðjónsson created the ‘Gudjonsson suggestibility scale’ (GSS), a psychological test that measures the suggestibility of a person.²⁵ The test involves reading a short story to the subject and then testing their recall, and relies on two different aspects of interrogative suggestibility: first, it measures how much an interrogated person yields to misleading questions, and second, how much this individual shifts their responses after they receive negative feedback (also known as yield and shift, respectively). Although the test has been subject to various criticisms over the years, it has been used in high-profile contexts such as court cases. 

Suggestibility is often used as a tool by marketers to tap into the subconscious mind of potential customers to influence their desires and purchasing behaviors. According to Harvard professor Gerald Zaltman, 95% of our purchasing decisions are subconscious and not driven by rational thought processes.²¹ It stands to reason, then, that the most effective way to get people to buy things is by tapping into their unconscious urges, the most important of which is emotion. 

For example, a company may use priming, a phenomenon that influences behavior through exposure to a stimulus, to affect how customers perceive or interact with a brand.²² If a customer’s mind is prepared or primed for a particular message or product, they are then more likely to be receptive to subsequent suggestions about buying or using that item. Imagine an advert which opens with images of pristine beaches and relaxing ocean waves – two seconds later, the camera pans to an ice-cold beer. The viewer’s mind was subtly primed to associate the drink with relaxation and enjoyment, creating a subconscious link between the product and positive emotions that may lead the viewer to buy the drink. 

The idea that customers are nonrational, suggestible creatures is nothing new. The first psychological theory of advertising, which maintained that consumers are under the hypnotic influence of the advertising copywriter and that their purchasing decisions are not the result of logical reasoning, was first proposed in the late 1890s by American psychologist Walter Dill Scott.²³ He believed that effective advertising should target instinctive and emotional responses, such as fear, love, desire, or curiosity, rather than relying solely on rational arguments or facts. You can see this in many adverts today; an ad for a new car will likely emphasize the excitement felt when driving the vehicle rather than the number of miles it does to the gallon. 

If you’ve ever used AI tools to complete a task, you’ll know that it’s easy to treat the information provided to you as fact. Suggestibility, it seems, can have an impact on how to engage with the information we receive from AI tools and our ability to critically evaluate it. 

Research into human interaction with predictive analytics found a correlation between suspension of disbelief and suggestibility. When we interact with AI characters such as chatbots, we tend to become attached to them the longer we engage with them and gradually suspend our disbelief. Over time, we become more suggestible and stop detecting inconsistencies, biases, and inaccuracies in what we’re being told, undermining our ability to critically engage with the AI tool.²⁴  

Aside from our trust in AI chatbots, suggestibility plays a crucial role in the way AI language models are trained and programmed to produce responses. For example, a developer can use ‘what if’ statements to potentially bypass the filters that language models use to process information in order to prompt them to explore certain scenarios and outcomes. This framing can have implications for AI’s decision-making processes and the risk of biases and inaccuracies. 

Suggestibility in child witnesses and testimony has been a common focal point in suggestibility research. Children’s witnesses are incredibly susceptible to suggestibility, specifically regarding the interview processes and the risk of suggestive questions. The drive to avoid suggestibility in the interviewing process has led researchers to identify correct ways to conduct forensic interviews. Researchers hope to find methods that prevent bias and misleading information from leading to false reporting or testimony.⁸

In a study conducted by Hritz, Royer, and peers, the research team explored possible interview techniques to reduce child testimony suggestibility. Previously, researchers demonstrated that children could speak emotionally and seemingly sincerely about events that had previously never occurred in a similar manner to children reporting actual events.^9,10 Additionally, a study by Kassin, Tubb, Hosch, and Memon conducted in 2001 surveyed 64 different eyewitness experts to assess the question of accuracy in children’s testimony and found that two-thirds of respondents stated that children were typically less accurate than adults in their testimony.⁸ This belief among experts that child witnesses are less reliable than adult witnesses compromises the retrieval of accurate information for evidence. These biases lead to different interviewing tactics, which result in children being susceptible to suggestibility.⁸

The researchers urged that prior to interviewing children, interviewers should examine children’s language, theory of mind, and emotional attachment. Only after doing this should interviewers use findings to prepare a line of questioning that tests alternative hypotheses, which may lower instances of suggestibility in children’s testimony.⁸

A study conducted by Lindsay and Johnson looked at how suggesting certain words affected participants’ memories. The research study set out to evaluate failures of the process which resulted in suggestibility in participants.¹¹

The study began by showing students a video of a car crash. Once viewing the original video, students were divided into different control groups and asked about the car’s speed. Different groups of students were then asked about the video using different vocabulary. Students in different groups were asked if the cars had “hit,” “smashed,” “collided,” “bumped,” or “contacted” each other.¹¹

The research study found that based on the severity of the word given to student groups, participants adjusted their estimation of the car’s speed based on the video they had viewed. The terms provided to students and used to describe the footage thus impacted their perception of the memory and altered it, demonstrating a clear instance of verbal suggestibility.¹¹

What it is

Suggestibility is the tendency to accept and act on ideas or information suggested by others, often without critical analysis or independent judgment.

Why it happens

Though it is still unclear why we range in suggestibility, the following factors impact our suggestibility: emotion, age, self-esteem and assertiveness levels, personality, upbringing, and attentional functioning.

Example 1 – Suggestibility can impact child testimonies

Suggestibility and its impact on witness testimony are studied extensively, specifically in regards to child witnesses. Children are extremely susceptible to suggestibility due to the nature of forensic interviewing processes. Previously researchers had noted that children could speak emotionally and seemingly sincerely about events that had never occurred. Additionally, a different study found that eyewitness experts believed that children were typically less accurate as adults in their testimony. These biases usually compromise the interview process resulting in children being suggested ideas or details by interviewers. Techniques like examining children’s language, the theory of mind, and emotional attachment before conducting interviews, and then using findings to prepare a line of questioning that tests alternative hypotheses, helped lower instances of suggestibility in children’s testimony.

Example 2 – Descriptive words can change our memory

Researchers Lindsay and Johnson conducted a research study to identify the impact of suggestibility when suggesting words to determine how it affected participants’ memories. In the study, participants were initially shown a car crash video and divided into different control groups. Different groups of students were then asked about the video using different vocabulary, describing the video in terms of the cars having been “hit,” “smashed,” “collided,” “bumped,” or “contacted.” The study found that students changed their recollection of the video based on the severity of the word they used by the interviewer and adjusted their estimation of the car’s speed.

How to avoid it

We can prevent or decrease suggestibility by developing awareness. Researchers can also limit suggestibility by using source identification tests and post warnings and pre-warnings in research studies.

Myth-Busting with Cynthia: Is Behavioral Science Manipulative?

Suggestibility can leave us vulnerable to manipulation of inaccurate or harmful information. But what about behavioral interventions, aren’t these trying to change how we act and what we believe? In this article, Cynthia Borja explores the myth that behavioral science is manipulative and sheds light on the rigorous theories, frameworks, and best practices that inform behavioral interventions.

Heuristics May Bias Judicial Decision-Making

We’ve seen how suggestibility can impact the course of justice, but judicial decision-making is actually vulnerable to several cognitive processes. Tom Spiegler briefly explores whether judges are rational decision-makers or intuitive thinkers following a hunch.