- Suggestion is an invisible but powerful influence on decisions.
- At times, it can lead to misinformation and risk. People are susceptible in boardrooms, courtrooms, and operating rooms.
- Greater awareness won’t eradicate it fully—but it can maximize decision control and reduce contaminated judgments.
Not much is written about the power of suggestion despite its importance in cognition and decision-making. But when one person influences another without consent—implanting an idea by appealing to the unconscious—it’s unlikely to end well. Researchers believe the effects of suggestion on how we think and what we remember are more pervasive than most people realize.
A Toxic Influence on Human Behaviour
The power of suggestion is an invisible influence on everyday behavior. We unconsciously respond to verbal and visual suggestions without realizing it. For example, when you see someone yawn, it often triggers a yawn of your own.
But yawning is the least of it. The problem is that in our busy lives, we don’t always see the insidious effects of suggestibility on our decisions. It’s associated with copycat crimes, paranormal experiences, herding, misconduct, prejudice, paranoia, false memories, and eyewitness testimony. It creates misinformation risk in boardrooms, courtrooms, and operating rooms.
Once we expect or anticipate something will happen, that idea influences our response expectancies.  I recently took my first post-pandemic holiday. Everything was perfect until I met a hotel guest who complained about everything from slow service to sand quality. I hadn’t noticed. Like the sunglass effect, life was instantly darker. On reflection, maybe the receptionist wasn’t that friendly.
This lens is often irreversible. But I had a choice: hammer out a one-star review on TripAdvisor or dissect what I had just heard. We need to do more of the latter.
A Prevalent Industry Force
In a court of law, judges have the power to overrule leading questions by savvy lawyers who use suggestions to land points about motives or wrongdoings. This mechanism influences jury decisions and distorts witness recall.
In 1974, psychologist Elizabeth Loftus demonstrated the sensitivity of eye-witness testimony to suggestion. Five groups watched a simulated traffic accident. Each was asked to estimate the average speed of the car before it hit the other. The verb "hit" was varied five times. Subjects estimated a much higher speed when hearing the word "smashed" compared to "contacted" or "hit." 
The choice of words evoked the idea of speed. This matters for witness recall and accuracy. The U.S. Registry of Exonerations attributes eye-witness misidentification to 69 percent of wrongful death penalty convictions.
In forensic settings, sloppy or nefarious police questioning carries consequences for wrongly-accused individuals.  Notorious cases include Steve Avery, the Central Park Five, and many others.
Individuals undergoing-emotional interrogations have confessed to appalling crimes. Some grow to believe themselves guilty. In 1988, Paul Ingram’s daughter accused him of abuse. After repeated denials, police urged Ingram to imagine committing the offense. He subsequently confessed to bizarre acts including satanic abuse. Psychologists later showed his susceptibility to false memories. Yet Ingram was sentenced and served 13 years.
A Controversial Tool
The power of suggestion has been shown to implant memories using hypnosis and other techniques. Subjects with planted memories may really believe they got lost in a shopping mall, spilled drinks at weddings, punched others, or were punched. Similarly, in therapy, some people are primed to remember things that never happened. Unsurprisingly, controversy exists over the validity of "recovered" memories in cases of child or domestic abuse.
In organisations, performance appraisals are riddled with suggestion and innuendo. If you’re flagged as a high performer, from that moment, you may be more likely to dress and behave like a high performer. If you’re labelled a low performer, performance often suffers as suggestions become self-fulfilling.
Retailers, marketers, and advertisers are experts at priming consumers to think a certain way. They pre-select prompts, simple gestures, and words. For them, suggestion is a source of revenue. But too many consumers fall into hopeless debt.
For others, suggestion is a source of entertainment. Professional mentalists use it to showcase "mind-reading" talents, recreating mental scenes with physical props and suggestive shapes. Human rights activists argue advances in brainwave monitoring techniques threaten privacy and personal autonomy.
Stop Invisible Hacking: Take Control
While most people internalize others’ ideas easily, efficacy depends on age, background, and personality. Individuals with low self-esteem tend to be more susceptible.  Child witnesses are typically less reliable than adults. And those with above-average intelligence may evaluate misinformation more actively.
You can maintain decision autonomy with nudge-based techniques drawn from behavioral economics:
- Deconstruct framing. Don’t blindly trust the message or messenger. Observe how others persuade you best. Communication is an underestimated weapon of influence. Notice tone and innuendo as much as the choice of words. Watch for how situations are framed as this distorts perception and memory.
- Use defaults. Researchers Brigitte Madrian and Dennis Shea applied the power of suggestion in a large U.S. firm to boost 401(k) savings through automatic enrolment. Their suggestion to use a 3 percent contribution rate shifted employees to exactly 3 percent.  Their suggestion to use money market funds rather than stocks led to a conservative strategy dominated by money market funds. This works.
- Pause and probe. People are cognitive misers and prefer not to think extensively. Beyond awareness, critical thinking and accuracy-checking can detect sleight-of-hand intentions. Pause in the moment to separate fact from fiction. Be more reflective and record important data or conversations to prevent errors.
The power of suggestion is an underestimated determinant of behaviour. Any process that shifts your intention without consent qualifies more as a force for good than evil. In high-stakes situations, it’s useful to know the difference. That’s just a suggestion!
Michael R. B., Garry, M. Kirsch I. Suggestion, Cognition, and Behavior. Current Directions in Psychological Science, 2012; 21 (3): 151
Loftus, E. F. (2005). Planting misinformation in the human mind: A 30-year investigation of the malleability of memory. Learning & memory, 12(4), 361-366.
Hooper, V. R., Chou, S., & Browne, K. D. (2016). A systematic review on the relationship between self-esteem and interrogative suggestibility. The Journal of Forensic Psychiatry & Psychology, 27(6), 761-785
Madrian, B. C., & Shea, D. F. (2001). The power of suggestion: Inertia in 401 (k) participation and savings behavior. The Quarterly journal of economics, 116(4), 1149-1187