The Suggestible Brain

what can make a bottle of cheap wine taste like a chateau margaux, make a placebo pill produce tangible health benefits,  and even lead us to remember events that never actually happened? the answer lies in the power of suggestion.

everyone is suggestible. and every day our realities are hacked by the power of suggestion. it influences how we perceive the world, how we feel, and even what we believe to be true. by understanding the science behind suggestion, we gain two vital advantages: we can protect ourselves from manipulation and, more importantly, learn how to use the power of suggestion to positively impact our own lives.

in this chapter, we’ll explore how suggestibility has played a pivotal role in human evolution, how suggestion underlies events ranging from the salem witch trials to 21st century election campaigns, and how it can be harnessed to treat mental health conditions like depression and anxiety. finally, we’ll show you how to tap into your own powers of suggestion to enrich your life and influence others for good. 

ready to unlock the secrets of this unseen force? then let's get started.

to fully flex the power of suggestion in your own life, you’ll first need to come to grips with two separate but very much linked concepts: that of suggestion and suggestibility.

while they may sound similar, their distinctions are subtle but significant. a suggestion is a type of communication designed to influence, to call up ideas or images in another’s mind, or imply that something is true.

suggestibility, on the other hand, is the degree to which someone is predisposed to accept and act on the suggestions of others. it’s important to clarify: having high suggestibility doesn’t equate to gullibility or an increased risk of being manipulated. in fact, suggestions can offer us valuable opportunities for self-discovery and personal growth. they compel us to measure our own beliefs and inclinations against those of others, and determine whether or not it’s worth changing our course of action or thought. 

conversely, a low level of suggestibility can present its own challenges. for example, someone who rigidly anchors themselves to their own viewpoint – like a skeptic unwilling to trust expert medical advice – may limit their ability to benefit from others’ insights. striking a balance between staying grounded in your own perspective and remaining open to advice or suggestions can improve decision-making and lead to better outcomes. even conflicting advice, while frustrating, can serve as a catalyst for refining your own judgments and choices with greater discernment.

throughout life, levels of suggestibility naturally fluctuate. during times of change or transition, we tend to be more open to suggestions: adolescents may lean into peer influence, new parents seek guidance from experienced caregivers, and someone reeling from a breakup might eagerly turn to friends for dating advice. these suggestion-heavy periods are times rich with input in how to navigate life. 

suggestibility, when harnessed thoughtfully, is a powerful asset. and as you’ll see in the next section, this openness to influence isn’t just a quirk of human behavior – it’s a trait that has evolved and served a vital purpose over time.

australia is a vast and often unforgiving land. european colonizers struggled to map it, and many of their attempts to navigate the continent ended in death. but the aboriginal peoples, indigenous to australia, developed an intricate and ingenious navigation system rooted in their deep connection to the land: songlines.

aboriginal songlines are oral storytelling and navigation systems that map the australian landscape through songs, each detailing the journeys of ancestral beings who shaped the land. these paths, sung in sequences, contain vital information on landmarks, water sources, flora, fauna, and survival practices. for millennia, they have enabled indigenous australians to traverse vast territories while preserving and passing down cultural knowledge.

how were these vastly complex songlines created and passed down so effectively? well, partly through suggestibility. the songlines are embedded in shared mythology. being suggestible to this mythology enabled listeners to absorb and vividly imagine the ancestral journeys and landmarks described in the songs, reinforcing memory through emotional and sensory engagement.

as the songlines illustrate, suggestibility carries a distinct evolutionary advantage. humans are inherently social creatures, and our ability to form and sustain communities has been key to our survival.communities rely on the efficient transmission of information, ideas, and meanings, both within groups and across generations. suggestibility is one of the tools that has enabled humans to learn, cooperate, and adapt efficiently.

 in early human societies, suggestible individuals could quickly adapt their behaviors based on the wisdom and experiences of others. for example, if an experienced member of the group identified a certain plant as poisonous or a particular animal as dangerous, a suggestible individual would instinctually avoid those threats without having to experience harm themselves.

in communal settings, where survival depended on cooperation, being suggestible allowed individuals to conform to group norms, a move that served to both strengthen bonds and reduce conflict among the group. suggestible individuals could better position themselves to be accepted within broader groups – groups which, in turn, provided them with protection, resources, and support.

suggestibility also facilitates the creation and transmission of cultural practices and rituals. in shamanic rituals, suggestibility fosters belief in the shaman’s healing powers and visions, creating a powerful placebo effect that can support physical and psychological well-being. in contemplative practices, like meditation and ritual chants, suggestibility helps practitioners achieve altered states of consciousness, often leading to spiritual insights and a stronger sense of community. 

in a stanford university study, participants were presented with two vanilla milkshakes. while they looked identical, one milkshake was labeled as containing 600 calories. the other milkshake was labeled as containing a mere 140 calories – participants were told it was a prototype of a new, healthy line of shakes that, thanks to state of the art food technology, were just as tasty as their more indulgent counterparts. the participants were instructed to drink each shake until they felt satiated. most drank far less of the indulgent high calorie milkshake before they reported feeling full, but were able to manage far more of the low-cal alternative.

do you see where this is going?

you guessed it. the labels were fake. both shakes were exactly the same, right down to ingredients and calorie count. the suggestion that one shake was more decadent was enough to make the participants feel fuller quicker than when they drank the “healthy” alternative.

here’s where it gets really interesting, though. the participants didn’t just perceive the two shakes differently. their physiological responses to the shakes were different, too. ever heard of ghrelin? it’s known as the “hunger hormone”. when it's present at high levels, it increases appetite; with low levels of ghrelin, appetite decreases. when drinking the decadent milkshake, participants' levels of ghrelin actually dropped. they didn’t just think the decadent milkshake made them feel fuller – the shake really did make them fuller, quicker.

our capacity for suggestibility shares direct links with our physical well being. it’s frequently been shown that our minds, mediated particularly through our powers of belief and the strength of our expectations, can exert significant influence over our bodily processes. perhaps the best known example of this phenomenon is the placebo effect. in placebo studies, individuals are given inert substances – placebos – but told they are receiving medication. frequently, these study participants report symptom relief, with measurable physiological effects. this is partly due to the brain's release of endorphins and other neurotransmitters, which can reduce pain and influence immune function. research has shown that placebo treatments can mimic the effects of actual drugs in conditions like pain management, depression, and even parkinson’s disease, where patients experience improvements in motor function due to placebo-induced dopamine release.

in a similar way, a person’s mindset and psychological outlook can influence their cardiovascular health. for instance, people who are suggestible to optimistic beliefs about their health often exhibit lower blood pressure and improved heart rate variability. this may occur through the reduction of stress hormones such as cortisol, which, when chronically elevated, can contribute to hypertension and inflammation. in studies, people trained to adopt a positive mindset, whether through therapy or suggestion, show better cardiovascular outcomes than their more pessimistic counterparts. our psychology and our physiology are inextricably linked – by using suggestibility to leverage the former, we can achieve beneficial outcomes for the latter.

professor elizabeth loftus, a leading expert on the effects of suggestion on memory, has a uniquely personal connection to her field. when she was fourteen years old, elizabeth lost her mother in a tragic drowning accident. at first, she had little memory of the accident but, when an older relative reminded elizabeth that she had been the one to find her mother’s body, she started to remember it more clearly, right up to the firemen on the scene who gave elizabeth oxygen.

years later, though, the relative called elizabeth to apologize. they had been mistaken and elizabeth had actually not found her mother’s body. through her relatives suggestion, elizabeth’s mind was implanted with, and went on to develop in great detail, what is known as a ‘false memory’

false memories occur when people recall events that either didn’t happen or happened differently from how they remember. this phenomenon has far-reaching implications, particularly in legal settings where eyewitness testimony can be affected by suggestive influence. research has shown that memory is highly malleable, and leading questions can shape an individual's recollection. for example, in studies conducted by elizabeth loftus, participants were shown videos of car accidents and then asked questions with varying language. those asked if cars “smashed” into each other reported higher speeds and more severe damage than those asked if cars simply “hit” each other. the subtle difference in wording was enough to alter their memories of the event.

this malleability of memory can have dire consequences, particularly in criminal investigations. subtle cues from investigators or repeated questioning can cause witnesses to “remember” details that align with the investigator's narrative, rather than the truth. additionally, repeated questioning and exposure to others' memories can reinforce these false recollections, making them feel more real over time. this has prompted reforms in how law enforcement and psychologists approach memory recall, aiming to minimize leading questions and use techniques that reduce the risk of implanting false memories. understanding the susceptibility of memory to suggestion emphasizes the need for careful, unbiased approaches in fields that rely on accurate recollection.

however, outside of the legal system, memory manipulation is often wielded with far fewer restrictions – especially in the world of politics.  take “push polls”, a tactic used in election campaigns to subtly influence voters. unlike genuine opinion polls, which aim to gather unbiased data, push polls are designed to introduce negative or misleading information under the guise of asking questions. by framing questions in a way that suggests certain "facts", these polls create associations in the respondent’s mind that can directly influence their beliefs and memories.

for example, a push poll might ask, “would you be more or less likely to vote for this candidate if you knew they were under investigation for corruption?” even if there’s no truth to this suggestion, the question plants a seed of doubt. over time, the individual might remember hearing about the candidate’s supposed involvement in corruption, without recalling the original source or whether it was true. this type of suggestive influence leverages the malleability of memory, relying on repetition and implication to create a lingering negative impression. essentially, push polls exploit suggestibility to shape voters' memories and perceptions, subtly influencing their opinions and potentially their voting decisions without any factual basis. this can have a significant impact on electoral outcomes, especially in closely contested races.

both loftus’s research and political tactics like push polls highlight the immense power – and potential dangers – of suggestion in shaping memory and, ultimately, reality. understanding this power is key to protecting against manipulation and ensuring fairness, whether in the courtroom or the voting booth.

in the 1950s, psychologist solomon asch conducted a series of groundbreaking experiments, now famously known as the asch studies. these found that individuals can often alter their beliefs, actions, and reasoning in order to conform to the expectations of a group. in one study, actors within a group of participants were instructed to describe a picture incorrectly. remarkably, many real participants followed suit, describing the picture incorrectly as well. in fact, the asch studies found that around 75% of participants conformed to a blatantly wrong answer, simply to avoid standing out or risking ridicule.

what does this show us? suggestion and expectation can create impact not just individually, but across group settings. at its extreme, this phenomenon can manifest as mass suggestion, also known as mass psychogenic illness – a psychological occurrence where people in a group display similar symptoms or behaviors without a clear physical cause.

a classic example of mass suggestion is the salem witch trials of 1692. a group of young girls claimed to experience mysterious fits and strange behaviors, which were attributed to witchcraft. these symptoms, likely triggered by stress, and social tensions within their puritan community, spread rapidly, leading to a series of increasingly wild accusations. ultimately, over two hundred people were accused of witchcraft, and twenty executed.

a more recent example occurred in 2011 in le roy, new york, where several high school cheerleaders began displaying uncontrollable tics and verbal outbursts. these symptoms resembled tourette's syndrome but had no medical cause. the behavior spread to other students, sparking a storm of media attention. specialists concluded that this was a case of mass suggestion, where stress and media exposure likely amplified symptoms within a close-knit group. 

today, there’s a new element to episodes of mass suggestion: social media. during the covid-19 epidemic adolescents spent increased amounts of time on platforms like tiktok. random outbreaks of vocal and motor tics among teen social media users have been traced back to videos of users sharing their own tics. more broadly, the amplified reach of social media’s suggestion has seen misinformation, trends, and emotional contagion influencing vast groups almost instantly. algorithms often promote sensational or emotionally charged content, creating "echo chambers" that reinforce shared beliefs and behaviors, whether factual or not. this can lead to panic, as seen with health scares or viral rumors, and even influence collective actions like protests or boycotts.

however, this power isn’t inherently harmful – it can also be harnessed for good. public health campaigns have successfully used mass suggestion to encourage beneficial behaviors such as vaccination, mask-wearing, and handwashing during outbreaks. by reinforcing these actions as societal norms, they’ve managed to shift behaviors on a large scale.

the power of mass suggestion continues to evolve alongside our understanding of group psychology and digital influence. while it poses significant risks, it also holds immense potential to shape the world positively – if used thoughtfully and responsibly. the question remains: how will we channel this power in the future?

in this chapter to the suggestible brain by amir raz, you’ve learned that suggestibility is a powerful evolutionary trait which influences our perceptions, behaviors, and even our physiological responses. by understanding the science behind suggestion, we can better protect ourselves from misinformation, use suggestion to improve health outcomes, and create positive social change through evidence-based influence.

okay, that’s it for this chapter. we hope you enjoyed it. if you can, please take the time to leave us a rating – we always appreciate your feedback. see you in the next chapter.