Podcasts > Huberman Lab > How Placebo Effects Work to Change Our Biology & Psychology

How Placebo Effects Work to Change Our Biology & Psychology

By Scicomm Media

Delve into the fascinating world of mind-body connection with "Huberman Lab" as neuroscientist Andrew Huberman examines the interplay between our beliefs and our biology. This episode uncovers how the seemingly intangible—our expectations and placebos—can manifest physical responses within us. Huberman takes listeners through the science behind how a person's prefrontal cortex can influence stress responses and even neurotransmitter release, bringing to light the potency of our beliefs on our bodily functions, from heart rate and blood pressure to hormonal alterations. Encounter stunning insights, including how placebo characteristics like complexity and color can amplify their effects, and why our genetics might predispose us to different levels of susceptibility to this powerful phenomenon.

Yet, Huberman is quick to delineate the boundaries of the placebo effect, emphasizing its limitations in addressing the physiological roots of severe health conditions despite its symptom-alleviating attributes. Through captivating studies—from hotel workers unknowingly engaging in "exercise" to shifts in ghrelin levels induced by sheer belief—the episode spotlights the intricate dynamics between cognition and physical health. Whether it's the idea that daily chores could count as a workout or the revelation that our thoughts about food alter our hormonal hunger responses, "Huberman Lab" invites listeners to explore the incredible implications of how our perceptions shape our physical reality, all while clarifying the extent and limits of our thoughts' influence.

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How Placebo Effects Work to Change Our Biology & Psychology

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How Placebo Effects Work to Change Our Biology & Psychology

1-Page Summary

Belief effects and placebos change real physiology

Andrew Huberman reveals that placebos, beliefs, and expectations can induce physical changes in the body including alterations in heart rate, blood pressure, and the release of neurotransmitters. The prefrontal cortex, responsible for predictions, uses neural pathways to affect physical responses, notably by connecting to the hypothalamus to influence stress responses. Expectations about drugs or behaviors can lead to changes in brain activity that align with those beliefs, exemplified by subjects who respond to a placebo as they would to actual nicotine. Moreover, he notes that more complex or invasive placebos generate stronger effects due to higher expected outcomes, and even the color of a placebo pill can influence its perceived impact. Classical conditioning can produce physical responses, and genetic differences also affect the magnitude of placebo effects, implying a biological underpinning to these experiences.

Health effects of placebos are limited

Huberman asserts that while placebos can help alleviate symptoms, their effects are not strong enough to cure serious ailments like cancer or asthma. In cancer treatment, while certain practices that reduce stress or enhance sleep may improve outcomes by lowering inflammation and stress hormones, placebos cannot shrink tumors. Likewise, in a study on asthma, while placebos reduced discomfort, they did not improve the underlying breathing issues that medication alleviates. These findings underscore the inherent limitations of placebos in treating the physiological root of serious health conditions.

Hotel workers improved health when told work was exercise

A study conducted on hotel workers demonstrates the influence of perception on health. Workers informed that their routine duties were equivalent to exercise saw health improvements such as weight and body fat reduction, and lower blood pressure, without any physical activity beyond their normal tasks. This suggests that recognizing daily activities as exercise could have a beneficial impact on health, indicating the potential of mindset in improving physical well-being through daily routines.

Thoughts can't directly control muscle growth

It is important to recognize that thoughts alone cannot manifest as increased muscle growth or strength. There is no direct link from the cognitive function of the prefrontal cortex that would trigger physical development in the muscles merely through the power of thought.

Information about food changes hormone responses

Beliefs about the nutritional content of food can significantly influence hormonal reactions related to hunger. In the "Mind Over Milkshakes" study, participants' ghrelin levels and feelings of fullness were swayed by their perception of calorie content, not the actual calories ingested. Those who thought they were indulging in a high-calorie shake experienced a greater reduction in the hunger hormone and greater satiety than those who believed they consumed a low-calorie shake, showcasing the impact of perception on physiological responses to food.

1-Page Summary

Additional Materials

Clarifications

  • The prefrontal cortex, involved in decision-making and planning, communicates with the hypothalamus, a key brain region for regulating stress responses. This connection allows the prefrontal cortex to influence the release of stress hormones like cortisol and adrenaline through neural pathways. By sending signals to the hypothalamus, the prefrontal cortex can modulate the body's physiological reactions to stressors, impacting heart rate, blood pressure, and other stress-related functions.
  • Classical conditioning is a psychological phenomenon where a neutral stimulus becomes associated with a reflex response through repeated pairings. Over time, the neutral stimulus alone can elicit the same response as the original reflex. In the context of placebos, classical conditioning can lead to physical responses similar to those produced by actual treatments or substances. This process highlights how our brains can link unrelated stimuli with physiological reactions, showcasing the power of learned associations in shaping our responses.
  • Genetic differences can impact the magnitude of placebo effects, meaning that individuals with certain genetic variations may experience stronger or weaker responses to placebos. These genetic variations can influence how the brain and body respond to expectations and beliefs, ultimately affecting the effectiveness of placebos in inducing physiological changes. The interplay between genetics and placebo responses suggests a biological basis for the variability in how individuals perceive and react to placebos. This highlights the personalized nature of placebo effects based on genetic factors.
  • Placebos can help alleviate symptoms by influencing the mind-body connection, but they are not powerful enough to cure serious illnesses like cancer or asthma. While placebos may improve outcomes by reducing stress or enhancing sleep, they cannot directly address the underlying physiological issues of these conditions. This limitation is due to the complex nature of diseases like cancer and asthma, which require targeted medical interventions beyond the scope of placebo effects. The effectiveness of placebos is more pronounced in symptom management rather than in treating the root causes of severe health conditions.
  • The study on hotel workers highlighted how perceiving daily work tasks as exercise led to health benefits like weight loss and lower blood pressure, even without additional physical activity. This suggests that changing one's mindset about routine activities can positively impact health outcomes. The findings emphasize the potential influence of perception on physical well-being through how individuals view and interpret their daily tasks.
  • Recognizing daily activities as exercise can lead to health improvements due to the mindset shift it creates. This perception can motivate individuals to engage more actively in their daily tasks, potentially increasing physical activity levels. The mental framing of routine activities as exercise may result in physiological benefits similar to those achieved through traditional forms of exercise. This highlights the power of mindset in influencing physical well-being through simple changes in perception.
  • The prefrontal cortex, responsible for thoughts and beliefs, does not have a direct pathway to trigger muscle growth. Physical development in muscles is primarily influenced by factors like exercise, nutrition, and hormonal responses, rather than solely by cognitive processes. While mindset and beliefs can impact physiological responses, muscle growth requires specific physical stimuli like resistance training to occur. The mind-body connection is important, but muscle growth is a complex process that involves more than just thoughts or beliefs.
  • Beliefs about the nutritional content of food can influence hormonal reactions related to hunger. Participants' ghrelin levels and feelings of fullness were affected by their perception of calorie content, not the actual calories ingested. This showcases the impact of perception on physiological responses to food, demonstrating how our thoughts about what we eat can influence our body's hormonal responses.

Counterarguments

  • While placebos can induce physical changes, the extent to which they can influence long-term health outcomes remains a subject of debate, and their effectiveness can vary widely among individuals.
  • The connection between the prefrontal cortex and the hypothalamus is complex, and while it plays a role in stress responses, other brain regions and factors are also involved, which may limit the influence of expectations.
  • The strength of placebo effects being tied to complexity or invasiveness may not always hold true, as some simple placebos have been shown to produce significant effects in certain contexts.
  • The color of a placebo pill's impact might be culturally specific and not universally applicable, suggesting that the perceived impact may not be consistent across different populations.
  • Classical conditioning's role in physical responses may be limited by individual differences in learning and memory, which could affect the conditioning process and its outcomes.
  • Genetic differences do influence placebo effects, but environmental and psychological factors also play a significant role, and the interaction between these factors is not fully understood.
  • While placebos cannot cure serious ailments, there is ongoing research into how placebo effects might be harnessed to complement traditional treatments and potentially improve outcomes in some conditions.
  • The study on hotel workers' health improvements could be influenced by factors other than perception, such as increased mindfulness about health or unintentional changes in behavior following the intervention.
  • The idea that recognizing daily activities as exercise can improve health may not apply to everyone, especially those with specific fitness goals or medical conditions that require targeted physical activity.
  • The "Mind Over Milkshakes" study highlights the influence of perception on hormonal responses, but it is important to consider that long-term nutritional habits and actual caloric intake play a critical role in health and cannot be overridden by beliefs alone.

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How Placebo Effects Work to Change Our Biology & Psychology

Belief effects and placebos change real physiology

Andrew Huberman sheds light on how placebos, nocebos, and belief effects are not just phenomena of the mind but also change biology and physiology, affecting heart rate, blood pressure, and neuromodulator release such as dopamine and adrenaline.

Prefrontal cortex controls physiology through labeled connections

Huberman describes the prefrontal cortex as a prediction machine, which affects physiology through well-defined neural pathways that connect to specific brain areas controlling bodily functions. These include neural circuits connecting the prefrontal cortex to the hypothalamus, which then influence functions like stress response.

Expectations generate placebo effects

Huberman emphasizes how beliefs about a drug or behavior can cause significant physiological changes that align with the perceived effects, even if the belief is incorrect. For example, subjects reacting to a placebo as if it were nicotine displayed brain activity changes corresponding to the amount of nicotine they believed they received, affecting cognitive tasks’ outcomes.

More invasive/complex placebo = greater effect

Huberman points out that the complexity or invasiveness of a placebo treatment, such as injections or medical devices, correlates with a stronger placebo effect. This is because the brain associates a greater level of invasiveness with larger expected outcomes.

Color impacts direction of placebo effect

The placebo effect can also be influenced by color—blue placebo pills are associated with sleep, red with stimulants, and yellow with the most significant antidepressant effect under the belief that they will relieve depressive ...

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Belief effects and placebos change real physiology

Additional Materials

Clarifications

  • A nocebo effect occurs when negative expectations about a treatment lead to more negative outcomes. It is the opposite of the placebo effect. Nocebos can induce real physiological changes in the body based on the patient's beliefs. The term "nocebo" was coined to describe this harmful response to negative expectations.
  • Neuromodulators are chemicals that regulate groups of neurons by binding to specific receptors, initiating signaling cascades that can have lasting effects on neural activity. They include neurotransmitters like dopamine, serotonin, and acetylcholine, influencing functions such as synaptic efficacy and neuronal connectivity. Neuromodulators can be released by neurons locally or act as hormones, affecting multiple brain regions and neural circuits. These chemicals play a crucial role in shaping brain function and behavior by modulating the activity of various neurons in the central nervous system.
  • The hypothalamus is a crucial brain region that plays a significant role in regulating stress responses by controlling the release of stress hormones like cortisol and adrenaline. It acts as a bridge between the brain and the body, receiving signals from the prefrontal cortex and other brain areas to initiate the body's physiological reactions to stressors. Through its connections with the autonomic nervous system and the pituitary gland, the hypothalamus coordinates various bodily functions in response to stress, such as increasing heart rate, blood pressure, and releasing energy for the "fight or flight" response.
  • The COMT gene encodes an enzyme called catechol-O-methyltransferase, which plays a crucial role in breaking down neurotransmitters like dopamine, epinephrine, and norepinephrine in the brain. Variations in the COMT gene can affect the efficiency of this breakdown process, leading to differences in neurotransmitter levels. These differences can influence various brain functions, including mood regulation, stress response, and cognitive processes. Therefore, variations in the COMT gene can impact how individuals respond to placebo effects due to its role in regulating neurotransmitter activity in the brain.
  • Epinephrine and norepinephrine are neurotransmitters and hormones that play crucial roles in the body's stress response. Epinephrine, also known as adrenaline, increases heart rate, dilates airways, and mobilizes energy stores in times of stress. Norepinephrine acts as both a hormone and a neurotransmitter, regulating blood pressure, attention, and mood. These chemicals are released in response to stress or danger, preparing the body for a "fight or flight" response.
  • The prefrontal cortex acts as a prediction ...

Counterarguments

  • The extent to which placebos change biology and physiology may be overstated, as some studies have shown that while subjective experiences can change, objective physiological markers may not always be significantly affected.
  • The role of the prefrontal cortex is complex, and while it has connections that influence physiology, it is not the sole controller, as other brain regions and feedback mechanisms are also involved.
  • Expectations may generate placebo effects, but these effects can be inconsistent and vary widely between individuals, suggesting that other factors besides expectations may play a role.
  • The correlation between the complexity or invasiveness of a placebo treatment and the strength of the placebo effect may not always hold true, as some simple interventions can also produce strong placebo responses.
  • The impact of the color of placebos on their effect is not universally accepted, and some research suggests that cultural differences and individual experiences can alter or negate these color associations. ...

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How Placebo Effects Work to Change Our Biology & Psychology

Health effects of placebos are limited

Placebos, while useful for managing certain symptoms, have clear limits, particularly in the treatment of serious conditions like cancer and asthma.

Placebos reduce cancer treatment discomfort, not tumors

Huberman addresses a common misconception about the role of placebo effects in cancer treatment. He clarifies that while implementing practices such as reducing stress or improving sleep can indeed improve cancer treatment outcomes, these should not be confused with placebo effects. Such practices have tangible physiological impacts, like decreasing inflammation and stress hormones, which in turn can contribute positively to cancer therapy. However, placebos themselves do not have the capability of shrinking or eliminating tumors.

Placebos reduced asthma discomfort, not breathing

In a study on asthma by Dr. Ted Kapchuk’s lab at Harvard Medical School, individuals were taken off their medication for a period, allowing for a direct comparison of the effects of their regular medication versus placebos. Huberman discusses how one group took their regular asthma medication and experienced improved breathing and reduced discomfort. In contrast, another group re ...

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Health effects of placebos are limited

Additional Materials

Clarifications

  • In cancer treatment, physiological impacts involve tangible changes in the body, like reduced inflammation and stress hormones, which can positively influence therapy outcomes. Placebo effects, on the other hand, are psychological responses to a treatment that can lead to symptom improvement without directly affecting the underlying disease. While practices like stress reduction can have physiological benefits, they are distinct from placebos as they involve measurable changes in the body's functioning. Placebos do not have the ability to shrink or eliminate tumors but can help manage treatment discomfort through psychological mechanisms.
  • In the context of asthma treatment, placebos can help reduce the perceived discomfort or symptoms experienced by individuals, such as feelings of tightness or wheezing. However, unlike actual medication ...

Counterarguments

  • Placebos may have a more significant impact on health outcomes than currently understood, as their effects on the patient's psychological state can indirectly influence physical health.
  • The definition of "placebo effect" could be expanded to include any positive health outcome resulting from a patient's belief in the treatment, which might encompass stress reduction and improved sleep.
  • The role of placebos in enhancing the effectiveness of actual medication through patient expectations and beliefs could be underappreciated.
  • The potential of placebos in treating certain symptoms could lead to reduced medication use, minimizing side effects and interactions in chronic conditions.
  • The ethical considerations of using placebos could be re-evaluated, especially if they can provide relief without the risks associated with active medications.
  • The study on asthma might not capture ...

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How Placebo Effects Work to Change Our Biology & Psychology

Hotel workers improved health when told work was exercise

An intriguing study on hotel workers reveals the power of perception and how it influences physical health. Workers who were informed that their daily activities constituted a good exercise regimen showed significant health improvements simply by recognizing their work as a form of physical exercise.

Workers in the study were split into two groups. One group was told about the calorie-burning and health benefits of their everyday tasks, such as cleaning rooms, which often include walking, bending, and lifting, all of which can be compared to a workout at the gym. The second group of workers performed the same tasks but did not receive information regarding the exercise potential of their work.

Remarkably, those workers who considered their work to be a form of exercise experienced a decrease in weight, blood pressure, body fat, waist-to-hip ratio, and body mass index. This finding suggests that viewing daily activities as a form ...

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Hotel workers improved health when told work was exercise

Additional Materials

Clarifications

  • Perception can directly influence physical health through a phenomenon known as the placebo effect, where believing something is beneficial can lead to actual improvements in health outcomes. In this study, when hotel workers perceived their daily tasks as exercise, their bodies responded positively, showing improvements in weight, blood pressure, body fat, and other health markers. This suggests that the mindset and beliefs individuals hold about their activities can impact their physical well-being, demonstrating the powerful co ...

Counterarguments

  • The placebo effect may account for some of the health improvements, rather than a direct result of perceiving work as exercise.
  • Correlation does not imply causation; the study may not have controlled for other variables that could have influenced the health outcomes.
  • The study's results may not be generalizable to all populations, as they are based on a specific group of hotel workers.
  • The long-term sustainability of health benefits from this perception change is unclear without longitudinal data.
  • The psychological impact of viewing work as exercise was not addressed, which could have both positive and negative effects on mental health.
  • The study may not have accounted for the intensity and duration of the physical activity performed by the workers, which are important factors in exercise benefits.
  • The findings could lead to an undervaluation of structured exercise programs and proper ...

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How Placebo Effects Work to Change Our Biology & Psychology

Thoughts can't directly control muscle growth

Despite some common beliefs about the power of thought influencing physical strength, it's crucial to understand the limitations of such ideas. There is no direct neural circuit or hormonal pathway from the prefrontal cortex, which is a region in the brain responsible for complex cognitive be ...

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Thoughts can't directly control muscle growth

Additional Materials

Clarifications

...

Counterarguments

  • While thoughts alone may not directly cause muscle growth, the placebo effect is a well-documented phenomenon where belief and expectation can lead to physical changes in the body, which could potentially influence muscle recovery or performance.
  • The mind-muscle connection, a concept used in bodybuilding and strength training, suggests that focusing on the muscle being worked can enhance the quality of the exercise and potentially lead to greater gains, although this is more about exercise efficiency than direct thought-induced muscle growth.
  • Psychological states can influence hormone levels, such as cortisol and testosterone, which in turn can have an indirect effect on muscle growth and strength.
  • Visualization techniques are often used by athletes to improve performance, and while they don't directly cause ...

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How Placebo Effects Work to Change Our Biology & Psychology

Information about food changes hormone responses

Recent findings reveal that our beliefs about the food we consume can significantly influence our body's hormonal responses, particularly with regard to feelings of hunger and satiety.

Beliefs about milkshakes changed ghrelin levels

The "Mind Over Milkshakes" study highlights how the mind can powerfuly affect the body's physiological reactions to food. Specifically, the study found that beliefs about the calorie content of milkshakes can alter levels of the hunger-related hormone ghrelin.

In the experiment, participants were given a milkshake that was 380 calories. However, the participants were misled to believe that the shake was either a 620 calorie 'indulgent' shake or a 140 calorie 'sensible' shake. Ghrelin levels were measured at baseline, just before consuming the milkshake (anticipatory), and again 90 minutes after consumption (post-consumption).

Remarkably, regardless of the milkshake's actual caloric con ...

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Information about food changes hormone responses

Additional Materials

Clarifications

  • Ghrelin is a hormone that plays a key role in regulating hunger and appetite. It is often referred to as the "hunger hormone" because it stimulates appetite, leading to increased food intake. Ghrelin levels typically rise before meals and decrease after eating, signaling to the brain that it's time to eat. This hormone is produced mainly in the stomach and acts on the hypothalamus in the brain to help regulate energy balance. In the context of the study mentioned, changes in ghrelin levels were observed based on participants' beliefs about the calorie content of the milkshake they consumed.
  • Anticipatory ghrelin levels are the levels of the hunger-related hormone ghrelin measured just before consuming a meal or food item. These levels can provide insight into the body's initial response to the expectation of eating and can influence feelings of hunger and satiety. In the context of the study mentioned, measuring anticipatory ghrelin levels helped researchers understand how participants' beliefs about the calorie content of the milkshake affected their physiological responses.
  • Subjective feelings of satiety refer to an individual's personal perception of fullness or satisfaction after eating. It is a subjective experience that varies from person to person and can be influenced by factors like beliefs, emotions, and past experiences with food. These feelings play a crucial role in regulating food intake and can impact eating behaviors and overall dietary patte ...

Counterarguments

  • The study may have a small sample size, which could limit the generalizability of the findings.
  • The placebo effect could be a significant factor in the study, and it might not specifically be beliefs about food that cause the change in ghrelin levels.
  • The study's design may not account for individual differences in metabolism, psychological state, or previous experiences with food, which could influence the results.
  • The study focuses on short-term hormonal responses and does not necessarily indicate long-term effects on weight or health.
  • The findings could be specific to the context of the experiment and may not translate to real-world eating behaviors where multiple factors influence food choices and satisfaction.
  • The study measures subjective feelings of satiety, which are inherently subjective and may not accuratel ...

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