Should You Trust "Gut Feelings" to Make Decisions?

Is it rational to trust your gut feelings? Does it matter if you face a decision that is personal versus a decision you have at work? Does the amount and reliability of information prompt you to make a decision solely on logic and rationality, or does gut feeling still play a part? Are gut feelings defined as an emotion or something else? These are questions that have prompted a great deal of research and discussion for hundreds of years.

A Definition of Gut Feelings

Gut feelings can be defined asan instinct or intuition; an immediate or basic feeling or reaction without a logical rationale, an instinctive feeling, as opposed to an opinion based on facts. If you have a gut feeling about something, you are sure even though you cannot give reasons. Gut feelings are also known as intuition.

Intuitionis the ability to acquire knowledge without proof, evidence, or conscious reasoning, or without understanding how the knowledge was acquired. Different writers give the word "intuition" a great variety of different meanings, ranging from direct access to unconscious knowledge, unconscious cognition, inner sensing, inner insight to unconscious pattern-recognition and the ability to understand something instinctively, without the need for conscious reasoning. Some philosophers contend that the word "intuition" is often misunderstood or misused to mean instinct, truth, belief, and meaning, whereas others contend that faculties such as instinct, belief and intuition are factually related.The word intuitioncomes from the Latin verb intueritranslated as "consider" or from the late middle Englishword intuit, "to contemplate".

Both Eastern and Western philosophers have studied the concept in great detail. In the East intuition is mostly intertwined with religion and spirituality, and various meanings exist from different religious texts. In the West, intuition does not appear as a separate field of study, and early mention and definition can be traced back to Plato. In his book Republic he tries to define intuition as a fundamental capacity of human reason to comprehend the true nature of reality. 

In his book Meditations on First Philosophy, Descartes refers to an intuition as a pre-existing knowledge gained through rational reasoning or discovering truth through contemplation. This definition is commonly referred to as rational intuition. Later philosophers, such as Hume, have more ambiguous interpretations of intuition. 

Immanuel Kant found intuition is thought of as basic sensory information provided by the cognitive faculty of sensibility (equivalent to what might loosely be called perception). Kant held that our mind casts all of our external intuitions in the form of space, and all of our internal intuitions (memory, thought) in the form of time.

According to Sigmund Freud, knowledge could only be attained through the intellectual manipulation of carefully made observations and rejected any other means of acquiring knowledge such as intuition, and his findings could have been an analytic turn of his mind towards the subject. In Carl Jung's theory of the ego, described intuition is an "irrational function", opposed most directly by sensation, and opposed less strongly by the "rational functions" of thinking and feeling. Jung defined intuition as "perception via the unconscious": using sense-perception only as a starting point, to bring forth ideas, images, possibilities, ways out of a blocked situation, by a process that is mostly unconscious.

 Instinct is often misinterpreted as intuition and its reliability considered to be dependent on past knowledge and occurrences in a specific area. For example, someone who has had more experiences with children will tend to have a better instinct about what they should do in certain situations with them. This is not to say that one with a great amount of experience is always going to have an accurate intuition.

Intuitive abilities were quantitatively tested at Yale University in the 1970s. While studying nonverbal communication, researchers noted that some subjects were able to read nonverbal facial cues before reinforcement occurred. In employing a similar design, they noted that highly intuitive subjects made decisions quickly but could not identify their rationale. Their level of accuracy, however, did not differ from that of non intuitive subjects.

Intuition, as a gut feeling based on experience, has been found to be useful for business leaders for making judgment about people, culture and strategy. Law enforcement officers often claim to observe suspects and immediately "know" that they possess a weapon or illicit narcotic substances, which could also be action of instincts. Often unable to articulate why they reacted or what prompted them at the time of the event, they sometimes retrospectively can plot their actions based upon what had been clear and present danger signals. Such examples liken intuition to "gut feelings" and when viable illustrate preconscious activity.

The Brain-Gut Connection

A research paper, published in Physiology and led by Florida State University, claims that gut-to-brain signals are a “powerful influence on emotions, mood and decisions” and are often a response to worrisome or threatening stumuli and events. 

According to Florida State neuroscientist Dr Linda Rinaman, the gut and brain are constantly communicating via the vagus nerve – a sprawling two-way network that’s 100 times larger than the surface of the skin and sends more signals to the brain than any other organ system in the body. The nerve carries top-down messages from the brain to the body as well as bottom-up messages commonly described as “gut feelings” and it is these that prompt us to evaluate a situation or avoid it altogether. 

Together with James Maniscalco, at the University of Illinois at Chicago, Rinaman suggests that these signals from our gastrointestinal tract can work as a red flag that actually stops us making bad or dangerous decisions. “The neuroscience of gut feelings has come a long way in my lifetime and we are learning more valuable lessons every day,” Rinaman said.“Vagal feedback signals are very protective and encourage caution.”

Similarly, the data also revealed that our diet can have a major impact on the quality of the gut’s signals and this can sometimes lead to altered mood or behaviour.

For example, Rinaman claims that a high-fat diet can lead to inflammatory response in the GI tract, which changes signals from the vagus nerve and can in turn lead to symptoms of anxiety and depression. “Evidence shows that modifying the diet, perhaps by consuming probiotics, can impact your mood and behavioural state," Rinaman explained.

Neuroscientist Antonio Damasio of the University of Southern California tells us that it is important to pay attention to “somatic markers.” Originating in the insula (the island in the brain responsible for social emotions like pride or guilt) and the amygdala (which cues our response to threats), they send messages that something just feels right—or it doesn’t. The more you pay attention to the outcome of trusting your intuition in combination with facts, the better your future decision-making can become.

Damasio tested this theory in an experiment called the Iowa Gambling Task, in which subjects could choose between decks of cards to win money. Among the choices: two “good” decks that turned up consistent profits and two others with riskier cards. Though it took about 50 cards to make a decision to switch decks and 80 cards to explain why, the subjects’ skin was also being monitored for response to stress. The physical reaction showed that after drawing just 10 risky cards, the body was already displaying signs of anxiety, which meant that their feelings were firing signals faster than rational thought.

Scientific evidence shows a strong connection between chronic diseases and inflammation. Inflammation is most commonly rooted in the gut, where around 70 percentof our immune system resides. Our food choices result in oxidative stress, setting the stage for inflammatory ailments such as depression, anxiety, brain fog, obesity and more. The health of your gut directly impacts the health of your brain. The gut communicates with our immune system and also communicates with the brain using, among other things, neurotransmitters. One function of neurotransmitters is that they that they send key messages to the brain, resulting in various effects on the body. Serotonin and dopamine are some well-known neurotransmitters that are typically associated with a good mood. In fact, while many believe that serotonin is primarily produced in the brain, it’s been found that up to 90 percentof serotonin is actually created in the gut.

Dr. Helen Messer, the Chief Medical Officer at Viome, which analyzes the gut microbiome, says “the bacteria in the gut make or consume the majority of neurotransmitters in our bodies.” Essentially, if your gut is producing an adequate amount of mood-improving chemicals like serotonin, then it will send signals to the brain that will result in various benefits such as better sleep and satiety. It’s obviously more complicated than that, but that’s the general rundown. So how do you influence your gut to help it produce the good neurotransmitters and other compounds that make the mind feel better? A lot of it has to do with eating the right diet that your gut needs.

Researchers at the University of Oxford have proposed an evolutionary framework to understand why microbes living in the gut affect the brain and behaviour, published in Nature Reviews Microbiology. Katerina Johnson (Department of Experimental Psychology) and Kevin Foster (Department of Zoology) assessed data from studies on the gut-brain axis to suggest how that gut feeling evolved.

Research has shown that gut bacteria (especially species belonging to Lactobacillus and Bifidobacterium) can influence social behavior, anxiety, stress and depressive-like behaviour. Katerina explained: "We know there are numerous possible mechanisms, including communication via the vagus nerve (major nerve linking the gut and brain), the immune system and hormonal changes, as well as the production of neuroactive chemicals by gut microbes. But why should we expect gut bacteria to affect behavior at all?" In their paper, Johnson and Foster consider the evolutionary pressures that may have led to that gut feeling.

One theory gaining momentum is that members of the gut microbiome actively manipulate our behavior for their own benefit. For instance, gut bacteria might change our behavior in ways that make us more sociable to increase their likelihood of transmission to new hosts. Indeed, it is intriguing that numerous species of gut bacteria can produce chemicals of identical structure to our brain's own neurotransmitters (or their precursors). However, in light of evolutionary theory, the authors suggest this scenario, that our brains are manipulated by our microbes, is very unlikely given the immense diversity of microbial species and strains inhabiting the gut. Professor Foster explained: "Any extra energetic cost invested by bacteria producing a neuroactive chemical to manipulate host behavior would make it very vulnerable to being outcompeted by other microbes not making this additional investment. The conditions favoring manipulation appear rarely satisfied by the genetically diverse ecosystem of the mammalian microbiome."

In addition, our physiology may have adapted to make use of our associated microbes. Similar to the "hygiene hypothesis," which posits that an absence of microbes impairs immune system development, we propose that we may have evolved to depend on our microbes for normal brain function, such that a change in our gut microbiome could have effects on behavior." Johnson and Foster suggest that an understanding of the evolution of gut-brain communication may help us to effectively engineer this microbial ecosystem with potential benefits for mental health and well-being.

Gastrointestinal conditions are incredibly common. About 20% of adults and adolescents suffer from irritable bowel syndrome (IBS), a disorder where abdominal discomfort or pain go hand-in-hand with changes in bowel habits. These could involve chronic diarrhea and constipation, or a mixture of the two. IBS is a so-called functional disorder, because while its symptoms are debilitating, there are no visible pathological changes in the bowel. So it is diagnosed based on symptoms rather than specific diagnostic tests or procedures. This is contrary to inflammatory bowel disease (IBD), a condition where the immune system reacts in an exaggerated manner to normal gut bacteria. Inflammatory bowel disease is associated with bleeding, diarrhea, weight loss and anemia (iron deficiency) and can be a cause of death. It’s called an organic bowel disease because we can see clear pathological changes caused by inflammation to the bowel lining.

Many experience anxiety and depression in response to the way the illness changes their life. But studies also suggest those with anxiety and depression are more likely to develop bowel disorders. This is important evidence of brain-gut interactions.

The brain and gut speak to each other constantly through a network of neural, hormonal and immunological messages. But this healthy communication can be disturbed when we stress or develop chronic inflammation in our guts.

Stress can influence the type of bacteria inhabiting the gut, making our bowel flora less diverse and possibly more attractive to harmful bacteria. It can also increase inflammation in the bowel, and vulnerability to infection.

Chronic intestinal inflammation may lower our sensitivity to positive emotions. When we become sick with conditions like inflammatory bowel disease, our brains become rewired through a process called neuroplasticity, which changes the connections between the nerve signals. Anxiety and depression are common in people suffering chronic bowel problems. Approximately 20% of those living with inflammatory bowel disease report feeling anxious or blue for extended periods of time. When their disease flares, this rate may exceed 60%.

Interestingly, in a recent large study 2,007 people living with inflammatory bowel disease were observed over nine years. The study found a strong association between symptoms of depression or anxiety and disease activity over time. So, anxiety and depression are likely to make the symptoms of inflammatory bowel disease worse long-term.

We all feel things in our gut – intuitions that give us subtle physiological alerts, stress and anxiety that unsettle us, bad reactions to food, and conversely feelings of contentment from the right food, or flutters from an exciting experience. But according to Dr. Emeran Mayer, what we feel is just a small fraction of what’s going on in a region of our body that is still quite mysterious – even to the experts. 

In his book, The Mind-Gut Connection,, Dr Mayer writes: "Your gut has capabilities that surpass all our other organs and even rival your brain. It has its own nervous system, known in scientific literature as the enteric nervous system, or ENS, and [is] often referred to in the media as the "second brain.""

As Mayer describes, this second brain consists of about 100 million nerve cells sandwiched between layers of the gut running all the way from the esophagus to the end of the large intestine. This ‘second brain’ and our regular brain use the same neurotransmitters and are connected through neural, endocrine, and immune pathways, so it truly is an integrated intelligent system with information flowing in both directions.

What makes the second brain unique from other organs is that – in animals at least – when it’s separated from the main brain it continues to pilot its complex activities on its own. 

The system is extremely interesting to researchers because of this independent streak, and the effect that it may have on our mental health. After his many years of research, Mayer humbly says it’s "highly plausible" that there is a connection between the gut and mental health conditions such as depression. Scientists from the University of North Carolina have found that gut bacteria produce neurotransmitters like serotonin, dopamine and GABA, all of which have associations with our mood. Often the medications people with depression take are designed to adjust the uptake of these neurotransmitters, a treatment scientists at the time designed thinking only of the brain, but it may now also have implications in the microbiome.

What makes it even more intriguing is that more than 95% of our body’s serotonin is produced and stored in the gut in specialized enterochromaffin cells, says Dr Mayer, adding: "By far the largest store of the molecule that plays such a big role in modulating our mood and our wellbeing – also appetite, pain sensitivity – is stored in the gut."

Other Research on Gut Feelings in Decision-Making.....

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