It is the natural intuition that cannot be explained - nor should be ignored.
A new study by researchers in the United States, among them Tuka Al Hanai, an Emirati PhD student at the Massachusetts Institute of Technology (MIT), has shed light on how gut feelings affect how many tests a doctor orders on a patient.
Ms Al Hanai and her colleagues developed an algorithm - a set of rules for a computer to follow - to carry out a “sentiment analysis” on a database of medical records from 60,000 intensive-care-unit patients admitted to a Boston hospital. The algorithm recorded positive and negative comments in the notes.
“We wanted to extract the emotive content in the doctors' notes, whether the emotive content has additional information than the standard profile of patients,” said Ms Al Hanai, a 29-year-old from Abu Dhabi.
The study is part of a growing body of evidence and recognition of the role gut feeling plays in medical science.
And it comes at a time when there is much talk of the role artificial intelligence could play in medical treatment, including how symptoms are spotted and diagnoses are made.
In what Ms Al Hanai describes as “a really nice” result, the researchers found that there was a correlation between the positive or negative content of a doctor's notes, and the tests he or she requested.
If a doctor felt negatively about a patient's condition, more tests were ordered, although if the negative feelings went beyond a certain point, the number of tests declined.
Crucially, the correlation was identified after the influence of the actual medical data for each patient was accounted for.
“The algorithm is telling us the doctor is seeing something more than is contained in the formal data,” said Ms Al Hanai, co-lead author of the study with Dr Mohammad Ghassemi of MIT.
Presented at an academic conference in July, the work was also written by Dr Jesse Raffa and Professor Roger Mark of MIT, and Dr Shamim Nemati and Dr Falgun Chokshi of Emory University in Atlanta, United States.
Professor Mark, a medical doctor with decades of clinical experience, said “of course” he was not surprised that a doctor's gut feelings were found to be important.
“Your clinical judgement is far better than machines and what you decide to do in a given situation is heavily influenced by your impression of the patient and what the patient's wants and desires might be,” he said.
If gut feelings do influence doctors, it raises the question of whether their decisions are better or worse as a result. Other scientists have looked into this intriguing question.
Among these researchers is Dr Ann Van den Bruel, a general practitioner (GP) in Antwerp, Belgium, whose academic appointments include being an associate professor at the University of Oxford. A doctor for 21 years, she has, like other GPs, experienced gut feelings about patients' illnesses herself.
“We were feeling it, but not talking about it because it was unscientific, it wasn't how we were trained,” she said.
One study that Dr Van den Bruel was involved with looked at the cases of nearly 4,000 children who had been assessed by GPs in Flanders, Belgium. Published in 2012, it considered whether going along with a gut feeling, defined as an “intuitive feeling that something was wrong even if the clinician was unsure why”, could make it less likely that a serious illness in the children was missed.
In more than 3,000 of the children, a non-severe illness was identified, but some of the cases in which children turned out to have a serious infection were missed. Going along with gut feeling, the results indicated, could have prevented this from happening in some instances.
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One of the key factors sparking gut feeling in the doctors was a concern among parents that their child's illness was abnormal.
Other research has also concluded that gut feeling is useful, notably a study in Denmark in 2014 that found that a GP's suspicions that a patient might have a serious illness could be as accurate a predictor of disease as scientifically recognised “alarm symptoms” like blood in the urine.
These recent studies on gut feeling are happening at a time when the role that artificial intelligence (AI) could play in medical diagnosis is increasingly being recognised.
To give one among numerous examples, reports in May indicated that US and European researchers had found that neural networks were better than experienced dermatologists at identifying skin cancer when examining images.
But could using AI mean losing out on the benefits of gut feelings, given that it seems unlikely that a computer could have them?
Dr Van den Bruel says that AI will be able to replace doctors only “for some specific situations”.
“The first one will be radiology, where I think that for interpreting, reading an image you don't need contextual information, you just need accurate interpretation. They will be the first ones to be replaced by machines,” she said.
“How far that will go, I don't know. There will be other situations where machines will contribute. The situations where gut feeling plays a role, it will be very, very difficult for AI. It's typically in a situation where a very, very rare occurrence is detected or suspected. It would be very, difficult to learn a machine to do that.”
While it seems that AI will not be able to carry out all of the functions of a regular doctor, Ms Al Hanai, who is due to complete her PhD this year, thinks that its input can be improved if computers are taught “what the doctor is seeing and experiencing”.
“That's an experiment or an avenue to explore, for example to deploy cameras or microphones to begin to look at the same things the doctor is looking at, or hear the same things the doctor is hearing, so they can learn in part the same things as the doctor,” she said.