Rat Study, Gut Response (Achievement Nudge)

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Last Updated on April 7, 2025 by Bill Truby

A study of rats showed that “gut instinct” has a powerful impact on how we react to life, especially when it comes to fear.

In Zurich, a team of researchers, led by Urs Meyer, studied rats and gut instinct. They found that, like us, rats have nerves that come FROM the brain and send signals to all of the vital organs. They also showed there are nerves in the stomach and abdomen that send signals BACK to the brain – the “Gut Response.”  

The rat study revealed that whenever there is a threatening situation or something that causes your gut to feel fear, a signal sent from the gut to the brain says, “Watch out! This feels fearful! Do something!” Ever felt it? Sometimes we don’t even know why, we just know our gut is telling us, “Something is wrong!” And when that happens, the brain listens. It takes protective action with that famous “fight or flight” syndrome. THE syndrome that causes stress.

But, there’s a problem. Your gut learned what is fearful and threatening through conditioned response. The original, legitimate threatening situation may not exist anymore. Your gut just THINKS it does because the current situation looks, sounds and feels like that fearful one in the past.

Let’s say, for example, your boss calls you into the office. That can look, sound and feel like the time when you were in trouble and your parents called you in for a talk. Your gut thinks it’s the same thing…but it’s not. But not having a brain, your gut sends the warning anyway. Voila, STRESS!!

To study this process, the researchers cut the vagus nerve in the rats, the nerve that sends signals from the gut TO the brain. They left the nerves that came FROM the brain to the gut intact. There were fascinating results. Cutting the vagus nerve changed the production of neurotransmitters and caused the rats to be more peaceful. They were less wary of open spaces, and less fearful of bright lights, as compared to rats with the vagus nerve still intact. When the gut didn’t signal the alarm, the rats were less stressed.

Of further interest; though the gut was effectively cut off from sending conditioned response signals to the brain, the brain could still send them to the body. If there WAS a real threat, the brain could send a signal to the body and react appropriately. The brain had discretion and choice. The gut did not.

This is an important implication for you and me because stress is one of the top killers in our country. If we can manage OUR gut signals, maybe we can reduce our stress. What can you do?

Remember, your gut doesn’t have a brain. Your head does, and you’ve got to use it. When you feel the fear signaled from your brainless gut, don’t react as if it’s real…UNTIL you’ve determined that it is.

I know from experience. MANY times, when I feel fear in my gut, it’s a false alarm. Though hard to dissuade it, and the feelings of fear may hang around for a while, I have worked to stop having conditioned responses to my conditioned responses – when my gut has a conditioned response and sends a fear signal, I don’t let my brain have a conditioned response and automatically react. Instead, I ask, “Is this real? Is it true?” If it is, I respond. If it isn’t, I don’t. You see…if my stomach growls…I growl back.

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This article is part of our ongoing Achievement Nudge series—short, witty, and often inspirational articles to spark your personal and professional growth. Explore more nudges on our blog, or sign up for our weekly Nudge and News email. Each edition includes an Achievement Nudge plus leadership, professional development, and personal growth videos and articles to keep you inspired and on track.

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