Lifesaving Value of Hope

This blog post was made by Jennifer Ravert, RN on February 9, 2023.
Lifesaving Value of Hope

In 1957, Dr. Curt Richter, a Harvard graduate and professor at Johns Hopkins University experimented on rats and published a paper, On the Phenomenon of Sudden Death in Animals and Man, in the Journal of Psychosomatic Medicine. He intended to expand upon research done on Voodoo by Walter Cannon in 1942 which questioned, “How can an ominous and persistent state of fear end the life of man?

In his first study, Dr. Richter wanted to know how long rats would attempt to keep themselves alive when faced with a seemingly hopeless situation. He did this by dropping twelve tame, domesticated, rats into jars half-full with water. Rats are physically capable of swimming, Richter knew this. So, how long would they swim for?

In the first experiment, upon being placed in water, three of the rats frantically explored the jar environment. They examined the predicament of their situation, took note of the inescapable slippery glass walls, dropped their heart-rates, and succumbed to drowning very quickly—within 2 minutes.

The nine remaining domesticated rats raised their heart-rates and treaded water in their jars for 40-60 hours. They struggled and fought to keep their heads up until they physically couldn’t anymore—and also eventually drowned.

Another experiment involved 34 wild rats Richter caught. These animals were stronger, bigger, aggressive, and more adapted to harsher environments. In theory, these rats would have more survival instincts than their gentler, domesticated, counterparts. After-all, these rats were independent from humans and had relied only on themselves for survival.

Yet, some of the wild rats barely even made it into the water, with several dying from cardiac arrest almost immediately from the terror of being handled by human hands.

Dr. Richter observed that after placing the remaining wild rats into jars of water, none showed the physiological manifestations of “fight or flight” and were dead within 1-15 minutes. Strangely, the wild rats did not even seem interested in preserving their lives. They did not flail or struggle much. It seemed as if they accepted their fate and surrendered to drowning with little fuss.

For the next experiment, Richter decided to test if he could change the results by introducing one critical concept to the rats—hope.

He gathered another group of rats, even more than the first experiments, and again placed them into the jars. This time, instead of leaving them alone to sort-out their crisis independently, he watched. As he saw the rats begin to give up within minutes, he reached in and plucked them from their predicament. He towel-dried them and allowed them to recover and rebuild their energy.

a tame white rat peeks out of a jacket pocket a tame white rat peeks out of a jacket pocket. Rat Stock Photo

He then returned them to the water.

What did the rats do after they realized that getting out of the situation was not actually impossible? Once they realized that a hand just might appear from above and rescue them?

The rats all swam nonstop for 60-80 hours! Yes, they did eventually drown as well… but not nearly as quickly or frequently as the previous subjects. Their hostility returned. They fought hard.

By today’s standards, these experiments were terribly cruel and inhumane. It’s uncomfortable to talk about, as these animals truly suffered. However, there is still relevance to what was done to the rats by Carl Richter and it’s very applicable in today’s medical community. Why did nine domestic rats swim for days when thirty-four wild rats did not?

Hope was the reason.

Most of the domestic rats had some expectation that their survival needs would be met by an outside force. Perhaps this is because they had been fed by human-hands and placed by human hands into the predicament. Somehow, they realized that intervention was possible. Believing their situation was not completely hopeless, they swam for their lives.

The wild rats had no such expectations. In their experience of the world, there would be no assistance. They had no previous experience with glasses full of water or of human action. They had only ever relied on themselves, and they did not struggle much when faced with a situation they could not escape. They accepted their fate. The rats did not expect to be saved. They knew of no such concept. They succumbed quickly.

Once Richter demonstrated to all of the rats that rescue was a possible outcome, the will to live was evident in all of the rats, pretty much equally. They were certainly in a precarious situation, but not a hopeless one. Even in a tiny rodent brain, having a little bit of hope for more life was an incredible motivating factor for perseverance and resilience.

Little rodent A little mouse Animal Stock Photo

Curt Richter observed that, “the sudden death phenomenon depends largely on emotional reactions to restraint or immersion comes from the observation that after elimination of the hopelessness the rats do not die.”

Hope is a powerful motivating factor for survival, and perhaps one of the most underappreciated. If rats can hold their heads above water for 80 hours because—just once—they were rescued and believed it to still be possible, imagine the steps a human would take to preserve life if they had the same optimism? Just like the rats, we too are lost without hope, which is essential in the face of adversity. We should take care to remember the lessons Dr. Richter’s rats taught us as they give us a much greater insight into the depths of our own endurance. If an animal believes it will drown, it will. If an animal believes that it might not drown, it is that hope that will drive the fight for more life.

If you would like to read Dr. Richter’s study in his own words, it is archived here:


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