THE LEGEND OF THE BOILING FROG IS JUST A LEGEND

by Whit Gibbons

December 23, 2007

Some queries are perennial, that is they arise again and again. The question of the boiling frog is one of them.

Q: I am a Ph.D. student in the Netherlands working in the field of experimental economics. I am doing laboratory tests on human behavioral responses to gradual economic changes. The behavior is connected to the "boiling frog" syndrome. I have heard that the metaphor itself is a hoax, but that assessment seems to depend on just a few articles, one by your hand. Is it true or a hoax?

A: I first received an inquiry about the boiling frog phenomenon several years ago from Joseph Pechmann, a noted amphibian conservation biologist. He himself had received a query from someone in Hamburg, Germany, who said, "I write a weekly column on scientific urban legends that my readers ask me about. This one is often told by consultants or activists: If you put a frog in boiling water, he will try to escape. If you put him in cold water and heat it gradually, the frog will remain in place until he's boiled. The lesson, to him (and consequently to us) is that gradual change is imperceptible. Frankly, I don't buy this. But I am looking for professional advice (and I don't want to boil frogs). Can you help me with this question?"

Joe was not sure what the answer was, so he referred the question to me. I made a few comments before passing the buck myself: "I have heard the anecdote many times, including in a sermon by a Southern Baptist preacher. In that case, the big bullfrog in a bucket of water that was being heated was a metaphor for how gradual habituation to a devilish situation leads to acceptance of an even worse one.

"Environmentalists equate the oblivious frog with people who refuse, for whatever reason, to recognize that the earth is under increasingly severe environmental stress. Although an answer that destroys an urban myth or a commonly held belief may disappoint some people, we are better off knowing the truth. With a real frog in real water, my bet is that as soon as it began to get uncomfortable the frog would jump out if it could.

"I personally have boiled no frogs, so I have no empirical evidence as to a frog's response to gradually heated water. But I am aware of experiments on responses of amphibians to high temperatures, so I feel certain someone familiar with those studies would have an impression of what a frog would do as the water warmed up. I am sending your question to Dr. Victor Hutchison at the University of Oklahoma to see what he says. I too am interested in his response."

Vic's answer was as follows: "The legend is entirely incorrect! The 'critical thermal maxima' of many species of frogs have been determined by several investigators. In this procedure, the water in which a frog is submerged is heated gradually at about 2 degrees Fahrenheit per minute. As the temperature of the water is gradually increased, the frog will eventually become more and more active in attempts to escape the heated water. If the container size and opening allow the frog to jump out, it will do so." Naturally, if the frog were not allowed to escape it would eventually begin to show signs of heat stress, muscular spasms, heat rigor, and then death.

So where does that leave us with the boiling frog as a metaphor for the human response to economic change or environmental degradation? Well, it's not true that you can induce a frog to willingly remain in boiling water by starting it off in cold water. But that does not diminish the truth of the message that the accumulation of imperceptible changes can have a significant effect on the economy and the environment. We need to be aware of what changes are occurring and to respond to them in a timely fashion. The metaphor lies in the frog's ability to escape from the container: if there's no way out, then the frog's fate is a foregone conclusion.



If you have an environmental question or comment, email