Voice of Science and Fairness

I wish to share an early experiment with my fellow evolutionary biologists. The key result of the experiment suggests that the length of an event staying in memory may be directly associated with the effect of the event on fitness.

The experiment was done many years ago on white-footed mouse (Peromyscus leucopus) when I was a graduate student at University of Western Ontario. It has never been published partly because I developed strong allergy to mice before the study is incomplete.

The story started when I was trapping white-footed mice with Longworth mouse traps and accidently caught a least weasel (Mustela nivalis), the most deadly enemy of wild mice. Out of curiosity I brought it back to our animal facility housing my mouse colonies on which I carried out genotyping and breeding experiment. The presence of a least weasel somewhere was almost immediately sensed by all the mice – they stopped regular eating and drinking.

For wild mice, there is no news worse than the arrival of a least weasel in their vicinity.

The news, while depressing for the mice, was found exciting by Dr. Martin Kavaliers who was at that time studying signal-transduction pathways of analgesics. Martin then did an experiment on my white-footed mice with a hot plate. The control mice, when being put on the hot plate, would lift and lick their feet constantly when the hot plate was turned on. In contrast, the mice exposed to the smell of the least weasel became so focused on the smell as to be oblivious of the burning heat under their feet – they did not lift or lick their feet as they should have when there is no weasel smell. Martin incidentally reported the least weasel as short-tailed weasel (Mustela ermine) which is bigger than the least weasel and would have a difficult time squeezing its way into a Longworth trap.

While Martin’s experimental mice were field-caught, the same phenomenon was also observed in lab-born white-footed mice that never had any real encounter with the least weasel, so that “memory” of the bad thing (i.e., the least weasel) may have been somehow encoded in DNA and re-enacted through proteins (which would be truly intriguing). In this way, the memory of the weasel becomes permanent and will not be eroded by the passing of time. (Of course there is also the possibility of new-born mice learning from others.)

I then did an experiment in my semi-natural enclosure which has been described in some of my early publications. The experiment also involved a hot plate, enclosed within a card box, and placed inside the semi-natural enclosure. In one part of the experiment (Memory-Of-Good-Thing-Expt), sunflower seeds and Purina rat chow were scattered on the hot plate, but the hot plate was never turned on. 

White-footed mice are crepuscular and active mostly during twilight hours. Similar to any other field mice, they are always cautious to new things added to their environment, and would investigate the box carefully before entering. After some initial exposure, however, the mice would recognize the box as a good source of food and would enter the box quickly to eat, and females would bring the rat chow back to their nest-boxes. If you take the box away for one day and put it back at the same location, the mice would still recognize the box and enter it readily without further investigation – their memory told them that it was a godsend. 

By the way, the white-footed mice have reasonably good memories and memorize the routes along which they dart from one hiding place to another. If you put a card box on such a route, they will typically dart head-on against the box, producing a loud sound breaking the silence of night, a consequence that the card box is not in their memory of the routes. Sometimes I wonder if they would run right into a predator if the predator knew their routes and just sit there with a wide-open mouth (They don’t, thanks to their smelling capabilities). Of course, there is also benefit of darting from one hiding place to another by using the map in the memory instead of by vision. These mice don’t see very well during twilight hours (Mice are not cats or owls). Relying on their vision might delay their escape from predators.

Leaving aside the many interesting biological aspects of the mice, let’s come to the other part of the experiment (Memory-Of-Bad-Thing-Expt), in which the setup is the same as Memory-Of-Good-Thing-Expt except that the hot plate did get turned on when mice were inside. These mice, experiencing the bad feeling of burning, avoided entering the box in spite of the inviting food inside. (A few things to keep in mind. Don't leave the hot plate exposed, otherwise mice will consider it unsafe and just take the food to a hidden corner to eat, so the experiment will not work. Also, females will always take the food on the plate back to their next boxes.)

The boxes were then taken away for three weeks, after which the mice were again exposed to their respective boxes. Those mice in the Memory-Of-Good-Thing-Expt seemed to have forgotten altogether the good food associated with the box. They resumed the cautious approach and restarted the investigation. In contrast, those mice in the Memory-Of-Bad-Thing-Expt appeared to instantly recognize the box as evil and avoided entering the box.

In short, memory of bad things lasts longer than memory of good things, at least in this particular case. From an evolutionary point of view, this is not difficult to understand. While the good thing may not enhance their fitness very much, the bad thing (the burning and the weasel) could do serious damage. I very much wish the conclusion generalized because it is important.

Mistakes are typically associated with bad feelings, but we learn from mistakes, with the consequence of a lot of bad feelings staying in our memory and lasting for a long time.

One corollary from the conclusion is that, when one gets old, if there is no constant reinforcement of good things and good feelings, then one could potentially be left with memory of bad things and bad feelings. This corollary was made particularly pertinent when a former colleague, a well-established Peromyscus researcher, Dr. Jerry O. Wolff, committed suicide, exactly seven years ago, on May 10, 2008. I met Jerry several times, mainly through conferences and through his visit to my former supervisor’s (Jack Millar) lab. We regarded Jerry as an excellent colleague and did not, and still do not understand why he would have chosen suicide to end his life. Had he lost good things and good feelings in his memory? Did bad things and bad feelings took an upper hand? While our knowledge of science and technology has progressed so much, our knowledge of hope and love has lagged so far behind.

We often see old people indulged in the so-called “good old days”, the kind of nostalgia that historians, psychologists and politicians all unanimously dismiss as mass delusion, i.e., a Garden of Eden that has never existed. Indeed, if we measure wealth, health, life span, degree of democracy and rationality in human behaviour, etc., we will find the present day beating all “good old days” by a wide margin. But do we have more human interactions to reinforce good things and good feelings in our memory if we get old today? Will our brain be gradually poisoned by the bad things and bad feelings?

The mouse experiment described above might also be relevant to parenting as well. Parents perhaps should be particularly cautious when dispensing punishment to their children, especially when parents sometimes do wish their children to remember the bad feeling of punishment for a long time. A child is likely to become troublesome and lost without constant reinforcement of good things and good feelings in his/her memory. A home should not be a transient Biblical Garden of Eden with a cruel one-strike law.

May we keep alive our fond memories of love and friendship until the end of our days!

(Written on May 10, 2015)

Religious people often feel offended when they are told that God has no place in science. They should not if they know the fundamental difference between science and religion.

Suppose we have a financially stressed government official who suddenly became a billionaire. People with a certain degree of curiosity would want to know how he suddenly became so wealthy. One may suggest that the official might have a recent raise in salary, but such a salary raise typically can explain very little of the dramatic change in his wealth. 

Now suppose that the official, through one of his representatives, issued a statement that God had made him rich by dumping a billion dollar in his bank account. Of course, an almighty God has infinite explanatory power of everything. Making someone wealthy surely would not raise any difficulty to His almighty hands. However, a right-minded person probably would not believe in such a statement and would most likely demand a thorough investigation of the financial dealings of the official.

The simple truth is that, when we are dealing with earthly matters, we are satisfied only with earthly explanations. A holy explanation has no place in such earthly matters and will simply be rejected outright.

Now suppose we have another scenario in which a fully grown and sexually active young man came to us with the information that he was only one day old. Any modern scientist would reject the age information as false because the information is incompatible with our observation of the young man being fully grown and sexually active. Given the cell replication rate in human development, one day is simply not enough for a zygote to transform itself into a fully grown and sexually active young man. Modern science will simply deny the existence of any man who is only one day old yet is fully grown and sexually active, and will conclude that the man is much more than just one day old. Even deeply religious people would probably deny the existence of such a man if the Genesis story of Adam and Eve was not recalled in time.

Just as modern science would conclude that a fully grown and sexually active man is more than one day old, it would also conclude that the earth, which has recorded many time-consuming changes, must be much older than a few thousand years. An earth that is only a few thousand years old raises the same difficulty as a fully grown and sexually active young man who is only one day old. Just as most of us will reject the idea of the one-day-old young man, most scientists will also reject the idea of a young earth. A holy explanation has no place in the physical world and will consequently be rejected.

Yes, an almighty God can make a billionaire out of a pauper, or a fully grown and sexually active young man who is only one day old, or an earth (or even a universe) jumping out of nowhere a few thousand years ago, but scientists deal with only earthly matters where invocation of a holy explanation is simply forbidden. Based on earthly laws (which are often better known as natural laws) governing the earthly matters, we reject the possibility that a pauper can suddenly become a billionaire through God, that a fully grown and sexually active man can be only one day old, or that an earth (or a universe) that has experienced numerous time-consuming changes was formed only a few thousand years ago.

The most fundamental difference between religion and science is that God is allowed as an explanation in the former but absolutely not in the latter.

In fact, Jesus had made this point by his well-quoted statement: "Render unto Caesar the things that are Caesar's, and unto God the things that are God's". Don't mix earthly matters with spiritual ones.

When scientists state that God has no place in science, they do not mean that scientists do not need love and are not caring. In fact, many of them are very loving and caring. By “God has no place in science” they only mean that God should never be invoked as an explanation for observed variation in things of nature. 

Scientists need public understanding and support in their practice of excluding God as an explanation for their observed changes in physical entities around us. Such a practice is sometimes quite challenging and difficult. For example, cancer remission has been observed in many cases, and many scientists have been wracking their brains day and night for an understanding of the remission so that they can better help those less lucky one. If we do allow God as an explanation, then the life of these scientists would be much simpler. Whenever they see a case of cancer remission, they will just give each other a knowing smile and say “He did it again”. But I doubt if any church or any religious group or any government would be willing to grant our scientists such an easy life. The world will indeed become quite a bit more hazardous if they do.

So don’t be offended if you are told that God has no place in science. If God does desire to be part of an explanation of the dynamic universe, He most likely will give us a clear sign. At the moment, I believe that His priority is with helping the victims of natural disasters and human atrocities, not with offering holy explanations of natural phenomena.

(Prompted by an article on the debate about including "creation science" in the science curriculum of public schools)

(Re-posted from my Google+)

One thing particularly strange in this world is that one can achieve much and do a great deal of good even if his or her religious belief is entirely wrong.

An engineer can design great cars or trains or ships or airplanes, and his belief that the universe was created 6000 years ago or took shape 4 billion years ago has little to do with his accomplishment.

A physics professor can create photonic sensors to monitor minute changes in temperature in a minute particle, and her belief that the universe was created 6000 years ago or took shape 4 billion years ago has little to do with her accomplishment.

A surgeon can direct his lancet to a tumour with amazing precision, and his belief that the universe was created 6000 years ago or took shape 4 billion years ago has little to do with his accomplishment.

A farmer can plan all his crops and execute his plans beautifully, and his belief that the universe was created 6000 years ago or took shape 4 billion years ago has little to do with his accomplishment.

A real estate agent can sell 50 houses per year, and her belief that the universe was created 6000 years ago or took shape 4 billion years ago has little to do with her accomplishment.

If these people believe that the universe was created 6000 years ago, let them keep their beliefs, because their beliefs about the universe do not really matter in their career.

But there are people who will almost do everything wrong in their career if they believe that the universe was created 6000 years ago, and these include astrophysicists and evolutionary biologists. For these people, their beliefs about the universe matter a great deal. Indeed, nothing they observe in nature makes sense without believing that the universe is very old.

So what can we say about science and religion? The world is quite complex and we cannot be expert in everything, especially not in both the physical and the spiritual worlds. If you know something that works for you, or some theory that makes sense to you, then stick to it and you will be fine. However, it is important to keep an open mind when that something stops working for you or that theory no longer makes sense.

The world changes, so do religious views and scientific theories, but one thing probably will stay for a long time with little change, and that is the scientific method of validating our beliefs and establishing new theories about the physical world through observation, experimentation, and conceptualization.

(Re-posted from my Google+)