Repeat after me: The best learning comes from replication

I have written so many columns now that I have to worry about repeating myself. I never actually worry about that in real life. I just go ahead and repeat myself. After all, repetition is the mother of all learning. My family, of course, has to determine which of the things I say are worth learning. I figure that’s their job, not mine. I say that all the time. 

Repetition in science is actually highly important. That is because nature is so variable. If I told you that humans all weigh 150 pounds, you would be pretty sure that wasn’t true, even though you couldn’t say for sure what they all weigh. One thing that would make me suspicious is that I don’t believe that is what I weigh. So either my scale is “weigh” off, or I’m not human. That immediately suggests two different experiments. 

I know that isn’t how we teach science in school. There, it all seems cut and dried. Just memorize all the answers, and you become a scientist. Many freshmen college students are shocked to learn that they don’t know everything. This is an easy mistake for them to make because for their entire lives, adults have been telling them what they know. Of course, the poor freshmen have to assume that by now they have learned it all. Only when they come face-to-face with things that no one knows does it dawn on them that they don’t know everything, and neither does anyone else. 

That last bit probably comes as a shock to a lot of adults as well. Many politicians are obviously confused on this matter and think they know quite a lot about science. Politicians dabbling in science is highly dangerous because science is dictated by the real world and politics is mostly fiction. I love reading fiction, but I wouldn’t want to live there. 

There are many ways to mess up in this world. If you are trying to find answers to questions about which there are no answers, it gets even worse. That is why scientists always look to see how many times the results of any experiment have been replicated. Let me explain some of the possible sources of error.

In the first place, you may have done the whole study wrong. Don’t worry too much about that kind of error because there are plenty of people who will be willing to point that out to you. Another problem is equipment failure or error. It is surprisingly difficult to measure any physical parameter accurately. In many cases, like the size of the cell membrane, or the size of an electron, things must be measured in extremely tiny numbers. In other cases the numbers may be unimaginably large, as in the distances between galaxies or the national debt. Wait! Sorry. I don’t think economics is a science. 

The biggest problem is that the physical world is variable and our techniques are unreliable. It is a small wonder that we have reached conclusions about anything. Well, except climate change, which the president has declared true. I have to admit he is probably right, the climate will change. 

The way scientists protect themselves from making mistakes is by replicating data. If we do an experiment several times, and we get similar results each time, we begin to believe that we are at least consistent in our approach. That doesn’t always mean that we are correct in our conclusions. Or maybe that’s just been my experience. Repeated results, however, generally carry more weight than isolated experiments.

So see, it’s not that I have forgotten what I said. It’s all due to my cautious, scientific nature that I have developed over years of careful analysis and deep thinking. My wife thinks I just like to hear myself talk. Hey, repetition is the mother of all learning! I say that all the time.

Gary McCallister, .(JavaScript must be enabled to view this email address), is a professor of biology at Colorado Mesa University.


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