The students in Mr. Seemy’s class are arguing about the morality of using animals in medical research. “I’m really passionate about stopping animal testing,” says Kyra. “I think about my dog, Jasper, and I think, ‘What if it were him?’ I know he can feel happy or sad, trusting or afraid. I can’t stand to imagine him in a painful experiment.”

“I can understand why you react so strongly to animal suffering,” says Aliyah, “but I’m passionate about the value of medical research. My mom is diabetic, and she would probably be dead now if it weren’t for past research on insulin using pancreases from dogs. I believe the benefit to my mom and millions of people like her justifies animal research.”

“I’ve read about the research you’re talking about,” says Kyra. “Those dog experiments led to the discovery of insulin about a hundred years ago. But there are all kinds of alternatives to animal research these days—computer simulations and things like that. Scientists have even started working with what they call “organs-on-chips.” They’re not computer chips; they’re little devices that use real, living human cells from various human organs. They can test drugs on lung cells or heart cells, and they can simulate real blood and air flow. It’s a more lifelike situation than just working with cells in a test tube or something.”

“That’s great,” says Aliyah. “But scientists still need to be able to test drugs and other treatments on whole living animals, or they won’t be able to predict how a treatment might affect a whole living person. What if you use a lung-on-a-chip to prove that a new asthma medication is safe for lung cells, but you don’t find out that the same medicine causes brain tumors? Studying the drug in rats before using it on people could save human lives.”

“You’re both raising a really interesting issue about models,” says Mr. Seemy. “When you test a medication on a rat or on one of these new organs-on-a-chip, you’re using the rat or the chip as a model of a real human. The model represents the thing you really want to know about—the human—without putting the human at risk.”

“It’s hard to think of either a rat or a chip as a model of a person,” says Anna. “Neither of them looks like a person.”

“True, but a model in this sense doesn’t have to look like the thing it represents,” says Mr. Seemy. “Models can be things that just represent an aspect of how something works.”

“I’d be happy to see the proportion of medical research that uses animal testing drop,” says Aliyah. “But only if we can really rely on alternative models to be at least as good as animals at representing human biology.”

Discussion Question:

Consider a live rat and a lung-on-a-chip (containing human lung cells) as possible models in an experiment on the effect of a medication on human lung tissue. In what ways do you think the rat is the better model (representation) in which to test new drugs? In what ways do you think the chip is the better model of a living human?