One for All, All for One: A Report on the Ethics of Model Organisms

Brian Smith shares his ethics & society case study, which he completed as part of our Young Scientist Program.

The use of animals in scientific research has long been a subject of controversy, dating back to at least 1822, when the British Parliament enacted new laws “relating to the Cruelty to Animals” (Nowlan). Movements like these set the precedent for animals’ treatment in research, with two critical pillars on which even modern model organism work stands:

  1. A person shall not perform on a living animal any experiment calculated to give pain, and
  2. The experiment must be performed with a view to the advancement by new discovery of physiological knowledge or of knowledge which will be useful for saving or prolonging life or alleviating suffering.

This “Cruelty to Animals Act of 1876” is the spiritual precursor for guidelines and regulations surrounding lab animals, such as the National Institute of Health’s “Guide for the Care and Use of Laboratory Animals.” In its 246 pages, this “Guide’ is “an internationally accepted primary reference on animal care and use” and its goal is to uphold “ the balance between ethical and science-based practice…to provide information that will enhance animal well-being, the quality of research, and the advancement of scientific knowledge that is relevant to both humans and animals.”

In order to engage in the ethical debate surrounding model organisms in research, it is imperative we understand the role they play. The National Institute of General Medical Sciences (NIGMS) explains that model organisms are “animals, plants or microbes that can be used to study certain biological processes…accessible and easily manipulated.” Much of the research done with model organisms attempts to be translational, so that “a finding made in fruit flies can shed light on a biological process in humans.” Neil Levy, Director of Research at the Oxford Centre for Neuroethics, notes that animals used in medical research are almost always killed during the course of, or at the termination of, the research. So the ethics of this practice revolve around whether these animals giving their lives to science is not only justifiable but beneficial enough for the animal’s death to be worthwhile.

The NIGMS provides several arguments for why model organisms are used: they are “generally grown quickly, are relatively simple and inexpensive to work with, and are widely available for use in experiments.” They cite examples like a study in yeast that identified the critical components of the cell cycle, a better understanding of which has facilitated the development of more effective cancer treatment drugs. Yeast is an easier model organism to defend than, for example, mice; yeasts are single-celled eukaryotes with which most humans have little-to-no interaction in their lives, while mice are much more blatantly alive and feeling. Studies with mice have “defined basic rules of circadian clocks, which drive daily biological rhythms, and revealed connections between these clocks and sleep deprivation, obesity, diabetes, depression and other human health conditions.” Arguments have been put forth that computer modeling should replace lab animals. However, as organisms can be made up of billions and trillions of cells, each performing different processes, it becomes difficult, expensive, and time consuming to do many experiments that would be more efficient when done with animals. These two approaches, the NIGMS concludes, can go “hand in hand, relying on each other to advance our understanding of health” – but for now computer models on their own cannot replace model organisms.

Neil Levy, on the other hand, focuses on the animal’s experience during the experiment.

The use of animal models also can involve the suffering of the animal. This suffering may be physical or psychological. Most animals are sophisticated enough to experience some degree of psychological distress: social animals kept in isolation, for example, may experience distress as a consequence. On the view assumed here, suffering is intrinsically bad, regardless of who is the subject of the suffering. The distress of a rat is not less morally significant because its subject is a rat, than is the same suffering of an adult human being. From a consequentialist view, we ought to act in such a way as to produce the best outcome, where the best outcome is measured by the best available balance of welfare over suffering, regardless of whose suffering it is.

Ethical debates can often be approached from two polar perspectives. An action’s ethical implications can be judged either by the motives of the person who carries it out, known as deontology, or the consequences of said action – called consequentialism. Kantian philosophy, a branch of deontology, maintains that the consequences of an action do not make them “right” or “wrong;” it is the motivation behind said action that determines its ethicality. Consequentialism, on the other hand, judges an action solely on its outcomes, so to a consequentialist, a morally right act produces a good outcome. In its most extreme form, consequentialism is encapsulated by the saying, “the end justifies the means.” Utilitarianism is an especially salient branch of consequential theory that states the best action is one whose outcome maximizes “utility,” usually in terms of the well-being of sentient entities. Utalitarianism’s founder described utility as the “sum of all pleasure that results from an action, minus the suffering of anyone involved in the action.” Through these different lenses, a more nuanced picture of the ethical situation is formed.

The issue of lab animals is polarizing, in that many take the standpoint that all animal experimentation is wrong. From a Kantian standpoint, all we can do if we wish to make model organism use as ethical as possible is approach our experiments without the intent to hurt or cause suffering; echoing the Cruelty to Animals Act of 1876, the sole purpose of the experiment should be the advancement of humankind.

The lens of consequentialism is especially fascinating in this debate, because it can be used to argue both for and against lab animal use. The NIGMS appeals to the positive outcomes humans reap from experiments involving model organisms: more effective drugs, a deeper understanding of our own physiology, an altogether healthier life. However, a consequentialist must also take into consideration Levy’s point, that the outcome can include animal distress and, sometimes, death. From a utilitarian consequentialist perspective, the morality of using lab animals may vary from experiment to experiment depending on the degree of “suffering” the animals must experience. Indeed, if a thousand fruit flies or mice die, but a number of human lives are saved by the resulting research, it boils down to an even more broad question: does all life have equal worth? To play the Devil’s advocate, I would ask whether a human would sacrifice themselves for a fly or a single yeast – or if another human would trade a human life for an animal’s. What this reveals, perhaps, is the importance of moral agency. It may be impossible to universally declare the moral “goodness” or “badness” of lab animal use; instead it comes down to the moral agent performing the experiment to maximize benefits and minimize suffering in order to make their experiment moral.

Part of the importance of this debate stems from its implications and the questions it raises in our future as a space-travelling race. What characterizes an organism as a biologically-fitting model organism differs from what makes it acceptable to use in laboratories; some animals feel pain, others do not. When our inevitably leaves Earth (under the hopeful assumption we are able to) to colonize the universe, do we bring Earth’s enormous biodiversity with us? What do we bring and what do we leave? Perhaps by that point, computer simulations will have reached a point where they can replace animal experimentation entirely – meaning any animals we bring with us would be for other, happier reasons.

In the end, this author does not disagree with the practice of model organisms. Rules are in place for the prevention of cruelty, and their use betters human quality of life, which in turn may provide the opportunity to improve the lives of all animal species in the future. What is important, though, is that this discussion on the ethics of their use occurs; if humans were not essentially the apex predator of Earth, and if a different species –or an alien race – were to employ us as model organisms in their research, would we not want the same treatment? The act of questioning our own actions, though, is the critical part. When the decision is made to use lab animals, which is often is, the benefits to both humanity and its own species must be weighed against the cost, so that no life is wasted. It is the ethical thing to do.



Levy, N. (2012) The Use of Animals as Models: Ethical Considerations. International Journal of Stroke 7.5: 440-442.

National Institute of General Medical Sciences. Using Model Organisms to Study Health and Disease. (2012) National Institute of General Medical Sciences, U.S. Department of Health and Human Services.

National Institute of Health. (2011) Guide of the Care and Use of Laboratory Animals, Eighth Edition. National Institute of Health, National Academic Press.

Nowlan, Catherine.(1999) An Act to Amend the Law Relating to Cruelty to Animals (15th August 1876).