Why test animals to treat humans? On the validity of animal models

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Abstract

Critics of animal modeling have advanced a variety of arguments against the validity of the practice. The point of one such form of argument is to establish that animal modeling is pointless and therefore immoral. In this article, critical arguments of this form are divided into three types, the pseudoscience argument, the disanalogy argument, and the predictive validity argument. I contend that none of these criticisms currently succeed, nor are they likely to. However, the connection between validity and morality is important, suggesting that critical efforts would be instructive if they addressed it in a more nuanced way.

Section snippets

Why test animals?

An article in the New York Times began with the subtitle, ‘Why test animals to cure human depression?’ (Kolata 2004). At first glance, it may seem obvious that testing animals can justify conclusions about human conditions like depression. After all, the practice has become routine. However, the nature of some animal models can make the connection between the model and the conclusions drawn seem somewhat mysterious. The focus of Kolata’s article is the Porsolt Forced Swim Test (or Behavioral

The pseudoscience argument

The pseudoscience argument has been elaborated by Catalano (1990) and echoed by Greek and Greek, 2000, Greek and Greek, 2002. Catalano argues that animal modeling is a pseudoscience in the sense that theories embodied by animal models are not subject to falsification by observation, as described by Popper (1959). Thus, animal models are not science but pseudoscience and are therefore not valid.

As an example, Catalano (1990, p. 18) describes a study by Louis Pasteur in which

nineteen Russian

The disanalogy argument

Although the pseudoscience argument is misdirected, it does lead us to an important consideration. Although animal models are not, as such, the sort of thing scientists seek to disconfirm, they still have to be able to serve the aim of theory testing. In other words, if animal models cannot appropriately connect hypotheses about human conditions with testable consequences, then they are idle and, for all practical purposes, not valid.

How do animal models connect hypotheses with testable

The revised disanalogy argument

Nevertheless, the disanalogy argument may be made more potent in a new form. Even behaviors that are dissimilar may be analogous in the sense that each plays a similar role in the life of the model and target. For example, giving stimulants to rats produces stereotyped rearing behavior, whereas giving stimulants to primates produces stereotyped scratching behavior (Willner, 1991, p. 14). Although rearing and scratching are dissimilar behaviors (no one would have difficulty telling them apart),

The predictive validity argument

Besides construct validity, another form of validity that researchers consider crucial in animal models is predictive validity. The predictive validity of an animal model is simply the extent to which the performance of the model predicts the performance of the corresponding target (Willner, 1991, pp. 3–9). In the case of the Porsolt Forced-Swim Test, the question is: to what extent does the effect of a certain drug on mice dunked in beakers predict the effect of the drug on depressed human

Animal models and animal kinds

One of the first obstacles to drawing conclusions about the validity of animal models is the nature of animal models themselves. What is an animal model? Many commentators on the subject use the term animal model in a way that is, I contend, incorrect and that falsely magnifies the apparent force of critiques of its validity. It would be distracting to propose and defend a definition of animal model (much less scientific model) here. However, the conceptual problem may be identified and

Validity and the morality of animal models

The validity of animal modeling is of interest in its own right but also because of the continuing controversy over the morality of using animals in medical experiments. The use of nonvalid methods is pointless, and it is not morally acceptable to inflict pointless suffering on animals. (Animal models are often designed to represent human suffering in some way and so involve the suffering of animals. It is possible that an animal model could confer a benefit on the animals involved, perhaps by

Validity and the precautionary principle

Uncertainty about the validity of animal models might be connected to moral problems in another way. Instead of seeking to establish the nonvalidity of animal models and then inferring their immorality, a critic could point to uncertainty about the validity of animal models and then invoke a version of the precautionary principle to argue for a prohibition. Such an argument could be represented as follows:

Animal modeling is a method of uncertain validity

A method of uncertain validity is not

Conclusions

Critics have raised at least three sorts of arguments in attempting to establish the general nonvalidity or pointlessness of animal modeling. At least so far, none of these arguments succeeds in making the case that animal modeling is necessarily or always nonvalid. The pseudoscience argument and the disanalogy argument fail, ultimately, because the concerns that they raise, although relevant, are misapplied or insufficient. The predictive validity argument fails because the doubts it raises

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