Animal Testing: pros, cons, and a bit of ethics thrown in for good measure

This is one of those subjects that often invokes strong opinionated debates, but at the end of the day if we didn’t disagree with each other we wouldn’t be human. Personally I kind of sit on the fence on some aspects of this debate; of course animal testing for cosmetic products etc is wrong, but what about animal testing in medicine? Is it ethical to test cures for diseases on animals? Are animals similar enough to humans to test on anyway? I’ll be addressing all of these questions within this blog, and will cover the pros, cons and take into account the ethical implications of testing on animals.

There are copious reasons why researchers choose to use animals to test upon. There are so many studies using animals it would be ridiculous to name them all but in psychology there are a few key things we use animal studies for. For instance, classical conditioning (Pavlov, 1927), operant conditioning (Skinner, 1947), aggressive tendencies in males and females (Wright and Wrangham, 1998; Wagner et al 1980; Carlson, 1998) … I could go on forever (but I won’t).

I will however discuss Skinner (1947) and his box. Skinner wanted to investigate the concept of operant conditioning through the use of his Skinner Box and either rats of pigeons. In the experiment the animals were required to complete behaviours such as pressing a lever, in the case of the rats, in order to release a food reward. The animals learnt through differential reinforcement (or punishment); i.e. if they pressed the leaver by accident they got a food reward and from this they began to learn that pressing the lever delivered the reward. As the image below shows there were both rewards and punishments within the box. From this piece of research Skinner was able to conclude that consequences such as rewards and punishments help to shape and also to predict human behaviour. We can see this happening in everyday life. For example, when you were a child if you put your hand on the front of the oven and it hurt you probably learnt not to do it again because the pain acted as a punisher. Whereas if you got a good school report when you were younger and your parents bought you sweets you would probably want to be rewarded again and so would continue to do well at school.

Experiments such as this have given us such an insight into the human mind, and also demonstrate our similarities with animals. However, as I usually like to do I will start with the cons associated with animal testing, and where better to start than with generalisability? Can we really generalise findings from animals to humans? It can be difficult to make generalisations from one species to another, however some people may disagree with that point reminding us that humans are in fact animals and have developed and changed over time just as rats, pigeons, and monkeys etc have. Starkey (2008) suggested that the obvious differences between humans and animals make it difficult to make generalisations. For example, it is not always appropriate to generalise findings from the brains of rats due to biological differences across species. We know that rats have a significantly smaller neo-cortex to brainstem ratio. We also know that primates, such as chimpanzees, have a larger neo-cortex but the proportions are still different to human beings. This makes any generalisations we may wish to make from the brains of one species to another difficult to do reliably.

Further disadvantages of using animal studies have been discussed in the literature (Stubblefield, 2009). Firstly, one interesting fact I discovered whilst researching this blog is that researcher’s bias towards gender is not just confined to human studies. Zucker and Beery (2010) suggested that many researchers avoid using female animals, just like in the past they avoided female humans. This bias can have just as many implications for research using animals in that, like with humans, we may not get a true representation of behaviour if we only look at one gender. If we’re measuring levels of aggression in rats we would need to observe males and females in order to compare if there is a difference between genders, and also within genders.

Another disadvantages or “con” of using animals for research is that it can be very costly. For example it’s very costly to house the animals for testing to ensure that they are healthy and ready to be studied. Similarly it is difficult for researchers to determine whether it is necessary to use animals; so is the product a necessity? Will the behaviour be reproducible in humans? These are both common questions asked by researcher when determining whether to use animals in their research. Murnaghan (2010a) has suggested that different methods of research are needed in order to reduce the number of animal studies. It was suggested that in vitro techniques may help to reduce the number of animal studies, but unfortunately the human body may be far more complex than we can study in this way. In later work Murnaghan (2010b) suggested that we can help to reduce ‘treating’ the animal by instead using computer technology to simulate answers to research questions (in other words we can use data from previous animal studies to predict findings using computer programs in the present).

I wanted to discuss the positives of animal research as well but have really struggled to find much support for animal studies, but this is what I did find: Animals are much easier to find than humans and researchers do not have to worry about the animals withdrawing from the study (which some may argue is also a disadvantage). Animals generally breed a lot quicker than humans which also aids studies into hereditary behaviours etc.

It’s also a lot easier for researchers to control and manipulate the situations and conditions that animals are in. Such things as how much food they’ve eaten, what they’ve drank, how much they weigh, how much exercise/activity they do, how long they sleep for etc etc. For example, one study I stumbled upon whilst looking for something else used flatworms to demonstrate memory transfer through cannibalism in flatworms. Basically, flatworms were taught that when a light came on above where they were they should expect a small electrical shock. The worms were described to have a conditioned response if they contracted their body at the first sign of light, even without an electrical shock. The worms were then cut in half and left to regenerate for 4 or so weeks before being retested in the light/shock condition. Results showed that both the head and tail sections retained what they had previously learnt, an interesting finding if you consider that we would expect the head half with the brain to retain previous learnt behaviours. It sounds cruel to cut the worms in half, and obviously this is not something that researchers can repeat with humans (definitely not ethical to cut people in half!) but it did provide an insight into different structures within the DNA of planarians, and if you’re interested in the weird and wonderful the link to the paper is below in the references (McConnell, 1962). This study required a lot of control, and it’s pretty difficult to get such a high level of control in a study with humans.

This leads neatly back to a few more issues with animal studies. Most animal studies are conducted in laboratory settings; which of course means high control and high internal validity. If you look at this from one point of view, high control and internal validity are good as we can be relatively confident that we are testing what we intend to test. However, laboratory experiments have very low ecological validity and low external validity as it’s very difficult to see how the behaviour may occur in the real world. For example, if you cage a chimpanzee its behaviour is going to be very different when it’s in a cage compared to when it’s in the wild. Imagine if you were confined in a cage and couldn’t do anything you wanted to do. You’d probably be pretty grouchy and not your normal self, thus a bad representation of real life behaviours.

Right before I drone on even longer I will quickly mention the ethics bit. In recent years there have been much stricter rules put in place to ensure the protection of animals in experiments. Animals should not be subjected to harm, just like humans, which helps to protect animals from cruelty in present day experiments. In the past animals were treated as if they did not have feelings and so were subjected to environments that were extremely damaging to them just for the progression of psychology. For example Harlow (1950s) conducted a relatively well known experiment in which he separated baby monkeys from their mothers and replaced the mothers with either a wire monkey with food or a furry, warn monkey. It was found that the monkeys that had a choice between either of the two “surrogate” mothers generally chose the furry monkey as they felt safer with it. The monkeys formed attachments with the furry surrogate, but still ate from the wire monkey. This study has given us valuable evidence for attachment in human infants, but at what cost? Many of the monkeys that were deprived of feelings of safety and comfort were unable to develop at the typical rate, often becoming aggressive or depressed, suggesting that children too need to form emotional attachments with their primary caregivers.

So, should we use animals in experiments? It’s a difficult question really. At the start of this blog I thought I was undecided about animal testing. Personally, now, I think that animals should be left alone as much as possible. They don’t have the choices that humans have when participating in an experiment. They can’t ask the experimenter to stop or tell them that they don’t want to participate as they simply don’t have the language. Animal testing in recent years has been monitored better to try and ensure animals are not damaged in experiments. Their use in psychology is something I’m undecided on as it’s difficult to generalise and if something is too unpleasant to test on humans then should we really do it to animals? Testing cosmetics on animals is a big no no for me, as for medicines I’m not too sure. I think if someone you knew well had a serious disease that animal testing may be able to provide a cure for your opinion may be very different that if you wanted to know if the latest shampoo has been tried and tested on animals.


Carlson (1998). Physiology of Behaviour, 6th edition.

Harlow, H. (1950s). Retrieved:

McConnell, J. V. (1962). Memory transfer through cannibalism in planarians. Journal of neuropsychology.

Murnaghan, I. (2010a). About Animal Testing. Retrieved from

Murnaghan, I. (2010b). New Technologies as Alternatives to Animal Testing. Retrieved from:

Pavlov, I. P. (1927). Conditioned Reflexes: An Investigation of the Physiological Activity of the Cerebral Cortex. Translated and Edited by G. V. Anrep. London: Oxford University Press

Skinner, B. F. (1947). Substitution in the pigeon. Journal of Experimental Psychology, 38, 168-172.

Starkey, G. (2008). Animal Models of the Brain: Ethical Considerations and Alternatives

Stubblefield (2009). The Pros and Cons of Animal Testing. Medical Science

Wagner et al. (1980). Aggressive Behaviour, 6, 1-7.

Wright & Wrangham. (1998). Morals, Demonic Males and Evolutionary Psychology. In Information and Biological Revolutions: Global Governance Challenges.

Zucker, I., & Beery, A. K. (2010). Males still dominate animal studies. Nature, 465.

Image 1 from: scheme _01.png/300px-Skinner_box_scheme_01.png

Image 2 from:


3 thoughts on “Animal Testing: pros, cons, and a bit of ethics thrown in for good measure

  1. ksarah20 says:

    Really interesting blog, you’ve obviously thought about a lot of the different sides and views on animal testing. You’ve covered some interesting “cons” to animals testing which I hadn’t thought about before, like the bias towards gender. I think you’ve that you’ve covered the pros and cons in a lot of detail, however I think you could have added (I know the blog is really long already!) your own opinion on what research you think should be allowed to use animals be it drug research or something else. Or how you think animals should be treated if they are tested on-the limitations to what you think researchers can do. Overall though I thought t was really good, hard to pick out anything other than good things to say 

  2. samstats says:

    You’ve definitely gone into a lot of detail here, and it’s very interesting.

    I just want to pick up on your question and discussion of whether animals are similar enough to humans to test on, as I see this a lot and it confuses me why it’s often included as an ethical point.

    The way I see it, that question is a purely scientific one and needs to be assessed on a case-by-case basis, with no input from ethics. Only then, once it has been established whether the similarities are great enough, should ethics be considered.

    I can’t personally see a way in which the question “Are animals similar enough to humans to warrant scientific testing?” can be answered as one problem, when “animals” can include anything from the tiniest insects to a beluga whale and “testing” can involve virtually anything. Of course testing stimulant drugs on goldfish is going to be of limited use when extrapolating to humans, but administering the same drugs to monkeys may tell us a lot about their action.

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