Nice post! I recently wrote Sentientia, Reversomelas, and the Small Animal Replacement Problem which sort of nuances your nuance by arguing that it's far from obvious something like moral circle expansion will eventually offset the problem. :) (although I discovered your post only now, after writing mine).
Great piece! You've put words to an idea that I imagine a lot of us (but at least myself) have had vaguely bouncing around in our heads for a while, namely that a strategic emphasis on the animals killed most numerously in the food system doesn't take human psychology into account. I'd love to see more research on the cow-chicken-fish elimination process (or see research that already exists) but like you, I've heard lots of anecdotal evidence suggesting this is true.
There's a real possibility the best way to help future farmed shrimp and insects is to try to expand society's moral circle to cows as fast as possible, on the way to further expansion to chickens and eventually shrimp and insects.
Another question I'd have for further research would be how quickly we can introduce concern for invertebrates once an individual or social group has opened up to concern for cows. A hunch would be that the process of moral circle expansion is subject to the basic principles of momentum: that once we overcome inertia on cows, each subsequent expansion gets easier and easier as long as we sustain momentum.
Adding Nuance to the Small Animal Replacement Problem: Moral Circle Expansion — EA Forum
Adding Nuance to the Small Animal Replacement Problem: Moral Circle Expansion
For those of you who are familiar with farmed animal advocacy[1], the small animal replacement problem[2], and moral circle expansion[3], you can probably get 80-90% of the value of this post by only reading the Summary. The Further Considerations section may provide additional value.
For those who are less familiar with these areas, the first couple of sections may provide you with useful context into the problem and relevant research.
Summary
In the context of animal ethics, and particularly the suffering of animals raised for food, the small animal replacement problem is the concerning situation where people stop eating larger animals and instead replace that consumption by eating smaller animals, resulting in the suffering and death of many more animals.[2] (For example, people who stop eating cows and pigs and instead eat chickens and fish will end up being responsible for the deaths of many more animals.) For good reason, many animal advocates have started to take the small animal replacement problem into account in their work to try to ensure that this situation doesn't happen.
But, the small animal replacement problem assumes that when people switch from eating larger animals to eating smaller animals, nothing else has changed in their beliefs or attitudes towards animals. In many cases, this assumption may be true. However, under the situation of moral circle expansion, this switch might be exactly what we would expect to see—the elimination of eating mammals first, followed by birds, followed by fish and other animals, roughly in the order of evolutionary similarity to humans and proximity to humans—and thus this progressive elimination (and replacement) might indicate psychological ethical progress. In the short-term, this replacement would result in an increase in the number of animals killed and eaten for food, but in the long-term this is the trajectory we might expect to see on the way towards the moral inclusion of animals in our societies. In fact, there is some evidence that this kind of progressive elimination may be the method that works the best with our human psychologies to get someone to move towards eliminating consumption of animals, with would make replacement an unfortunate but necessary step.
Combined, the implications of current research show that we should at least consider the possible benefits of moving society through a moral circle expansion that humans are naturally inclined to, or to think about the potential costs and difficulties of advocating for animals in a different order.
For animal advocates, some recommendations might be this:
(Note: these are copied from the Conclusion.)
Continue trying to reduce replacement risks where possible in the actions we take.
When an action with a replacement risk does not appear to coincide with moral circle expansion (or a similar longterm benefit), then reconsider taking that action at all.
When an action with a replacement risk does appear to coincide with moral circle expansion, consider the case that short-term replacement may be an unfortunate but psychologically strategic step for humans on the way to their total elimination of eating animals. If you do decide to proceed, then do what you can to move people through the replacement stage as quickly as possible.
More research is needed into the last recommendation above, especially since that is the new recommendation that is being introduced in this post. But barring further research, it is at least something to take into account.
When possible, we should still try to prevent replacement. But we should also be aware of the situation where elimination and small animal replacement are signs of moral circle expansion, and in that situation replacement may be an unfortunate effect on the way towards more complete elimination of eating animals.
The Small Animal Replacement Problem
When it comes to advocating for farmed animals, it seems like low-hanging fruit to advocate against eating cows. From the climate perspective, raising cows for food is a large source of climate emissions and environmental destruction, and from the health perspective, there are studies that clearly link cow meat consumption with cancer. Plus, cows are mammals, so they share many behaviors, appearances, and expressions with ourselves and other animals who we care about, like dogs, making them easier to empathize with.
However, advocating against eating cows results in a very big question: what, then, should the person eat instead?
A common answer in modern society is: chickens. Being vegetarian is relatively uncommon, which means people aren't likely to completely give up eating animals simply because of giving up eating one animal, and pig meat is still classified as "red meat" which comes with many of the same health concerns as cow meat. Plus, chickens are cheap to raise and don't have nearly the same environmental emissions that cows and pigs do. Thus, switching from eating cows (or pigs) to chickens starts to seem like a reasonable thing to do.
Unfortunately, for those of us who consider animal suffering as worthy of consideration, this replacement leads to a lot more suffering, especially taking into account that chickens are raised in some of the worst environments out of all farmed animals. Kelsey Piper at Vox has the numbers: "And while a cow suffers and is slaughtered to produce around 500 pounds of meat, a chicken produces about four to five pounds of meat. So a switch from beef to chicken is actually a switch from a tough life for one cow to an awful life for around 100 chickens."[4] If someone were to choose to replace their cow consumption with fish, the numbers would be even more staggering (see graph below).[5]
Thus, from an animal suffering perspective, advocating against eating cows suddenly seems like a terrible strategy if people are going to start eating more chickens or fish instead. Indeed, we could generalize this by saying that any strategy seems bad if it results in people switching from eating fewer larger animals to more smaller animals (from cows to chickens, from pigs to fish, etc.), especially if the smaller animals are raised in environments that cause more suffering. This general dilemma is known as the small animal replacement problem.[2]
Moral Circle Expansion
However, this situation becomes more complicated when we consider moral circle expansion.[3]
The concept of moral circle expansion has existed for millennia, but it was most recently named and popularized by Peter Singer in his book The Expanding Circle, where he says:
The circle of altruism has broadened from the family and tribe to the nation and race, and we are beginning to recognize that our obligations extend to all human beings. The process should not stop there. In my earlier book, Animal Liberation, I showed that it is as arbitrary to restrict the principle of equal consideration of interests to our own species as it would be to restrict it to our own race. The only justifiable stopping place for the expansion of altruism is the point at which all whose welfare can be affected by our actions are included within the circle of altruism. This means that all beings with the capacity to feel pleasure or pain should be included; we can improve their welfare by increasing their pleasures and diminishing their pains. The expansion of the moral circle should therefore be pushed out until it includes most animals.[6]
If we're just considering animals that we eat, though, which animals come first as the circle grows?
Moral Circle Expansion and Farmed Animals
Human empathy towards an individual of another species appears to be strongly correlated with how close we are to that species evolutionarily. The further apart we are in evolutionary history, the less empathy we feel.[7] Other research shows a similar correlation when looking at shared "bio-behavioral traits".[8]
Simply put, humans seem to naturally have more empathy towards other animals who are close to us evolutionarily and similar to us in appearances and behavior. The more dissimilar we get, and the further away evolutionarily, the less empathy we feel.
If we were to rank the animals that we eat according to similarity to humans, the list would be ordered as follows: cows and pigs (and other mammals), then chickens (and other birds), then fish (and other sea life).
As we're thinking about moral circle expansion, this is probably also the order most natural to humans when including these species in moral consideration: first, we start to consider cows and pigs as morally worthy of consideration; then chickens and other birds; then fish and other sea life.
Moral Circle Expansion and the Replacement Problem
It quickly becomes apparent that if we were to stop eating animals in the order of natural human empathy, and we were to replace that consumption by eating animals further down on the empathy scale, then we would be consuming a much larger number of animals and causing much more suffering.
Additionally, if animal advocates simply try to encourage people to eat less meat or to recognize other animals as worthy of consideration, we may find ourselves in this same situation: if a person chooses to eat less meat, they may start by eliminating cows and pigs from their diet, due to some mixture of moral, health, and environmental reasons. If a person begins the process of bringing other animals into their moral consideration, they will probably start with mammals (like cows and pigs). Thus, even without us explicitly advocating against eating cows and pigs, people might start there anyway.
Further Considerations
Is there a way around this? Or are we doomed to the necessity of the small animal replacement problem as a required step along the path towards eventually reducing farmed animal suffering as much as possible?
In this section, we'll explore some of the primary considerations that I think are important when thinking through the small animal replacement problem.
People Probably Won't Care About Chickens Before Caring About Cows
One of the conundrums with the small animal replacement problem, from an ethical advocacy perspective, is that the research shows that people aren't naturally inclined to expand their moral circles to include chickens and fish before include other mammals like cows and pigs.
This seems to indicate that if we're trying to persuade people to expand their moral circles, we need to use one of these strategies:
Make the case for ethical inclusion of mammals first, then chickens and fish (a strategy that may be vulnerable to the small animal replacement problem); or
Make the case for inclusion for all of these animals simultaneously, such as educating people about the concept of speciesism and its implications.
What seems like a flawed strategy, however, is trying to advocate for ethical inclusion of chickens and fish first. We can't know for certain that this is a bad strategy without further research, but this hypothesis seems in alignment with current research on how humans empathize with other animals. Anecdotally, it also seems that people frequently give up eating meat in the "cow/chicken/fish" order on their way to becoming vegetarian.
As a hypothesis, consider this—it could be the case that in the long-term, the best strategy for eliminating animal consumption would be to get people to expand their moral circle step by step in the order that humans naturally empathize with other animals, and to move through this progression as quickly as possible, even if that resulted in a period of increased numbers of smaller animals being raised and killed for food. Perhaps it's much easier, given our current society, to advocate for ethical inclusion of cows and pigs; and perhaps it's much easier to advocate for chickens and fish once people have already expanded their moral circles to include other mammals who we've traditionally eaten. If true, this strategy would have negative consequences for smaller animals in the midterm while potentially resulting in less suffering and more lives saved in total. (This is just a hypothesis to illustrate the point—I don't have a strong intuition on the efficacy of this idea, and I'm not aware of research that shows people's progression through these stages.)
If we're not trying to morally persuade people, then this consideration becomes less important—for example, if we're trying to change behavior based on price, health, climate change, etc. Unfortunately, when it comes to many of those other domains, eating chickens instead of cows seems like the reasonable thing to do if we don't also include animal ethics, as we'll discuss in the next consideration.
Multiple Pressures Are Pushing People to Eat Smaller Animals Already
Even without considering the small animal replacement problem in animal advocacy work, there are already numerous pressures driving people in society to change their consumption, especially in the direction of eating more chickens and fish.
Environmental pressures—Raising cows for food is a large driver of climate change, much larger than the climate impact caused by raising chickens. As the climate crisis becomes more urgent in the public's eye, more people might switch to eating more "climate-friendly" animals such as chickens.
Health pressures—"Red meat" (i.e. meat from mammals such as cows and pigs) has been linked to cancer and other health conditions. There has been much health messaging over the past several decades advocating that people switch from eating cows and pigs to eating chickens or fish instead, for health reasons.
Economic and supply pressures—At least in the US, chicken consumption has been increasing steadily since around the 1940s. The reasons for the increase include government competitions to breed bigger birds, the growth of chicken science, the short time required to breed multiple generations of chickens (thus allowing faster artificial selection for desirable traits), and World War II rations on red meat, to name a few reasons.[9] Fish consumption has also been increasing, with aquaculture (fish farming) responsible for nearly all of the increase in the volume of fish produced (as measured in metric tons, not individual fish).[10]
So an important question to ask here is: what are the implications for animal advocacy work if society is already doing this work of replacing larger animals with smaller animals? Although of course, in many ways society is simply adding the consumption of smaller animals; per capita meat consumption in the US has been rising for decades, not withstanding some deviation in the last ten to fifteen years. And so people still have plenty of opportunity to replace their existing consumption of large animals with even more smaller animals, multiplying the numbers of chickens and fish raised and killed for food—a situation we are trying to avoid.
Rather Than Advocating Elimination, Consider Advocating Plant-Based Replacement
One potential way to try limiting the downside risks is to advocate for plant-based replacements rather than elimination.
If, for example, our primary message is to "stop eating cows" or "stop eating animals", then this framing may be vulnerable to the small animal replacement problem. The animals people are likely to stop eating are the big ones, and due to various societal pressures these people are often more likely to switch to a different animal product rather than a plant-based one.
If instead, our primary message is to "replace your beef with beans" or "replace your pork with pintos" (or some other more-expertly crafted message), this framing—if effective (a very important "if")—might result in more true animal product elimination and less replacement of large animals for small.
If Economic Forces Are a Primary Driver, It Could Make Sense To Focus Predominantly on Chicken and Fish Alt Protein Products
There is a compelling case to be made that economic forces will be able to shift society away from consumption of animals much faster than moral advocacy will, and organizations like The Good Food Institute focus exclusively on this space.[11]
For someone who thinks this and who is in the alt protein industry, it could make sense to focus most efforts on the creation of products to replace smaller animals, unless there are reasons why competing on price and taste with these products are significantly harder. All else being equal, an excellent plant-based chicken product that is the same price or cheaper than the animal-based chicken product will spare many more animals than a plant-based cow product, if price and taste are most of what fundamentally matter for most consumption habits.
Conclusion
This post is not at all meant to dissuade people from taking the small animal problem seriously. It is instead meant to add nuance to the discussion and point out some considerations that we should take into account when planning our strategies.
Specifically, the theory of moral circle expansion and the research on human empathy towards other animals shows that humans are more likely to empathize with similar animals—such as cows and pigs—before empathizing with animals who are less similar—such as chickens and fish. Cognitive dissonance research also shows us that someone who stops eating cows (for whatever reason) may be more likely to include them in their moral circle, since they don't need to defend their consumption of cows any longer.
Combined, all of this research should get us to at least consider the possible benefits of moving society through a moral circle expansion that humans are naturally inclined to, or to think about the potential costs and difficulties of advocating for animals in a different order.
Final Recommendations
For animal advocates, some final recommendations might be this:
Continue trying to reduce replacement risks where possible in the actions we take.
When an action with a replacement risk does not appear to coincide with moral circle expansion (or a similar longterm benefit), then reconsider taking that action at all.
When an action with a replacement risk does appear to coincide with moral circle expansion, consider the case that short-term replacement may be an unfortunate but psychologically strategic step for humans on the way to their total elimination of eating animals. If you do decide to proceed, then do what you can to move people through the replacement stage as quickly as possible.
More research is needed into the last recommendation above, especially since that is the new recommendation that is being introduced in this post. But barring further research, it is at least something to take into account.
I used AI to fix transcription errors, rerrarange the ideas, and suggest tweaks to the title and some sentences.
Three of the most exciting projects to come out of EA in recent years are, in a vague sense, CEA spinouts:
* Kairos is directly a spinout of CEA and now handles most support for university AI safety groups. Basically everyone I've found who knows them is really excited about what they do
* NEST is an opinionated ideas-fi...
This post presents the executive summary from Giving What We Can’s impact evaluation for 2025. At the end of this post we share links to more information, including the full report and...
Nice post! I recently wrote Sentientia, Reversomelas, and the Small Animal Replacement Problem which sort of nuances your nuance by arguing that it's far from obvious something like moral circle expansion will eventually offset the problem. :) (although I discovered your post only now, after writing mine).
I'd be curious to have your thoughts!