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Why do we care how smart animals are?

Intelligence plays a role in how we treat them. Maybe it shouldn’t. 

Our author’s encounter with an urban duck had her questioning just what we value in animals.
Tim Graham/Getty Images

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Part of The Animals Issue of The Highlight, our home for ambitious stories that explain our world.


One year ago, just before the pandemic hit, I fell in love with a duck.

It was weird. I’d never remotely been interested in birds before.

But then Molly the Mallard, as I dubbed her, decided to nest in a flowerbed on the sidewalk right outside my office. She looked so vulnerable, laying eggs in the middle of bustling Washington, DC, that I couldn’t help but get emotionally invested. What would happen to her and her future ducklings? The nearest body of water was a few miles away — would they safely manage to find their way to it? How?

Molly triggered empathy in others, too. Every day on my way into the office, when I tried to peek at the eggs beneath her iridescent blue feathers, I’d notice that other people had left well-intentioned but somewhat nonsensical things beside her: Half a poppyseed bagel. A cup of water. A bowl full of falafel leftovers.

Lockdown put a sudden end to our ministrations. Stuck at home, I worried about whether Molly would be okay. I soon took it upon myself to learn all about birds: how some use the sun and stars to navigate, while others sense the Earth’s magnetic field; how individual birds, far from being mechanistic bundles of instinct, can make autonomous choices to split off from their migrating flock; how crows solve complex puzzles; and more.

I was wowed by avian intelligence. Popular books like Jennifer Ackerman’s The Genius of Birds urged me on in this direction. I never saw Molly again, but the more impressed I grew with birds’ smarts, the more my empathy for her and other animals like her increased.

That’s very common. Faunalytics, a nonprofit that researches animal-related issues, recently surveyed more than 1,000 Americans on their beliefs about different species. The responses showed that people are more likely to want to help an animal — for example, by signing petitions — when they believe that animal to be intelligent.

Lately, I have begun to question this impulse. Covid-19 has made it obvious that we live in an interconnected world where one infected animal, smart or not, can turn all our lives upside down. We ignore the well-being of animals and their ecosystems at our own peril. So is intelligence really the right yardstick to use when deciding which animals are worth protecting?


From the 1993 blockbuster Free Willy to the recent Netflix documentary My Octopus Teacher, a core premise of the animal rights movement — that intelligent, autonomous creatures deserve our moral concern — has seeped into pop culture.

As we’ve learned more about whale language, the movement to save the whales has grown. As we’ve learned that octopuses are brilliant puzzle-solvers and escape artists, the calls to stop eating them have gotten louder. People are rethinking farm animals like pigs, too; as the evidence mounts that pigs are smarter than human toddlers (they can use tools and play video games!), so do the arguments against eating them.

After a slew of beluga and orca whales were discovered captive in Russia in 2019, protesters took to the streets to call for their release. In one survey, many respondents said they were more likely to help an animal they found intelligent.
Mikhail Pochuyev/TASS

Groups such as the Nonhuman Rights Project even go to court on behalf of chimpanzees, elephants, and dolphins. They try to win legal rights for their “clients,” and their arguments are primarily based on the animals’ intelligence. For example, in 2013 the group filed a lawsuit on behalf of Hercules and Leo, two chimps used in lab research, arguing that they have the right to be freed from captivity given their “complex cognitive abilities.” The lawsuit failed. Yet it demonstrated the way some in the animal rights movement have used intelligence to make their case.

But using intelligence as our yardstick for determining how much to care about an animal can too easily lead us astray, in large part because we suffer from an anthropocentric bias: We tend to think something counts as intelligence only when it looks like human intelligence. And if we humans use a faulty yardstick, that has broad implications for animals — from our failure to preserve species to decisions about how we farm and eat them.

“There’s a risk that if we talk in terms of ‘these animals are really smart and therefore we should protect them,’ then we risk reinforcing the idea that you need a certain kind of intelligence in order to be worthy of protection,” said Jeff Sebo, a professor of environmental studies and philosophy at New York University. “That might work well for some animals but less well for animals who are intelligent in different ways that we might not notice or appreciate.”

Ever since Aristotle developed the idea of the Scala Naturae, a “Natural Ladder” that classified some animals as higher life forms and others as lower, human beings (at least in the West) have underestimated the cognitive complexity of other species. Take chickens, for example. We’ve assumed they’re unintelligent and depicted them that way — remember the mindless sidekick in Moana and the paranoid bird in Chicken Little? Yet scientists have found that chickens have social lives and maternal instincts and even the ability to do basic math.

It’s not just chickens. The more scientific research we do, the more we learn that creatures ranging from pigs to honeybees are smarter than we’d thought.

As the scientist and author Robin Wall Kimmerer once said in an interview, “I can’t think of a single scientific study in the last few decades that has demonstrated that plants or animals are dumber than we think. It’s always the opposite, right?”

The primatologist Frans de Waal argues that it’s high time we recognize that every species has its own brand of smarts. Each is perfectly adapted to its particular environment and survival needs. Squirrels, for example, bury nuts before winter and can remember the location of thousands of hiding places.

“I even forget where I parked my car,” de Waal has written. So squirrels have an intelligence we don’t have. Sure, they would flunk a basic arithmetic test that a human child would ace — but that’s a pointless comparison, de Waal says. “It seems highly unfair to ask if a squirrel can count to 10 if counting is not really what a squirrel’s life is about.”


Sentience is the ability to have conscious experiences like pleasure and pain. Many philosophers — most famously, Peter Singer — argue that sentience, not intelligence, is the right yardstick for moral value, and this view is at the center of today’s broader animal welfare movement.

It makes some intuitive sense. If you can’t feel pleasure or pain, then it doesn’t matter to you what happens to you. So if you’re a rock, I should be able to kick you down the street for fun without feeling bad. But if you’re a mouse, I have a moral obligation not to do that, because being kicked will feel really bad for you.

But as with intelligence, humans constantly underestimate the sentience of other species. For example, many people think of fish as emotionally vacant, though recent experimental studies challenge that view. (It turns out romantic breakups really suck, even for fish.)

A photograph of a clownfish.
Many have debated the sentience of fish. But science challenges the idea that fish don’t have emotional lives.
Stephen Chernin/Getty Images

Sebo believes that sentience is the most plausible basis for moral worth, but nevertheless said, “I am a bit humble here because I recognize that sentience is the next on a list of features that we share with other animals.” Historically, societies started by thinking that being a male human is what matters, he explained, and then expanded the notion to believe that being a human is what matters, and then that being an intelligent animal is what matters, and now that being sentient is what matters.

“In light of that history, we should be a little skeptical of our current impression that we happen to now be fully morally enlightened and are including everybody we should be including,” Sebo said. “We have to recognize the fact that we’ve always been wrong before!”

This open-mindedness means that he’s willing to consider that even plants might be sentient.

In recent years, some scientists have argued that plants have a degree of sentience. They send out biochemical distress signals to other plants, they have some form of memory, and they “seem to lose consciousness” when sedated in scientific experiments.

But the idea that plants are sentient is hotly contested. When I asked Singer his thoughts on it a couple of years ago, he said he doubts that a tree can experience a negative state such as pain. “Is there something that it’s ‘like’ to be a tree when that tree is being chopped down or not getting water and therefore dying? My guess is no.”

Sebo is not so sure. After all, when a plant isn’t getting enough nourishment, it visibly strains and twists toward the light, suggesting it seeks out certain outcomes and avoids others. Is it possible that we just have a problem recognizing this as sentience because plants don’t have brains, eyes, and the other markers we humans associate with sentient beings?

“We do have this pro-animal bias, so we’re more likely to see them as sentient than we are plants,” Sebo said. “When you study plant cognition and see how plants can learn, remember, and communicate, you do start to question that.”

Other questions also plague the camp that values sentience above all, and trying to answer them gets very difficult very fast. If you think sentience confers moral worth, exactly how much sentience is required to make the cut? And how do you measure it? Do you start counting the number of neurons in each animal and use that as a proxy? Is that really a good stand-in?

“Those are all really complicated questions,” Sebo said, “but honestly, I think that we have no reasonable alternative but to face those questions.”


We could, however, sidestep them entirely. We could believe that anything that’s alive has moral value. Or, even more expansively, we could believe that anything that supports living things has moral value (think ecosystems like lakes or mountains). Environmental philosophers call the first position biocentrism and the second ecocentrism.

Chris Cuomo, a philosopher at the University of Georgia, believes these approaches are much better than the sentience perspective. She told me a narrow focus on animal sentience “replicates a neoliberal tendency to focus our moral concern only on individual suffering,” and not on holistic ecosystem health or degradation more broadly. “It really leaves a lot out.”

By contrast, biocentrists and ecocentrists are likely to concern themselves with climate change that destroys entire ecosystems and bad environmental practices that make pandemics more likely, instead of only worrying about the suffering of certain individual animals.

These environmental views are by no means new — many Indigenous peoples and non-Western religious groups, such as Jains in India, have lived by them for millennia. In fact, the European philosopher and doctor Albert Schweitzer was taking inspiration from Jainism when he developed the philosophy he called “reverence for life,” whose emphasis on nonviolence to all living things had a deep effect on the Western environmental movement.

Now, views like these are starting to gain more ground, not just in the halls of philosophy departments but also in the courts.

If you care about the whale, some philosophies argue you ought to care about the krill, which is necessary for the whale’s survival — and, while you’re at it, the ice, too, because it sustains the krill.
Olivier Morin/AFP via Getty Images

The nascent “rights of nature” movement, which tries to win legal personhood status for ecosystems, has notched several victories in the past dozen years. Rivers, forests, and lakes have already won rights in countries like Ecuador, Colombia, India, New Zealand, and, yes, the United States. For example, Lake Erie became a legal “person” in 2019, enabling citizens to sue on behalf of the lake whenever its right to flourish is threatened — that is, whenever it’s in danger of major pollution.

There are different ways to flesh out the environmental views. You might decide that all living things, or all ecosystems that support living things, have intrinsic moral value. Or you might decide that their value is just instrumental — that Antarctic sea ice is valuable but only because it enables tiny krill to flourish, and the krill is valuable but only because it feeds the bigger and brainier whale.

Philosophers tend to get really hung up on the intrinsic versus instrumental debate, but honestly, it may not matter much at this point. Even if you only care about the highly intelligent and sentient whale, you’d better start caring about krill and sea ice, too — and fast, because without them, that whale may not survive much longer.

For that matter, this year has brought home the realization that even if you only care about humans, you should probably start caring a lot about bats. Although for me, bats don’t inspire the same affection I felt for Molly the Mallard — I actually find them creepy — I should have been at least as concerned about their well-being a year ago as I was about the duck’s. If we were all taking greater care not to mess with bats and other wildlife and their ecosystems, we could make emerging pandemics much less likely.

Still, there are tricky problems with the environmentalist views. What should we do, for example, when the needs of different species conflict?

Australia has been dealing with this problem recently. It has a huge population of feral cats that has been wiping out lots of native plants and animals, especially small marsupials and rodents. Desperate to preserve its unique species, the Australian government in 2015 announced that it would kill 2 million cats. Immediately, animal rights activists became apoplectic; more than 160,000 people signed petitions; and celebrities including Brigitte Bardot wrote to the government to stop the “animal genocide.”

If you believe intelligence is the yardstick for moral worth, you might try to solve this dilemma by determining which is smarter, a cat or a rodent. But if instead you believe all life has moral value, then what?

Cuomo’s answer: “We should take the cats’ interest into account, while we also protect the wildlife. If we can’t do both, then we admit that it’s a tragedy, and we try to make up for it or do it better next time.”

In other words, sometimes there will be tough trade-offs, and the best thing we can do is have the integrity to recognize that we’re making a fallible choice. As Schweitzer once put it, we should be “conscious of acting on subjective grounds … and know that [we] bear the responsibility for the life which is sacrificed.”

The numbat, a rare anteater indigenous to Australia, was so severely threatened by predators — namely, the massive population of feral cats in Western Australia — that at one point, the species dwindled to just 1,000 animals.
Auscape/Universal Images Group via Getty Images

Kimmerer reaches the same conclusion in her book Braiding Sweetgrass: Indigenous Wisdom, Scientific Knowledge, and the Teachings of Plants. The scientist describes how she had an algae-filled pond in her yard that she wanted to clear out so her daughters could swim in it. As a member of the Citizen Potawatomi Nation, though, she believes that all life has moral worth. So as she raked out the muck and found that it was full of tadpoles, she plucked them all out so they could go on living. Then she inspected the pond water under her microscope and saw a ton of teensy organisms, each one a moral dilemma. She writes:

As I raked and plucked, it challenged my conviction that all lives are valuable, protozoan or not. As a theoretical matter, I hold this to be true, but on a practical level it gets murky, the spiritual and the pragmatic bumping heads. With every rake I knew that I was prioritizing. Short, single-cell lives were ended because I wanted a clear pond. I’m bigger, I have a rake, so I win. That’s not a worldview I readily endorse.

But it didn’t keep me awake at night, or halt my efforts; I simply acknowledged the choices I was making. The best I could do was to be respectful and not let the small lives go to waste. I plucked out whatever wee beasties I could and the rest went into the compost pile, to start the cycle again as soil.

In a way, it’s an unsatisfying solution. We’re trained to want to clear-cut hierarchies, objective moral truths. And yet, why should we expect nature to come inscribed with any such thing?


It makes sense that there would be no easy answers. We humans are ourselves animals, not static brains in vats. So our moral beliefs about other beings are always shaped by our evolving historical, social, and economic conditions, and by our relationships to those beings.

For most of human history, we couldn’t have survived and thrived without killing or exploiting animals for food, transportation, and energy. As the philosopher Elizabeth Anderson points out, the social conditions for granting animals moral rights didn’t really exist on a mass scale until recently (although certain non-Western societies did ascribe moral worth to animals).

“The possibility of moralizing our relations to animals,” she writes, “has come to us only lately, and even then not to us all, and not with respect to all animal species.”

Anderson has noted that we feel different levels of moral obligation to different species, and that has to do not only with their intrinsic capacities like intelligence or sentience, but also with their relationships to us. It matters whether we’ve made them dependent on us by domesticating them, or whether they live in the wild. It also matters whether they’re fundamentally hostile to us.

Thinking about vermin is a great (if disgusting) way to bring this point home. If you find bedbugs in your house, nobody expects you to say, “Well, they’re maybe sentient and definitely alive, so they have moral value. I’ll just live and let live!” It is absolutely expected that you will exterminate the shit out of them.

Why? Because with vermin, Anderson writes, “there is no possibility of communication, much less compromise. We are in a permanent state of war with them, without possibility of negotiating for peace. To one-sidedly accommodate their interests … would amount to surrender.”

Anderson’s point is not that intelligence and sentience don’t matter. It’s that lots of other things matter, too.

Embracing this value pluralism makes things tricky. It suggests that the best we can do is look at creatures’ intelligence and sentience and aliveness and relationships to us as clues about their importance. But it doesn’t tell us how to weight those clues and what to do when they conflict.

Annoying, isn’t it?

But value pluralism can also give us more ways to make the case for protecting animals. Since we know that people are more likely to want to help animals they believe to be intelligent, it may make sense to keep harping on intelligence for now and hope to keep expanding the circle of moral concern. That might look like asking people to care even more about whales and octopuses and Molly the Mallard today, in the hopes that tomorrow they will take the lives of factory-farmed animals — or bats, for that matter — just as seriously.

At the same time, as climate change and pandemics threaten us all, we can also make the case for protecting whole ecosystems. We can remind each other that if we only care about animals that appeal to us, we’re going to end up harming all animals, including ourselves.

Sigal Samuel is a staff writer for Vox’s Future Perfect, covering artificial intelligence, neuroscience, ethics, and the intersection of technology and religion.

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