Moody chickens? Playful bumblebees? Science decodes the rich inner lives of animals.

Sasha Prasad-Shreckengast is trying to get into the mind of a chicken.

This is not the easiest of feats, even here at Farm Sanctuary in Watkins Glen, a scenic hamlet in the rolling Finger Lakes region of upstate New York. For decades the sanctuary has housed, and observed the behavior of, farm animals – like the laying hens Ms. Prasad-Shreckengast is hoping to tempt into her study.

Chickens, it turns out, have moods. Some might be eager and willing to waddle into a puzzle box to demonstrate innovative problem-solving abilities. But other chickens might just not feel like it.

Ms. Prasad-Shreckengast also knows from her research, published this fall in the Journal of Applied Animal Welfare Science, that some chickens are just more optimistic than others – although pessimistic birds seem to become more upbeat the more they learn tasks.

“We just really want to know what chickens are capable of and what chickens are motivated by when they are outside of an industrial setting,” Ms. Prasad-Shreckengast says. “They have a lot more agency and autonomy. What are they capable of, and what are they interested in?”

In other words, how do chickens really think? And how do they feel? And, to get big picture about it, what does all of that say about chicken consciousness?

In some ways, these are questions that are impossible to answer. There is no way for humans, with their own specific ways of perceiving and being in the world, to fully understand the perspective of a chicken – a dinosaur descendant that can see ultraviolet light and has a 300-degree field of vision.

Yet increasingly, scientists like Ms. Prasad-Shreckengast are trying to find answers. What they are discovering, whether in farm animals, bumblebees, dogs, or octopuses, is a complexity beyond anything acknowledged in the past.

(At least in Western culture, that is. The 17th-century philosopher René Descartes, for example, ushered in an influential idea that understood animals to be mere mechanical “automatons.” Ascribing feelings or emotions to animals, he and his many followers believed, was misguided.)

Researchers have found myriads of indications of perception, emotion, and self-awareness in animals. The bumblebee plays. Cuttlefish remember how they experienced past events. Crows can be trained to report what they see.

As a result, a growing number of scientists and philosophers believe there is at least a realistic possibility of “conscious experience” in all vertebrates, including reptiles and fishes, and many invertebrates.

Given these findings, many believe there should be a fundamental shift in the way that humans interact with other species. Rather than people assuming that animals lack consciousness until evidence proves otherwise, isn’t it far more ethical to make decisions with the assumption that they are sentient beings with feelings?

Ms. Prasad-Shreckengast’s study takes place in the wide hallway of Farm Sanctuary’s breezy chicken house. Unlike in pretty much any other chicken facility, the birds here come and go as they please from spacious pens.

Following up on her previous research, she has designed a challenge that she hopes will appeal to most of her moody chickens. It is a ground-level puzzle box, with a push option, a pull option, and a swipe option. Birds are rewarded with a blueberry when they solve a challenge.

There is also a free treat option in the puzzle box, a way for the researchers here to measure something called “contrafreeloading.” This term describes a behavior animals demonstrate when they choose to work for a reward rather than just freeloading from readily available food. (Scientists are still debating why most animals contrafreeload. They are also interested in the exception to the rule: the domesticated cat, who appears perfectly happy to take food without expending any effort.)

Team members monitor a series of gates to the puzzle block, opening them when the birds are inclined to enter and letting them out if the chickens have had enough.

The idea of consent – which is a basic, foundational principle in the study of human behavior – is also a hallmark of animal studies here at Farm Sanctuary. To the uninitiated, this might sound absurd, with images of chickens signing above the dotted line.

But it is not actually all that rare. Studies of dogs, dolphins, and primates all depend on the animals agreeing, in their own way, to participate. Behavioral data would be skewed without it. And before she came to Farm Sanctuary, Ms. Prasad-Shreckengast worked in a canine cognition lab. Few people would bring their pet dogs in for research and then force them to do things they don’t want to do, she points out.

So consent matters from both a scientific point of view and an ethical one, she says.

Do animals have conscious experiences? Evidence is strong.

A group of Biologists and philosophers this past April unveiled The New York Declaration on Animal Consciousness at a conference at New York University in Manhattan.

The statement declared that there is “strong scientific support for attributions of conscious experience to other mammals and to birds.” It also said that empirical evidence points to “at least a realistic possibility of conscious experience” in all vertebrates and many invertebrates, including crustaceans and insects. Since April, hundreds more scientists and moral thinkers around the world have added their names.

Spearheaded by Kristin Andrews, professor of philosophy and the research chair in animal minds at York University in Canada, the idea emerged from conversations she had with two colleagues, Jonathan Birch, a philosopher at the London School of Economics and Political Science, and Jeff Sebo, director of the Center for Mind, Ethics, and Policy at New York University.

The three were talking about all the new research demonstrating the complexity of animals’ inner lives. They wondered if there was a way to highlight how these studies were shifting attitudes.

“People were dimly aware that new studies were identifying new evidence for consciousness – not only in birds, but also reptiles, amphibians, fishes, and then a lot of invertebrates, too,” says Dr. Sebo. “But there was no central, authoritative place people could look for evidence that the views of mainstream scientists were shifting.”

Discovery after discovery over the past decade has illuminated an increasingly complex, communicative, and feeling world of nonhuman creatures.

For instance, trees communicate, and fungal networks send messages throughout a forest. Species such as sea turtles and bats use electromagnetic fields, a force we cannot even perceive, to guide their movements and migrations. Snakes see infrared light, birds and reindeer see ultraviolet light, and dolphins use sound waves to navigate underwater.

Author and journalist Ed Yong uses the German term umwelt to describe an organism’s unique sensory perspectives. His book “An Immense World” details the various ways animals experience their world.

He uses the metaphor of a large house with many windows looking onto a garden. Each animal has its own window. But there are other windows as well, each with a different view of the same place. We humans have our own window, our own particular umwelt. Our eyes see only certain wavelengths and frequencies of light. Our ears perceive limited ranges of sound. Our noses have limited ranges of smell.

For generations, the dominant perspective has been that the human perspective is the best view in the house, with the most complex and complete picture of reality.

But there hasn’t been a species studied over the past 20 years that hasn’t turned out to exhibit pain. There hasn’t been a species that hasn’t turned out to be more internally complicated than people expected, Dr. Andrews says.

“There hasn’t been any animal that we’ve looked at and asked, ‘Do they feel pain with the set of pain markers that are well established?’ And we’ve said, ‘Oh, yeah, there’s zero evidence,’” she says. “We don’t find any of them.

“So my view is that we’re going to be finding these kinds of indicators of cognitive behavior, of behaviors indicating animals feel pain or feel pleasure, in probably all animals.”

But does that mean consciousness?

“Just that word, ‘consciousness,’ is the problem,” Dr. Andrews says. “The thing that everybody in the field agrees on is that consciousness refers to feeling – ability to feel things. ... But then if you start asking people to give a real, concrete definition of consciousness, they’re not able to do it.”

What exactly IS consciousness?

The concept of consciousness has kept a small army of moralists, physicists, and theologians busy for generations. Today there is an entire field called “consciousness science,” in which academics debate the philosophical and physiological meanings of the word.

The concept, after all, can take on different tones. Anesthesiologists have one interpretation of “conscious.” Psychologists have another. Philosophers and religious scholars also have their own varying views.

An increasing number of mainstream scientists and researchers also point to a consciousness that is outside individuals, sometimes called “universal consciousness.”

For the purposes of the declaration, researchers said, they focused on what is called “phenomenal consciousness.” This is the idea that “There is something that it’s like to be a particular organism,” explains Christopher Krupenye, professor of psychological and brain sciences at Johns Hopkins University.

Phenomenal consciousness can be a bit of a hard concept to get one’s head around at first, he says. But it basically means that an animal experiences the world not as a machine, but as a being. Phenomenal consciousness is what you are experiencing right now in your body with the sight of words on a page as you read this article.

There is another type of consciousness often called “metacognition,” in which a being is aware of what’s going on in its own mind. It is recognizing, for instance, that the temperature you feel is unpleasant, and then thinking that perhaps you should turn up the thermostat. It is recognizing that the words on the page are too small and that you should grab your reading glasses.

“Theory of mind” is another connected concept. You recognize that another person reading this article is not you, but that they can have an experience similar to yours.

Current research, including Dr. Krupenye’s, suggests that both dogs and primates display all these forms of consciousness.

In one of his studies, for instance, he was able to track eye movements of chimpanzees, bonobos, and orangutans in order to gauge whether or not they expected an unseen ape to see them through a transparent barrier. He found these primates were able to assume another being was having a similar but different experience from what they were having themselves, given their own perspective on the world.

Other studies show that dogs look to their owners for assistance when they do not understand a command, and that they look for clues and more information when they are having difficulty solving a task. Researchers believe this indicates dogs recognize their own ignorance – a sign of metacognition.

But of course there’s no way to prove, or even fully understand, what dogs or apes are experiencing, Dr. Krupenye says.

“You’re identifying one of the core philosophical challenges in this area of research,” he says. “With the case of phenomenal consciousness, in humans we take it as the case that if they verbally report they feel X or Y, we agree that’s what they are feeling. With animals, we can’t ask directly for them to verbally report.”

So researchers use alternative indicators to gauge how a nonhuman animal is thinking or feeling – such as tracking eye movement. But even this gets tricky. What about an animal whose umwelt isn’t visual at all?

“My dog’s experience of the world is much more dominated by smell data and much less by sight data,” says Dr. Sebo. “Different kinds of experiences might cause them different bodily pleasure and pain, but also different emotional pleasure and pain.”

For years, researchers were cautioned not to anthropomorphize their subjects, or bestow human traits upon other animals. Most scientists still agree with many of the tenets of this.

Dogs, for instance, don’t necessarily like what humans like, and most researchers agree that it is ethically important to keep those distinctions in mind. Think here about a dressed-up poodle. Its clothing and accessories are about human preferences. But the poodle might prefer an odor on the neighbor’s lawn. That’s a dog preference. Ethicists say it is important to be aware of this distinction, and not behave as if the poodle actually loves pompoms.

Many animal researchers now say worries about anthropomorphism went too far. The human umwelt might be different from those of other animals, they say, but there is still a deeper quality of being-in-the-world that is similar.

Heather Mattila, a biologist at Wellesley College in Massachusetts, generally tries to sidestep the question of consciousness in the bees she studies – even though it’s what most interests her students.

Trying to determine consciousness leads down a complicated philosophical path, she says. It is difficult to prove anything. She is an empirical scientist, which is all about working with solid, replicable studies.

But in her personal opinion, there’s no question: Bees likely have consciousness. She watches bees map locations, share information, and dance in a way that appears excited when they have found a particularly tasty food source. (She has learned to write “vigorous” rather than “excited” in research papers to avoid sparking the critiques of reviewers.)

Other researchers have also detected play behavior in some bees. All in all, the insect’s behavior reminds her of the rescued dog she grew up with – an animal that convinced her that other species had full personalities and cognition. “In a human mind, we would just assume consciousness is involved,” Dr. Mattila says.

“We should aspire to treat them compassionately.”

But assuming consciousness in other species brings up profound moral quandaries. If it turns out that animals do have feelings, or if they do participate in this big, amorphous concept called consciousness, what would that mean for the way humans interact with the rest of the living world?

The scholars who signed the New York declaration tried to stay ambiguous on that point.

“All of these animals have a realistic chance of being conscious, so we should aspire to treat them compassionately,” says Dr. Sebo at New York University. “But you can accept that much and then disagree about how to flesh that out and how to translate it into policies.”

For Dr. Mattila and others, the possibility of consciousness has meant limiting the extent to which her scientific experiments cause harm.

“I know many strict vegans would not approve of me keeping honeybees on campus, but I feel like I’m supporting them,” Dr. Mattila says. “I specifically try to do experiments that don’t cause them pain or suffering. ... I try to let them have a good life and observe how they operate within that good life.”

But it also has her thinking more broadly about how humans and other animals cross paths and interact with each other. Should the real possibility of complex animal consciousness make a difference in where we build roads? Should it guide how we “consciously” take control of ecosystems? And should it impact how, and what, we eat?

Such ethical considerations could impact an array of human activity. “It’s culturally inconvenient to think that animals are conscious,” Dr. Mattila says.

Especially farm animals. Although research on animal sentience and intelligence has expanded to include a host of different species, there is still a gap when it comes to the animals we kill for food.

The agricultural industry has long focused on animal welfare within the context of the food system, and there have been industry-wide efforts to slaughter animals in the most humane way possible.

But a group of international researchers in 2019 published a report in the journal Frontiers in Veterinary Science that found a decided lack of information on the “physico-cognitive capacities” of farm animal species.

While there has been loads of research on animal husbandry, there has not been all that much investigation into animals’ conscious experiences outside their role as food products for humans.

To Ms. Prasad-Shreckengast and others at Farm Sanctuary, there are clear reasons for this. The first is that we generally want to distance ourselves from those creatures we eat. Multiple studies have shown that meat-eaters engage in something called “cognitive dissociation” to help alleviate the discomfort that comes if one starts to learn about the emotions or physical experiences of a pig or cow or chicken.

But there are also funding issues. Most scientific research on farm animals is funded by agricultural schools focused on industrial practices or is funded by large agribusiness companies themselves. And farm animals generally live in a way that some scientists say is not conducive to understanding individual sentience.

“When you’re thinking of chickens, specifically in a barn with 30,000 chickens, you can’t see an individual,” says Ms. Prasad-Shreckengast. The study she published this October focused on the behavior of Cornish hens – usually slaughtered after they reach 6 weeks of age.

There isn’t a lot of existing information about the Cornish hen’s interior life, she says, because they aren’t usually allowed to live long enough to study as adults.

Farm Sanctuary is explicit in its promotion of a vegan diet – it was founded by a California-born animal activist named Gene Baur, whose work revealing animal cruelty at industrial farms and slaughterhouses helped lead to animal welfare laws.

Because of that, however, critics have called its animal science research biased – a charge researchers here reject.

“There’s no reason to not offer somebody the benefit of the doubt of sentience, the benefit of the doubt of consciousness, and to provide research methods that respect their agency and autonomy,” Ms. Prasad-Shreckengast says. “You can still do really good science with those ethics in place.”

On tours at Farm Sanctuary, guides introduce visitors to goats who make family groups; cows who, when no longer confined to dairy barns, prance and play and take care of their young; and pigs who, given the space, build themselves nests in a barn but go outside to relieve themselves.

It is an explicit effort to introduce humans to the individuals within other species, says Mr. Baur. The purpose is simple: to normalize empathy for fellow creatures.

“What we’re trying to achieve here are relationships of mutuality with us and other animals, where everyone benefits by the interaction, instead of relationships of extraction, where those with power take from those without,” he says.

Promoting a vegan ethic, however, isn’t the only valid way to understand the relationship between humans and farm animals – even for those convinced they have consciousness.

For Dr. Andrews, the key thinker behind the New York declaration, the question of how to live in a world of infinite consciousnesses has more to do with negotiation than with moral absolutes.

She believes it is impossible to completely avoid causing harm. The bacteria on our skin are disrupted when we wash. Animals in the wild eat other animals. When she finds flower-
eating aphids in her garden, she kills the insects to save the plants.

“It’s about acknowledging that harms are part of life, and we’re committing some harms, but we’re trying to minimize the harm that we do when we’re making our choices,” Dr. Andrews says.

It’s also recognizing that humans are not separate or unique, but part of an ecosystem with a dazzling array of individuals and understandings of the world – and a dazzling array of consciousness.

“It’s driving us to see ourselves as part of an integrated system of biology,” she says. “And that is probably better for the planet.”