The Declaration of Animal Consciousness

For centuries, science operated under the assumption that most animals were simply biological machines that reacted to stimuli without any internal experience. That view has officially shifted. On April 19, 2024, a prominent group of biologists and philosophers convened at New York University to sign “The New York Declaration on Animal Consciousness.” This document formally asserts that there is strong scientific support for conscious experience in animals far beyond mammals and birds, extending to reptiles, fish, and even insects.

What is the New York Declaration?

The New York Declaration on Animal Consciousness represents a pivotal moment in neurobiology and animal ethics. While the 2012 Cambridge Declaration on Consciousness established that mammals, birds, and octopuses likely possess consciousness, the new 2024 declaration significantly widens the net.

The signatories, including leading figures like philosopher Jonathan Birch from the London School of Economics and neuroscientist Anil Seth, argue that the evidence is now too strong to ignore. The declaration makes two primary claims:

1. There is strong scientific support for attributions of conscious experience to mammals and birds.
2. There is a “realistic possibility” of conscious experience in all vertebrates (including reptiles, amphibians, and fish) and many invertebrates (including cephalopod mollusks, decapod crustaceans, and insects).

This does not mean scientists are claiming a mosquito has the same thoughts as a human. Instead, it argues that these creatures likely possess “sentience,” which is the capacity to have subjective experiences, such as feeling pain, pleasure, or perceiving the world around them.

The Evidence: Why Scientists Changed Their Minds

This shift isn’t based on sentimentality. It is based on rigorous data collected over the last decade. Researchers have moved away from simply looking for human-like brain structures and started looking for complex behaviors that suggest an inner life.

The Mirror Test and Fish

For a long time, the “mirror self-recognition test” was the gold standard for consciousness. If an animal recognized that the reflection in the mirror was itself (usually by touching a mark placed on its body), it was deemed self-aware. Great apes and dolphins passed. Most others failed.

However, recent studies by researchers like Masanori Kohda have shown that the cleaner wrasse (a small tropical fish) can pass this test. When marked with a brown dye that looks like a parasite, the fish will see the reflection and attempt to scrape the spot off against a rock. This suggests a level of self-awareness previously thought impossible for fish.

Bees Playing for Fun

Insects have historically been viewed as reflex-driven automatons. Yet, research led by Lars Chittka at Queen Mary University of London has challenged this view. His team demonstrated that bumblebees would repeatedly roll wooden balls around an arena. They were not getting food for doing this. They were not being trained. They appeared to be doing it simply because it was rewarding. In human terms, they were playing.

This behavior suggests that bees can experience positive affect (pleasure or enjoyment). If an animal can play, it implies it has an inner emotional state, which is a hallmark of consciousness.

Pain Avoidance in Crustaceans

Decapod crustaceans (crabs, lobsters, and shrimp) are often cooked alive based on the belief that they do not feel pain. However, experiments have shown that hermit crabs will leave a high-quality shell if they receive an electric shock inside it, but they will tolerate a lower level of shock to keep a good shell if the alternative is a poor one. This trade-off suggests they are not just reflexively reacting to damage. They are weighing the “cost” of the pain against the value of the shell. This decision-making process points toward sentience.

The "Realistic Possibility" Standard

A key phrase in the declaration is “realistic possibility.” The scientists are not stating that we have absolute proof that a snake contemplates its existence. They are stating that the neurological and behavioral evidence is substantial enough that we can no longer dismiss the idea.

The declaration emphasizes that when there is a realistic possibility of conscious experience, it is irresponsible to ignore it in ethical decision-making. This is an application of the “precautionary principle.” If there is a decent chance an animal can suffer, we should act as if it does until proven otherwise.

Implications for Animal Welfare and Law

The signing of this declaration is likely to have concrete impacts on laws regarding animal treatment, farming, and laboratory research.

Legal Protections

We are already seeing legal frameworks catch up to this science. The United Kingdom passed the Animal Welfare (Sentience) Act in 2022, which formally recognized decapod crustaceans (crabs and lobsters) and cephalopod mollusks (octopuses and squid) as sentient beings. This law mandates that government policy must consider the welfare of these animals. The New York Declaration provides the academic backing needed to push for similar legislation globally, potentially extending protections to farmed fish and even insects used in agricultural feed.

Laboratory Research

Science relies heavily on model organisms like fruit flies (Drosophila) and zebrafish. If these animals possess a form of consciousness, ethical oversight committees (IACUCs) may need to revise their protocols. Currently, strict welfare guidelines apply mostly to vertebrates like mice and monkeys. If fruit flies are recognized as potentially sentient, researchers might be required to use anesthesia or provide pain relief for insects, which would fundamentally change how biological research is conducted.

The “Pest” Paradox

This declaration creates difficult ethical questions regarding pests. If cockroaches and mosquitoes possess sentience, how do we justify extermination? The declaration does not argue that all lives are equal or that we cannot protect our homes. However, it introduces the idea that even pest control should perhaps focus on methods that are quick and humane, rather than slow-acting poisons that might cause prolonged suffering to a conscious being.

Summary of the Shift

The New York Declaration on Animal Consciousness effectively ends the era of “anthropocentrism” in consciousness science. We can no longer assume that consciousness is a unique superpower reserved for humans and their closest hairy relatives.

By acknowledging that a lizard basking in the sun or a bee buzzing among flowers is likely having a subjective experience, science is inviting us to look at the natural world with a new level of respect and complexity. The lights are on in many more houses than we previously thought.

Frequently Asked Questions

What is the difference between the 2012 Cambridge Declaration and the 2024 New York Declaration? The 2012 Cambridge Declaration focused primarily on mammals, birds, and octopuses, asserting they had the substrates for consciousness. The 2024 New York Declaration expands this scope significantly to include reptiles, amphibians, fish, and insects, emphasizing a “realistic possibility” of sentience in these groups.

Does this mean plants are conscious? No. The declaration specifically addresses animals. While plants exhibit complex reactions to their environment, they lack the nervous systems and centralized processing structures that are currently understood to be required for the subjective experience of “feeling” or sentience.

What defines “sentience” in this context? Sentience is defined as the capacity to have subjective experiences. It is not about high-level math or language. It is about the ability to feel things like pain, pleasure, comfort, hunger, or fear. If there is “something it is like” to be that animal, it is sentient.

Will this stop people from eating meat? The declaration is a scientific statement, not a dietary mandate. However, it does provide ammunition for animal welfare advocates who argue for better living conditions and more humane slaughter methods. It shifts the argument from “do they feel?” to “how much do they feel?”

Are insects really conscious? The declaration states there is a “realistic possibility.” Evidence like bees playing or fruit flies displaying fear-like states suggests their behavior is more than just pre-programmed code. They may have a basic form of subjective experience, even if it is very different from human consciousness.