Do octopuses, squids and crabs feel emotions?

At the end of 2021, the United Kingdom considered invertebrates – such as cephalopod molluscs and decapod crustaceans – sentient beings, capable of experiencing emotional pain, after analyzing more than 300 scientific articles on the matter. The British government then decided to suggest their protection through its Animal Welfare Bill to prevent their suffering.

The country would thus join a handful of nations that recognize the sentience of these invertebrates, thereby prohibiting, for example, certain customs such as boiling live lobsters, instead of ending their lives ethically. The decision is based on evidence that emotions and felt experiences – known as sentience – are not limited to humans and other mammals.

The country would thus join a handful of nations that recognize the sentience of these invertebrates, thereby prohibiting, for example, certain customs such as boiling live lobsters, instead of ending their lives ethically. The decision is based on evidence that emotions and felt experiences – known as sentience – are not limited to humans and other mammals.

"A report from the London School of Economics, commissioned by the UK government, has concluded that there is strong enough evidence to say that decapod crustaceans and cephalopod molluscs are sentient," says the University of York professor and philosopher. Kristin Andrewsholder of the York Research Chair in Animal Mind.

But how do you define an emotion? What is the moral relevance of animal experiences? This topic has been the subject of debate for years both in affective neuroscience and in philosophy, and now a consensus on moral and ethical criteria and implications seems to be emerging.

In an analysis published in the journal Science, scientists Frans de Waaldirector of the Living Links Center at Emory University, and Kristin Andrews, from York University, discuss the political and moral implications of emotion recognition in this group of animals.

Animal reflexes or emotions?

More than a decade ago, the same debate revolved around whether fish felt pain. Until recently, it was thought that they only had nociception, that is, they reacted unconsciously to noxious stimuli, such as when we remove our hand from the hot stove before knowing that it is going to burn us. It was then believed that they responded to pain reflexively, but without any associated feeling.

The scientific community deduced that since nociception did not necessarily reach the central nervous system and consciousness, it was not equivalent to sentience, which in this case was equivalent to experiences with value, considered by the organism as attractive/positive or aversive/negative.

As de Waal and Andrews explain in their analysis, this debate was settled when it was discovered that fish learn from encounters with negative stimuli by avoiding dangerous places. A study showed that they remember these areas because they felt and neurally processed the harmful experiences.

“In the last century it was said that animals are like response machines to stimuli, but then the exceptions arrived: first primates, dolphins, elephants, dogs and other mammals, then birds and fish. Now we have come to invertebrates and there are all kinds of new studies on bumblebees, bees, etc.”, de Waal stresses to SINC.

The same happens with octopus, squid and crabs. "The usual argument is that they react to negative events (such as blows or being caught by humans), but they don't feel anything," details the expert in ethology.

However, the scientific literature shows that, like fish, these animals remember the places where negative things happened, "which means that they must have experienced these events, therefore, they feel", continues the expert for who all animals with brains are sentient.

Thanks to an experiment, a job on crabs that hide from bright light in the lab by going into a hole, showed that these crustaceans remember the holes where they were shocked and avoid them. "They felt and they remembered," says de Waal.

Language as a sign of suffering

Before the 1980s, this same discussion it was centered around human babies being subjected to surgical procedures by doctors with little or no anesthesia. The reason is that only verbal statements of pain were accepted as evidence of these internal states, and the absence of language was equated with the absence of these. That is, by not speaking, babies were thought to feel nothing.

“The importance of language is overrated. People thought: without words, there are no feelings, there is no conscience”, recalls de Waal. Despite overwhelming scientific evidence that babies do feel pain, that attitude didn't change until the 1980s.

“Language is the way we communicate feelings, but feelings can happen without language. This was difficult for the scientific community to understand. Added to this were the prejudices about what we consider animals to be, as if humans were not animals”, emphasizes the ethologist.

In their writing, the two scientists estimate that recognizing the sensitivity of invertebrates opens up a moral and ethical dilemma. Humans can say what they feel, but animals don't have the same tools to describe their emotions. "However, the research done so far strongly suggests their existence," says Andrews, who works on a research project called Animals and Moral Practice.

How then to treat octopuses and crabs?

For researchers, the time may come when people accept that crabs, shrimp and other invertebrates feel pain and other emotions. "Actually, it is about re-educating our way of seeing the world," says the scientist, for whom it is still an open question to know how we should treat certain species. "We need more cooperation between scientists and ethicists," she adds.

According to the authors, this is a moral decision: “We cannot act as if these animals do not have feelings, nor treat them as if they were stones. But the question of how to keep them or whether to eat them is a moral question that we cannot decide,” says de Frans de Waal.

“We have to stop acting like animals are insensitive. This applies to both the agricultural industry and laboratories. We tend to treat invertebrates differently from mammals, such as mice and rats, but there is no strong scientific argument for doing so."

Frans BM de Waal and Kristin Andrews. 'The question of animal emotions' Science