Are animals conscious? How new research is changing minds

Charles Darwin enjoys a near god-like status among scientists for his theory of evolution. But his ideas that animals are conscious in the same way humans are have long been shunned. Until now.

"There is no fundamental difference between man and animals in their ability to feel pleasure and pain, happiness, and misery," Darwin wrote.

But his idea that animals think and feel was seen by many as scientific heresy among many, if not most animal behaviour experts.

Attributing consciousness to animals based on their responses was seen as a cardinal sin. The argument went that projecting human traits, feelings, and behaviours onto animals had no scientific basis and there was no way of testing what goes on in animals’ minds.

But if new evidence emerges of animals’ abilities to feel and process what is going on around them, could that mean they are, in fact, conscious?

We now know that bees can count, recognise human faces and learn how to use tools.

Prof Lars Chittka of Queen Mary University of London has worked on many of the major studies of bee intelligence.

"If bees are that intelligent, maybe they can think and feel something, which are the building blocks of consciousness," he says.

Prof Chittka’s experiments showed that bees would modify their behaviour following a traumatic incident and seemed to be able to play, rolling small wooden balls, which he says they appeared to enjoy as an activity.

These results have persuaded one of the most influential and respected scientists in animal research to make this strong, stark and contentious statement:

"Given all the evidence that is on the table, it is quite likely that bees are conscious," he said.

It isn't just bees. Many say that it is now time to think again, with the emergence of new evidence they say marks a "sea change" in thinking on the science of animal consciousness.

They include Prof Jonathan Birch of the London School of Economics.

"We have researchers from different fields starting to dare to ask questions about animal consciousness and explicitly think about how their research might be relevant to those questions," says Prof Birch.

Anyone looking for a eureka moment will be disappointed.

Instead, a steady growth of evidence for a rethink has led to murmurings among the researchers involved. Now, many want a change in scientific thinking in the field.

What has been discovered may not amount to conclusive proof of animal consciousness, but taken together, it is enough to suggest that there is "a realistic possibility" that animals are capable of consciousness, according to Prof Birch.

This applies not only to what are known as higher animals such as apes and dolphins who have reached a more advanced stage of development than other animals. It also applies to simpler creatures, such as snakes, octopuses, crabs, bees and possibly even fruit flies, according to the group, who want funding for more research to determine whether animals are conscious, and if so, to what extent.

But if you're wondering what we even mean by consciousness, you're not alone. It’s something scientists can’t even agree on.

An early effort came in the 17th century, by the French philosopher René Descartes who said: "I think therefore I am."

He added that "language is the only certain sign of thought hidden in a body".

But those statements have muddied the waters for far too long, according to Prof Anil Seth of Sussex University, who has been wrestling with the definition of consciousness for much of his professional career.

"This unholy trinity, of language, intelligence and consciousness goes back all the way to Descartes," he told BBC News, with a degree of annoyance at the lack of questioning of this approach until recently.

The "unholy trinity" is at the core of a movement called behaviourism, which emerged in the early 20th Century. It says that thoughts and feelings cannot be measured by scientific methods and so should be ignored when analysing behaviour.

Many animal behaviour experts were schooled in this view, but it is beginning to make way for a less human-centred approach, according to Prof Seth.

"Because we see things through a human lens, we tend to associate consciousness with language and intelligence. Just because they go together in us, it doesn’t mean they go together in general."

Some are very critical of some uses of the word consciousness.

"The field is replete with weasel words and unfortunately one of those is consciousness," says Prof Stevan Harnad of Quebec University.

"It is a word that is confidently used by a lot of people, but they all mean something different, and so it is not clear at all what it means."

He says that a better, less weasley, word is "sentience", which is more tightly defined as the capacity to feel. "To feel everything, a pinch, to see the colour red, to feel tired and hungry, those are all things you feel," says Prof Harnad.

Others who have been instinctively sceptical of the idea of animals being conscious say that the new broader interpretation of what it means to be conscious makes a difference.

Dr Monique Udell, from Oregon State University, says she comes from a behaviourist background.

"If we look at distinct behaviours, for example what species can recognise themselves in a mirror, how many can plan ahead or are able to remember things that happened in the past, we are able to test these questions with experimentation and observation and draw more accurate conclusions based on data," she says.

"And if we are going to define consciousness as a sum of measurable behaviours, then animals that have succeeded in these particular tasks can be said to have something that we choose to call consciousness."

This is a much narrower definition of consciousness than the new group is promoting, but a respectful clash of ideas is what science is all about, according to Dr Udell.

"Having people who take ideas with a grain of salt and cast a critical eye is important because if we don’t come at these questions in different ways, then it is going to be harder to progress."

But what next? Some say far more animals need to be studied for the possibility of consciousness than is currently the case.

"Right now, most of the science is done on humans and monkeys and we are making the job much harder than it needs to be because we are not learning about consciousness in its most basic form," says Kristin Andrews, a professor of philosophy specialising in animal minds at York university in Toronto.

Prof Andrews and many others believe that research on humans and monkeys is the study of higher level consciousness – exhibited in the ability to communicate and feel complex emotions – whereas an octopus or snake may also have a more basic level of consciousness that we are ignoring by not investigating it.

Prof Andrews was among the prime movers of the New York Declaration on Animal Consciousness signed earlier this year, which has so far been signed by 286 researchers.

The short four paragraph declaration states that it is “irresponsible” to ignore the possibility of animal consciousness.

"We should consider welfare risks and use the evidence to inform our responses to these risks," it says.

Chris Magee is from Understanding Animal Research, a UK body backed by research organisations and companies that undertake animal experiments.

He says animals already are assumed to be conscious when it comes to whether to conduct experiments on them and says UK regulations require that experiments should be conducted only if the benefits to medical research outweigh the suffering caused.

"There is enough evidence for us to have a precautionary approach," he says.

But there is also a lot we don’t know, including about decapod crustaceans such as crabs, lobsters, crayfish, and shrimp.

"We don’t know very much about their lived experience, or even basic things like the point at which they die.

"And this is important because we need to set rules to protect them either in the lab or in the wild."

A government review led by Prof Birch in 2021 assessed 300 scientific studies on the sentience of decapods and Cephalopods, which include octopus, squid, and cuttlefish.

Prof Birch’s team found that there was strong evidence that these creatures were sentient in that they could experience feelings of pain, pleasure, thirst, hunger, warmth, joy, comfort and excitement. The conclusions led to the government including these creatures into its Animal Welfare (Sentience) Act in 2022.

"Issues related to octopus and crab welfare have been neglected," says Prof Birch.

"The emerging science should encourage society to take these issues a bit more seriously."

There are millions of different types of animals and precious little research has been carried out on how they experience the world. We know a bit about bees and other researchers have shown indications of conscious behaviour in cockroaches and even fruit flies but there are so many other experiments to be done involving so many other animals.

It is a field of study that the modern-day heretics who have signed the New York Declaration claim has been neglected, even ridiculed. Their approach, to say the unsayable and risk sanction is nothing new.

Around the same time that Rene Descartes was saying "I think therefore I am", the Catholic church found the Italian astronomer Galileo Galilei "vehemently suspect of heresy" for suggesting that the Earth was not the centre of the Universe.

It was a shift in thinking that opened our eyes to a truer, richer picture of the Universe and our place in it.

Shifting ourselves from the centre of the Universe a second time may well do the same for our understanding of ourselves as well as the other living things with whom we share the planet.