Squid can solve complex puzzles, bees have different levels of exploration based on previous experience, and crabs avoid environments where they have experienced pain in the past. However, most countries in the world still do not recognize that such invertebrates also have emotions or feel pain. Britain is now considering including some shellfish as sentient beings in an amendment to the Animal Welfare Act. In the journal “Science”, researchers argue that this is long overdue from a scientific point of view – but also raises new ethical questions.
Can animals feel? This question is more complex than it first appears and has been the subject of controversy for decades. For a long time, researchers assumed that animals react to pain stimuli via the peripheral nervous system – similar to how we reflexively pull our hand away from a hot stove before we have even registered the pain cognitively – but do not evaluate the pain emotionally or experience it as negative. The ability of mammals, birds, and bony fish to have sensation is now widely recognized and recognized in many animal welfare laws. Lobsters, on the other hand, can still be cooked alive and there are hardly any animal welfare standards for other invertebrates either.
No language – no emotions?
“A report commissioned by the UK government from the London School of Economics (LSE) concludes that there is sufficient evidence that decapods and cephalopods are sentient,” explains philosopher Kristin Andrews of the University of York in Canada. Together with the behavioral researcher Frans de Waal from Emory University in Atlanta, she discusses the current state of research on emotions in animals and the resulting ethical implications in the journal Science.
“People accept verbal statements about internal states as evidence of those states and, conversely, sometimes equate the absence of language with the absence of those states,” Andrews and de Waal explain. According to the classic assumption, those who are unable to report on their emotions do not have any emotions either. Doctors and scientists even applied this principle to human infants up until the 1980s: “Because the physicians were skeptical that preverbal human babies could feel anything, they operated on them without anesthesia,” the authors report.
Invertebrates with feelings
“By the time the medical community recognized infant pain in the 1980s, the evidence was so overwhelming that physicians could no longer pretend that infants were immune to pain,” they write. “We’re at a similar point where invertebrates can no longer be treated as if they only have a nociceptive response to noxious stimuli.” Among other things, studies have shown that crabs exposed to experiments in certain environments receive electric shocks received, avoided these environments in the future. “An exclusively unconscious perception of pain cannot explain associative learning because there is no motivation to avoid the stimulus unless it feels bad at the time,” the authors write. In addition, it can be assumed that animals feel other emotions apart from pain. “Invertebrates such as octopuses show curiosity when exploring, affection for single individuals, or excitement in anticipation of a future reward,” Andrews describes.
A study of bees even found that past experiences, positive or negative, influence how optimistic or pessimistic the animals behave and that these differences are reflected in the nervous system. If the bees were exposed to stress, for example by being shaken in a container, they were less willing to try new things compared to unstressed conspecifics. They also found decreased levels of neurotransmitters such as dopamine and serotonin in their nervous system, similar to those seen in people suffering from depression. “In any mammal, a pessimistic behavioral response coupled with physiological signs of stress would be taken as a sign of negative emotion. The same logic should be applied to insects,” say Andrews and de Waal.
Ethical Implications
If it is actually accepted that invertebrates can also have emotions and, for example, feel pain, this would have numerous ethical implications. “It is not difficult to see that the denial of emotion in animals has been morally favorable in the history of human exploitation of animals,” the authors write. “Although we are used to thinking about how our actions affect other people, recognizing the widespread sentience of animals requires that we also recognize – and consider – our effects on other species.”
While we can assume that a lobster, given the opportunity, would not consent to being cooked alive, for many other species we still lack the knowledge of how to handle them appropriately. According to Andrews and de Waal, ethicists and biologists must therefore work together to jointly find a framework for future moral treatment of animals.
Source: Frans de Waal (Emory University, Atlanta, USA) and Kristin Andrews (York University, Toronto, Canada), Science, doi: 10.1126/science.abo2378