Scientists make a powerful claim about how animals are similar to humans

Could the animals we share our planet with be as evolved as us?
Loukia Papadopoulos

In August 2020, two neuroscientists from Harvard University studied zebrafish to determine whether animals had feelings. What they discovered was that internal brain states existed in animals. 

Now, researchers from Leiden University have also revealed that animals could have feelings. According to a thought-provoking commentary published March 10 in the scientific journal Affective Science, we should assume that they do.

Authors Mariska Kret, a cognitive psychologist at Leiden University, Jorg Massen of Utrecht University, and Frans de Waal of Emory University and an endowed professor in Utrecht, contend that animals are similar to humans in this powerful area of the mind.

Many studies conducted

The authors state that research on emotions and feelings in animals and humans is plentiful and offers enough circumstantial evidence to back up their assertion.

"Emotions can be investigated experimentally in animals, and very well," explains Jorg Massey in a press release issued this week about the commentary. "These [investigations of emotion could be conducted on] primates, but also birds and even bees."

The researchers further added that new methods are constantly being developed for testing emotions in animals, such as using thermal cameras that can measure the physiological response of an animal to a frightening image. Therefore, researchers can combine various methods to accurately and adequately study emotions in animals.

"No single method can measure emotion directly, but by combining different methods, we make the picture as complete as possible," said Kret.

An overwhelming amount of evidence

The researcher indicated that past studies had given overwhelming evidence that animals can interpret emotions and even empathize with others. This is particularly true in the case of chimpanzees.

What does this mean for our future interaction with animals? The researchers state we should assume that animals process emotions and act accordingly.

"Let's assume that animals also have feelings unless proven otherwise. And in the meantime, we should continue to study whether and how animals subjectively interpret emotions. If we better understand animals' emotions and possible feelings, we will be better able to respond to their needs," said Massen.

The theory brings us up many questions related to animal testing. If animals have feelings, then the circumstances they are subjected to during research may be too much for them to bear. Is it time we changed our approach to animal testing?

Article Abstract: 

Do nonhuman animals (henceforth, animals) have emotions, and if so, are these similar to ours? This opinion piece aims to add to the recent debate about this question and provides a critical re-evaluation of what can be concluded about animal and human emotions. Emotions, and their cognitive interpretation, i.e., feelings, serve important survival functions. Emotions, we believe, can exist without feelings and are unconsciously influencing our behavior more than we think, and possibly more so than feelings do. Given that emotions are expressed in body and brain, they can be inferred from these measures. We view feelings primarily as private states, which may be similar across closely related species but remain mostly inaccessible to science. Still, combining data acquired through behavioral observation with data obtained from noninvasive techniques (e.g., eyetracking, thermography, hormonal samples) and from cognitive tasks (e.g., decision-making paradigms, cognitive bias, attentional bias) provides new information about the inner states of animals, and possibly about their feelings as well. Given that many other species show behavioral, neurophysiological, hormonal, and cognitive responses to valenced stimuli equivalent to human responses, it seems logical to speak of animal emotions and sometimes even of animal feelings. At the very least, the contemporary multi-method approach allows us to get closer than ever before. We conclude with recommendations on how the field should move forward.

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