We often attribute feelings and emotions to members of other mammalian species.
Our dogs are loyal, while our cats are haughty. Orcas who live in aquarium tanks miss the open sea, and chimpanzee mothers mourn for infants that have died.
The list goes on and on.
Entire ethical movements are based on a belief that cultivated animals feel pleasure and pain in the same ways that we do. One current example is the push to recognize higher animals like dolphins and chimpanzees as “intelligent non-human persons.”
But how much can we learn about our own emotions by looking for emotions in animals? Is there a better way to do comparative studies?
It’s no surprise that some researchers approach the study of human feelings and emotions through animal studies. Both behavioural and evolutionary psychologists often operate by asking whether specific human emotions (fear, anger, etc.) are present in other animals. This approach requires a good deal of presumption that emotions, and our labels for them, are sufficiently clearly defined and understood to make such comparisons meaningful.
But in “Rethinking the Emotional Brain,” Joseph LeDoux of the Center for Neural Science and Department of Psychology, New York University, proposes a different approach. His article, published in the February 23, 2012, issue of the journal Neuron, suggests a methodology that “shifts the focus from questions about whether emotions that humans consciously feel are also present in other animals, and toward questions about the extent to which circuits and corresponding functions that are present in other animals (survival circuits and functions) are also present in humans.”
LeDoux notes that in the last decade thousands of papers with the word “emotion” in their titles have been published. But what does “emotion” mean? In the first paragraphs above, I used “feelings” to denote primary affects (unease and calm, alertness and relaxation, etc.) and “emotions” to denote the specific mental states into which we enter in response to different feelings in different contexts (pride, resentment, liking, approval, etc.). But in many studies these basic terms are used in many different ways, to the point that “feelings” and “emotions” sometimes are meant to represent the same things.
LeDoux argues that the definition problem that dogs research into emotions becomes dramatically worse when we attempt to study emotion in animals. “While there are certainly emotional phenomena that are shared by humans and other animals, introspections from human subjective experience are not the best starting point for pursuing these. How, then, should the aspects of emotion relevant to animals and humans alike be pursued?”
One core problem is that human subjects have language, and language profoundly changes our perception of emotions, the feelings we associate with certain mental states. LeDoux writes that it is “unlikely that specific emotions … could come about without words.” And, he continues,”an animal brain cannot partition emotional experience in this way.”
With caveats like the fluidity of definitions and the influence of human language, LeDoux promotes an approach to the comparative study of emotion that avoids as much as possible the use of “emotion words” and focuses instead on what he calls “survival functions” — the activation of hardwired brain circuits that respond to environmental situations like predator danger, reproductive opportunity, and others.
LeDoux writes that “the aim is to offer a framework for thinking about some key phenomena associated with emotion (phenomena related to survival functions) in a way that is not confounded by confusion over what emotion means.”
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In short, LeDoux argues that while there are hardwired response circuits in the brain, these circuits are not associated with a particular emotion, as many neuro- and evolutionary psychologists assume. Instead, survival circuits are associated with the environmental situations in which we experience feelings that we label with our familiar words for emotions. In effect, then, LeDoux is arguing against the notion of writers like Ekman and Haidt that our core emotions are themselves hardwired.
He writes that different theories have different lists of basic emotions. Questions persist about both experimental methodology and a lack of consistency in what constitutes an emotional response. Others criticize the assumption that emotions are physical states, rather than social constructs. And so on.
Enter survival circuits. LeDoux notes that all lifeforms, even bacteria, which recoil from harmful chemicals, have innate responses to survival situations. He proposes that studying these universal circuits offers an entry point for comparative neurobiology between species. Using this approach, for example, the absence of language in other animals ceases to be an intractable problem.
LeDoux identifies a basic group of core survival circuits: “defense, maintenance of energy and nutritional supplies, fluid balance, thermoregulation, and reproduction.”
And despite the fact that “brains of vertebrate organisms vary in size and complexity,” LeDoux writes, “there is a highly conserved organizational plan that is characteristic of all vertebrate brains.” In other words, dolphins and chimps may not have words for emotions, but like us they have brain circuits that respond to survival situations.
The bulk of LeDoux’s article presents a long and complex discussion of the brain activity associated with survival circuits. It’s a useful and detailed presentation, but it’s also beyond the scope of this article.
The key point for our purposes is that LeDoux’s approach seeks to avoid the rapids by taking a different arm of the river, creating “a species-independent set of criteria” to define “brain systems that detect significant events and control responses that help meet the challenges and opportunities posed by those events.”
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Much later in his long paper, LeDoux returns to the question of how to approach the study of emotion in other animals.
What about other animals? To the extent that nonhuman organisms have consciousness and cognition, capacities that allow the observation, appraisal, and categorization of survival circuit activity or global organismic states, they can have feelings when survival circuit activity or global organismic states occur.
For LeDoux, this means that “if we can understand what underlies conscious feelings in humans, we can then search for whether those mechanisms are present, and to what extent they are present, in other animals.” He concedes that this is the direct opposite of the approach he wishes to take with the direct study of human emotions.
But just as the survival circuit question should be asked about whether mechanisms in other animals are present in humans, the question of whether mechanisms shown to be present in humans are present in other animals seems only addressable in the other direction. We can never know whether another animal has conscious emotional feelings, but we might be able to determine whether the mechanisms that make of consciousness and feelings possible in humans also present in other animals.
In conclusion, while LeDoux agrees that “consciousness and feelings are topics that are best studied in humans,” he is sensitive to the barrier between human and animal minds. We can be quite confident that other humans experience feelings and emotions much as we do, but other animals lack some of our cortical resources, and there is no way of knowing for sure that other animals do, indeed, have feelings that we would recognize as “emotions.” Nonetheless, the survival circuit approach offers a “way in” to useful comparative study.
We will never know what an animal feels. But if we can find neural correlates of conscious feelings in humans (and distinguish them from correlates of unconscious emotional computations in survival circuits), and show that similar correlates exists in homologous brain regions in animals, then some basis for speculating about animal feelings and their nature would exist. While such speculations would be empirically based, they would nevertheless remain speculations.
All in all, “Rethinking the Emotional Brain” is an absorbing read. To my non-expert eye, it appears to offer a useful and relatively objective way of approaching comparative neuroscience.