Have We Misunderstood Our Emotions?

This is the third of a series of posts related to my new book, The Deep History of Ourselves: The Four-Billion-Year Story of How We Got Conscious Brains, that explores mind and behavior in the context of the four-billion year history of life on earth. These posts, and others, can be found by visiting the home page of my Psychology Today blog, I Got a Mind to Tell You.

We often assume that the behaviors we see in those around us reflect what is on their minds. For example, when one is freezing in front of a snake or fleeing from a bear, we take it for granted that a feeling of fear is the cause. Why else would one respond in this way?

Charles Darwin adopted this commonsense approach in his 1872 book, The Expression of Emotions in Man and Animals. It has, ever since, been the foundation of a widely accepted view of what emotions are and how they are wired in the brain. But I think he was wrong.

Emotions are not, as Darwin proposed, and many still believe, pre-programmed, innate states of mind. They are, instead, in my view, mental states that are cognitively assembled as the situation unfolds. Darwin’s mistake was his assumption that because we often respond in a particular way when we consciously experience an emotion like fear, fear must be the cause of responses.

To understand why I think Darwin led us astray on this topic, let's look at research on the brain area of the amygdala. Neural circuits in this area are responsible for behavioral responses, like freezing and fleeing, when one is in harm’s way. Consistent with Darwin’s logic, the amygdala has thus come to be thought of as the brain’s fear center, a nugget that generates the experience of fear, which, in turn, drives the behavioral and physiological responses we associate with the feelings. We have first-hand knowledge of such states from our inner experiences when in danger. And we readily attribute them to other people when they are responding to danger, and also to our animal cousins when they respond in ways similar to us.

It is perfectly natural to think, as Darwin did, that fearful experiences, and the body reactions that often go with them, are entwined in the brain. While Darwin was a deep biological thinker, historians of psychology have noted that his forays into mental life were considerably less rigorous. Recent work in psychology and neuroscience gives us reason to agree.

Compelling studies question the conclusion that the subjective feeling we know as fear is a hard-wired state ingrained in ancient circuits inherited from animals. For example, the subliminal presentation of visual stimuli to people using quick exposures and other techniques prevent awareness of the stimulus. When threatening stimuli are presented in this way in brain imaging studies, the amygdala is activated, and body responses, such as sweating, are elicited. However, the participants do not have any awareness of having seen the stimulus and do not report feeling fear.

This makes sense in light of other studies showing that while body responses to threats are disrupted in people who have suffered damage to the amygdala, the ability to report feeling fear is not consistently abolished. The amygdala, in other words, is indeed hard-wired by evolution to detect and respond to certain kinds of threats, but not necessarily to make feelings of fear. A number of other points made elsewhere also support the idea that the amygdala does not make fearful feelings.

The implications of this conclusion come to full light once viewed in a larger evolutionary context. Detecting and responding to danger is not something only done by humans and other mammals (dogs, cats, rats), or even just other vertebrates (birds, reptiles, fish). Invertebrates, like flies, bees, and worms, also have to detect danger to stay alive.

In fact, all organisms, no matter how simple or complex, must do this in the course of daily life, including single-cell organisms. Bacteria, for example, lack a nervous system but still detect toxic chemicals and respond by moving away.

The comparison hardly stops there. Like us, bacteria also have to incorporate nutrients, balance fluids and ions, and reproduce. When we engage in such behaviors, we talk about mental states of fear, hunger, thirst, and pleasure. But the biological mechanisms that control such behaviors did not arise to make mental states. They arose as part of the physiological toolkit that a lifeform, an organism, must possess in order to live and to reproduce its kind.

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But the more complex the body an organism possesses, the more complex is its particular behavioral solutions. For example, unicellular bacteria absorb nutrients directly, but most animals have specialized systems for acquiring food and extracting nutrients, and different animals do these things differently depending on the kind of body they possess. The survival requirements of life are universal, but the implementations are specific to the body plan each species possesses.

Survival behaviors (eating, drinking, defending, copulating) are controlled by nervous systems in animals. In all vertebrate animals, the amygdala coordinates defensive behaviors in situations of danger (invertebrates don’t have our kind of nervous system, and thus don’t have an amygdala, but they have their own defense circuits). Such behaviors reflect, in a deep sense, the primordial requirements of life.

How, then, do our emotions come about, if not as mental states preprogrammed in ancient circuits? A key contemporary idea is that emotions are cognitive interpretations of situations in which psychological or physical well-being is potentially at risk. Cognitive theories arose in the 1960s through the work of Stanley Schachter and George Mandler. There are numerous contemporary proponents, such as Lisa Feldman Barrett, James Russell, Gerald Clore, Andrew Ortony, Klaus Scherer, and Matt Lieberman, to name a few. This is not a fringe idea, despite the attention that so-called basic emotions theory attracts.

My cognitive theory has been in the works since the late 1970s. For me, a key cognitive factor that goes into the making of fear is your fear schema, your personal mental model of what fear is, based on all the experiences you have had with danger throughout your life. Fear, like all emotions, is thus personal—it involves you. Like all organisms that have ever lived, you can react behaviorally to dangerous stimuli. But if you are not aware that you are in danger, you cannot feel fear—no self, no fear.

If emotions like fear are personal, why are they so universal? It is the danger, not fear, that is universal. Every culture has words for things important to their lives. In brains that can assemble conscious states involving the self, fear is simply the name or label for the experience that results when one is aware of being in danger. The activity of survival circuits adds intensity to, but does not dictate, the nature of the experience. Personal and cultural memories do that.

Emotions are thus first and foremost conscious experiences. We will not fully understand how they work until we understand consciousness. Fortunately, the science of consciousness is currently a thriving area of research.

And one emerging conclusion is that areas of the prefrontal cortex are key to conscious awareness. If those of us on this conceptual track are correct, fear does not bubble up pre-formed out of ancient circuits but is instead individually assembled by prefrontal circuits. The prefrontal cortex has unique cellular features in humans and is known to be involved in cognitive processes that are key for human conscious experience—hierarchical reasoning about relations, prediction on the basis of limited information, and higher-order conceptualization, including of one’s self as a psychological entity with a past and a future, and inescapable mortality.

The amygdala controls defensive behavior, but cortical circuits make fear

Source: Joseph LeDoux, The Deep History of Ourselves (Viking, 2019)

An important practical implication of this perspective is that it helps us to understand why the effort to find new, effective treatments for debilitating fear and anxiety have been so disappointing. Research in this area has relied on studies measuring behaviors controlled by survival circuits in rodents. If emotions, instead, are products of complex prefrontal circuits with unique features in humans and lacking in other animals, it makes sense that medications emerging from rodent studies should not be expected to change subjective human feelings of fear and anxiety.

This does not mean that such medications are useless. A person with social anxiety, despite still experiencing a mental state of fear or anxiety, may find herself less timid behaviorally and less physiologically aroused when attending a party while on the medication. Addressing both kinds of symptoms, subjective and behavioral, is thus important, but different kinds of treatments may be needed to target the different circuits involved.

The intuition that fearful feelings and defensive behaviors are psychologically and biologically entwined has long dominated scientific views about emotion. But when findings begin to challenge such long-held assumptions, we need to be prepared to change how we think. This is not simply a matter of intellectual curiosity. Our well-being is at stake.