Descartes' Error: Emotion, Reason, and the Human Brain

Damasio observes that cells and tissues make up an organism, and its survival hinges on the biological processes that maintain the integrity of these cells and tissues. The brain therefore has neural circuits that assist and monitor biochemical processes in the body to ensure the proper functioning of the whole organism. Instincts can drive these neural circuits and control the organism’s behavior. For example, animals have a fight or flight response when they detect the presence of a predator, and the release of adrenaline may enhance their physical faculties. Instincts are therefore capable of generating a specific behavior or inducing a physiological state without conscious thought. They can contribute to survival directly by forcing an action or indirectly by inducing conditions advantageous to the organism.

Emotion and feelings manifest these instincts. In humans, they are part of the basic regulatory mechanisms indirectly known to the individual. For example, a prolonged period of low blood sugar levels induces hunger pangs that the organism can feel and that can push it to act to remedy its hunger. (Other regulatory mechanisms cannot be known to or controlled by the individual, such as the production of blood cells).

Instincts encourage survival by inducing changes in the body in response to stimuli, thus ensuring its integrity and proper functioning. They can take the shape of a meaningful body state (such as hunger), a recognizable emotion (such as fear), or a combination of both. The stimulus can originate from the “visceral” inside (low blood sugar), the outside (the presence of a predator), or the “mental” inside (anticipation of a disaster).

Damasio categorizes these instincts, which exist in humans at birth, as a “preorganized mechanism” (122). They help categorize events as positive or negative depending on their potential impact on survival. Furthermore, they offer a basis of reference for the classification of future experiences. In other words, the body and mind work together to increase the chances of survival of the whole organism. The author concludes that the mind is embrained and embodied.

The reciprocity of body/mind and brain/mind is evident in the powerful role hormones play in affecting behavior. For example, the cerebrum can release oxytocin—which both the brain and body produce—to regulate metabolism, while the body may release it during childbirth or orgasm. It can induce a range of motions, including grooming and locomotion, and can encourage certain behaviors, such as maternal instinct or bonding between sexual partners. Thus, evolutionary adaptation intrinsically ties the mind and body, unconsciously or consciously.

Organisms that have not developed a complicated brain system depend on drives and instincts for survival. However, their success rate hinges on their own complexity and that of their environment. Damasio believes humans are more complex than certain animals due to their capacity to reason and think. However, unlike Descartes and other religious or philosophical thinkers, the author credits human biology more than the metaphysical spirit for this distinction. The next step in modern science is to use neurobiology to investigate this theory of adaptive supraregulations in complex brain structures. However, Damasio cautions that scientists must not reduce the human experience to biology; he calls for the interdisciplinary use of methodologies in neurobiology and the social sciences.

Damasio opens with a comparison. Animals who only possess old brain structures, such as reptiles, demonstrate response selections based on instinct and often live in simple environments; meanwhile, organisms whose brains include modern components, such as the neocortex, lead more complex lives and must consider more factors when making decisions. Biologically, the difference between old and new brain sectors is blatant: The first handles “basic biological regulation down in the basement,” while the latter “deliberates with wisdom and subtlety” upstairs in the neocortex (131). However, Damasio warns that this does not paint the whole picture. Reasoning also involves the hypothalamus, which is subcortical. Damasio explores the extent to which the human brain’s cortical and subcortical structures are responsible for rational and non-rational decision-making, respectively. He proposes that emotion and feeling link these structures and processes.

Damasio proposes a distinction between early emotions (primary emotions) and those experienced later in life (secondary emotions). Primary emotions exist at birth, and the most universal of these are happiness, sadness, anger, fear, and disgust. Humans are prewired to respond in a particular way to certain features of stimuli in the world or in the body. For example, a human may instinctually feel fear when it sees a large creature or hears growling. The brain is thus preconfigured to respond to certain types of stimuli, or innate dispositional representations, and induce fear. The organism does not need to recognize a stimulus to elicit a bodily response, such as the instantaneous decision to fight or flight. Biologically, the limbic system, the amygdala, and the anterior cingulate cortex manage these primary emotions.

Secondary emotions are the next stage in human development and allow the organism to form connections between stimuli and primary emotions. In other words, the body remembers an object or situation that elicited a body state as a body-image. The association of a particular stimuli with a specific emotional response enables the organism to later anticipate certain situations before they happen. If the organism encounters a growling wolf in the forest and remembers it in association with fear, the organism may learn to approach the forest and wolflike creatures more carefully in the future. These acquired dispositional representations can increase chances of survival in complex environments because the organism may plan around rather than just react to stimuli. The limbic system alone cannot manage all secondary emotions, so the framework broadens to include the prefrontal and somatosensory cortices. Through experience, secondary emotions can also allow for more subtle variations of the five universal emotions. Damasio concludes that in patients with prefrontal cortex damage, secondary emotions are impaired, while primary emotions are intact. These patients can still show fear if they encounter unexpected situations but are incapable of experiencing more complex emotions. Broadly speaking, damage to the limbic system affects the proper functioning of primary emotions, while damage to the prefrontal cortices affects secondary emotions. In other words, both subcortical and neocortical structures are involved with reasoning because both are responsible for monitoring the body state and for processing emotions.

Damasio believes that a third variety of emotions, “background feeling,” preceded the primary and secondary emotions in evolution. It designates a body state that happens between emotions and is essentially the “default” setting of the body when emotions do not alter its landscape. Background feeling exists because the mind is in a constant state of mapping changes in the body structure. There are two main methods of mapping. The first is “on-line” dynamic body maps. They catalogue our muscles and visceral inside (through proprioception and interoception respectively) and provide information on the current body state. The second is “off-line” body maps, which are dispositional and dormant. However, they can activate and superimpose on “on-line” representations to provide an idea of what the body “tend[s] to be like” (152). This is evident in the phantom limb syndrome, where people who have lost a body part are still capable of feeling its presence. Without an on-line input of the missing limb, the dispositional representation that memory has stored prevails. Similarly, people who had anosognosia may have damage in the structures that are responsible for body-state mapping, which renders them incapable of recognizing change in their current body landscape. Since they cannot update their outdated body images, the author infers that they no longer have an integral understanding of self. He concludes that body states are “not algorithmically predictable by the brain” (158) because their configurations are effectively endless; instead, the brain relies on live reports from the body to understand them. If the reports no longer function, the understanding of self becomes impaired.

Damasio distinguishes between “feeling” and “emotion” and does not use them interchangeably because all emotions generate feelings if an organism is alert, but not all feelings originate in emotions. Damasio defines a feeling as the conscious and continuous “experience of what your body is doing while thoughts about specific contents roll by” (147). In other words, changes in the body state can elicit an emotional response. If that response happens while the organism is alert, and the mental image of the change superimposes on the image of the body state before the change, the organism feels it.

Feelings can alter body states. For example, a genuine smile prompts movement in facial muscles that the anterior cingulate controls, some of which the person cannot wilfully activate. To make their performances more convincing, actors use “method acting,” a technique that requires them to recreate the real emotion in their bodies. In doing so, they are engaging neural and chemical processes that alter the body state and that they can feel, enabling a more genuine expression. Similarly, body states can also force a feeling. Psychologist Paul Ekman’s research has proven that wilfully making an expression, for example, a smile, can lead to subjects experiencing the emotion related to that body state, such as joy.

The brain alone can conjure some feelings, bypassing the body (and thus emotional body states) entirely. While the usual feedback loop operates between mind and body, Damasio believes that the mind can concoct images of an emotional body state without re-enacting it in the body. The author calls these “as if” devices. They can elicit certain feelings, which differ from those brought about by emotions. These learned “as if” devices can potentially help the organism conserve energy since they might not require a neural or chemical response.

When considering the body, the mind, and emotions as an integral unit whose operation depends on cognitive systems, it becomes evident that feelings, the active perception of those changes, are just as cognitive. Their operation depends on biology, and their main concern is reflecting the state of the body. However, unlike emotions, the biological processes that enable feeling are harder to map. Damasio offers no explanation and does not believe that a complete answer is forthcoming without a better understanding of the nature of human consciousness. While neurochemical processes can alter certain feelings (for example, medication can alleviate anxiety), feelings cannot be reduced to neurons or chemistry. He concludes that feelings are just as concrete as vision or speech but that this materiality should not reduce their loveliness or wretchedness.

Damasio explains his somatic-marker hypothesis, prefacing it by defining what constitutes reasoning and decision-making. According to him, decision-making is the ultimate purpose for reasoning, and choosing a specific response option is the result of decision-making. Reasoning and deciding require knowledge about the situation at hand, the available options of action, and their consequences. It also implies an inherent capacity to sort and weigh situations, options, and consequences. For this framework to hold, memory and rationality are indispensable prerequisites. Damasio proposes that emotions are equally important.

Nevertheless, not all decisions require this much conscious input. Some choices can be undetected and unconscious. For example, when blood sugar level drops in an individual, the hypothalamus reacts to this decline by inducing hunger without requiring the individual’s conscious input or awareness. Other times, decisions can be made consciously but without reasoning. An individual who sees a falling brick may quickly move away or protect their heads without having to weigh their options. Decisions made after conscious deliberation and rational reasoning have long been considered to originate from separate biological mechanisms than automatic ones. Cartesian philosophy places reason (the human spirit) entirely outside the body. However, Damasio argues, this is false; they operate under the same neurobiological core.

Nevertheless, reasoning and deciding in a “mathematical” sense differs from reasoning in a “social” sense. Those in the Phineas Gage matrix do not perceive their logic as impaired; rather, they make poor decisions in their inter- and intrapersonal spaces. Damasio believes that this is because the personal and immediate social domain is “closest to our destiny” and “involves the greatest uncertainty and complexity” (169-69). Choosing advantageously in the social context (that is, picking the course of action that best ensures personal survival through securing shelter, financial solvency, and good social standing) involves complex and expedient decision-making in an ever-changing environment.

The author offers the following scenario: Individual A, a CEO, receives an offer to sign a partnership agreement with company X for the potential benefit of profit. However, A’s best friend, the CEO of company Y, hates company X. If A signs with company X, it will significantly damage A’s relationship with company Y and best friend. Damasio outlines two methods to reason through this process: The first is the route of “high-reasoning” touted by philosophers like Kant and Descartes, which asks A to weigh the pros and cons of each course of action without any emotional input. This how Phineas Gage and Elliot reason. However, this method is inefficient at best and impossible at worst; it requires the individual to “hold in memory the many ledgers of gains and losses” (171) in each scenario. It also requires compiling and comparing all combinations. The permutations are almost infinitely numerous, and in a real-life situation the decision must be prompt. Without an instrument to expedite the process and rule out certain factors, the choice is incredibly difficult.

The second method of decision-making is based on the somatic-marker hypothesis. The key difference between the two is the consideration of emotions. If an unpleasant “gut feeling” accompanies envisioning a given response option, it can immediately bias decision-making without any cost/benefit analysis. The soma (body) “marks” an image and associates a visceral or non-visceral sensation with it. In doing so, it immediately reduces the available options by automatically discarding the ones emotionally associated with losses and increases the accuracy and efficiency of decision-making.

The somatic-marker framework is mostly learned through education and socialization and belongs in the process of secondary emotions. However, it has its basis in primary emotions, which generate somatic states in response to certain types of stimuli and form the basis for accumulating and marking more complex somatic states later. Damasio further argues that the formative set of somatic markers are acquired before adulthood. Their proper development rests on the premise that both brain and society (culture) operate normally. On one hand, when certain areas of the brain are affected, developmental sociopathy, a condition that decreases or removes feeling, can arise. On the other hand, a “sick culture” may also skew somatic markers, such as in the extremist culture of Nazi Germany, in the Soviet Union, during the Chinese Cultural Revolution, or during the Pol Pot regime (171-72).

The prefrontal cortices make up the main neural system responsible for the acquisition of somatic markers and secondary emotions. Damasio offers four reasons for this. First, the prefrontal cortices inhabit the brain region most involved with the constant monitoring of activities in the mind and body. Second, they process signals from the bioregulatory sectors of the brain. Third, they categorize dispositional representations specific to the individual’s personal and unique experiences, which enhance decision-making, prediction, and planning. Finally, they connect directly to sectors of the brain responsible for eliciting motor and chemical responses. Thus, the prefrontal cortices (especially the ventromedial sector) are particularly suited for regulating somatic markers because they help assess situations and the body state and then connect these two with the individual’s unique experience.

In addition, some somatic markers are covert. Damasio posits that not all decision-making involves a conscious feeling, so evolution likely developed an even more economic and automated system. This decision-making process involves making a “symbol” or “surrogate” of a somatic marker that can bypass the triggering of body states. Intuition most easily illustrates this covert route, as it enables people to find a solution without reasoning while conserving energy and time. It involves the automatic elimination of options that are implausible without conscious effort.

Thus, the oldest form of decision-making is biological regulation; the next involves the personal and social realms. In addition are the abstract-symbolic operations of reasoning, such as in art and science. Somatic markers act as an instrument of bias that expedites decision-making and increases the likelihood of a positive outcome. They do not replace other forms of rationality such as logical and mathematical reasoning. They require working memory, a healthy brain and culture, and basic attention to function. Nevertheless, when they are properly accumulated and categorized, they allow for the generation of diversified combinations and boost memory and attention. They are the criteria that individuals use to order their choices from most to least advantageous.