48 pages • 1 hour read
Descartes' Error: Emotion, Reason, and the Human Brain
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Part 3, Chapter 9-PostscriptumChapter Summaries & Analyses
Part 3, Chapter 9 Summary: “Testing the Somatic-Marker Hypothesis”
Damasio describes testing the limits of the somatic-marker hypothesis. First, he used skin conductance response to see whether patients with prefrontal damage could still elicit a change in their somatic state. The process involved using various types of stimuli on a patient and running an electric current under their skin to test whether their autonomic nervous system increased the production of fluid from the skin’s sweat glands in response to the stimuli. Damasio found that patients with and without prefrontal damage both had an increase in fluids secretion from sweat glands, indicating a change in their somatic state. However, when confronted with emotional imagery, all subjects without prefrontal damage saw a change in their skin conductance responses, while those with prefrontal damage, including Elliot, did not at all. Even though they could describe the images they saw in detail and knew what types of emotional response would be appropriate, they could not get their bodies to respond to the images. In other words, clinical testing revealed a clear distinction between primary and secondary emotions, which indicated that the somatic-marker hypothesis was worth pursuing.
The second test, the “Gambling Experiments”—which Damasio’s postdoctoral student, Antoine Bechara, devised in collaboration Hanna Damasio and Steven Anderson—evaluated the expediency and accuracy of decision-making. It involved four decks of cards placed upside down. The player received an initial sum of money, and the goal was to gain as much (or lose as little) as possible during the game. The player was to turn cards from any deck they chose, one at a time. Depending on the card they got, they received money (reward) or had to pay a fee (punishment). The player was unaware of the total number of rounds they were allowed to play or which cards yield which results. They were told whether they earned or lost a certain amount after turning a card but were not allowed to keep a precise tally of gains and losses. The results were announced at the end of each round. Unbeknownst to the players, the game was set for 100 rounds, and two of the decks yielded less reward with less risk, while the remaining two paid more but also penalized significantly more.
The results were very revealing. Players without prefrontal cortex damage sampled from all four decks but eventually gravitated toward the safe stacks because they sensed that the lower penalties would eventually give them an advantage. Players with prefrontal damage, on the other hand, repeatedly gravitated toward the high-risk decks, often ending the game in significant debt. Even more revealing, Elliot described himself as risk-averse and conservative yet consistently played at higher risk than the control subjects who considered themselves risk takers. Damasio considers this test is revealing because it mimics real-life decisions, which are generally full of uncertainty and require immediate choices. The only way to minimize risk is to “generate hunches, estimates of probability, by whatever means possible” (206).
Damasio outlines three potential explanations for Elliot’s results. First, his actions were no longer controlled by punishment, only by reward. Second, his actions were more sensitive to reward than to punishment. Finally, although he was sensitive to both punishment and reward, they did not contribute to his automated marking or to his prediction of future outcomes; therefore, he gravitated toward the option that offered immediate reward. To rule out the first two options, Damasio’s team repeated the gambling game, but this time turning cards immediately led to punishment and was only interspersed with rewards. Elliot performed the same as in the first rounds: He avoided the bad decks immediately after being punished but then returned to them much more often than the control subjects did.
At the end of these experiments, Damasio could confirm that the difference in patients in the Phineas Gage matrix lies in their inability to mark an emotion for the prediction of future outcomes. He dubs this predicament as “myopia for the future” (209). To further prove this theory, he repeated the gambling experiment and combined it with the skin conductance response test. Damasio found that as the game progressed, the control group saw changes in their skin conductance in anticipation of turning over cards in the bad decks, which indicated that they foresaw a potentially negative experience. However, players with frontal lobe damage expressed no anticipatory responses in skin conductance. Even if they could reason that a deck might be bad, they could not act on it without proper somatic signaling. Their neural systems could not help them avoid negative situations.
Part 3, Chapter 10 Summary: “The Body-Minded Brain”
Damasio argues that perceiving the world is not only about receiving signals from the environment but also about acting on them. Perception involves both mind and body. For example, if an individual walking alone at night perceives that they are being followed, the mind and body both acknowledge the threat and initiate changes to ensure survival. If flight is the chosen option, the organism’s energy availability, metabolic rate, and immune system readiness all shift toward contributing to this goal. The body constantly interacts with the world and continuously relays the information to the mind and back through neural circuits. More importantly, the body requires information from the environment to maintain homeostasis and balance.
In this way, neural circuits evolved to help the organism meet its functional requirements. They continuously monitor the organism’s state as it interacts with and reacts to the environment; the mind grows from this system of perception, and the body contributes significantly to the mind’s proper functioning. Damasio argues that the concept of self is a biological state that is being constantly updated, not a “little man” in the brain that acts as a central inspector. To illustrate this, he presents the thought experiment of the brain in a jar. Those who fail to see the intrinsic link between mind and body would be inclined to believe that the brain would still experience normal thought processes. Damasio, however, considers the brain without a body incapable of sending out signals to assess the environment—unable to sense modifications in the body state and thus devoid of all indications of life. While neurological “as if” devices can mimic signals of the body-state, these devices differ from real signals that circulate from body to mind and vice-versa.
Developing a mind ensures survival by giving organisms a way to adapt to changes unforeseen in the genome. Therefore, if the mind’s primary goal in evolution was to ensure the survival of the organism, the body must have been its priority. For example, most interactions with the environment happen either within the body’s boundary or outside it. To assess an interaction, the mind must first be capable of understanding the geography of the body’s boundary. If the mind can pinpoint the locale of an interaction within the body’s boundary, it can respond appropriately by targeting the area. For interactions with stimuli outside the body’s boundary, the signal must be double: One comes from the body in the area where the stimuli happened and the other from the sense organ itself (sight, sound, smell, taste, etc.). Damasio thus argues, “When you see, you do not just see: You feel you are seeing something with your eyes” (221). Therefore, while the mind constantly monitors the body state, most of these interactions are in the background.
The body is a constant ground reference for the mind to reconstruct a subjective understanding of reality because consistency is necessary for an organism to make sense of its environment. Damasio explores this point further: If the body is a ground reference, the primordial representation system plays a role in human consciousness.
Damasio acknowledges the difficulty in assessing the biological bedrock of what constitutes consciousness: An organism absolutely needs to be awake and alert to have a sense of self, but not all that are awake and alert have a sense of self. For example, people who lose their capability to see are generally capable of describing this change in relation to the self—of knowing the changes in their bodies. However, complete anosognosics are incapable of locating their problem in relation to the self. Damasio thinks that this is because they have sustained damage to their neural self and thus cannot reconstruct a current image of the body state to compare to the old.
The neural self includes two sets of representations that are constantly updated. The first set concerns autobiographical events, such as the notion of identity, routines, and aspirations. The second set represents the body as it is currently and compares this to how it is generally. The state of the self is continuously remade from the ground up to form an evanescent reference state for the mind. This process is undetected unless an event prevents the remaking of this reference state. In anosognosics, the system no longer informs the mind about the current state of the body and therefore compromises the neural self.
Damasio believes that the brain is constantly holding, making, and remodeling the dispositional self as it interacts with the world. An object being represented will cause the organism to respond to that representation. However, a third step might emerge at the end of this process: The organism might note that its state of self is changing because of its response to the object. If this third step takes place, then the organism has a concept of the metaself, and from this arises the concept of subjectivity. Rather than simply responding, subjectivity allows the organism to form an image of itself in motion.
The mind evolved primarily to care for the organism that owns it. Interactions are therefore crucial for the organism to function properly and to have a sense of self.
Part 3, Chapter 11 Summary: “A Passion for Reasoning”
Damasio reiterates that his theories are hypotheses and, while probable, nonetheless require additional confirmation. Reasoning is informed by feelings and requires the integrity of appropriate brain systems to function. It is enmeshed in the mind as well as in the body. It is slowly forged with experience and requires motivation and drive for proficiency. Reason is neither pure nor completely immaterial. If Damasio’s theory is correct, it entails a reconfiguration of current sociocultural assumptions.
First, the author cautions that feelings do not override or weigh more importantly than reasoning just because they are part of the process. Accurately understanding the world still requires empirical verification and logical reasoning. However, acknowledging the embodied nature of the mind might encourage society to consider the vulnerability of “the world within” (233). Invisible injuries, such as those to Elliot’s brain, can still compromise rationality and the self.
Cartesian philosophy has many interpretations, one of which may even claim that Descartes only touted the superiority of reasoning without commenting on its precise origin. Whatever the case, Damasio believes that Descartes’ fundamental error was in his complete separation of mind from the biological organism. His philosophy remains influential in both research and practice, inherently pushing scientists away from understanding the mind through neurobiology or neurochemistry. As a result, many do not consider diseases that affect the mind but are invisible to the human eye as real and see human rationality as immaterial and immovable, when it is in fact fragile, unique, and finite. Damasio hopes that this changes in the future: His own vision paints the soul and spirit as complex and unique states of an organism. What dignifies and diversifies the mind and spirit is precisely that they are embodied.
Postscriptum Summary
The postscriptum offers a brief survey of the current situation in the medical field, both in practice and in schools. It paints a grim picture in which students are not taught about the normal mind unless they take classes on psychology, neuropsychology, or neuroscience. Similarly, medical schools instruct students on diseases of the mind (psychopathology) without ever delving into normal psychology. As a result, students graduate without a strong understanding of the concept of humanity (in other words without appropriate levels of sympathy for the patient), even though an established fact is that the efficiency of medical treatment is highly dependent on the patient’s overall attitude.
Cartesian bias has retarded the progress of neurobiology in Western medicine by several decades. In addition, it has significantly reduced the effectiveness of diagnosis and treatment of diseases of the mind. Damasio suspects that these shortcomings are what push patients toward alternative forms of medicine. Nevertheless, the author urges the continuation of research and is confident that he is on the right path.
Recent discoveries revealed that pain and pleasure are both necessary for an organism to operate efficiently. They are clear deviations from the body-state at base and are both innate dispositions. Their function is to properly configure drives and instincts, which can later develop into complex decision-making strategies. This is especially the case with pain, which Damasio believes is more efficient at steering people away from trouble. However, after further investigation, he began viewing pain as separate from suffering. Damasio retells the story of a patient rendered immobile with constant pain. After undergoing prefrontal leucotomy, he became relaxed and serene. When asked about his state, he replied that he still felt pain but was fine now. Damasio suspects that the brain could no longer engender suffering, even though his mind still mapped “images of pain” as part of his body landscape.
What prompted Damasio to write Descartes’ Error was his hope for insight into neurobiological knowledge to affect the shape of human destiny. He hopes that with greater understanding of the mind-body integrality, the field of medicine may develop humane and effective treatments to alleviate suffering.
Part 3, Chapter 9-Postscriptum Analysis
The final third of Descartes’ Error focuses on testing the hypotheses that Damasio proposed in Part 2 and explores his scientific methodology while establishing the plausibility of the somatic-marker hypothesis. These chapters are not as dense as previous chapters in their use of neurobiological terms but instead illustrate Damasio’s theory through practical tests. This is the final step in the standard scientific method.
Damasio exclusively dedicates Chapter 9 to describing the process and results of the skin conductance test and the gambling experiment on patients like Elliot who have prefrontal cortex injuries. Through the skin conductance test, Damasio confirmed that individuals in the Phineas Gage matrix were capable of primary but not secondary emotions, which corresponds to the somatic-marker hypothesis. The gambling experiments shed more light on this by demonstrating that in the face of uncertainty, Elliot and other patients with prefrontal cortex injuries were incapable of sensing or anticipating potentially bad outcomes. Compared to the control group, they continuously gambled at higher risk and consistently had losses at the end of the experiment.
These results reaffirm the somatic-marker hypothesis, which stipulates that the body associates certain situations with a particular emotion. This dynamic allows a certain level of instinctual anticipation: In a similar future situation, the individual recalls the emotion felt in the initial instance, and this biasing factor helps them avoid unpleasant or dangerous outcomes. As a result, even self-identified risk takers in the control group gambled less avidly than Elliot, who considers himself conservative and risk averse. Without knowing the rules of the game, the control group, aided by their emotions, learned to instinctually avoid risky situations and thereby minimize their losses. Elliot and other patients with prefrontal cortex injuries, however, despite being perfectly rational, could not rely on somatic markers to anticipate results and therefore chose immediate reward or immediate avoidance of punishment.
After confirming the plausibility of the somatic-marker hypothesis, Damasio turns to exploring its implications. Most notably, it means that the concept of the neural self becomes highly dependent on the capacity for the body to communicate its condition to the mind. Selfhood is therefore constructed and reconstructed from moment to moment based on the mind’s superimposing the image of the current state of the body over the image of its general state. Anosognosia, the neuropsychological condition that prevents people from recognizing their own disability, results from damage sustained to the neural self. In the final paragraphs, Damasio points out the fragility of the human condition and invites additional research on the topic of emotions and reason.
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