Biology Magazine

The Feeling of Rationality

By Realizingresonance @RealizResonance


Elliot’s case is peculiar from a psychological perspective and tragic from a personal one. A benign tumor the size of a small orange was successfully removed from where it had grown in his midbrain above his nasal passages. Unfortunately portions of Elliot’s frontal lobe were damaged and had to be removed as well. The tragic consequence was that he retained most of his physical and mental faculties, giving the outward impression of being capable, except he was also systematically unable to make the proper decisions for himself. Elliot was intelligent according to objective testing, yet he was seemingly idiotic when faced with real life situations. He could not keep a job, failed in his marriages, and exasperated his loved ones again and again with his astoundingly poor choices. A localized trauma to the prefrontal cortices, predominantly in the ventromedial sector, had robbed Elliot of his ability to make social decisions without apparently ruining his reasoning intellect.

Antonio Damasio’s answer to the puzzle of why Elliot can display abstract reasoning on the one hand, and still not be able to apply that reasoning when it matters socially, is the Somatic Marker Hypothesis. Damasio suggests that what we think of as higher level, human reasoning is not localized to a particular part of the brain, like the old notion of a tiny homunculus. Rather, the decision making process is assembled out of an interplay between our minds and bodies, coordinating older, non-learned brain activity, like drives and instincts, and newer brain functions, like language and logic. Damasio (128) argues, “Nature appears to have built the apparatus for rationality not just on top of the apparatus of biological regulation, but also from it and with it.”

According to Damasio, innate emotional responses to stimuli, like primitive fear and pleasure, are correlated with particular bodily sensations, which through memory and learning become associated with various responses to previous social situations. When remembering past experiences the images recalled are not just visual, but also trigger milder versions of the somatic, or bodily, sensations tied to them. An example of this effect at work can be experienced in the familiar sick sinking feeling one gets in the gut when recalling a dreadful experience, like receiving a poor revue by a boss at work. When confronted with every day choices, the images that attach to the potential outcomes of those choices come equipped with somatic markers which automate, or shortcut, the decision making process by strongly encouraging or discouraging a choice through body signaling. We are reminded of why we do or do not want to do a thing, without dwelling on it or even realizing. The quasi-emotional tingling of intuition facilitates reason, rather than the traditional view that feelings cloud reason. Damasio theorizes that Elliot is missing the impulses that signal to normal people about the adverse consequences of our choices before we make them.

In order to test the Somatic Market Hypothesis, Damasio and his colleagues researched similar and related cases. They also developed controlled experiments. Damasio’s evidence is presented below:

E1: Elliot had localized trauma in the ventromedial sector of his prefrontal cortices.

E2: Elliot displayed a loss of faculties for proper decision making which resulted in many unfortunate social consequences, and he consistently failed to learn from these mistakes.

E3: A loss of outward emotional expression, except in fleeting outbursts, and apathy towards his own personal circumstances were also new symptoms of Elliot’s condition.

E4: In cognitive testing Elliot demonstrated no loss of intelligence and an apt awareness of social convention, and when discussing hypothetical scenarios and his reasoning ability appeared intact.

E5: The historical cases of Phineas Gage and others illustrate the same correlation between prefrontal trauma and pathology.

E6: Stroke victims with damage in the same areas of the brain can develop a neurological condition known as Anosognosia, which is an inability to recognize ailments, such as their own partial paralysis, and this has also been correlated with an inability to make appropriate personal decisions.

E7: In controlled testing, patients with prefrontal damage showed a lack of the skin conductance response experienced by control groups when viewing images of horrific scenes. This was associated with the awareness in at least one patient that they no longer felt the way they used to feel when seeing such negative images.

E8: In additional tests involving a gambling game, patients with prefrontal damage failed to learn which strategies of risk management would avoid drastic losses, while the control subjects picked these up quickly in the process. This was also correlated with a lack of skin conductance response associated with the experience, and anticipation, of gambling losses exhibited by the control subjects.


T0: Damage to the ventromedial sector of the prefrontal cortices, as in Elliot’s case, can result in a person’s loss of awareness s of somatic markers which impedes their ability to make sound rational decisions.


T’0: Human decision making is automated by somatic responses which are provoked by bodily imaginings of potential outcomes.

Potential rival conclusions for the evidence presented by Damasio are similar to the alternatives that face Evolutionary Psychology in general, which I think is an approach that is in turn supported by the Somatic Marker Hypothesis. The traditional view is that rationality is opposed to emotions, and suggests decision making is best when one can coldly apply a cost/benefit analysis without the burden of feelings and intuition. Mind/Body Dualism is an alternative which Damasio explicitly rejects as well, as is evident in that he named his book on the subject, Descartes’ Error. I have ranked the possible explanations below:

T0: Somatic Marker Hypothesis

T1: Rationality and Emotion are Opposing Cognitive Forces

T2: Mind/Body Dualism

Damasio’s hypothesis is the best explanation for the evidence provided. Dualism fails because it has no answer for the puzzling cognitive conditions associated with prefrontal cortex damage, without suggesting that those parts of the brain are the conduit between the body and only the part of the soul responsible for social reasoning. This requires an ad-hoc explanation for the composition of the soul and degenerates into fanciful speculation and contradiction, since it makes no sense for an insubstantial thing to have specialized parts. Damasio is also successful in promoting the idea that pure intellectual power alone is insufficient to account for human reasoning, and that instincts, drives and emotions are an instrumental factor in sound decision making. The Somatic Marker Hypothesis is thus a counterintuitive way to think about intuition, at least relatively speaking.

Jared Roy Endicott

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Works Cited

Damasio, Antonio. Descartes’ Error. New York: Penguin Books, 1994.

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