Descartes’ Error

Descartes’ Error

Author: Antonio Damasio


The main assertion made by this groundbreaking book on human emotions is simply that our feelings are right at the centre of ‘the loop of reason‘, playing a positively influential role in decision-making and social behaviour (page xvi-xvii). The book’s main argument is that emotions are indispensable for making good decisions because gut feelings and intuitions serve as important sources of cognitive information (page xviii). The author’s contention, epitomised by his somatic marker hypothesis, overturns the conventional neuroscience paradigm that feelings have little, if any, constructive role in decision-making; on the contrary, his hypothesis argues that emotions are as important as attention and memory when it comes to making the right choices (pages 158-159, 166, 172, and 175).

Emotion. Jeff Hitchcock on Flickr.

The main foundation for the author’s somatic marker hypothesis are the lessons he gleaned from studying two unique patients, one historical and the other contemporary. The patient that contributed most to his understanding of the importance of emotions in decision-making was Phineas Gage; this was the railroad worker who sustained a brain injury when a tamping rod he was using to set up an explosion accidentally penetrated his brain and disastrously compromised his emotional control and his ability to make rational decisions. In what turned out to be the first insight into how emotions influence decision-making, the author’s reconstruction of Gage’s brain injury revealed that both his ventral prefrontal cortices were damaged by the penetrating injury (pages 3-11 and 22-23). These were the same brain areas that were damaged in the author’s own patient named Elliot who had a meningioma which compromised his prefrontal lobes. The consequence was that Elliot became incapable of making reasoned decisions, of managing his time, of keeping sight of his goals, and of learning from his mistakes. However, despite these remarkable impairments, the author noted that Elliot retained his intellect and skills, and maintained a ‘flawless memory for his life story’ (pages 34-38). 

By Polygon data were generated by Database Center for Life Science(DBCLS)[2]. – Polygon data are from BodyParts3D[1], CC BY-SA 2.1 jp, Link
The author’s observations of Gage, Elliot, and subsequent patients with damage to the ventromedial prefrontal cortices enabled him to demonstrate the way emotional deficits impair decision-making. He established that without emotions, the decision-making landscape is ‘hopelessly flat‘ and ‘cold-blooded‘, and this impairs the ability to assign values to options, an important stage in making correct choices (pages 45 and 51). The book explains that emotions function as an ‘automated alarm signal‘ which flags up the adverse consequences of options, and by ‘narrowing the field of viable options’ in this way, emotions increase ‘the accuracy and efficiency of the decision-making process’ (pages 160 and 173). Although emotions provide their decision-making information rapidly and unconsciously, the author asserts that their contributions are reliable as they are based on previous practice and past experience (page xix). And because the influence of emotions is ‘immense’, the author depicts emotions as ‘winners among equals‘ in the decision-making process (page 160).

A blackjack hand at the casino. Images Money on Flickr.

The author dedicated a major part of the book to describing the anatomical and functional foundations of decision-making and emotions. For example, the author demonstrated that the prefrontal cortex is suitably placed for decision-making because it receives inputs from both the brain and the body, making it singularly ‘privy to signals about virtually any activity taking place…at any given time’, in the mind and the body (pages 131-139 and 181-183). The prefrontal cortex is therefore acquainted with our feelings – the pervasive background overall pleasant or unpleasant state of the body ‘when it is not shaken by emotion’; our intuitions – the subconscious effect of inputs from the body; and our emotions – specific perceptions such as happiness, sadness, anger, fear, and disgust (pages 187-189 and 149-152). The book also maps out the brain structures and pathways which participate in generating the different emotions, for example, the limbic system structures such as the amygdala, the hypothalamus, the brainstem and the anterior cingulate – neural circuits which are ‘critical for survival‘ (page 118-119 and123).

Illustration of Brain Regions. NIH Image Library on Flickr.

The awareness that emotions significantly influence decision-making has profound ramifications for society in general, and health care in particular. The major implication is that the current Western approach to disease, rooted in the mind-body dualism propounded by the philosopher Rene Descartes, is flawed. The author, a neurologist, specifically blamed Western medicine for its ‘Cartesian-based neglect of the mind‘ which he said disregards the psychological consequences of physical diseases, and the physical impact of psychological disorders (pages 248-251). This ideology, the author goes further to state, has also hindered the development of effective management of diseases, and, by ignoring ‘the human heart in conflict’, it has indirectly contributed to the success of alternative medicine (pages 256-257). The author asserts that the impact of this ‘Cartesian split‘ on mainstream medicine, and on neurology particularly, has been to deny healthcare the ‘humanity with which medicine does its job’ (page 255). The author however acknowledged that the tide is changing and medicine is realising the importance of alleviating psychological pain, and it is beginning to understand that ‘how people feel about their medical condition is a major factor in the outcome of treatment’ (page 256 and 266).

Your mind has left your body. Bill Smith on Flickr.

The author supports the arguments he made in the book with reference to a wide range of research findings beyond his own studies. For example, he cited the evidence from several gambling and skin-conductance experiments which show that people with frontal lobe damage are unable to learn how to avoid bad choices, or to inhibit themselves from making risky gambles. These studies demonstrated that frontal lobe damage impairs decision-making by inducing a ‘myopia for the future‘, an  exaggerated tendency to focus only on short-term advantages (page 209, 221, 214, and 217-218). Other sources the author cited are experts such as Joseph LeDoux on emotions, and Daniel Kahneman on decision-making. He also made diverse references to the arts, such as Richard Wagner’s Tristan and Isolde, on the power of passionate emotions, and to William Shakespeare’s Othello, on the range of expressive emotions (pages XX, 121 and 130).

Inspiration. Hartwig HKD on Flickr.


This seminal book on the importance of emotions in decision-making gives an important insight into how the mind requires both reason and intuition to choose between options. It overturns the traditional view that emotions are hazardous to decision-making, and it places gut instincts at the centre of cognition. The author’s prose is conversational, and the narrative style makes it easy to follow the very academic subjects he expounds. His depiction of clinical cases and anecdotes is exhaustive, but many of the diagrams he used to illustrate his arguments did not seem to add more to the excellent text. Whilst some of the content is very academic, such as his discussion of the themes of dispositional representation and categorised contingencies, the author made great efforts to explain these concepts.

Overall assessment

This is an excellent book, exploring concepts that are central to all aspects of human life – decision making and social behaviour. It highlights the importance of emotions in the most important decisions we make, pointing out their benefits and downsides. The author extracted important and profound lessons for society especially with regard to how a poor understanding of emotions impacts on health. The book’s perspectives are important to medical practice, and I highly recommend it to all doctors.

Book details

Publisher, Place, Year: Vintage Books, London, 1994
Number of chapters: 11
Number of pages: 312
ISBN: 978-0-099-50164-0
Star rating: 5
Price: £5.43

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