I am, therefore I think

Antonio Damasio takes exception to Descates’ observation, “I think, therefore I am” in his 1994 book ‘Descartes’ Error’. The overarching theme of the book is exploration of the concept of self, and identifying the physiological processes that underlie decision making of individuals.

Rather than a simple exploration of an idea, Damasio methodically takes his readers through the scientific process involved in addressing any problem. We start the book with identification of the issue at hand, introduction of the various players, development of a hypothesis, designing of experiments to test it and finally interpret the results to inform the greater community of the inferences.

The first third of the book concentrates on case studies. We are introduced to various patients and the brain lesions that have impaired their emotional and decision making capabilities.

Without lowering the level of discourse or easing up on the use of scientific jargon, Damasio provides a platform for teaching his audience about the overall anatomy of the brain, the difference between the cortical and sub-cortical structures. He then dwells into the structure, function and connectivity of the neurons, their biochemistry about the neurons, their parts, roles and finally the neurochemistry of the brain.

As we go from one patient to another, we learn about different brain structures and how lesions or injury to these parts are associated with different symptoms.

Damasio spends a decent amount of time explaining the molecular basis of behavior. Not only do we learn about the influence of the brain on the body and that of the body to the brain. Additionally, he explains how human control over our instincts as being a possible outcome the brain circuits that have evolved to learn acquired social rules.

Where Damasio shines the best in his book is the distinction that he draws between emotion and feeling. While emotion is the body state, representing the electrical and chemical make up of the body at a given time, feeling refers to the cognitive juxtaposition of the body images with context.

With these ideas in mind, we are next introduced to the concepts that underlie Somatic Marker Hypothesis, the theory of mind that analyzes the decision-making processes of our brain. Briefly, when presented with a stimulus, a thought or a future scenario, images are created in our brains, which result in somatic (body) changes manifested as something as simple as rising of the blood pressure. Presentation of any stimulus or a real life situation with social consequences thus leads to a possible physical change that can show our emotions.

He finally concludes the second portion of his book explaining how the somatic markers lead to inherent biases within the brain, which explains the different behaviors and risks that people are ready to undertake.

The third and final part of the book deals with experimentation to test the somatic marker hypothesis that was developed in the previous chapter. We learn of experiments designed to simulate real world complex decision making process. The results from these show how brain injury can lead to an impediment to sound decisions. This is used as a proxy for the bad social and economical decisions that patients of brain damage have shown in their lives.

All of this sets the stage for Damasio to explain his choice of the title. Descartes’s observation was based on his belief that the idea of self originates from the existence of a working brain and that it is the brain that distinguishes us from other animals. However, Damasio through his somatic marker hypothesis lays shows the opposite, thus correcting Descartes’ to “I am, therefore I think”. We learn of the constant feedback loop between the body and the brain that underlies our perception of self and that of others. Any breakdown within this loop leads to an altered, incomplete view of what it means to be a human being.

Sitting at the intersection of psychology, neuroscience and philosophy, I find this book highly enjoyable and recommend it book to anyone who wishes to explore what it means to be a human and if we can ascribe certain aspects of humanity to other species.