anatomy of the brain

How we make decisions is a subject of lively investigations in neurobiology. What is the anatomical substrate of decision making? Do we actually make a decision, or is it mostly pre-made for us by our own subconscious part of the brain? Which raises the related question: do we have any  free will, or are we totally preprogrammed by our genes, cultural background, and our personal history?

An anatomy lesson

The process of decision-making starts with thousands of circuits widely dispersed deep in the brain that have any relevance, however tenuous, to the decision at hand. The amount of information vying for attention even for the simplest decision is overwhelming. A lot of the stuff (about 85% of it) comes from previous experiences, cultural frameworks, social biases, even childhood memories, all deeply embedded in the subconscious. About 15% of the information comes from the neocortex, the outermost layer of the brain, where conscious rational thoughts take place. The first step in the process of sifting through the avalanche of data is to organize and classify the information. This is done by the right anterior cingulate cortex. Once the information is organized it is distilled into a manageable form and presented to the prefrontal cortex, the executive center of the brain. There the brain CEO weighs the info and makes the decision. It feels to us as if we made a conscious decision (“I am going to confront this bully of a boss”) never realizing that we were primed to make this decision a long time ago (“my dad always told me to stand up to bullies”, “it was embarrassing to have my mom intervene at school in my behalf”, “I wanted to be a lot more muscular when I grew up”, “my army buddies used to mock me”, “why am I so nerdy”, “why do women want to be ‘just friends’ with me?”). Such processes occur not only when we make small personal decisions. History is replete with examples of big national decisions that are largely subconscious, although ostensibly deep analysis was involved (“Dad didn’t finish the job in Iraq” “I’ve got to redeem the family honor”, “I was never appreciated by my parents”, “don’t mess with Texas”, “I am going down in history as an inconsequential President”).  How much of this process can be ascribed to deliberate, conscious, “free will”? Hard to quantify, but neurobiologically  speaking 15% won’t be off the mark. Pretty sobering thought.

You would think that if most of our decision-making is not conscious, there should be great interest in that “buried” part component. Consider the field of Economics. Until a few years ago economists built theoretical models based on humans as “economic man”, meaning that we are perfectly rational beings making all our decisions based on maximizing our benefit”. It took two psychologists, Daniel Kahnemann (of the Hebrew University in Jerusalem) and his colleague Amos Tversky (of Haifa University in Israel), to look at humans as something less than perfectly rational decision makers. And so was born the field of Behavioral Economics, which is all the rage in Economics today, and for which Kahnemann received the Nobel Prize in Economics in 2002 (unfrtunately, Tversky died before the prize was awarded). One of their great discoveries was people’s irrational aversion to risk. When confronted with the choice of taking little risk for little reward or taking a moderate degree of risk and gain a very large financial reward, they would opt for the low risk option. This risk- aversive behavior is apparently deeply rooted in our evolution. In the days when confronting a predator or a hostile band was a high risk proposition, the prize of survival went to the risk-averse. Financial behavior apparently was not a factor in natural selection in the Pleistocene period.

A paper in Psychological Science shines a new light on the dark world of our subconscious decision making. Boaz Keysar and his colleagues (all psychologists at the University of Chicago) used the Kahnemann games of financial risk/reward.  But they asked a seemingly strange question: Would you make the same decisions in a foreign language as you would in your native tongue? It may be intuitive that people would make the same choices regardless of the language they are using, or that the difficulty of using a foreign language would make decisions less systematic. In brief, they ran six studies, all showing that people who make decisions in a foreign language are less risk-averse. Why? The authors propose that thinking in a foreign language frees the decision making from much of the emotional and cultural “baggage” that we carry when we think in our native tongue. Neurologically, we use a lot more of our neocortex and less of the deeper structures where our past experiences and biases are buried.

I immediately found myself testing the hypothesis on myself, since English is not my native tongue; Hebrew is. Within seconds I came across words that carried heavy psychological meaning for me in Hebrew and were totally neutral in English. As an adolescent I used to belong to a leftist youth movement In Israel. Words like “capitalist” or “bourgeoisie” or “profit” used to carry a negative connotation. All capitalists where fat, mean-looking, heartless exploiters. Profit was ill-gotten unless you lived on a Kibbuz (a communal farm), and worked with your hands to make it. American culture and the buffer of the English language it interposed between my conscious and subconscious robbed any emotional content from these words. Make a tidy profit? Of course, where do I sign up?

Dov Michaeli, MD, PhD
Dov Michaeli, MD, PhD loves to write about the brain and human behavior as well as translate complicated basic science concepts into entertainment for the rest of us. He was a professor at the University of California San Francisco before leaving to enter the world of biotech. He served as the Chief Medical Officer of biotech companies, including Aphton Corporation. He also founded and served as the CEO of Madah Medica, an early stage biotech company developing products to improve post-surgical pain control. He is now retired and enjoys working out, following the stock market, travelling the world, and, of course, writing for TDWI.


  1. When I was a marketeer we were taught people make decisions emotionally not rationally. So this blog makes total sense to me. In meditation practice we are taught to think less and listen more. It seems that 85% of our thought process is repetitive and emotional. How do I increase rational thought and decrease emotional thought? It seems then I could increase my intelligence.

    • Jim
      Your real life experience about emotions’ role in decision making is right on the mark. It took scientists decades to catch up with your experience.
      I htink the best answer to your question regarding increasing rational thought and decreasing emotional thought can be found in David Brooks’s book “The Social Animal”: “The key to a well-lived life is to have trained the emotions to send the right signals and to be sensitive to their subtle calls.” In other words, you can’t reduce the emotional component, but you can consciously train them to respond in a good way.


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