Decisions and the Brain

What Is a Decision?
In order to be able to scientifically measure decision-making, we define decisions as "taking an action." There are multiple decision-making systems within each of us. The actions we take are a consequence of the interactions of those systems. Our irrationality occurs when those multiple systems disagree with each other.

The Tale of the Thermostat
Your brain is a decision-making machine, a complex but physical thing. Like any physical process, there are multiple ways in which decisions can go wrong. Being a physical being does diminish who you are, but it can explain some of the irrational choices you make.

The Definition of Value
Value measures how much one is willing to pay, trade, or work for a reward, or to work to avoid a punishment. Value is not intrinsic to an object, but must be calculated anew each time. This produces inconsistencies, in which different ways of measuring value can produce different orderings of one's preferences.

Value, Euphoria, and Do-It-Again Signal
Pleasure and value are different things. One can have pleasure without value and value without pleasure. They are signaled by different chemicals in the brain. In particular, the brain contains a signal for "better than expected," which can be used to learn to predict value. The lack of expected reward and the lack of expected punishment are separate processes (disappointment, relief) that require additional neural mechanisms.

Risk and Reward
Defining decision-making in terms of action-selection creates the potential for decisions that are illogical from a value-based perspective. The mammalian decision-making components, which can produce conflict between action options.

The Decision-Making System

Multiple Decision-Making Systems
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Reflexes
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Emotion and the Pavlovian Action-Selection System
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Deliberation
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The Habits of Our Lives
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Integrating Information
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The Stories We Tell
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Motivation
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The Tradeoff Between Exploration and Exploitation
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Self-Control
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The Brain with a Mind of its Own

The Physical Mind
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Imagination
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Addiction
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Gambling and Behavioral Addictions
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Post-Traumatic Stress Disorder
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Computational Psychiatry
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The Human Condition

What Makes Us Human?
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The Science of Morality
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The Conundrum of Robotics
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