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New book peers deep into the brain to understand how we make decisions

Have you ever wondered why human beings do the things we do? Or why our actions are often at odds with our stated intentions? These questions are the subject of a new book by A. David Redish, Ph.D., a professor in the Department of Neuroscience at the University of Minnesota.

In his book, The Mind Within the Brain: How We Make Decisions and How Those Decisions Go Wrong, Redish explores the complexity of how we make decisions and how our brain processes information.

Health Talk sat down with Redish to learn more about his new book.

HT: Tell me a little more about The Mind Within the Brain

ADR: One of the main points of the book is that making a decision is about processing information – it’s about using your past experiences to figure out how to take the right action at a given time.  It turns out that there are multiple ways to process that information which ends up creating different “decision-making systems” within you.

For example, deciding which college to go to (a slow and complex deliberative decision) is a very different process than deciding whether or not to swing at a baseball (a fast procedural decision). And both of these are different from the emotional decision of whether you like a painting or a friend. Each of these systems turns out to use different parts of your brain to process information about the world in different ways.

The other interesting thing is the fact that we are physical brains means that our decision-making systems have “vulnerabilities” or “failure-modes.” In a sense, this is taking an engineer’s view of the mind and the brain – understanding how something works allows us to ask “What can make the system work incorrectly?”  This leads us to a new view on addiction, gambling and other psychiatric problems such as PTSD as the consequence of break downs in the system.

Most importantly, being a physical brain does not diminish our ability to be human or our ability to be conscious or to have free will.  It merely provides a more complete description of what it means to be a conscious human being.

HT: So, what is a decision?

ADR: One of the problems with the field of decision-making is defining it in the first place. I started from a simple definition of decision-making as the process that “selects an action.” Although this sounds simple, I mean it to include both simple actions like deciding to walk to the fridge to get milk, complex learned actions like deciding to hit a baseball or throw a pass to a receiver, and complex deliberative actions like deciding where to go to college.  Defining decision-making in this way allows us to ask the neuroscientific question of “How do we decide to take a given action?” and “What is the process that underlies it?”

HT: How do our brain’s decision-making systems work?

ADR: The key to the book is the idea that there are multiple decision-making systems that work in tandem with each other.   They can be separated based on the information processing that they do.  In the book, I lay out four action-selection systems – a deliberation system, a procedural (think sports) system, a Pavlovian or emotional system, and (since any action is a decision) your reflexes are also an action-selection system.  In addition, we need to include four support systems – our perceptions, the actions themselves, our motivations, and finally, a “situation-categorization” system that recognizes the situations we experience.

HT: Knowing all this, why do we make irrational decisions?

ADR: I think the better question is “Why are we inconsistent?”  Irrationality assumes that there is a rational goal that we are striving for.

Inconsistency is a direct consequence of having multiple decision-making systems competing with each other. Sometimes we act deliberatively, taking time to think long and hard about what we should do, while other times we act emotionally (driven by the Pavlovian system) or by letting long-learned actions go (driven by the procedural system). It is important to note that each of these processes have their advantages and their disadvantages. A soldier reacting violently to a surprising touch on the shoulder is misusing the procedural system; but that same system may have kept that soldier alive in war and it is the same system necessary to play a musical instrument. A kid overeating Halloween candy is misusing the Pavlovian system; but that same system turns out to be necessary for appropriate social interactions. Even deliberation is not always a good thing. Take Hamlet, for example, who deliberated too long before acting.

HT: How were you able to unlock some of the brain’s mysteries regarding decision-making?

ADR: A large part of the issue for me personally has been the work that’s been done in my lab and others over the last few years looking at how non-human animals (rats in our case) make decisions.  These animals make decisions in ways that are remarkably close to humans. For example, we now know that rats can deliberate over choices, imagining the possibilities and evaluating those possibilities.  Because we’ve been able to see the actual information processing happening in these animals making decisions, we’ve been able to connect that to how humans seem to be making decisions.

HT: Finally, how did using multiple disciplines help lead to your conclusions?

ADR: Decision-making is a very large field with contributions ranging from psychology, robotics, economics, neuroscience, to neuroeconomics and computational psychiatry.  Each of these fields has a different set of tools that allows a different perspective on the problem.  What’s remarkable (I think) is how similar the conclusions have been from these different perspectives.

You can pick up a new copy of Redish’s book by visiting Amazon or Oxford University Press.

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