MPA First Friday Forum Presentation: Taking an engineer’s viewpoint on dysfunction in decision-making

On Friday, December 5, 2014, Dr. A. David Redish presented at the Minnesota Psychological Association’s First Friday Forum. The title of his presentation was, “The Mind within the Brain: Implications for Psychology and Psychiatry.”  He presented new ideas from his new book titled, The Mind within the Brain: How we make decisions and how those decisions go wrong.  Dr. Redish has provided a summary below.

At the MPA’s First Friday Forum in December, 2014, I presented a new perspective on psychological and psychiatric dysfunction – if we understand the underlying processes of how we interact with the world (including with each other), then we should be able to identify how and where those processes can break down and how better to treat those breakdowns.  These ideas arise from the burgeoning field known as “Computational Psychiatry” which uses information processing (computation) to connect neuroscience (mechanism) with psychology (behavior).   The presentation concentrated on two new ideas – first, the concept of failure mode, and second, a careful identification of the processes underlying decision-making.

The term failure mode comes from engineering and is about identifying the weak links in a system.   For example, when a bridge collapses, we want to know what allowed the bridge to collapse.   If we know that there are weak gusset plates and that the bridge cannot take the weight we expect, then we can strengthen those gusset plates and we can limit the weight on the bridge.   Similarly, a computer virus accesses processes within the operating system of your computer by finding code that can be executed in unexpected ways.   Knowing where the failure modes of a system are allows us to prevent and treat those potential dysfunctions.  But this means that if we want to understand how the human decision-making system can break down (where the failure modes are), then we need to understand how humans make decisions.

We start from a careful definition of decision-making as action-selection – any time one takes an action, we will say that one has made a decision.   This works both for simple actions (hitting a baseball) and more complex actions (where to go to college).   Even getting married is, in the end, an action – eventually you and your partner stand in front of a community and say “I do” and the community agrees to treat you and your partner differently.  What is interesting about this definition is that we can now look at information processing and ask How did you come to that decision?

Looking at the information processing of decisions, we find that decisions depend on an interaction of three informational components – one’s past experiences (memory), one’s interpretation of the current state of the world (perception, recognition of the situation), and one’s goals (motivation, needs, desires).  But it turns out that there are different ways that these three components can be processed to select the action.

The key is to look at the computations that they need to perform.   For example, one way to make a decision is to deliberate over possibilities.   Deliberation entails a serial imagination and evaluation of future outcomes.  Deliberation is very flexible (knowing that doing something would lead to a consequence does not require one to act on that knowledge), but is also slow and effortful (imagining that future takes time and computation).  If one is going to act the same way every time, one could learn to “categorize-and-act.”   This second system we call the procedural system because it entails slowly learning action sequences which can be executed quickly (like hitting a baseball) in response to specific situations (a pitch over the plate).   Both the deliberative and procedural systems are learned over the course of a single person’s life (think practicing to hit that baseball), but there are two additional action-selection systems that depend on learning that occurred beyond a single lifespan or individual.   One of those systems is the reflex.   By our definition of decision-making as action-selection, a reflex is a decision-making system – it has been learned evolutionarily and has only a limited range of learning that can occur within a given person, but your reflexes are different from a cat’s, and that is part of what makes you you.  The fourth system I call Pavlovian because it is what Pavlov’s dogs were doing – the Pavlovian action-selection system is about species-specific behaviors that you learn to release at the right time.   For example, you don’t have time to learn to run from the lion – you have to get that right the first time.   However, the Pavlovian system can learn that there will be a rustle in the grass when the lion is stalking you, become fearful of that rustle in the grass, and decide to “run!”, but the Pavlovian system cannot learn to do jumping jacks in response to that lion.  One particularly interesting thing is that much of human social interaction arises from this Pavlovian system (species-specific behaviors released in certain situations, think laughing with your friends).  There are also support systems that are needed – how do we actually act (we walk), how do we perceive (we perceive objects not stimuli), how do we decide what motivates us (what are our needs and desires), and how do we define the state of the world (we create a narrative for ourselves).   Each of these support processes also has underlying failure modes that can appear in an individual, and each of these support systems can be a target of treatment.

What is interesting about this machinery is that all of the different fields that study decision-making (neuroscience, psychology, psychiatry, sociology, robotics, economics, computer science, etc.) have come to similar conclusions about the multiplicity of decision-making processes.   Importantly, the fact that we are beginning to understand how decision-making happens within the human brain does not preclude the existence of mind.   Yes, we are physical brains, that’s who we are.   But we still also are minds – the mind is the brain.   One of the most interesting consequences of this focus on these multiple decision-making systems is to look at ourselves as these multiple, interacting decision-making processes.   Part of what makes me different from you is that my Pavlovian system is different from yours.   When you fall in love, it’s you who has fallen in love (love is a very Pavlovian system), not some separate being hidden within you.   When you make the basket in a basketball game, that’s you making the basket (sports is a very procedural system), not some other being.   A sports star gets “in the zone” not “out of body.”  These are the things that make us human.  We are not superficial surfers riding an underlying wave.  Nor are we charioteers trying to control wild horses.   We are the wave and the surfer.   We are both the charioteer and the horses.  To quote Walt Whitman’s Song of Myself, “I am large, I contain multitudes.”

A. David Redish, Ph.D., is a Distinguished McKnight University Professor of Neuroscience at the University of Minnesota and the author of the new book The Mind within the Brain: How we make decisions and how those decisions go wrong.  


Redish, A. D. (2013) The Mind within the Brain: How we make decisions and how those decisions go wrong. Oxford University Press.

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