The Mind within the Brain: How We Make Decisions and How those Decisions Go Wrong
A. David Redish
New York: Oxford University Press
363 pages
Paperback list: $35.00, Kindle $14.29
Publication date: July 13, 2013
There are a lot of books being published these days about brain research. A. David Redish adds to the mix a substantive work sure to spark debate. The Mind Within the Brain is not an easy read, drawing from multiple disciplines (including neuroeconomics!), each having their own vocabularies and methodologies. You don't want to try speed-reading this puppy. But it is worth a look. The author, a neuroscientist at the University of Minnesota, has a flair for explaining complex ideas, and he uses humor and personal stories to keep the lay reader interested. (He also has kindly included appendices for us neuroscience neophytes.) Know that Redish has done some important work here, challenging some of our assumptions about how the brain works and paving new ways for working with some of the most challenging problems involving the brain.
Redish argues that as scientists draw closer to comprehending how "the mind within the brain" makes decisions, solutions to such vexing and misery-causing afflictions like PTSD, dementia and addiction become real possibilities. Brain research today is a kind of last frontier. President Obama last spring introduced a $100 million research initiative to map the human brain, drawing comparisons to President Kennedy's goal to put a human on the moon in the 1960s. The Mind Within the Brain offers some intriguing ideas at the forefront of this frontier.
The centerpiece of the book is the author's theory of how humans (and many other animals) make decisions. The prevailing view, he argues, has been that we make decisions as "the conscious deliberation over multiple choices." Instead, Redish contends that humans (and other animals) behave according to "an interaction of multiple decision-making systems." The classic metaphor for decision-making has been that of a rider atop a horse -- the rider being the conscious "decider" trying to tame the unconscious desires and fears of the animal below. The author says a more apt analogy of the brain and its neurological system is that of a Toyota Prius, which has two types of power generators (gasoline and electric) as well as braking, steering and other subsystems. All of the systems are designed to work together to make the Prius go. With multiple systems operating at the same time optimally, the mind chooses which appropriate action to take, and like the Prius, if it is not operating optimally, the result can be an accident waiting to happen.
There are four decision-making systems according to Redish's model of the mind: reflexive, deliberative, Pavlovian and habit-based. The reflexive system has been hardwired into our bodies (spinal cord, peripheral nervous system and central brainstem) by evolution, he says; in fact, reflexive action is taken milliseconds before the brain is aware. When our hand touches a hot object, we pull back immediately -- our nerve fibers carry action potentials at a speed of 150 meters per second. The rapid speed is a product of our animal ancestors avoiding predators in the wild. Similarly, he says, insects like crickets and cockroaches have evolved a set of very small hairs on antennae on their tails. The hairs are connected to leg-muscle controls that enable them to flee from a threat, such as a stomping foot, in less than 20 milliseconds.
The second system, the Pavlovian, is the one we know from the Russian experiments in which dogs learned to salivate when a bell was rung at mealtime. It is different from an unconditioned reflex in that it is a learned behavior. The Pavlovian action-selection system works in response to a given situation based on an "emotional characterization" of it. Emotions, Redish says, are based in biochemical changes (heart rate, release of neurotransmitters, respiration) that comprise response sets that have been learned over "genetic timescales."
Pavlovian learning plays a role in an action-selection system, in which the unconditioned responses are actions learned over an evolutionary timescale. Imagine living on the savannah where there are lions that might hunt you. You can learn that the rustle in the brush predicts that a lion is stalking you and you can learn to run from the rustling grass, but you don’t get a chance to learn to run from the lion: you’ve got to get that right the first time.
The third action-selection system, deliberative, is the one we most often associate with being human (though other animals do it, as you will see shortly). The deliberative system is the "what would happen if," algorithmic process of the brain. It deliberates over decisions and is capable of complex planning and flexibility. It is useful for one-time decisions, Redish says, but is limited because it takes time and resources to process all of the possibilities. Deliberation requires complex processing of different memories, imagining possible futures and storing a map of possibilities. It is the kind of information processing and action selection that researchers are trying to replicate with artificial intelligence. Remember when Deep Blue defeated chess grandmaster Garry Kasparov in 1997? The computer was using one part of the deliberative system -- searching through seemingly countless scenarios. The human brain, however, does more than sort through algorithmic possibilities; it also "caches" information so that it does not have to sort through every possible scenario. Until recently it was generally thought that deliberative thinking is solely found in the human brain. Redish, however, cites experiments in which rats have exhibited future planning thinking in their navigation of mazes.
The last decision-making system, the author says, is the habit system -- simply learning the best action to take in a given situation. This is an automatic, stored response. Unlike the hard-wired reflexes, the habit system can learn to take any action, according to Redish. The habit system works on the abstract level learning caches of actions (like a particular route to work) and "chunked" motor actions (walking, playing a musical instrument). You may recognize the habit system when, as a commuter, you find yourself at your workstation and can't recall having driven there. (Or, more startlingly, he says, you go on a weekend errand and discover you have unconsciously driven to your work!)
Redish adds that the four decision-making systems are supported by four other systems that enable the decisions to be carried out: motor control to physically carry out the decision, perceptual processes for receiving and interpreting sensory information, situation recognition to deal with multiple stimuli and motivation, which takes into account our evolution-based needs as well as mediates our conflicting goals, desires and needs. With four processes for deciding and four additional support systems, you can see how complex the mind is and how it is possible that we can go so wrong ( which Redish calls "failure mode") in our decision-making.
Sometimes failure occurs due to physical damage to the brain. Redish offers the example of Phineas Gage, a railroad worker in the 19th century who had 13-pound, three-foot-long piece of iron blasted through his skull. In spite of the severity of the accident, Gage survived, living another 12 years. Much of his mental ability remained intact -- memory, physical and sensory abilities, intellectual and language capacities. However, the accident destroyed the prefrontal parts of his brain, leaving him unable to make decisions as well as recognize emotions. (His personality was said to be profoundly changed as well -- after the accident he was said to be profane, stubborn and impatient -- no duh!)
Fortunately having a piece of iron blast through your cranium is not something most of us have to deal with; however, we face other failure modes, such as addiction, emotional volatility and PTSD. To demonstrate the concept of failure mode, a term which Redish borrows from the engineering world, he proposes the analogy of the thermostat. The author says a thermostat is designed to perceive the external world, determine what needs to be done and then takes action -- but what if the thermostat is broken? Like a thermostat, parts of our decision-making brain may at times contribute to an internal representation of reality that may be incorrect. Abusing a drug can be a result of multiple failure modes:
There are several dozen different ways that this machinery can make the wrong choice—the Pavlovian system can assign increased emotional motivation to a drug, the Deliberative system can misjudge the expected outcomes of a choice, the Procedural (habit) system can overvalue or automate too quickly, the situation-recognition system can overseparate or overgeneralize situations, etc. Each of these different failure modes or vulnerabilities could have an effect of driving the addict to continue making the addictive choice.
Knowing how these systems are vulnerable can help the addict avoid relapse. For example, using self-control requires paying attention and energy, the author argues. Stress or fatigue can lead us to fall back into harmful habits that we have stopped. The wise recovering person will attempt to avoid vulnerability in the case of fatigue by getting rest. This holistic understanding of addiction reframes our understanding of self-control as something that is less a constant capacity and more like a "muscle" that can be more or less capable depending on one's physiological state. Because the brain consists of multiple decision-making systems, Redish says addiction treatment must "normalize vulnerabilities," that is, plan for the inevitable roadblocks to sobriety (as in the case of stress and fatigue mentioned above). Also, the complexity of systems' vulnerability requires that different treatments will be indicated for different kinds of addictive behavior and the failure modes they involve.
Of course, there does not need to be an identifiable pathology like dependency for a human being to encounter problems in the decision-making of the mind. Redish reminds us that we humans are narrative creatures, telling stories to make meaning out of our experiences. The problem is that "memories of the past are reconstructed, rebuilt each time anew and not necessarily correct," the author says. We do this because the mind's work is contingent on so much input -- reflexive, Pavlovian, deliberative and habitual, not to mention sensory and valuative data -- the mind cannot tolerate an indeterminate and chaotic state; so we develop "stories of our lives" which may not be entirely true or helpful. Redish says a colleague discovered this truth in a dramatic way working with heart patients who have internal defibrillators or ICDs. An ICD can save the life of a person who has an irregular heartbeat by detecting the irregularity and shocking the heart to return to a normal rhythm. However, the firing of the ICD can also be an extremely negative experience -- the stricken person is often shocked sometimes multiple times with greater and greater voltage, resulting in a traumatized mind making strange associations:
These ICD patients have the strangest negative associations with things in their lives. (Redish's colleague) wanted to know what made the patient decide that the fork was the culprit and not the spoon, or that it was the act of sitting in a chair and not laughing with one’s friends.
Redish's view of the mind within the brain reminds the reader of the Buddhist understanding of no self, the mind serving merely as a witness to the many changing sensations and thoughts happening from moment to moment.
The Mind Within the Brain has implications for some of humankind's deepest mysteries. If there is no mind apart from the overlapping operations of the decision-making brain, what does this say about religion and morality? (The author touches upon both topics.) Will there be robots someday like us with "a mind of their own"? (Redish seems to think so.) What makes us uniquely human when animals seem to have similar decision-making capacities? Redish has laid out a fascinating model for studying these and many other questions that our amazing but vulnerable minds yearn to answer.