Please don’t be confused. The topic of The Motivated Brain is still motivation and how neuroscience can add to our understanding of it. But for today I’d like to arrive at this topic through a circuitous route: NASCAR. In particular, consider for a moment what it means for a racecar to accelerate. One way to think about it is like a physicist would, and to describe acceleration in terms of the abstract concepts and rules such as velocity, distance, and time. Another way to think about it is like a mechanic would, and to characterize acceleration as a product of mechanical objects such as gears, pistons, and axels and their interactions. The distinction between how a physicist and a mechanic thinks about acceleration contains some deep insights into one of the most important debates in neuroscience and psychology right now, which is about the mind, the brain, and how the two relate.

On one extreme of the mind-brain debate are people who argue that the mind and psychological concepts such as self and emotion are far enough removed from the brain that nothing useful can come of studying it. This stance is similar to the one physicists take on acceleration. In this view, which I’ll caricature as the “dualist” perspective, the conceptual level of analysis prevails to the exclusion of the physical. On the other extreme of the debate are people who argue that the brain directly gives rise to the mind, so studying the brain can reveal everything about psychological concepts. This argument is akin to how mechanics view acceleration. It assumes that understanding the physical world will explain the conceptual one, which I’ll caricature as the “reductionist” perspective.

I like the physicist vs. mechanic analogy for the mind-brain debate because it reveals the absurdities of both extremes and points to a clear third perspective. Take the extreme dualist position first. Sure, you can explain acceleration in the abstract as change in velocity over time. That abstract rule applies to NASCAR racers, but it applies just as well to any other object that accelerates, too. That would be fine if we are interested in understanding acceleration in general, but different ways of generating acceleration, for example using a combustion engine versus a trebuchet, will cause radically different trajectories. If we’re interested in the human mind rather than minds in general, then we’ll want to know something about the human brain. The extreme reductionist perspective is no less silly. A good mechanic can tell you exactly how a given car accelerates and can even build something that accelerates out of a bunch of individual parts that don’t. But to say that the engine is acceleration doesn’t make any sense, and knowing all about the engine tells you nothing about how other factors like resistance can affect acceleration or how that car’s ability to accelerate relates to those other factors.

David Brooks recently drew popular attention to this debate in a New York Times column in which he came down mostly on the dualist side. He rightly noted that there is not a one-to-one relationship between mental states and brain states (just like a racecar can achieve the same velocity in two different gears), and arrived at the typical bromide that multiple levels of analysis are needed to understand the mind. In the terms of my analogy here, it takes a physicist and a mechanic to explain how a NASCAR racer accelerates. But I think we can come up with a much more specific answer to the question of how the mind and brain are related, and one that also suggests a research agenda that moves the debate into new territory.

The approach I take to answering that question is more pragmatic than either of the two extreme camps. After all, good science strives to answer questions that are too important to be limited by mere methodology. In my work (and fantasy life), I’d rather be a NASCAR driver than a mechanic or a physicist. If my car is broken, I call a mechanic. Neurosurgeons and psychiatrists have been successful at treating certain mental illnesses for years using mostly mechanical interventions. If I’m trying to learn how to design a better car from first principles, I call a physicist. Psychologists made enormous headway on the ever-elusive challenge of motivating behavior change using self-related concepts years before neuroimaging came into vogue.

What’s the point in asking whether a mechanic or a physicist can tell you more about acceleration? The important question is being able to identify when one or the other or both are useful. The new field of translational neuroscience embraces this utilitarian approach. Using the NASCAR metaphor, this field seeks to learn how to make racercars faster, safer, and more cost effective. For example, my colleagues and I recently wrote a paper describing a translational neuroscience approach to improving self-control in which we argue that existing (psychological) interventions are effective, but can be made even more so with additional tweaks from knowledge gained from neuroscience. Brain imaging should have no special status in psychology, but neither should questionnaires, laboratory experiments, or any other single type of data. But that doesn’t mean there aren’t times when one contains more information than another—sometimes the best tool is a screwdriver and other times it’s a pencil. The best thing the field can do now is figure out when to use which.

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