ACSBlog: The Blog of the American Constitution Society

by Kent Greenfield, Professor of Law and Law Fund Research Scholar, Boston College Law School & Distinguished Faculty Fellow, Center on Corporations, Law & Society, Seattle University School of Law

News from the world of science: a symptom of a certain kind of brain injury is that the victims end up thinking like economists.

Let me back up for a moment.

One of the most welcome developments in the legal academy over the last decade or so has been the decline of the law-and-economics movement.  Undoubtedly one of the most influential “law and” movements over the last quarter century, its first popularizers were heavily embedded in the neoclassical school of economics, which bases its predictions on the so-called “rational actor” theory of human behavior.  Humans are assumed to make choices based on a cost/benefit analysis, maximizing their own utility.  Adherents to law-and-economics theory have applied that assumption in crafting rules in areas as diverse as criminal law, corporate law, and family law. 

The problem, of course, is that the economists’ view of rationality is ridiculously narrow – so narrow that Judge Posner could admit in his Law & Economics text that “it would not be a solecism to speak of a rational frog.” 

Especially over the last decade or so, the neoclassical version of law and economics and the rational actor theory on which it is based has been attacked from several sides, both from within economics and without.  So-called behavioral economics has been especially influential, deconstructing the rational actor theory using insights from psychology, providing a much more sophisticated (if messier) account of human behavior.  These more sophisticated models of human behavior take into consideration bounded rationality, limited willpower, as well as a richer definition of self-interest.  Study of actual humans show that choices are malleable and easily manipulated, preferences can be created and destroyed, and individuals in fact make decisions based on emotions and principles other than utility maximization.

One of the paradigmatic “tests” that behavioralists use is the so-called ultimatum game, where one person is given an amount of money and told to propose a split with a partner.  If the partner rejects the proposed split as too low, neither person gets any money.  The economically “rational” thing for the partner to do is to accept any proposed split, since getting something is better than nothing.  But as it turns out, most partners reject deals they consider too unfair – they would rather get nothing than let the other person get an unfair amount.  These games have been tried throughout the world – I have tried them in my own classroom – and the results are remarkably consistent.

Another test that behaviorists use is to ask people to imagine their behavior is a range of hypotheticals.  One set asks about a runaway boxcar about to hit a group of five workers.  When asked whether they would flip a switch to divert the train onto another spur, killing just one worker, most people say that they would.  But when asked if they would push someone in front of the train to stop it from killing the five workers, most people say no.  The two are identical from a strict utilitarian point of view, but most human beings (me included) see a difference.

In this context, two recent New York Times articles caught my eye.  Both go beyond psychology to the actual physiology of the brain.  Jeffrey Rosen’s March 11 Times Magazine piece on “Neurolaw” referenced a “remarkable technique” called transcranial magnetic stimulation (TMS), which can stimulate or inhibit certain sections of the brain, temporarily altering what people think and feel.  Experimenters at the University of Zurich had people participate in ultimatum games, while TMS disrupted portions of their prefrontal cortex.  Subjects whose prefrontal cortexes were disrupted tended to accept low offers, while those subjects whose brain activity was not disrupted tended to reject them as insulting (as is typical).  The subjects whose brain activity was disrupted “were able to suppress their indignation and to pursue the selfishly rational conclusion that a low offer is better than nothing.”

Even more fascinating was Benedict Carey’s March 22 article “Brain Injury Said to Affect Moral Choices.”  Scientists studying people who have suffered brain damage to a part of the prefrontal cortex have found that they make decisions with less compassion and with more utilitarian “rationality.”  The scientists asked the subjects questions such as the runaway boxcar hypothetical.  Those with the injuries were twice as likely as those with undamaged brains to push someone in front of the train.  The damaged area of the brain, the scientists hypothesize, “put a finger on the brain’s conscious, cost-benefit scale weighing moral dilemmas.”  Those without proper brain function in that area end up making decisions with a more “utilitarian cost-benefit analysis.”

These findings are almost too sweet for those of us who rail against the constrained view of human nature contained in the mainstream law-and-economics literature.  Those humans who think and act like economists predict are those who suffer from brain damage, or those for whom brain damage can be temporarily simulated.  To be fully human is to act with spite, compassion, confusion, love.  Economists may not understand this, but the rest of us do.