Neurolaw is all the rage these days. The lure to explain behavior and social norms such as free will under the lens of reductionist biology abounds. And there is no question that the wealth of information about brains and behavior has vastly increased during the past twenty years. Yet the disparity between what is truly known about the link between biology and human behavior and the normative claims populating legal and science scholarship is breathtaking. Often ignored is the extreme complexity of the human mind and the infancy of the methods used in examining brains and behavior. Several recent articles highlight this simple and important fact.
Addiction as Voluntary
A recent study in the journal Neuron is making some waves (also covered in Scientific American Mind). The article Cocaine but Not Natural Reward Self-Administration nor Passive Cocaine Infusion Produces Persistent LTP in the VTA suggests that the chemical and neuronal changes seen in the brains of people who abuse cocaine may only occur when the drug is ingested voluntarily. While the study was conducted with laboratory rats, it's worth noting that most neuroscience studies also employ rodents to study structural changes in the brain. And this is but one study, but it is a powerful one insofar as it suggests that addiction may not result only by exposure to substances themselves. Rather addiction likely involves salient psychological choices on the part of the drug abuser. Such evidence stands in stark contrast with the pleas of modern mental health to view addictions only as mechanistic outputs of the brain.
What We Don't Know About Brain Scans
There's been a lot written about brain scans and what they reveal about human behavior. What is often less discussed is what is not known about how brain scans work and the assumptions that these technologies utilize to arrive at their compelling pictures. The brain scans in question are not structural ones (i.e., the ones your doctor might prescribe if you had, say, a tumor), rather what is in question are functional brain scans (also known as fMRI). These scans are premised on their ability to detect increased bold use by neurons (know as the BOLD technique). The idea is that increased blood flow shows increased neuronal activation. Yet the mystery of fMRI has always been where does the BOLD response come from. A recent paper in the Proceedings of the National Academy of Sciences appears to answers that question (also profiled in Scientific American Mind). Yet as noted skeptic Michael Shermer (and others) discuss, interpreting brains scans remains a tricky business.
Ultimately, neuroscience can tell us a lot about our brains, but it's limited in what it can tell us about our humanity. That's a lesson many scholars need to learn.