The Neuro-Scientific Basis of Morality
Genetic predispositions combine with environmental stimuli to produce ethics.
Posted Jun 04, 2019
In deriving foundational principles of morality, Immanuel Kant declared, “the ground of obligation must be looked for, not in the nature of man nor in the circumstances in the world in which he is placed, but solely a priori in the concepts of pure reason.”
Patricia Churchland, professor emerita of philosophy at the University of California, San Diego and author, among other books, of Neurophilosophy: Toward a Unified Science of the Mind-Brain, does not agree. Morality, Churchland claims, “does not and cannot emerge from pure logic alone,” or from laws derived from religion.
In Conscience, Churchland draws on recent scientific research to demonstrate that genetic predispositions combine with environmental stimuli to produce ethical systems. The path from biology to morality runs along these lines: Genes dispose us to be social animals. Evolution favors this development. Human beings bond with others with varying degrees of self-sacrifice. The circuitry supporting sociality, self-care, and social norms begets conscience.
Neurobiological data, Churchland acknowledges, does not tell us which ethical option should be preferred. Nor does it tell us precisely how neural networks regulate behavior. But the evidence does support the conclusion that wiring that is genetically ready at birth stimulates a disposition to care, which in turn produces a motivation to acquire the social practices—table manners, food sharing, respect for the flag, marriage, slaveholding—of the community. “Once learned,” Churchland writes, “social norms become part of a developing extended neural network, in cortex as well as subcortical structures.” Of course, some individuals challenge social norms. And psychopaths do not abide by them. But these responses, Churchland suggests, can also be explained by differences in the brain.
Informative, accessible, and engaging, Conscience introduces readers to studies in genetics, evolution, psychology, anthropology, and philosophy that examine interactions between nature and nurture. Many of them will be of interest to readers of Psychology Today. Rooted in the “rich connections” between the basal ganglia, the frontal cortex, and the hippocampus, reinforcement learning “is a marvel,” Churchland points out. In addition to Pavlovian conditioning, instrumental conditioning through reward and penalty prediction (in which toddlers, for example, get toys when they point at them and ask) link learning and deciding. Stress reduces self-control, constraint satisfaction, and prospective optimization; changes to the nervous systems enhance the attraction of immediate rewards and diminish the appeal of longer-term preferences. For heroin addicts, wanting and liking sometimes diverge. To tell us what to watch for, dopamine release follows positive outcomes; serotonin when a choice turns out badly; releases are calibrated to the size (actual or counterfactual) of the gain or loss.
Churchland also introduces us to cognitive pattern generation, the “breakthrough concept” devised by the neuroscientist Ann Graybiel at MIT. A cluster of neurons in the basal ganglia, Graybiel discovered, is organized to enable us to perform multi-step, semi-habitual actions, previously performed successfully. Although we can—and do—customize to fit specific cases, the general form works well when we drive a car and often when a nurse triages patients in an emergency room. Internalizing norms is efficient and can reduce anxiety, but, Churchland acknowledges, rituals can also “become problematic habits.”
“The yearning for moral authority is altogether understandable,” Churchland concludes. “But certainty is the enemy of knowledge.” To be human, she implies, is to struggle to find the balance between respecting (internalized) social norms and recognizing the flaws in them; between trusting our own conscience and acknowledging that, “even with the best of motives, we will sometimes err and our conscience will churn.” We “can strive to continue learning from our social experience,” she maintains, and from the findings of brain scientists.