Carl Eric Fisher in Nautilus:
Ideas about willpower and self-control have deep roots in western culture, stretching back at least to early Christianity, when theologians like Augustine of Hippo used the idea of free will to explain how sin could be compatible with an omnipotent deity. Later, when philosophers turned their focus away from religion, Enlightenment-era thinkers, particularly David Hume, labored to reconcile free will with the ascendant idea of scientific determinism. The specific conception of “willpower,” however, didn’t emerge until the Victorian Era, as described by contemporary psychology researcher Roy Baumeister in his book Willpower: Rediscovering the Greatest Human Strength. During the 19th century, the continued waning of religion, huge population increases, and widespread poverty led to social anxieties about whether the growing underclass would uphold proper moral standards. Self-control became a Victorian obsession, promoted by publications like the immensely popular 1859 book Self-Help, which preached the values of “self-denial” and untiring perseverance. The Victorians took an idea directly from the Industrial Revolution and described willpower as a tangible force driving the engine of our self-control. The willpower-deficient were to be held in contempt. The earliest use of the word, in 1874 according to the Oxford English Dictionary, was in reference to moralistic worries about substance use: “The drunkard … whose will-power and whose moral force have been conquered by degraded appetite.”
In the early 20th century, when psychiatry was striving to establish itself as a legitimate, scientifically based field, Freud developed the idea of a “superego.” The superego is the closest psychoanalytic cousin to willpower, representing the critical and moralizing part of the mind internalized from parents and society. It has a role in basic self-control functions—it expends psychic energy to oppose the id—but it is also bound up in wider ethical and value-based judgments. Even though Freud is commonly credited with discarding Victorian mores, the superego represented a quasi-scientific continuation of the Victorian ideal. By mid-century, B.F. Skinner was proposing that there is no internally based freedom to control behavior. Academic psychology turned more toward behaviorism, and willpower was largely discarded by the profession.
That might have been it for willpower, were it not for an unexpected set of findings in recent decades which led to a resurgence of interest in the study of self-control. In the 1960s, American psychologist Walter Mischel set out to test the ways that children delayed gratification in the face of a tempting sweet with his now-famous “marshmallow experiment.” His young test subjects were asked to choose between one marshmallow now, or two later on. It wasn’t until many years later, after he heard anecdotes about how some of his former subjects were doing in school and in work, that he decided to track them down and collect broader measures of achievement. He found that the children who had been better able to resist temptation went on to achieve better grades and test scores.1 This finding set off a resurgence of scholarly interest in the idea of “self-control,” the usual term for willpower in psychological research.
These studies also set the stage for the modern definition of willpower, which is described in both the academic and popular press as the capacity for immediate self-control—the top-down squelching of momentary impulses and urges. Or, as the American Psychological Association defined it in a recent report, “the ability to resist short-term temptations in order to meet long-term goals.”
More here.