on evolution.

The Victorian middle-class citizens who formed the bulk of Freud’s patients had intensely strong wills, making it difficult for therapists to break through their ironclad defenses and their sense of what was right and wrong. Freud’s therapies had concentrated on ways to break through and let them see why they were neurotic and miserable, because once those people achieved insight, they could change rather easily. By mid century, though, people’s character armor was different. Wheelis' and his colleagues found that people achieved insight more quickly than in Freud’s day, but then the therapy often stalled and failed. Lacking the sturdy character of the Victorians, people didn’t have the strength to follow up on the insight and changer their lives.

— Baumeister and Tierney’s “Willpower”