After the devastation of the Rusty Crash, the survivors vowed to never let humanity wreck the planet again. They slowly rebuilt new, smaller, more eco-friendly cities, but there was still conflict between people. About a century after the Crash, a group of scientists from every city contacted one another in order to study the problem of human conflict. They rediscovered the idea of the "halo effect", where Rusty science had shown that beautiful people were treated better, got in less trouble, and were generally more happy and successful. The scientists thought that if they made everyone beautiful humanity would stop killing each other and make the world a better place. They designed early Pretties to call upon evolutionary instincts of cooperation and courtship in everyone who saw them. Although it did help a little, the early prototype Pretties still fought with one another despite their beauty. The scientists agreed that something else had to be done if they were to eliminate war forever, so they secretly developed the lesions.
Altering several small areas of the brain, lesions created a new type of Pretty that was compliant, unaggressive, and happy. Impossible to make into soldiers, Pretties could never go to war. Unlikely to rebel against the system that made them so happy and so beautiful, humanity could be kept in an idyllic, manageable state forever.
On their sixteenth birthdays, Uglies undergo the Operation that makes them Pretty. The Operation aims for a vulnerable, delicate look by including a full skin graft for perfect, clear skin; cosmetic surge for perfect symmetry, large jewel-toned eyes, full lips, and so on; improved immune systems; and the replacement of teeth and other bones with much stronger materials. The standards of beauty are determined by the global Pretty Committee, who keep in contact with one another to make sure the Pretties in one city don't wind up prettier than everybody else. The secret brain lesions are also given to people during this Operation and are at their strongest effect at this stage, rendering New Pretties incapable of doing much more than constantly partying in New Pretty Town. Unlike Uglies, they enjoy fireworks every night, a hole-in-the-wall that can create almost anything they want, and various technologies to play with including bungee-jackets and floating ice rinks. They even have pleasure gardens specifically designed for lovers. They can go through several cosmetic surgeries a week to make themselves look the way they like, such as implanting jewels into their eyes or getting flash tattoos. Some surgeries are reversed after serving a specific purpose, such as costume surge for a party. New Pretties are usually drunk or hung-over, possibly encouraged to help keep their minds in a pretty-haze until they completely forget about their "ugly days".
New Pretties have simplified slang that mainly consist of the terms "bubbly" and "bogus". Bogus is a negative term synonymous with "bad". Bubbly is a positive term synonymous with "good" that can describe everything from a clear-thinking state of mind to champagne.
Middle Pretties' brains have adapted to the lesions so its effects are not as strong, making them grow bored with the mindless fun of New Pretty Town. They begin taking exams and upper-level courses to help determine what careers they'll have. People who had been tricky as Uglies and resistant to the lesions as Pretties are marked for special jobs requiring quick thinking, such as firefighters, surgeons, and wardens, and consequently have the lesions removed from their brains. Once they are assigned jobs, middle Pretties move into single-family houses in the suburbs to raise their gardens and families. Couples are encouraged to have only one child every ten years in order to help control population size and to discourage the formation of strong sibling bonds. Littlies live with their parents until they turn twelve, at which point they officially become Uglies.
As middle Pretties age, they are given minor operations that replace youth with markers of wisdom and kindly authority.
Late Pretties are often known as crumblies. Ususally around age eighty, they retire from their jobs and move to assisted-living homes in Crumblyville, where they tend to their gardens. They can receive life-extension surgery that allows them to live into their middle-hundreds.