The instincts that transhumans are born with, whether they are humans, human-based AGIs, or uplifts, are unsuited to post-singularity worlds at least as often as not. To those who are willing, however, this need not be a problem. Their ancient but irrelevant instincts can be replaced with those designed to meet the world they now live in.
An instinct set is created in imitation of an effective AI. Neural networks are trained to perform sets of tasks in simulation. Once they have achieved acceptable levels of success, the methods they have developed are analyzed, and the networks are streamlined. Ideally, the result is a breakdown of successful behaviors into sets of rules, and a neural network that follows those rules. These are the guidelines used during psychosurgery to wire new impulses and intuitions. Done correctly, someone who has never seen a gun in person will dive for cover instantly when fired upon, and day-traders will feel no reason to throw good money after bad.
Instinct sets can cover any topic that can be simulated, and range from "Game Theory in Politics" to "Freefall for Mud-Farmers" and "Surviving Exposure to Vacuum".
Most of the effects of an instinct sets should be roleplayed. Mechanically, they can be treated as re-fluffed skillsofts.