[johndallman]

Esmology is an IQ/VH skill from GURPS Horror: The Madness Dossier that provides the ability to exploit the fundamental programming of the human mind, as laid down millennia ago by the Anunnakku, the key opponents of that setting. It has no default, and no skills default to it; there are prerequisites of a Hidden Lore skill specific to the setting, and either a related talent, Esmologist, or a special training regime that is a cut-down version of Trained by a Master.

The main use of this skill is to predict the behaviour of groups of people, either en masse (a mob, the stock market), based on doctrine or training (how a squad will move, how a hospital will evacuate) or group-steered action (how the legislature will vote, how the police will respond to a clue). It's very effective at this; the name of the skill comes from Greek "esmos", a swarm of bees. Additionally, a successful skill roll works like a complementary skill, but for +3, to any attempt to modify the behaviour of a social group, such as a Propaganda campaign, or for an Influence roll. This does not stack with the bonus for Manipulation methods from Social Engineering, since it's pushing many of the same buttons.

Yes, this skill lets you treat people like rats in a maze. It's from a horror setting, by Ken Hite. Don't expect it to be nice. It is specific to Madness Dossier, and shouldn't exist in games outside that setting, except maybe in extreme tinfoil-hat-paranoia Illuminati games.

Esmology is a useful example of a skill that exists because of an important difference between the real world and a game world. Differences in reality, philosophy, or the way minds work are far more likely to be unsettling than mere advances in technology or the presence of human-scale magic. GURPS has a framework for dealing with those, in TLs and new specialisations of existing skills, but other kinds of change have to be handled on a case-by-case basis.

I've played a Madness Dossier campaign, and we had an Esmologist in the party, but she mostly used the skill for influence, rather than prediction. As far as my character remembered ...