Some Skill Explanations

The below skills and their descriptions are largely drawn from the Call of Cthulhu rules published by Chaosium. These notes however represent my interpretation of them, and are, like everything else, open to discussion.

I. Several skills can be used to influence the behavior of other characters.

Fast Talk and Persuade are very similar skills, either of which can be used to talk a non-player character into doing something they otherwise might not be inclined to do - allow passage, lend money, overlook a minor crime, decide that their idea was bad.

The difference lies in the application. Fast Talk is swift and should be accompanied by some witty retort or capsule of glibness. Likewise, the effect is brief; people who have been fast-talked realize it soon enough. Persuade, however, is more permanent. A successful persuasion check indicates that the player's character has constructed a sound argument, made a good case for their point of view, or played on the other character's sympathies in such a way as to truly bring them around to the PC's point of view. Persuasion demands a little more dialogue, description, or - at the least - the passing of time in social intercourse.

Credit Rating can represent one's actual line of credit, but it is also one's good name. Thus it can be used to obtain goods and favors as well as to exert social pressure on other characters. "Do you know who I am?" could be all a famous person needs to say in a troublesome social situation.

Bargain can be used to lower prices or to trade for goods in desperate situations. (I don't think I've ever had to roll this in all my years of running Call of Cthulhu games, as credit ratings are usually sufficient for obtaining most goods.)

None of the above skills have any effect on other player characters!

II. There are several skills having to do with stealth or perception. Some of these skills have overlapping effects.

Sneak is moving without being seen. Move Silently is moving without being heard. Not too surprisingly, the goal of a Hide check is to remain in one place without being seen or heard. 

Conceal, on the other hand, is used to hide objects, either on one's person or in the environment.

Listen strains a player character's hearing to detect clues about hidden or quieted beings. It can be used against Move Silently and Hide.

Spot Hidden is about visual clues. It can be used against Sneak, Hide, and Conceal.

III. Various other skills demand a little explanation.

Psychology can reveal clues about a person's intentions, state of mind, or emotions. It might reveal clues about a character's worldview, and in rare situations it might be used in lieu of Fast Talk. Psychoanalysis diagnoses mental illness and treats it. Psychoanalysis can be applied either through long term treatment including drugs and therapy, or through a brief session of the talking cure. In either case, it restores sanity. Under the right circumstances Psychoanalysis might be useful in lieu of a Persuade roll.

The Own Language skill is rarely used, except for compositions, deciphering particularly strong accents or novel dialects, or reading one's own language in archaic usage or script. Any character with more than a base skill in Other Language is assumed to speak that language well enough for the interactions demanded by everyday life; no rolls are usually needed. Rolls are required for reading and comprehending complicated compositions, understanding broken or unfamiliar forms of the language, or for instances of communication under severe pressure.

Identifying and mixing compounds with specific physiological effects falls under Pharmacy. Compounds with no specific physiological effects are covered by Chemistry.

Respectively, Drive, Pilot, Pilot Boat, are about using automobiles, aircraft, and boats. Ride is for 'piloting' beasts, as well as for working beasts of burden. Operate Heavy Machinery allows a character to pilot and manipulate bulldozers, cranes, etc.

Anthropology is the study of human evolution and contemporary culture. Passing an anthropology check could provide information about a religious ritual, an ancient pelvis, or a folk tale. (Usually a knowledge roll is all that is needed to identify a language.) Pre-contemporary cultures and events are covered by History, but pre-historic cultures are covered by Archaeology. The techniques of excavation and preservation are included in the latter skill, whereas most of the historian's research techniques are covered by Library Use.

Whereas Biology's data is derived from laboratory settings, Natural History is basically a field enterprise. A biologist would be the better geneticist, physiologist, and anatomist, but a natural historian would excell at taxonomy, ecology, and evolution. (Back in the 1920s, genetics had not yet found its place in Darwinian theory.)

First Aid is on-the-spot treatment that can restore a few hit points and stabilize a dying person. Skilled medical treatment, with or without supplies is covered by Medicine, which restores more hit points. Both may be used on the same wound, but a wound may only be successfully treated one time for each skill. Of course, one may apply medical treatment or first aid on one's self.