Weird Styles for a Weird Instrument
Bass players are weird. This is because it takes a weird personality to take up an instrument like the bass; everyone knows that no one ever listens to the bassist, that bassists are cursed by God, and that groupies have a special sense that allows them to sense the curse and steer clear of bassists. I guess they have to have a certain attitude to not care about any of all this. It pretty much follows that weird people like bassists would invent suitably weird ways of playing their instruments, and since there's little room for creativity in left-hand technique on a stringed instrument (apart from various masochistic finger-stretching exercises cleverly disguised as bass lines), they've turned to developing strange right-hand techniques instead. Having just escaped alive from a meeting of the secret bassist world domination conspiracy, I hereby present E2 with an incomplete list of these styles, including descriptions of the individual techniques, and examples of bassists who use them:
A bass pick is a good deal thicker, heavier and larger than your typical guitar pick, because of the heavier gauge of the instrument's strings. The bass player typically grasps the pick between his thumb and index and middle fingers. The trick to successful pick playing is to have the grasp to be firm enough that the pick won't fall from your hand (dropping your pick in the middle of a gig would be quite embarrassing), yet loose enough that it can be moved quickly and comfortably across the strings. Pick players mute the strings by using the palm of their hands. An advantage of pick playing is that it is relatively easy to achieve high speed (important for players of punk and metal), and that the sound yielded by the pick is a hard "hard plastic on metal" twang that is very suitable for the harder music styles. That sound is regarded as a disadvantage by some, and many players feel that they have a closer "touch" with their instrument if playing with their fingers. Also, bass elitists tend to regard pick playing as an "inferior" style, and that picks belong in guitarists' hands. Examples of pick bassists who don't care about such drivel include Slayer bassist Tom Araya, Motörhead's Lemmy Kilmister and ex-Metallica bassist Jason Newsted.
There are endless variations of how to play a bass without a pick. Originally, bassists played using a strange style called "thumb plucking", where they plucked the strings using (surprise!) their thumbs, much like how classical guitarists sometimes play. Very old basses have finger rests below the strings, which confuses modern bass players no end. However, this style is seriously limited in the speed department, making it problematic on a rhythm instrument such as a bass. While there are a few (typically beginner) bassists who play with just one finger, modern fingerstyle players usually play using the "two-finger style", plucking the strings by alternating their index and middle fingers across the strings. Typically, the thumb is anchored to the bass by resting it on a pickup, although some players prefer to anchor to a string (this is known as a "moving anchor"), which has the added benefit that the string serving as anchor is muted. Fingerstyle bassists mute strings using their palms, or by allowing a finger to land on the string to be muted after it has plucked the string that should ring. Another quirk is that some players always alternate between the two fingers, while others "rake" one finger across multiple strings. Fingerstyle is used in just about all genres, from jazz to death metal. Two-finger fingerstyle players of note include the late ex-Metallica bassist Cliff Burton, Black Sabbath's Geezer Butler and jazz legend Jaco Pastorius (who, as an interesting side note, had monstrously large hands and almost equally long index and middle fingers).
Unfortunately, two fingers don't always quite cut it. There are several commonly used three-finger styles, but the two most used are the gallop and the speed fingering techniques. The gallop is played by playing a "ring->middle->index, ring->middle->index, ..." finger pattern in rapid succession, which yields a very characteristic sound because of the slight delay between the strike of the index finger and the following strike of the ring finger. A notable gallop style player is Steve Harris, and you can hear the technique used brilliantly on just about any of Iron Maiden's albums.
Speed fingering was developed primarily by players of 80's speed metal or 90's thrash metal or death metal, because the sheer speed of the songs made two-finger style impractical, and featured rhythms that weren't suitable for the gallop. The obvious solution would be to take up pick playing (obviously, guitarists using picks had no problems keeping up), but some bass players decided to keep using fingers, either because they had jazz or classical music backgrounds, or because they were just plain weird. Speed fingering is played using a repeating "ring->middle->index->middle->...." pattern, which eliminates the delay characteristic in the gallop, and allows much more speed for the experienced player than two-finger style. Examples of players who use this style include Cannibal Corpse bassist Alex Webster, as well as Steve DiGiorgio, known from Death, Sadus, Testament and several other bands. A less well-known player of this style is the author of this node.
Dream Theater bassist John Myung plays his insane solos with all four fingers. He is a very, very sick man. Four-finger playing is very rare, because the small size of the little finger makes it extremely hard to attain a decent sound with it.
This style is almost universally used by funk bassists, and almost never used by anyone else. It has a very distinctive sound, characterized as it is by the very sharp, bright attack. It is also quite difficult to learn, but very satisfying (and fun) to play once you've gotten the hang of it. Basically, you're treating your bass as if its strings were a percussion instrument, which means you get to think like a drummer and bassist rolled into one. It is often just called "slap", although anal retentive pedants like me like to point out that it is in fact a combination of two techniques: The slap is the technique of striking a string with the side of the thumb (by a quick rotation of the wrist), and the pop (which has nothing to do with the music genre of the same name) is the technique of quickly "yanking" a string out from the bass using the index or middle finger, letting it "thwack" back in place (and making that characteristic funky sound in the process). It is possible to achieve quite impressive speed using this style (important, since many funk compositions feature lots of 16th notes), because the index finger can be placed below the string (ready for the pop) while the slap is taking place. Typically, assuming a 4-string bass, the two deeper strings are slapped, the two higher strings are popped. Famous users of this style include Primus frontman Les Claypool, Red Hot Chili Peppers bassist Flea, and just about any serious funk bassist on the planet.
While this is not often used as a general-purpose technique, it is often used as an element in bass solos, as an added touch after a slap/pop sequence, or occassionally to drive a regular rhythm. Tapping originated as a guitar technique (Eddie Van Halen was in part responsible for popularizing the two-handed tapping style), and is performed by quickly pressing the string down, but on the neck of the bass (on the fingerboard) rather than on the body. This allows the player to quickly play some very complex sequences, and some of the technique's masters can make their bass sound almost as if it was two instruments being played simultaneously. Bassists who tap a lot include Stu Hamm (who played with the Steve Vai band, but is most known for his solo project -- rare for a bassist), Billy Sheehan and the aforementioned Les Claypool.
Politically Correct Disclaimer
I have assumed that the bass player is right-handed. This is because I am a bigoted pig. If you are left-handed and play a left-hand bass, make the appropriate changes.