The bass guitar or electric bass is similar in appearance to the guitar but with a longer neck and only 4 to 6 strings. It is usually tuned one octave lower than the four lowest pitched strings of the guitar and is played with the fingers or thumb, by plucking, slapping, popping, tapping, thumping or picking the strings with the right hand, while the left hand presses the strings on the neck to change the tones or notes. Like the electric guitar, the bass guitar is plugged into an amplifier and speaker for live performances. While bass lines vary widely from one style of music to another, the role of a bassist, to anchor the harmonic framework and establish the beat, is one of the most important jobs there is.