Left hand thumb (For Right-handed Bassists)

[afzoomie67]

I've watched videos of numerous bassists, and realize, at times, they use their left hands thumb to play notes on the E string. I learned this is wrong, but why do some people do it and could you develop any problems with playing this way v. without using your thumb on the E string? What are the pros/cons of this?

[Jay2U]

It is sometimes more practical to use a finger or thumb which is just in the right position at the time. If I play with a pick, I tend to do a lot of muting with the left hand, the thumb included, as it happens to be there. Sometimes it's just practical to do a quick hammer-on and pull-off with a thumb. I don't see pros or cons, as long as you're happy. Remember, there is no need to develop a deviating style, but it's not prohibited. As long as you don't force anything, I don't see why or how you would develop a problem.