When a tv show is taped in front of a live studio audience, is the audience told when to laugh, clap, and make a big deal over a certain scene?

This question goes the same for late night talk shows. Because sometimes I don’t find a scene very funny, but the audience just loves it and goes beserk and laughs a lot. Sometimes a person’s laughter in the audience can get annoying, like some will have a deep, guttral laugh that sound like a seal and I don’t think the scene was that funny.

If this is true, then why does the audience need to be told what to do? Does it bring in more home viewers this way? I don’t understand the process behind this.