Does lullaby really have hypnotic effect?
Personally, I think it is useful, and maybe for some people, the hypnotic effect of math problems is better. Known as the most relaxing song in the world, Weightlessness, with a total length of 8 minutes 10 second, can give you enough time to fall asleep. It can lower the listener's heart rate and reduce anxiety. For me, this kind of light music has a good hypnotic effect.