Can you tell me why those bubbly-pop noises were even invented to go along with some notifications on cell phones and computers?

I don’t like them. They make me feel like I’m 5 years old. WWF has bubbly-pop noises every time I move a tile, so I keep my computer on mute most of the time, except when watching a specific video.

One time I was in a waiting room, and some lady was playing something, or maybe texting, and her phone kept going “bubbly-pop! bubbly-pop!” every few seconds for the next 15 minutes. I found it extremely annoying, as I was trying to read a National Geographic article on the evolution of languages.

What was the reasoning behind creating such pre-school sounds for notifications, etc.?