Background sound effects

Being new to Apple, I'm not used a lot of the sounds and things. For example, there are sounds that I hear every so often while in the middle of doing something.

I thought it was Photoshop autosaving, but Photoshop is closed.

I know what the notification sounds for mail and alerts are, so it's not them.

The ones I'm referring to sound a bit like a 'woosh' or 'swish' - sort of like the sound a sword makes when being swung fast.

Does that make sense? And do you know what I'm referring to?