For example, if you hunt to the east and find good game, you'd keep hunting to the east. Eventually you'd kill everything over there or get them to move, and your hunting would get worse. The optimal approach might be to randomize the direction you hunt, so that game doesn't learn where you're hunting.
The society couldn't say WHY the ceremony was good, but long term if they kept applying the ceremony they'd have better outcomes than societies that didn't.
Sometimes superstition is just that ... but I'd also bet there are unintuitive/surprising benefits behind a lot of it.