Dr. Matt Walker

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I've taken a look at this, and so far, I think for white noise machines, the data is equivocal.

There was a recent study, a review article, I think it looked at about 37 different studies.

I could have this wrong.

And what they found was that there was no reliable, robust directional effect of white noise machines on sleep.

Some studies demonstrated that it helped sleep.

Some studies didn't change sleep.

Some studies suggested it may make sleep a little bit worse.

Just nothing reliable.

Correct.

And one of the positive studies in that scenario was a study that was done in New York City.

And it was in a region where there was a lot of external sound pollution and noise.

As you could well imagine, it's New York City.

And sure enough, that's where they got some really nice benefits of the white noise machine.

So I think it is, you're right, context-dependent.

There was an interesting recent study that came out from Eterman Learners Group at the University of Texas, San Antonio.

And they didn't use white noise.

They used pink noise.

Now, what's the difference?

Pink noise has a little less what we call power or intensity in the higher frequency ranges of the sound spectrum.