[nickolai]

>However, if my other half comes home and starts having a phone conversation–at a significantly lower volume in another room–the muffled voice really distracts me.

I find hearing a muffled conversation is actually worse than hearing a plain conversation. My pet theory is that either way, the brain has to commit some resources to parse the voice into actual concepts, but if the conversation is muffled it has to do even more work to 'clean the signal'. Using resources that are taken from your concentration ability.

You can consciously try to ignore the voice as much as you want, your subconscious still have to parse it. At least i've never been able to avoid it. I think that thats why white noise or music does not affect concentration nearly as much as a conversation of the same Db-level.

[mechanical_fish]

This is why headphones, noise-canceling or not, are not a perfect solution to the problem of conversational noise. You can still hear conversation through noise-canceling headphones; it's just quieter. And not necessarily so quiet that you don't parse it.

You can try to train yourself not to parse conversation, to think of it as a slightly irritating set of noises. I think we all try to do this to some degree – it may be one reason why programmers are famously uncommunicative when we're in the zone. I mumble and wave people away when I'm trying to sustain focus, and even if I deliberately break focus I tend to take a couple of minutes to snap out of it and get back into the flow of conversation, and in the meantime I struggle to produce words.

But, like you, I'm not convinced that consciously ignoring words really works. Your brain is still parsing them at some level. It's like the studies which show that noise, in general, is stressful, even if that noise is just white noise. Your brain is trying to find signal in the noise. It never really stops trying. The more noise there is, or the more structure your brain detects in the noise, the harder it will try.

Studies have shown, and my own experience bears out, that voices are hardest to tune out, and that structured music is also relatively distracting: Your brain parses music too. Ambient music, which is deliberately designed not to attract conscious attention, works better for me. White noise works, too, to some degree, but silence is still best.

Of course, some people are conditioned to have noise all the time. These people are both lucky and unlucky, in my opinion.