No study will convince me about music and my personal ability to focus. It needs to be the right music (Emancipator, Nicola Cruz, etc) but I can write 2000 to 5000 lines of high quality, tested code with the right song on repeat for the day and I know its the same for many others.
First, the point of a study is to be generalizeable - that is, to apply to as many people as possible, usually other than oneself. If a particular technique applies to you, that's great! However, most people aren't you. Starting with a known general principle/technique (most people can't multitask) will, on average, put you in a better position than randomly picking someone's anecdotal evidence.
Second, there are many documented cases where self-assessment of one's own traits or capabilities is inaccurate. Performance while cognitively impaired (alcohol & sleep deprivation), assessment of skill as a novice (Dunning-Kruger), and the ability to multitask are all well-known cases of it, with many more lesser known (e.g. whether one is a "visual" or "verbal" learner[1]) - so, you should be wary about having too much self-confidence in your own capabilities, especially for something as poorly-understood as software engineering.
> First, the point of a study is to be generalizeable
That's why I specified myself. I completely understand the difference between generalizable results and individual results.
> many documented cases where self-assessment of one's own traits or capabilities is inaccurate
I completely understand that self-assessment is flawed, but there is also something to understanding oneself and trusting a self-assessment that is born out over decades of experience. I have never even come close to being as productive as I can be with the right musical piece and sharing this insight with others may prompt further research that sheds new nuance on the topic.
that's the key. You are possibly using 'the right song' to isolate yourself, so that helps you concentrate. The fact that it's on repeat also makes you don't pay much attention to it anymore. But try to listen to 'the wrong song', or worse 'the wrong new song', and it's probably going to have some effect.
I mostly listen to 'concentration music' and lo-fi without vocals. Put something more complex and with lyrics...
I used to find that listening to music without lyrics (classical, movie themes, etc.) did it. Lately though I just listen to a local radio station that plays music I like.
I think I'm convinced that the difference is how well I know the music - listening to the radio is all songs that I've heard hundreds of times, so I don't think I'm subconsciously spending effort listening to the lyrics since I know them already?
For me my poor English becomes an advantage here - I can listen to rock music and completely ignore lyrics, if they are in English and I don't deliberately focus on them. But if the radio starts playing something in my own language then it becomes distracting, even if I heard the song hundreds times before.
