Effectiveness of "non-focused" learning Is anything known how effective is "non-focused" learning. For example when I am focused on something else (watching TV, doing work in the office) while listening to language learning material (words and phrases and their translations for example). Or playing scales on your guitar while watching TV (okay, seem to be more invovled then merely listening, but I guess you get the idea).

So is there anything known about that, or any studies on that?

EDIT: I do not have found any studies, mainly because I do not know what to search for, googling terms like "non-focused learning", "passive learning", "distractive learning" do not give anything useful. I have a minor in psychology and if I see a study I can relate it to what I am looking for, but I am not a researcher in psychology. So this question came up out of curiosity of my own (and to be honest, its quite practical if possible to learn something by "not even trying" to say in lax language). I know about the 10k rule of expertise, and they always talk about "deliberate practice", obviously the kind of practice I am looking for is not deliberate, but maybe someone asked if its still beneficial, even if on a much smaller scale. I would suspect that it is not difficult to design studies for it, just let people perform some task, tell them its the main task, then do some distraction in the background (which is the supposed learning content, melodies, words whatever). Then afterwards (obviously to the surprise of the subject) ask question about that your let it perform a task to access gained knowledge.
I think this is a somewhat controversial area of research. On one hand

Participants were asked to predict the weather after receiving a repeated set of cues. During part of the learning, researchers added a second task where participants had to keep a running mental count of high tones that they heard, thus adding an element of distraction.
The results showed that when doing single-task learning, the brain used the region associated with declarative memory, while the habit memory region was associated with dual-task learning.
The dual-task learning did not affect the participants' ability to predict weather at the time, but it reduced their knowledge about the task during a follow-up session later.

On the other:

Psychologists know that the things we learn in one context might not be remembered in another. Famously, investigators once showed that words learned while scuba diving are easier to recall underwater than on dry land. Now Brown University psychologists suggest something similar happens with distraction. The researchers trained 48 people to hit a computer-screen target using a wonky touch pad—tracing up, for example, might move the cursor diagonally—and later evaluated them on their ability to quickly hit the mark. During both training and the test, participants were randomly selected to do a distracting second task: counting letters on a screen. Those distracted during just one phase performed poorly when tested, but those who had done the letter-counting task during both training and testing performed just as well as those who had trained and been tested without distractions, according to the results published in February in Psychological Science.
The consensus remains that distraction is typically bad for learning, the scientists explain. But if you anticipate a distracting testing or performance environment, try to mimic those distractions as you study or practice to avoid being caught off guard.

So distractors are generally bad, but not always.
There's even more controversy whether background music helps or doesn't with school activities or learning other stuff.