My $0.000002: You dont need a study to know delegating task X can make you worse at task X, nor do you need one to know its vacuously true and avoidable.
The world is more complex, though: maybe people delegate thinking in some areas to be able to have more resources to think about other areas that are more relevant to them?
This is not necessarily true if you spend more than 2 seconds thinking about it.
If I'm raking leaves all day I eventually reach diminishing returns. My arms might even start to get tired and actually make me lose skill. Now I got a leaf raking robot which is not perfect but does 50% of the job and gives me free time to recover my hands and research new leaf raking techniques, maybe even invest into a leaf blower. Did I not become better at raking leaves?
People are not calculators - all these simplistic takes are frankly insulting to human capability.
Pretty much. I don't know the vast majority of phone numbers of family and friends because my phone remembers it for me.
When you delegate demands, you reallocate your resources.