Comment by PinkMilkshake

This is what I can gather from skimming some articles in a lazy research attempt:

* Almost all evidence shows multitasking is not actually possible

* Some evidence shows attempting to do so anyway results in IQ reduction and loss of ability to focus

* Some evidence shows this reduction lasts even after you are done

* Some evidence shows this reduction is due to permanent physiological changes in the brain

'Brain damage' might be going to far.