Multitasking

Multitasking sometimes can be more difficult when these tasks are similar, but a little easier if they are different . An example would be talking on the phone and write an email is difficult because they involve similar thought processes in order to generate meaningful sentences , talking while playing the piano is not so difficult. but people do not have these problems multitasking and belong to 2% of the population
Montalvo, O. (2016)
Source
http://www.bbc.com/future/story/20160218-why-multi-tasking-might-not-be-such-a-bad-idea