Article: Multitasking Damages Your Brain And Career, New Studies Suggest

Research conducted at Stanford University found that multitasking is less productive than doing a single thing at a time. The researchers also found that people who are regularly bombarded with several streams of electronic information cannot pay attention, recall information, or switch from one job to another as well as those who complete one task at a time.

Humans are not meant to multitask, because our brain can only do one thing at a time. Rapidly switching back and forth from task to task is inefficient.

The frequent multitaskers performed worse because they had more trouble organizing their thoughts and filtering out irrelevant information, and they were slower at switching from one task to another. Ouch.

Multitasking reduces your efficiency and performance because your brain can only focus on one thing at a time. 

Research also shows that, in addition to slowing you down, multitasking lowers your IQ. A study at the University of London found that participants who multitasked during cognitive tasks experienced IQ score declines that were similar to what they’d expect if they had smoked marijuana or stayed up all night. IQ drops of 15 points for multitasking men lowered their scores to the average range of an 8-year-old child.