First, the bad news: your brain was never designed to multitask well:
To put it bluntly, research shows that we can’t multitask. We are biologically incapable of processing attention-rich inputs simultaneously.
Across the board multitasking lowers productivity:
Our results show that multitasking is bad for productivity even if one is not concerned with average duration.
Neither gender is better at it:
We do not find any evidence for gender differences in the ability to multitask.
But if multitasking doesn’t work, why do we do it so often? It makes us more emotionally satisfied, even if it makes us less productive:
“…they seem to be misperceiving the positive feelings they get from multitasking. They are not being more productive – they just feel more emotionally satisfied from their work.“
So you’re probably going to keep doing it anyway. Is there any way to get the emotional boost and not have it reduce your productivity so much?
Yes. Playing video games might makes you a better multi-tasker:
We examined the relation of action video game practice and the optimization of executive control skills that are needed to coordinate two different tasks. As action video games are similar to real life situations and complex in nature, and include numerous concurrent actions, they may generate an ideal environment for practicing these skills (Green & Bavelier, 2008). For two types of experimental paradigms, dual-task and task switching respectively; we obtained performance advantages for experienced video gamers compared to non-gamers in situations in which two different tasks were processed simultaneously or sequentially. This advantage was absent in single-task situations. These findings indicate optimized executive control skills in video gamers. Similar findings in non-gamers after 15 h of action video game practice when compared to non-gamers with practice on a puzzle game clarified the causal relation between video game practice and the optimization of executive control skills.
Source: “Video game practice optimizes executive control skills in dual-task and task switching situations” from Acta Psychologica, Volume 140, Issue 1, May 2012, Pages 13–24