‘Why the modern world is bad for your brain’ published in the Guardian by neuroscientist Dr. Daniel J Levitan summarises how the world of tweeting/ emailing and watching tv at the same time is bad for your health. It causes stress and releases hormones that 'overstimulate your brain and cause mental fog or scrambled thinking'.
Perhaps not so much strict multi-tasking (could do with a definition), but the experiments conducted by the widely respected Bjork Human Learning and Forgetting Lab at UCLA explain how the process of learning that involves variation and difference aids long term memory retention.
In Veronica Yan’s presentation from the lab’s experiment from 1.52 mins in from this video the following comes as a surprise. Two sets of participants were tasked with recognising the styles of 12 different artists. One set studied one artist’s work, before they moved onto another. The other group studied the same artists but in a random fashion. Contrary to presumed belief, the second group ‘learned the styles a lot better’, says Yan.
Professor Bjork refers to the process of learning which involves deep engagement, like the random sampling of artists, as ‘desirable difficulties’. So while switching from a supposedly different task to task may have its problems according to Neuroscientist Dr Daniel J Levitan, switching foci on elements in a learning process helps your memory, says Professor Bjork’s lab.