Multitasking is out. The new thing is Continuous Partial Attention (CPA):
With continuous partial attention we keep the top level item in focus and scan the periphery in case something more important emerges. Continuous partial attention is motivated by a desire not to miss opportunities. We want to ensure our place as a live node on the network, we feel alive when we’re connected. To be busy and to be connected is to be alive.
Linda Stone is the one credited with coming up with the idea.
There is some interesting research being done to discover why there’s a bottleneck in in the brain and why the brain can then only work on one thing at a time.
A good analogy are computer processors. Until recently, most computers were single core (one processor). This meant that they could only perform one operation at a time.
However, most modern operating systems are multithreaded. This means that the computer can do (or at least appears to be able to do) multiple operations at once. It accomplishes this by creating threads of processes (task) that each take a turn using the single processor. In short: multitasking.
Nowadays, many computers have multiple processors on a single chip. This allows for for true multitasking, assuming your program of choice is designed to use multiple processors. The most common applications that take advantage of multiple processors are video and photo editing software. Why? Graphics often need to be generated and this just happens to be a perfect task that can be split up and parted out to multiple processors.