Multi-tasking is really called "context switching" by people who study productivity. As mentioned above, you can't DO more than one thing at a time. Some are better at switching rapidly between tasks than others. There is a hit in total productivity because there is "overhead" associated with ending one task and beginning another. This has been studied to death in the software development business and 2 things are found to be true: 1-code is done faster and is of better quality when it is worked on for long uninterrupted stretches of time 2-nobody in the software business ever works on code for long uninterrupted stretches of time
