the costs of "multi-tasking": why task-switching is expensive

earlier this week, i was explaining why multi-tasking is no good to a new client and thought i’d share. i think i’ll just share rapid-fire bullet point style:

• multi-tasking isn’t real. as explained beautifully over here, the brain can only handle one cognitive function at a time. the only exception to this is that you can do one cognitive task while doing a physical task that you’re very familiar with (like walking or sketching or knitting).
• when people think they’re multi-tasking, they’re often just missing information. sometime soon, i think i’m going to count the number of times someone is texting while i’m talking to them and they ask me “what?” after i’m done talking to them. i would estimate three people do this to me daily.
• missing information is costly. this point speaks for itself. however, a less obvious cost to missing information while multi-tasking is the time and energy it takes to go find the information again OR the time it takes to fix a mistake that impacted someone else.
• task switching, which is what multi-tasking actually is, undermines productivity. this is contrary to how many of us are being (culturally) trained. we live in a society where doing more is seen as better, regardless of whether or not you have capacity for what you’re doing. it’s a vicious cycle whereby being overworked or frenzied creates a situation in which the frenzied stated of being is the only way to make ends meet (speaking economically and socially). some of this is an economic failure, but some of it is just cultural. but i digress… multi-tasking doesn’t actually help you do more things well, it allows you to do many things in a mediocre way. by preventing focus, multi-tasking undermines depth in production (and maker time is SO important to producing good work). additionally, as weinshenck mentions in her article, multi-tasking requires energy from your pre-frontal cortex. your pre-frontal cortex is critical to being productive. so when you occupy your pre-frontal cortex, you diminish your own ability to be creative.
• context switching is incredibly expensive. i learned via the trello blog (which is a pretty amazing productivity resource whether or not you use trello) the most detrimental type of task-switching is context-switching. this is when you’re doing one type of work and then you quickly switch to a different type of work. this undermines flow is the one and creates a slow on-ramp to flow in the other.
  
  for example, you’re working on a complicated excel spreadsheet. you’ve got lots of information in your head about what goes where and how you need to make equations to get the numbers you need. then, an email pops up and you go to your inbox to respond to it. this is the most expensive type of switch. to use the analogy of a computer, your RAM (short-term memory) was filled with information needed to finish that spreadsheet. without that information floating around in your short-term memory, you actually can’t get to the answer you need. when you switched to your email, your brain dumped all that stuff from your RAM and started filling it up with email information: who is this email from? what’s the context that this email is about? how do i need to respond in a politically appropriate way? etc. when you return to the spreadsheet, you have re-up all the information you had dumped before to finish the task. the time it takes to reacquaint yourself likely would have been saved if you had just finished the spreadsheet and then gone to deal with the email later.
• we’re actually bad at re-focusing. i read a while ago that it takes most people 25 minutes to return to a task at work after being interrupted. a different one (that i can’t find right now) said it takes most people 12-15 minutes to get back into flow once knocked out of it.

wow. there’s actually a lot more to this, but i’m out of time. part 2 coming some day!

ps - this post has a lot to do with cognitive budgeting. i probably should wrap all those posts into a series or something…