In the agile world we have a few exercises to show the effects of multi tasking.

Last year I when I did a personal agility workshop with Gerry Kirk, he teached me a new one. He learned it from Alan Cyment

It became my favorite exercise about MT.
Take a group of about 10 to 20 people.
We divide the  group in two. The two parts are standing in a row facing each other.

We do 3 exercises in multiple ways.

1. a complex hand exchange (like in a child song) or things like one of these handshakes
2. Count from 1 till 10 with your partner using your fingers. (Person A: shows 1 finger, then person B : 2 fingers, person A shows 3 fingers…)
3. “sing” a song. Person 1 says one word and then her partner says the second word and then again person 1.

The first round we do the exercise in sequence. First exercise 1, then exercise 2, then exercise 3.  What makes this exercises harder is that for each exercise you have a different partner. So after you have finished exercise 1, one row shifts one position to the left. (and the first person moves to the last position.) And the same again after you have finished exercise 2.

In the second round, people start the first exercise and when the leader says so, the group switches to exercise 2 or 3. Now this is when it becomes interesting as people have to remember where they were and they have to find their new partner and remember at what part of that exercise they where.

This exercise reminds most participants about their worklife. Always changing priorities, finding partners back. Before you can do a small task, the priorities have changed again.

One of the interesting things about this exercise, is that everytime I did this, in the first round all 3 exercises are finished in less time then finishing the first exercise in round 2.

So switching priorities does no help, not even to give the impression that things move faster.