There is an area in the Task Set up which you can set to Notify Default Users. You will can check these settings to see whose name is set as the default. To do this please follow the below steps:
From the home page, click Account Settings followed by Task Setup.
Select the relevant module from the list.
There will be a setting called Default Users to Notify at the bottom of the page. Enter a name into this box and click it when it appears in the list. You are able to select as many users as you wish.
Click Save to retain these settings.
Repeat the above steps for each Module as required.