When looking at the inventory of one of the LEGO games ([as if you were missing a part][1]), you can see these are clearly labelled "MICRO FIGURE" 

![enter image description here][2]

On [Bricklink][3] they are known as 'Microfig', Lego Digital Designer refers to them as 'Micro Figure.


  [1]: https://service.lego.com/en-gb/replacementparts/#BasicInfo
  [2]: https://i.sstatic.net/4VgxE.png
  [3]: http://www.bricklink.com/catalogItem.asp?M=85863pb003