Yeah, like Nemric said, but more specificly:

click the key in the bottom right to pull up the animation controls

use your mouse to draw a box and select all of the little green boxes for your figure's head (or to get more precise, expand the head controls and select only the blink parameter)

press the brown button to make all of the little green boxes turn into little brown boxes

your animation will now be linear based rather than spline (curve) based

hope this helps!