Why did they use Bezier curves for their transition intermediate value functions? Most of the text I've read on how humans interpret "smoothness" is that logari

Why did they use Bezier curves for their transition intermediate value functions? Most of the text I've read on how humans interpret "smoothness" is that logarithmic (or exponential) are the norm [1]. [1]: e.g., "...in many areas, our responses to stimuli are logarithmic, not linear in nature." http://everything2.com/title/exponential http://everything2.com/title/exponential