The Massachusetts Bike Coalition has a couple of video clips on-line to show an example of what catches the eye at night... often used in safety classes.

From the front:
http://www.massbike.org/police/mpg/nightfront.mpg

... and from the back:
http://www.massbike.org/police/mpg/nightrear.mpg

(Warning: these are some whomping big files if you click on the link...)

But do note how the pedal motion shows up, as well as the reflective vest and human form...