On the 737/757/767 the artificial feel system of both the ailerons and the rudder consist of an input which moves a roller up a cam. The shape of the cam allows the roller to move in either direction i.e left/right or up/down depending on the direction of the input. The roller is held in the centre and 'neutral' position of the cam by spring force. The input you make into the control system moves the roller out of the neutral position in the cam and follows the cam profile-this is all against the force of the spring which provides the feel. So the feel comes from the cam profile and spring force.
The artificial feel system for the elevator is a little more complex. Basically there is a elevator feel computer system which provides feel to the control column mechanically. Now, this computer is purely mechanical. It has inputs from typically two hydraulic systems, pitot and static air pressure in pneumatic form not electronic, and a position input from the stabiliser which is also mechanical and not electrical.
Hope that makes sense!