B757 Undifferentiated or Other Model
Flight Crew Last 90 Days 130; Flight Crew Total 10000; Flight Crew Type 4500
Aircraft Equipment Problem Less Severe
Aircraft
While at cruise at FL360 we began to experience what felt like someone applying short; brisk; rudder inputs.  These varied between left and right input; and there was no discernible pattern.  The ride was smooth so as not to confuse this with any turbulence--supported by the Flight Attendants (FA) who all remarked they noticed the unusual behavior. After we realized it was a continuing anomaly; and because there were no indications of any rudder input by lower EICAS or actual rudder pedals; we [notified] ATC.  We initiated the descent; referenced the QRH to our situation as practical; and continued to [destination]. The anomaly lessened considerably below FL200; and the flight terminated without further incident. Upon arrival at the gate we were informed there was at least one historical event on this airplane related to rudder control.
[Report narrative contained no additional information].
B757 flight crew reported noticing uncommanded rudder inputs in cruise flight. Crew decided to continue to destination.