Driver monitoring system for a vehicle and method for driver monitoring

A driver monitoring system for a vehicle has at least one output device, a monitoring module, and a control module. The output device is configured to output at least one attentiveness warning. The monitoring module is configured to monitor a driver of the vehicle and to recognize inattentiveness states of the driver. The control module is configured to accumulate a duration of the recognized inattentiveness states within a finite time window having a predetermined length in order to determine an accumulated inattentiveness duration for the finite time window and to actuate the at least one output device for the output of the at least one attentiveness warning based on the accumulated inattentiveness duration and a tempo measure of an increase of the accumulated inattentiveness duration.