``Traditional noise research'' is based upon the psychophysics of auditory perception and neglects the ecological meaning of physical noise measurements. In contrast, ``ecological noise research'' emphasizes that sounds have a psychological function, regarding annoyance caused by acoustical signals not compatible with these psychological functions. In the present paper, this functional approach is extended, also implying the biological function: Assuming a harmful environmental variable affecting the individual's (Darwinian) fitness, there is a possibility that a neural detector will evolve (the input of which is the sensory stimulation correlated with this variable, while the output is motivating the actions capable of diminishing that sensory input) thereby possibly interrupting ongoing behavior. Event-related integration of sensory data is an essential part of this detector, causing the experienced annoyance to be composed of components representing number, average intensity, and average duration of the disturbing events. Because the energy-equivalent sound level L[inf eq] is composed in this manner, annoyance, measured by the L[inf eq], can indeed be considered a possible-loss-of-fitness signal (PLOF signal). Therefore, ``traditional'' and ``ecological'' noise research are not as contradictory as suggested above. However, the old problem of how to find the conditions influencing the annoyance rating can now be replaced by the question: Which conditions shaped the PLOF-detector in the evolution of men?