the groves and thompson dual-process theory of habituation posits that two separate processes exist in the central nervous system that interacts to produce habituation. the two distinct processes are a habituation process and a sensitization process. the dual-process theory argues that all noticeable stimuli will elicit both of these processes and that the behavioral output will reflect a summation of both processes. the habituation process is decremental, whereas the sensitization process is incremental enhancing the tendency to respond. thus when the habituation process exceeds the sensitization process behavior shows habituation, but if the sensitization process exceeds the habituation process, behavior shows sensitization. groves and thompson hypothesize the existence of two neural pathways: an "s-r pathway" involved with the habituation process, and a "state pathway" involved with sensitization. the state system is seen as equivalent to a general state of arousal.