Rumination syndrome the syndrome in mentally healthy patients appeared thereafter. At first, adult rumination was described and treated as a benign condition. It is now described as otherwise. While the base of patients to examine has gradually increased as more and more people come forward with their symptoms, awareness of the condition by the medical community and the general public is still limited. The chewing of cud by animals such as cows, goats, and giraffes is considered normal behavior. These animals are known as ruminants. Such behavior, though termed rumination, is not related to human rumination syndrome, but is ordinary. Involuntary rumination,
Chewing gum took place prior to cognitive testing. The precise mechanism by which gum chewing improves cognitive functioning is however not well understood. The researchers did also note that chewing-induced arousal could be masked by the distracting nature of chewing itself, which they named "dual-process theory", which in turn could explain some of the contradictory findings by previous studies. They also noticed the similarity between mild physical exercise such as pedaling a stationary bike and chewing gum. It has been demonstrated that mild physical exercise leads to little cognitive impairment during the physical task accompanied by enhanced cognitive functioning afterwards. Furthermore, the