An investigator attempted to ascertain the effects of hunger on aggression in cats. She took ten cats, kept them in individual cages, and put them on a food deprivation schedule such that at the end of two weeks the cats weighed 80 percent of their normal body weight. She then put the cats in pairs for 15 minutes and watched to see if aggression or fighting took place. In all cases, the cats showed the threat posture, and in most cases fighting occurred. The investigator concluded that hunger increases aggression.