The Second Doctor noted that human beings had, in addition to their five senses, instinct. (TV: The Evil of the Daleks)
The Fourth Doctor told Borusa that he had taught him nothing that instinct couldn't provide better. He later described Leela as a creature of instinct. (TV: The Invasion of Time)
Weeping Angels would engage their quantum-locking on instinct when they believed they were being observed. (TV: Flesh and Stone)
When the Triskele divided themselves into three parts, their instinct became the Uncreators. (AUDIO: Storm Warning)
According to Nyssa, arachnids knew how to build webs by instinct. (AUDIO: Alien Heart)