Instinct is the innate tendency of understanding a particular pattern, triggered by natural tendency or impulse. Most often instincts are not based on previous experience, but can be inherited. While it is commonly used by biologists to describe the fixed action pattern in animals, psychologists prefer to define it as motivational forces in humans. The main sign of instinctive behavioral pattern is that it is actuated by external force, and do not require any modification or prior experience and is spontaneous. Read the article to know more about these famous instinct quotations and sayings.