Curiosity (from Latin curiosus 'careful, diligent, curious,' akin to cura 'care') is a quality related to inquisitive thinking such as exploration, investigation, and learning, evident by observation in human and many animal species. The term can also be used to denote the behavior itself being caused by the emotion of curiosity. As this emotion represents a thirst for knowledge, curiosity is a major driving force behind scientific research and other disciplines of human study. Although many living beings have an innate capability of curiosity, it should not be categorized as an instinct because it is not a fixed action pattern; rather it is an innate basic emotion because while curiosity can be expressed in many ways, the expression of an instinct is typically more fixed and less flexible. Curiosity is common to human beings at all ages from infancy through adulthood, and is easy to observe in many other animal species.