Exogenous (or exogeneous) (from the Greek words "exo" and "gen", meaning "outside" and "production") refers to an action or object coming from outside a system. It is the opposite of endogenous, something generated from within the system.
- In attentional psychology, exogenous refers to attention being drawn without conscious intention (see Posner, 1980). An example of this would be attention drawn to a flashing light in the periphery of vision.
- In linear regression, it means that the variable is independent of all other response values.
- In biology, "exogenous" refers to an action or object coming from the outside of a system. For example, an exogenous contrast agent in medical imaging refers to a liquid injected IV in the patient that enhances visibility of a pathology, such as a tumor.
- In biology, an exogenous factor is any material that is present and active in an individual organism or living cell but that originated outside of that organism, as opposed to an endogenous factor.
Posner, M.I. (1980), Orienting of attention. Quarterly Journal of Experimental Psychology, 32: 3 – 25.