Exogeny

In a variety of contexts, exogeny or exogeneity (from Greek ἔξω éxō 'outside' and -γένεια -géneia 'to produce') is the fact of an action or object originating externally. It contrasts with endogeneity or endogeny, the fact of being influenced within a system.

  • In an economic model, an exogenous change is one that comes from outside the model and is unexplained by the model.
  • In econometrics, an endogenous random variable is correlated with the error term in the econometric model, while an exogenous variable is not.[1]
  • In biology, an exogenous contrast agent in medical imaging for example, is a liquid injected into the patient intravenously that enhances visibility of a pathology, such as a tumor. An exogenous factor is any material that is present and active in an individual organism or living cell but that originated outside that organism, as opposed to an endogenous factor.
  • In geography, exogenous processes all take place outside the Earth and all the other planets. Weathering, erosion, transportation and sedimentation are the main exogenous processes.
  • In attentional psychology, exogenous stimuli are external stimuli without conscious intention.[2] An example of this is attention drawn to a flashing light in the periphery of vision.
  • In ludology, the study of games, an exogenous item is anything outside the game itself. Therefore, an item in a massively multiplayer online game would have exogenous value if people were buying it with real world money rather than in-game currency (though its in-game cost would be endogenous).
  • In materials science, an exogenous property of a substance is derived from outside or external influences, such as a nano-doped material.
  • In philosophy, the origins of existence of self, or the identity of self, emanating from, or sustaining, outside the natural or influenced realm, are exogenous.

ReferencesEdit

  1. ^ Wooldridge, Jeffrey M. (2009). Introductory Econometrics: A Modern Approach (Fourth ed.). Mason: South-Western. p. 49. ISBN 978-0-324-66054-8.
  2. ^ Posner, M. I. (1980). "Orienting of Attention". Quarterly Journal of Experimental Psychology. 32: 3–25.

External linksEdit

  •   The dictionary definition of exogeny at Wiktionary