According to Freud, the 'reality principle' assumes dominance over the 'pleasure principle' as human beings mature, offering strategies for the attainment of desired objects which may involve postponement, detours, or even their entire renunciation. The reality principle modifies the pleasure principle but does not entirely subsume it. It is first born out of the recognition of the need to evolve techniques of self-preservation (e.g. hunting, gathering, storing) but in social organisms becomes culturally extensive and complex.
Whilst the principle is referred to in Freud.s earliest writings in the 1890s, its first extensive consideration in "Formulations on the Two principles of Mental Functioning" (1911), a short but fascinating …
Clark, Robert. "Reality Principle [Realitätsprinzip]". The Literary Encyclopedia. First published 24 October 2005
[http://www.litencyc.com/php/stopics.php?rec=true&UID=1615, accessed 24 January 2017.]