The English Wikipedia article on the default effect (the source already cited on this entity) describes the concept, its endogenous and exogenous forms and its applications in detail but names no year, paper or author for when it was first described or named; a full raw-extract read of the article (9384 characters) contains no four-digit year at all.
What would resolve this A citable paper, textbook or reference work naming the year and author or authors who first described or coined the term for the default effect.
Openbehavioral economicsWikipedia: Default effect