A rumour or rumor (see spelling differences), is often viewed as "an unverified account or explanation of events circulating from person to person and pertaining to an object, event, or issue in public concern" (33) However, a review of the research on rumor conducted by Pendleton in 1998 found that research across sociology, psychology, and communication studies had widely varying definitions of rumor. Thus, rumor is a concept that lacks a particular definition in the social sciences. But most theories agree that rumor involves some kind of a statement whose veracity is not quickly or ever confirmed. In addition, some scholars have identified rumor as a subset of propaganda, the latter another notoriously difficult concept to define. A pioneer of propaganda studies, Harold Lasswell defined propaganda in 1927 as referring "solely to the control of opinion by significant symbols, or, to speak more concretely and less accurately, by stories, rumors, reports, pictures, and other forms of social communication" (1927:9). Rumors are also often discussed with regard to "misinformation" and "disinformation" (the former often seen as simply false and the latter seen as deliberately false, though usually from a government source given to the media or a foreign government). Rumors thus have often been viewed as particular forms of other communication concepts.

Psychology of Rumor (1902)

French and German social science research on rumor locates the modern scholarly definition of it the pioneering work of the German Louis William Stern in 1902. Stern experimented on rumor involving a "chain of subjects" who passed a story from "mouth to ear" without the right to repeat or explain it. He found that the story was shortened and changed by the time it reached the end of the chain. His student was another pioneer in the field, Gordon Allport.

Psychology of Rumor: Three Types (1944)

"A Psychology of Rumor" was published by Robert Knapp in 1944, in which he reports on his analysis of over one thousand rumors during World War II that were printed in the Boston Herald's "Rumor Clinic" Column. He defines rumor as

'' a proposition for belief of topical reference disseminated without official verification''. So formidably defined, rumor is but a special case of informal social communications, including myth, legend, and current humor. From myth and legend it is distinguished by its emphasis on the topical. Where humor is designed to provoke laughter, rumor begs for belief.

Knapp identified three basic characteristics that apply to rumor: 1. they're transmitted by word of mouth; 2. they provide "information" about a "person, happening, or condition"; and 3. they express and gratify "the emotional needs of the community." Crucial to this definition and its characteristics is the emphasis on transmission (word of mouth, which then was heard and reported in the newspaper); on content ("topical" means that it can somehow be distinguished from trivial and private subjects--its domain is public issues); and on reception ("emotional needs of the community" suggests that though it is received by an individual from an individual, it is not comprehended in individual but community or social terms).