What does reader response criticism mean? And how would one use it?

Reader Response Criticism, as the very name suggests, refers to a school of literary theory which emphasises the reader's experience of a literary work, recognises the reader as an active agent who completes the meaning(s) of a literary text through interpretation(s).

The school originated in the 1960s and expressed itself more fully in the 1970s and 1980s in America and Germany in the works of Norman Holland, Stanley Fish, Wolfgang Iser, Ronald Barthes and others. Stanley Fish's observation that " The 'I' of the reader always colors the text" may be taken as a basic clue to the whole idea.

Reader Response Criticism thus stood in opposition to Formalism and New Criticism which did not recognise  the intention or authority of the reader/audience in the evaluation of a literary text.

Perhaps in I.A.Richards' readings of texts of poetry at Cambridge in 1929, there were the seeds of this school or approach.