Biographical fallacy is a term from literary criticism used to refer to the error of evaluating a text on the basis of its emotional effects on a reader. It is a fallacy though to interpretate literature through the life of an author.The term is one of the main principle of New Criticism( dominant trend from the 20s to the 60s). One figure of this trend is T.S. Eliot with his impersonal poetry and artificial craft.
That´s what u find in the America of the 50s. You can´t write about yourself and there ´s a narrow capacity of moving to express the poet´s feelings. With all this background an important book appeared , Life Studies (Robert Lowell:1959), a book that reflected stylistic changes that seemed more in line with the popular openness of Beat and Confessional poetry. It opened the way to next biographical experiments and openness of the feelings in the poem. Sylvia Plath was a traditional , neo-romantic and expressionist poet. In the early 60s she started to write confessionalist poetry or what´s the same, poetry about herself. She followed Robert Lowell as a leader.