Final answer:
Frida Kahlo was the artist not formally associated with the Surrealists but used a similar approach in her autobiographical works. She focused on painting her reality rather than dreams, with surrealistic elements present in her style.
Step-by-step explanation:
The artist who was not a member of the Surrealists but used a similar approach to the Surrealists in autobiographical works is Frida Kahlo. Although Kahlo's work featured surrealistic elements and she was influenced by Surrealist concepts, she did not formally align herself with the movement, instead claiming that she painted her own reality rather than dreams. In contrast, artists like Salvador Dalí, Joan Miró, and Diego Rivera had different degrees of association with the Surrealist movement, with Dalí and Miró being prominent members, and Rivera being Kahlo's husband and fellow supporter of Mexican political and cultural nationalism.