Rationale for imprinting Edit. The reason for imprinting is unknown. Sam Uley believes that a shape-shifter imprints on the person with whom he has the best chance to reproduce. How this applies to Jacob Black and Renesmee Cullen is debatable.Billy Black, however, thinks that imprinting is designed to make the shape-shifter stronger.here are stages to imprinting, especially if the shape-shifter imprints on a child, or otherwise someone very young. 1st stage —If the imprintee is young, the shape-shifter will act as an older sibling.