The friend's consciousness gets "impressed" by their measurement of the spin, and therefore they may assign a wave function to it according to the nature of their impression. Wigner, having no access to that information, can only assign the wave function formula_27to the joint system of spin and friend after the interaction. When he then asks his friend about the measurement outcome, Wigner's consciousness gets "impressed" by the friend's answer: As a result, Wigner will be able to assign a wave function to the spin system, i.e., he will assign to it the wave function corresponding to the friend's answer.