A common tripartite strategy employed in empirical studies on folk concept of personal identity goes as follows: First, describe a hypothetical transformation (e.g. amnesia, brain transplantation, reincarnation, PVS, change of moral character). Second, check whether the study participants judge post-transformation individual to be identical to the pre-transformation individual. This is most often done by checking whether study participants refer to the post-transformation individual by the name that was originally introduced to refer to the pre-transformation individual. Third, use these data to draw conclusions about identity criterion(-ia) employed by the folk. For example, if transformation involves loss of all autobiographical memory, but participants still use the same personal name, conclusion is made that autobiographical memory is not considered by the participants to be necessary for identity preservation.In this paper I discuss the most common version of the second step of this strategy. Namely, methodological assumption that participants' use of personal names is indicative of their judgments about numerical identity of individuals. Depending on the study, this assumption is employed as one (sometimes both) of these two inferential strands: 

(A) 'No longer Yusuf' → 'no longer the same person/individual' 
(B) 'Still Yusuf' → 'still the same person/individual'

In this paper I claim that neither of these two strands can be used to draw reliable conclusions about folk judgments of numerical identity. I also claim that neither of these two strands can be sufficiently justified by appeal to the Kripkean notion of rigidity (which is a standard move in psychological literature in question).

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