It is debatable who or what is decisive in determining which change in a human characteristic can be considered an improvement. Answers to this question are relatively undisputed when it comes to characteristics for which assessment criteria that are not person-specific are available. In sports doping, for instance, any intervention that reliably improves performance in a particular sport is considered an enhancement, even if it may worsen an athlete's life situation in another way, for example because it is associated with serious side effects. There are also intersubjectively valid assessment standards for cognitive abilities, e.g. in the form of IQ tests. However, in both the physical and cognitive domains, there are cases where people do not wish to enhance but rather to diminish a particular trait or ability. For example, when it comes to forgetting troubling experiences, the person concerned will consider a decrease in memory performance an improvement. The targeted deletion of upsetting memories can only be regarded as memory enhancement if the perspective of the person affected is decisive in determining whether a change represents an improvement. Especially in the aesthetic field, it is difficult to question subjective evaluations. For example, the term "body modification" is used to describe extreme interventions that are perceived by the majority as mutilation rather than embellishment. Nevertheless, it might be reasonable to also recognize decorative scars and conspicuous piercings as aesthetic enhancement, because they are regarded by the affected persons themselves as improvement of their outer appearance.