For over half a century market segments have been considered objective groupings of individuals which marketers identify, understand, and target with advertising messages. The process of market segmentation has, therefore, occupied a position of moral neutrality. An increasingly popular method of segmentation is by consumer personality, with advertisers targeting messages to specific personality types. This paper explores personality segmentation, and presents empirical evidence to support the proposition that personality metrics that are used to assign individuals to segments may, in fact, be manipulable by advertising executions themselves. Quite apart from the implications that this has for the business efficacy of the segmentation process, the ethical implications particularly as applied to children - are considerable.