participants of different ages and cultures. However, while genotypic temperament trait dimensions might appear across different cultures, the phenotypic expression of personality traits differs profoundly across different cultures as a function of the different socio-cultural conditioning and experiential learning that takes place within different cultural settings. Moreover, the fact that the Big Five model was based on lexical hypothesis (i.e. on the verbal descriptors of individual differences) indicated strong methodological flaws in this model, especially related to its main factors, Extraversion and Neuroticism. First, there is a natural pro-social bias of language in people's verbal evaluations. After all, language is an invention of group dynamics that was developed to facilitate socialization and the exchange of information and to synchronize group activity. This social function of language therefore creates a sociability bias in verbal descriptors of human behavior: there are more words related to social than physical or even mental aspects of behavior. The sheer number of such descriptors will cause them to group into the largest factor in any language, and such grouping has nothing to do with the way that core systems of individual differences are set up. Second, there is also a negativity bias in emotionality (i.e. most emotions have negative affectivity), and there are more words in language to describe negative rather than positive emotions. Such asymmetry in emotional valence creates another bias in language. Experiments using the lexical hypothesis approach indeed demonstrated that the use of lexical material skews the resulting dimensionality according to a sociability bias of language and a negativity bias of emotionality, grouping all evaluations around these two dimensions. This means that the two largest dimensions in the Big Five model might be just an artifact of the lexical approach that this model employed. Limited scope One common criticism is that the Big Five does not explain all of human personality. Some psychologists have dissented from the model precisely because they feel it neglects other domains of personality, such as religiosity, manipulativeness/machiavellianism, honesty, sexiness/seductiveness, thriftiness, conservativeness, masculinity/femininity, snobbishness/egotism, sense of humour, and risk-taking/thrill-seeking. Dan P. McAdams has called the Big Five a "psychology of the stranger", because they refer to traits that are relatively easy to observe in a stranger; other aspects of personality that are more privately held or more context-dependent are excluded from the Big Five. There may be debate as to what counts as personality and what does not and