Shyness is most likely to occur during unfamiliar situations, though in severe cases it may hinder an individual in their most familiar situations and relationships as well. Shy people avoid the objects of their apprehension in order to keep from feeling uncomfortable and inept; thus, the situations remain unfamiliar and the shyness perpetuates itself. Shyness may fade with time; e.g., a child who is shy towards strangers may eventually lose this trait when older and become more socially adept. This often occurs by adolescence or young adulthood (generally around the age of 13). In some cases, though, it may become an integrated, lifelong character trait. Longitudinal data suggests that the three different personality types evident in infancy – easy, slow-to-warm-up, and difficult – tend to change as children mature. Extreme traits become less pronounced, and personalities evolve in predictable patterns over time. What has been proven to remain constant is the tendency to internalize or externalize problems. This relates to individuals with shy personalities because they tend to internalize their problems, or dwell on their problems internally instead of expressing their concerns, which leads to disorders like depression and anxiety. Humans experience shyness to different degrees and in different areas.