Research suggests that no unique physiological response, such as an increased heart beat, accompanies socially withdrawn behavior in familiar compared with unfamiliar social situations. But unsociability leads to decreased exposure to unfamiliar social situations and shyness causes a lack of response in such situations, suggesting that shyness and unsociability affect two different aspects of sociability and are distinct personality traits. In addition, different cultures perceive unsociability and shyness in different ways, leading to either positive or negative individual feelings of self-esteem. Collectivist cultures view shyness as a more positive trait related to compliance with group ideals and self-control, while perceiving chosen isolation (introverted behavior) negatively as a threat to group harmony; and because collectivist society accepts shyness and rejects unsociability, shy individuals develop higher self-esteem than introverted individuals. On the other hand, individualistic cultures perceive shyness as a weakness and a character flaw, while unsociable personality traits (preference to spend time alone) are accepted because they uphold the value of autonomy; accordingly, shy individuals tend to develop low self-esteem in Western cultures while unsociable individuals develop high self-esteem.