http://www.smartplanet.com/business/blog/smart-takes/why-am-i-shy-new-study-offers-insight-on-introverts/5744/
Researchers have determined that about 20 percent of people are born with a personality trait called “sensory perception sensitivity,” or SPS, which facilitates an inhibited, even neurotic, demeanor.
Colloquially, we say those people are “slow to warm up” to social situations, or may cry easily, or offer deeper than expected thoughts, according to the study.
The results suggested that highly sensitive individuals:
* Prefer to take longer to make decisions.
* Are more conscientious.
* Need more time to themselves in order to reflect.
* Are more easily bored with small talk.
Those attributes complement previous research, which found that highly sensitive individuals are more bothered by noise and crowds, affected by caffeine, and easily startled compared to “non-sensitive” individuals.
All that may seem obvious, but the research suggests that sensory sensitivity is a result of an inherent nature to be more attentive to experiences — not the other way around.