Although many people feel that expectations for personal space (usually about 18 inches for americans) are innate, members of many cultures are used to noticeably less personal space than we are, which to demonstrate that our expectations for personal space are:
a. the direct result of hormonal differences in the limbic system
b. usually negotiable and not all that hard to change
c. a part of our culture and as such are learned, rather than innate
d. very difficult to measure accurately
e. something that is innate, more an instinct than something that is learned