Historical changes in American self-interest: State of the Union addresses 1790 to 2012

•Traits related to self-interest have increased over the past 30 years.•Researchers neglect changes beyond this period for other markers of self-interest.•We examined changes in American self-interest using State of the Union addresses.•Self-interest was low during the 19th century but rose during the 20th century.•We discuss possible causes and implications of these increases in self-interest.

Many psychological theories of morality suggest that satisfying our own self-interest motives and desires at the expense of others is the default condition in early childhood development, but that humans eventually learn to behave selflessly in the interest of others. Recent research examining societal increases in traits related to self-interest (e.g., narcissism) in the US finds increases in such traits over the past 30 years. The current study examined changes in self-interest from 1790 through 2012 using presidential State of the Union addresses. Self-interest (relative to interest in others) was low during the 19th century but rose after the turn of the 20th century.