Sociometer theory is a theory put forward by Mark Leary in 1999, proposing that humans have evolved a form of psychological meter, or gauge, which monitors the degree to which other people value and accept them. Leary named this monitor a sociometer, and proposed that this evaluation of the individual’s level of acceptance by others is a determinant of self-esteem.
Leary, M. R. (1999) “Making Sense of Self-Esteem“. Current Directions in Psychological Science 8 (1) , 32–35 doi:10.1111/1467-8721.00008
See video lecture by Mark Leary: Overreactions to Trivial Events: Why Do People Sometimes “Lose It” Over Minor Things?