In humankind, mutual grooming relates closely to social grooming, which is defined as the process by which human beings fulfill one of their basic instincts, such as socializing, cooperating and learning from each other. In research conducted by Holly Nelson (from the University of New Hampshire) and Glenn Geher (State University of New York at Platz), individuals who chose their romantic partner reported more mutual grooming than others who focused in other types of relationships. Hence, this study hypothesized that mutual grooming related to relationship satisfaction, trust and previous experience of affection within the family. They claim that even though humans do not groom each other with the same fervor that other species do, they are groomers par excellence. Therefore, human mutual grooming plays an important role in pair bonding. In the same investigation, researchers found that individuals with more promiscuous attitudes and those who scored high on the anxiety sub-scale on an adult attachment style measure tend to groom their partners more frequently. These findings were also consistent with some of the functions of grooming: potential parental indicator, developing trust and courtship or flirtation.