Homophily (from Ancient Greek ὁμός (homós) 'same, common' and φιλία (philía) 'friendship, love') is a concept in sociology describing the tendency of individuals to associate and bond with similar others, as in the proverb "birds of a feather flock together".
Those that belong in the same religion are more likely to exhibit acts of service and aid to one another, such as loaning money, giving therapeutic counseling, and other forms of help during moments of emergency.
[14] Additionally, as more users begin to rely on the Internet to find like minded communities for themselves, many examples of niches within social media sites have begun appearing to account for this need.
This response has led to the popularity of sites like Reddit in the 2010s, advertising itself as a "home to thousands of communities... and authentic human interaction.
"[15] As social networks are largely divided by race, social-networking websites like Facebook also foster homophilic atmospheres.
In a research article, McPherson, Smith-Lovin, and Cook (2003) write that homogeneous personal networks result in limited "social worlds in a way that has powerful implications for the information they receive, the attitudes they form, and the interactions they experience.
"[17] This homophily can foster divides and echo chambers on social networking sites, where people of similar ideologies only interact with each other.
[20] Isomorphic sources: The connections between people who occupy equivalent roles will induce homophily in the system of network ties.
According to one study, perception of interpersonal similarity improves coordination and increase the expected payoff of interactions, above and beyond the effect of merely "liking others.
[24] One study of this shift in a network's user base from danah boyd (2011) found that this perception of homophily impacted many individuals' preference of one site over another.
Some studies have claimed that homophily facilitates access information,[26] the diffusion of innovations and behaviors,[27] and the formation of social norms.
[28] Other studies, however, highlight mechanisms through which homophily can maintain disagreement, exacerbate polarization of opinions, lead to self segregation between groups, and slow the formation of an overall consensus.
However, it is recently found that there exists a non-trivial sets of dataset where homophily principle doesn't hold, i.e. heterophily, and GNN performance is unsatisfactory.