Homophily

Homophily (i.e., "love of the same") is the tendency of individuals to associate and bond with similar others, as in the proverb "". The presence of homophily has been discovered in a vast array of network studies. More than 100 studies that have observed homophily in some form or another and they establish that similarity breeds connection. These include age, gender, class, and organizational role.

Individuals in homophilic relationships share common characteristics (beliefs, values, education, etc.) that make communication and relationship formation easier. The opposite of homophily is heterophily or intermingling.

Homophily is a metric studied in the field of social network analysis in which it is also known as assortativity.

Homophily between mated pairs in animals has been extensively studied in the field of evolutionary biology in which it is known as assortative mating. Homophily between mated pairs is common within natural animal mating populations.

To test the relevance of homophily researchers have distinguished between baseline homophily and inbreeding homophily. The former is simply the amount of homophily that would be expected by chance given an existing uneven distribution of people with varying characteristics, and the second is the amount of homophily over and above this expected value, typically due to personal preferences and choices.

In their original formulation of homophily, Lazarsfeld and Merton (1954) distinguished between status homophily and value homophily.

The authors find that individuals with similar social status characteristics are more likely to associate with each other than by chance. "Status" includes both ascribed characteristics like race, ethnicity, sex, and age; and acquired characteristics like religion and education. In contrast, value homophily involves association with others who think in similar ways, regardless of differences in these status characteristics.

Social networks in United States today are strongly divided by race and ethnicity, which account for the greatest proportion of inbreeding homophily (though classification by these criteria can be problematic in sociology due to fuzzy boundaries and different definitions of race). Smaller groups have lower diversity simply due to the number of members, and this tends to give racial and ethnic minority groups a higher baseline homophily. Race and ethnicity also correlates with educational attainment and occupation, which increase baseline homophily further.

...
Wikipedia