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8

Influence and Homophily

Social forces connect individuals in different ways. When individuals get

connected, one can observe distinguishable patterns in their connectivity

networks. One such pattern isassortativity, also known associal similarity. ASSORTATIVITY

In networks with assortativity, similar nodes are connected to one another

more often than dissimilar nodes. For instance, in social networks, a high

similarity between friends is observed. This similarity is exhibited by sim-

ilar behavior, similar interests, similar activities, and shared attributes such

as language, among others. In other words, friendship networks areassor-

tative. Investigating assortativity patterns that individuals exhibit on social

media helps one better understand user interactions. Assortativity is the

most commonly observed pattern among linked individuals. This chapter

discusses assortativity along with principal factors that result in assortative

networks.

Many social forces induce assortative networks. Three common forces

areinfluence,homophily, andconfounding. Influence is the process by INFLUENCE,

HOMOPHILY,

AND

CONFOUNDING

which an individual (the influential) affects another individual such that

the influenced individual becomes more similar to the influential figure.

Homophily is observed in already similar individuals. It is realized when

similar individuals become friends due to their high similarity. Confound-

ing is the environment’s effect on making individuals similar. For instance,

individuals who live in Russia speak Russian fluently because of the envi-

ronment and are therefore similar in language. The confounding force is

an external factor that is independent of inter-individual interactions and is

therefore not discussed further.

Note that both influence and homophily social forces give rise to assor-

tative networks. After either of them affects a network, the network exhibits

more similar nodes; however, when “friends become similar,” we denote

that as influence, and when “similar individuals become friends,” we call

it homophily. Figure8.1depicts how both influence and homophily affect

social networks.

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