"social worlds in a way that has powerful implications for the information they receive, the attitudes they form, and the interactions they experience." This homophily can foster divides and echo chambers on social networking sites, where people of similar ideologies only interact with each other. Causes and effects Causes Geography: Baseline homophily often arises when the people who are located nearby also have similar characteristics. People are more likely to have contact with those who are geographically closer than those who are distant. Technology such as the telephone, e-mail, and social networks have reduced but not eliminated this effect. Family ties: These ties decay slowly, but familial ties, specifically that of domestic partners, fulfill many requisites that generate homophily. Family relationships are generally close and keep frequent contact though they may be at great geographic distances. Ideas that may get lost in other relational contexts, will often instead lead to actions in this setting. Organizations: School, work, and volunteer activities provide the great majority of non-family ties. Many friendships, confiding relations, and social support ties are formed within voluntary groups. The social homogeneity of most organizations creates a strong baseline homophily in networks that are formed there. Isomorphic sources: The connections between people who occupy equivalent roles will induce homophily in the system of network ties. This is common in three domains: workplace (e.g., all heads of HR departments will tend to associate with other HR heads), family (e.g., mothers tend to associate with other mothers), and informal networks. Cognitive processes: People who have demographic similarity tend to own shared knowledge, and therefore they have a greater ease of communication and share cultural tastes, which can also generate homophily. Effects 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." Another study claims that homophily produces tolerance and cooperation in social spaces. However, homophilic patterns can also restrict access to information or inclusion for minorities. Nowadays, the restrictive patterns of homophily can be widely seen within social media. This selectiveness within social media networks can be traced back to the origins of Facebook and the transition of users from MySpace to Facebook in the early 2000’s. 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