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Abstract

Similarity breeds connection. This principle--the homophily principle--structures network ties of every type, including marriage, friendship, work, advice, support, information transfer, exchange, comembership, and other types of relationship. The result is that people's personal networks are homogeneous with regard to many sociodemographic, behavioral, and intrapersonal characteristics. Homophily limits people's social worlds in a way that has powerful implications for the information they receive, the attitudes they form, and the interactions they experience. Homophily in race and ethnicity creates the strongest divides in our personal environments, with age, religion, education, occupation, and gender following in roughly that order. Geographic propinquity, families, organizations, and isomorphic positions in social systems all create contexts in which homophilous relations form. Ties between nonsimilar individuals also dissolve at a higher rate, which sets the stage for the formation of niches (localized positions) within social space. We argue for more research on: (a) the basic ecological processes that link organizations, associations, cultural communities, social movements, and many other social forms; (b) the impact of multiplex ties on the patterns of homophily; and (c) the dynamics of network change over time through which networks and other social entities co-evolve.
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Annu. Rev. Sociol. 2001. 27:415–44
Copyright c
°2001 by Annual Reviews. All rights reserved
BIRDS OF A FEATHER:Homophily
in Social Networks
Miller McPherson1, Lynn Smith-Lovin1, and
James M Cook2
1Department of Sociology, University of Arizona, Tucson, Arizona 85721;
e-mail: mcpherson@u.arizona.edu; smithlov@u.arizona.edu
2Department of Sociology, Duke University, Durham, North Carolina 27708;
e-mail: jcook@soc.duke.edu
Key Words human ecology, voluntary associations, organizations
Abstract Similarity breeds connection. This principle—the homophily princi-
ple—structures network ties of every type, including marriage, friendship, work,
advice, support, information transfer, exchange, comembership, and other types of re-
lationship. The result is that people’s personal networks are homogeneous with regard
to many sociodemographic, behavioral, and intrapersonal characteristics. Homophily
limits people’s social worlds in a way that has powerful implications for the infor-
mation they receive, the attitudes they form, and the interactions they experience.
Homophily in race and ethnicity creates the strongest divides in our personal envi-
ronments, with age, religion, education, occupation, and gender following in roughly
that order. Geographic propinquity, families, organizations, and isomorphic positions
in social systems all create contexts in which homophilous relations form. Ties be-
tween nonsimilar individuals also dissolve at a higher rate, which sets the stage for
the formation of niches (localized positions) within social space. We argue for more
research on: (a) the basic ecological processes that link organizations, associations,
cultural communities, social movements, and many other social forms; (b) the impact
of multiplex ties on the patterns of homophily; and (c) the dynamics of network change
over time through which networks and other social entities co-evolve.
INTRODUCTION
People with different characteristics—genders, races, ethnicities, ages, class back-
grounds, educational attainment, etc.—appear to have very different qualities. We
often attribute these qualities to some essential aspect of their category member-
ship. For example, women are emotional, educated people are tolerant, and gang
members are violent. These essentialist attributions ignore the vast differences in
the social worlds that these people occupy. Since people generally only have sig-
nificant contact with others like themselves, any quality tends to become localized
insociodemographicspace.Byinteractingonly with others whoarelike ourselves,
0360-0572/01/0811-0415$14.00 415
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416 MCPHERSON ¥SMITH-LOVIN ¥COOK
anything that we experience as a result of our position gets reinforced. It comes to
typify “people like us.”
Homophily is the principle that a contact between similar people occurs at a
higher rate than among dissimilar people. The pervasive fact of homophily means
that cultural, behavioral, genetic, or material information that flows through net-
works will tend to be localized. Homophily implies that distance in terms of
social characteristics translates into network distance, the number of relationships
through which a piece of information must travel to connect two individuals. It
also implies that any social entity that depends to a substantial degree on networks
for its transmission will tend to be localized in social space and will obey certain
fundamental dynamics as it interacts with other social entities in an ecology of
social forms.
The literature on these ecological phenomena is spread through the studies
of social networks, voluntary associations, social capital (at the individual and
community levels), social movements, culture, organizations, and a variety of
substantive topics that are affected by network processes. Because the principle of
homophily is so key to the operation of these systems, we use it as our organizing
concept. We first review the classic uses of the concept, then briefly summarize the
voluminousevidence for thisempirical pattern. In particular,we focusonthe many
types of network relationships that researchers have found to be homophilous,
and on the wide range of dimensions on which similarity induces homophily.
We then examine the sources of homophily, focusing on the social structures
that induce propinquity among similar others and the cognitive processes that
make communication between similar others more likely. Finally, we end with
implications for future research.
HOMOPHILY: A BASIC ORGANIZING PRINCIPLE
A pattern as powerful and pervasive as the relationship between association and
similaritydid not go unnoticedin classical Westernthought.In Aristotle’sRhetoric
and Nichomachean Ethics, he noted that people “love those who are like them-
selves” (Aristotle 1934, p. 1371). Plato observed in Phaedrus that “similarity
begets friendship” (Plato 1968, p. 837).1The positive relationship between the
similarity of two nodes2in a network and the probability of a tie between them
was one of the first features noted by early structural analysts (see a historical
review in Freeman 1996). Social scientists who began systematic observations
of group formation and network ties in the 1920s and 1930s (e.g., Bott 1928,
1Both Aristotle and Plato stated in other locations (Aristotle 1934:1155; Plato 1968:837)
that opposites might attract, so it would be inappropriate to think of them as unambiguously
anticipating later social scientific observations.
2A “node” is any element (person, organization or other entity) that can be connected (or
not) to other nodes through relational ties in a network.
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HOMOPHILY IN SOCIAL NETWORKS 417
Wellman 1929, Hubbard 1929) noted that school children formed friendships and
play groups at higher rates if they were similar on demographic characteristics.
The classic citation in the sociological literature seems to be Lazarsfeld &
Merton’s (1954) study of friendship process in Hilltown and Craftown. Lazarsfeld
& Merton drew on the theoretical work of Simmel (1971) and Park & Burgess
(1921). Their use of the term “homophily” coalesced the observations of the early
network researchers and linked it to classic anthropological studies of homogamy
(homophily in marriage formation). They also quoted the proverbial expression of
homophily,“birdsof afeather flocktogether,”which ashas beenused tosummarize
the empirical pattern ever since.3
Studies of Homophily Across the Century: Methodological
and Substantive Progressions
The earliest studies of homophily concentrated on small social groups, in which
an ethnographic observer could easily ascertain all of the ties between members
(whether those ties were behavioral, like sitting together at a cafeteria table, or
reported, as when an informant tells about his or her close friends). Therefore,
our first systematic evidence of homophily in informal network ties came from
school children, college students, and small urban neighborhoods. The initial
network studies showed substantial homophily by demographic characteristics
such as age, sex, race/ethnicity, and education (e.g., Bott 1929, Loomis 1946),
and by psychological characteristics like intelligence, attitudes, and aspirations
(e.g., Almack 1922, Richardson 1940).
Bymid-century a vigorous researchtradition had grown,with two mainthemes.
As issues of race and school desegregation dominated the US political arena, many
researchers focused on the extent of informal segregation in newly desegregated
schools, buses, and other public places (see review in Schofeld 1995). While ob-
servation of relationships eventually lagged behind the study of prejudice and
other attitudinal measures, researchers found strongly homophilous association
patterns by race and ethnicity (although these behavioral patterns were sometimes
weaker than the attitudinal prejudice). A second tradition began with the strong
assumption that peer groups were an important source of influence on people’s be-
havior (especially among adolescents). Whether the focus was positive influence
(e.g., of college aspirations) or negative influence (e.g., of deviant subcultures),
cross-sectional association between some individual characteristic and the corre-
sponding characteristics of that individual’s friends were used as evidence for the
potency of peer context.
3Lazarsfeld & Merton attributed the proverb to Robert Burton (1927[1651]:622). Like
Lazarsfeld & Merton, Burton acknowledged his own conceptual predecessors in classic
Western thought. The closest to the modern proverb is Diogeniasnus’ observation that
“Jackdaw percheth beside Jackdaw” (quoted in Burton 1927[1651]:622).
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418 MCPHERSON ¥SMITH-LOVIN ¥COOK
The 1970s and 1980s produced a change in scale of the evidence on homophily,
as researchers applied the technology of modern sample surveys to the study of
social networks for the first time (see a brief review in Marsden 1987, pp. 122–24).
Whether in large-scale studies of schools (Duncan et al 1972, Shrum et al 1988),
communities (Laumann 1966, 1973, Verbrugge 1977, Fischer 1982), or the US
population as a whole (Burt 1985, Marsden 1987), we now had information about
the networks in large systems with the ability to generalize to a known population.
Theselarge-scalestudies also allowedus to measure homophilysimultaneously on
multiplecharacteristics, just astheoreticaldevelopmentsaboutcross-cutting social
circles (P Blau 1977) made us aware of the importance of a multidimensional view
for the integration of society.
Recent work has concentrated on the organizational contexts of networks (and,
to a lesser extent, on networks connecting social entities above the level of the
individual—organizations, movements, web pages, and the like). An interest in the
effects of networks on both individual careers and organization success fostered
many studies of connections in work organizations (Ibarra 1997, Burt 1992, 2000),
in the work force more generally (Campbell 1988, Lin et al 1981a,b, Ibarra &
Smith-Lovin 1997), or on the interconnected resources necessary to accomplish
tasks in the business world (e.g., Aldrich et al 1989, 1996, Burt 1998). As studies
moved back to the context of social organizations, longitudinal data occasionally
became available to sort out the effects of selection, socialization, and attrition
(Hallinan & Smith 1985, Matsueda & Heimer 1987, Podolny & Baron 1997; see
review in Burt 2000).
Types of Relationships
Researchers have studied homophily in relationships that range from the closest
ties of marriage (see review in Kalmijn 1998) and the strong relationships of
“discussing important matters” (Marsden 1987, 1988) and friendship (Verbrugge
1977, 1983) to the more circumscribed relationships of career support at work
(Ibarra 1992, 1995) to mere contact (Wellman 1996), “knowing about” someone
(Hampton & Wellman 2001) or appearing with them in a public place (Mayhew
etal 1995). Therearesome subtle differencesthat wementionbelow,butingeneral
the patterns of homophily are remarkably robust over these widely varying types
of relations. The few studies that measured multiple forms of relationship (notably
Fischer 1982 and others who have analyzed his data) show that the patterns of
homophily tend to get stronger as more types of relationships exist between two
people, indicating that homophily on each type of relation cumulates to generate
greater homophily for multiplex than simplex ties.
The analytic strategies for analyzing homophily have varied almost as widely
as the types of ties. Some researchers, guided by Blau’s (1977) theoretical ideas,
have concentrated on the relative frequency of in-category and out-category ties
(Blau et al 1982, McPherson & Smith-Lovin 1987). The fact that these patterns are
powerfully affected by the relative size of groups in the pool of potential contacts
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HOMOPHILY IN SOCIAL NETWORKS 419
is one of the central insights of the approach. Others discuss homophily as a devi-
ation from what a baseline model of random assortment would predict. Here, the
concept represents a bias that leads similar people to associate more often than
they would be expected to, given their relative numbers in the opportunity pool
(Coleman 1958, Marsden 1988, Mayhew et al 1995).4Many other researchers
simply use the homogeneity of a network or the similarity of a dyad, measured
on some characteristic, as a source or outcome of social processes, without being
clear whether this homogeneity is created by demographic opportunity or selec-
tion within that opportunity framework (e.g., Fischer 1982). Perhaps surprisingly,
full network measures of heterogeneity and measures of dyad similarity often are
not strongly related; Marsden (1990: footnote 7) finds the correlations of diversity-
based and difference-based personal network measures range between .47
and .63.
We review all of these variants in the work below, attempting to distinguish
between homophily effects that are created by the demography of the potential tie
pool as baseline homophily and homophily measured as explicitly over and above
the opportunity set as inbreeding homophily.5In addition, we occasionally intro-
duce related research on range, density, embeddedness, and other concepts closely
related to homophily but not equivalent. See Campbell et al (1986) for a discus-
sion of how different measures of density, diversity, and multiplexity coalesce as
indicators of network range.
Evidence about Homophily: Salient Dimensions
Lazarsfeld & Merton (1954) distinguished two types of homophily: status ho-
mophily, in which similarity is based on informal, formal, or ascribed status, and
valuehomophily, which isbased on values,attitudes, andbeliefs. Status homophily
includes the major sociodemographic dimensions that stratify society—ascribed
characteristics like race, ethnicity, sex, or age, and acquired characteristics like
religion, education, occupation, or behavior patterns. Value homophily includes
the wide variety of internal states presumed to shape our orientation toward future
behavior. We begin with the former, then move to the latter because they often
prove to be derivative of social positions themselves.
4Fararo & Skvoretz (1987) called this feature tau bias in their theoretical formulation, while
Marsden(1988) calledit inbreedingor social distance, depending on whetherthe dimension
was two category, ordered category, or continuous in nature.
5While one might be tempted to think of inbreeding homophily as equivalent to choice
homophily[a conceptused inMcPherson &Smith-Lovin (1987) torefer toselections within
voluntary organizations5], notice that we use ‘inbreeding’ here to refer both to homophily
induced by social structures below the population level (e.g., voluntary organizations and
other foci of activity), to homophily induced by other dimensions with which the focal
dimension is correlated (which Blau 1977 called consolidation), and to homophily induced
by personal preferences. Therefore, it does not in any sense indicate choice or agency
purified of structural factors.
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420 MCPHERSON ¥SMITH-LOVIN ¥COOK
RACE AND ETHNICITY Race and ethnicity are clearly the biggest divide in social
networks today in the United States, and they play a major part in structuring the
networks in other ethnically diverse societies as well. In this domain, the baseline
homophily created by groups of different sizes is combined with the differences in
racial/ethnic groups’ positions on other dimensions (e.g., education, occupation,
income, religion) and the personal prejudices that often result from the latter to
create a highly visible, oft studied network divide. We find strong homophily on
race and ethnicity in a wide array of relationships, ranging from the most intimate
bonds of marriage (Kalmijn 1998) and confiding (Marsden 1987, 1988), to the
more limited ties of schoolmate friendship (Shrum et al 1988) and work relations
(Lincoln & Miller 1979, Ibarra 1995), to the limited networks of discussion about
a particular topic (Schneider et al 1997), to the mere fact of appearing in public
together (Mayhew et al 1995) or “knowing about” someone else (Lawrence 2000).
Even the negative ties of crime victimization and rape follow the pattern (South &
Felson 1990, South & Messner 1986).
In a national probability sample, only 8% of adults with networks of size two or
more mention having a person of another race with whom they “discuss important
matters” less than one seventh the heterogeneity that we would observe if people
chose randomly from that population (Marsden 1987). People also are much more
likelyto report that theirconfidants are connectedto one another ifthese confidants
aresame race (Louch2000). Of course,peopleoften mentionspousesand other kin
as confidants, so the powerful marital homogamy on race increases the homophily
of confiding relations. But the degree of the racial heterogeneity is still only one
fourth the potential, even if we look only at people who mention no kin in their
discussion network (Marsden 1987).6
This summary picture includes powerful elements of both baseline homophily
and inbreeding homophily. Baseline homophily within most opportunity struc-
tures—the national population, SMSAs, workplaces, and other foci of activity—
leads Anglos to have much more racially homogeneous networks than any other
racial or ethnic group. African Americans and Hispanics fall at moderate lev-
els of homophily, while smaller racial and ethnic groups have networks that are
dominated by the majority group (see Marsden 1987 for the clearest example of
this ordering; Laumann 1973, p. 45, provides an excellent early treatment). Blau
and his colleagues (Blau et al 1982a,b, 1984, 1991, Blum 1984) have demon-
strated that many facets of ethnicity (e.g., mother tongue, national origins, ethnic
group, and region of birth) also display this characteristic. Interestingly, African-
American/Anglo contacts are the occasional exception to the pattern, in that their
intermarriage rates are not well explained by their population distributions (Blau
6Other ways of measuring interracial friendships have produced higher estimates of cross-
race contact, but there is good evidence that these other measures underestimate homophily
(Smith 2000). Asking people if they have a friend or confidant who is of another race leads
people to search their memory more broadly for any cross-race tie, oversampling cross-race
ties relative to same-race ties in memory and possibly creating interviewer demand effects.
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HOMOPHILY IN SOCIAL NETWORKS 421
et al 1982). This rare failure to support Blau’s structural predictions about base-
line homophily is a result of the fact that areas where African Americans are
a larger part of the population also show larger African-American/Anglo differ-
ences in education, income and other social class variables. Once the extent of
these group differences (which Blau calls consolidation) is controlled, the ef-
fect of population distributions again predicts the homogeneity of ties. Blau’s
structural ideas have remarkable power in explaining both positive (intermarriage,
friendship) and negative (crime) contacts (e.g. South & Messner 1986, Sampson
1984).
The baseline phenomenon is important not just in large populations, but also in
more limited settings like classrooms and work organizations. Reskin et al (1999)
report that almost one in four business establishments employ no minorities, while
slightly more than one quarter employ fewer than 10% minority. Similarly, the
National Organization Study found that 34% of all establishments are all white;
the median establishment is 80% white (Kalleberg et al 1996, p. 53–55). Ibarra
(1995) found that racial/ethnic minorities in such a skewed workplace have much
more heterogenous advice and support networks than their majority counterparts.
Instrumental networks of mentoring and advice show this pattern more strongly
than social support networks, because minorities reach beyond the bounds of their
localorganization andoccupational levelto achievesomesame-race friends(Ibarra
1995, Lincoln & Miller 1979). In classrooms, where children have fewer options
for moving outside the organizational bounds, being in a numerically small racial
category makes cross-race friendships more likely to grow close over the course of
aschool year(Hallinan &Smith 1985),probablybecause thereare fewersame-race
alternatives in the setting.
The extraordinary level of racial/ethnic homophily is due not just to baseline
phenomena,however.Thissociodemographic feature alsoleads tothehighest level
of inbreeding homophily (in-group deviations from a random assortment model)
of all the characteristics that researchers have studied. Racial homophily occurs in
friendship networks by the early grades (at least in the Southern towns and urban
neighborhoods where researchers have tracked it). In the third grade, for example,
Shrum et al (1988) observed only two thirds of the cross-race friendships expected
by chance. Racial homophily increases steadily until only 10% of expected cross-
racefriendshipsareobservedin middleschool,then levelsoutfor therestof thehigh
school years. Boys are less homophilous in their racial choices than girls, probably
because of the nature of boys’ play in larger, less intimate groups (Maccoby 1998).
In both schoolchild and adult studies, African Americans display more inbreed-
ing homophily than do Anglos (and, in the school studies, show it earlier) (Shrum
et al 1988, Marsden 1988). Since this pattern of inbreeding homophily works
against the pattern of baseline homophily (which would lead African Americans
to have networks of mostly majority members), it suggests that (a) foci of activ-
ity are more segregated for smaller racial/ethnic categories or that (b) minorities
actively counteract the markedly cross-race patterns generated by the opportunity
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422 MCPHERSON ¥SMITH-LOVIN ¥COOK
structure to generate some same-category contacts.7Laumann (1973), in his clas-
sic analysis of the Detroit Area Study, provided an unusually detailed analysis
of ethnic and religious friendship. He found a rank order correlation of .821
between an ethnic group’s size and its tendency to select friends from within the
group (Laumann 1973, p. 45). These choices were structured to a substantial de-
gree by the overlap between ethnic, religious, and socio-economic characteristics
(Laumann 1973, p. 67–68). In an unusual study of five different ethnic groups in
Toronto, Ooka & Wellman (2001) found that more recently arrived groups had
more homophilous job search networks. The pattern was accentuated among less
educated, first generation respondents, reinforcing the idea that other domains of
segregation(residential, voluntaryassociation, occupation,language, etc.)and hid-
den value homophily (information, attitudes, tastes, etc.) may drive the inbreeding
process (see also Kalmijn 1998, p. 410, Marsden & Gorman 2001).
SEX AND GENDER The homophily ofnetworks withregardtosexandgender poses
a remarkable contrast to that of race and ethnicity. Race and ethnic homophily
are dominated by the strong structural effects of category size and by category
differences on many socially important features (education, income, residence,
etc.). In contrast, men and women are roughly equal in number and are linked
together in households and kinship networks that induce considerable similarities
in residence, social class, and other characteristics. Until men and women enter the
sexsegregated voluntaryassociation structureandlabor force, mostsex homophily
is created by inbreeding rather than baseline phenomena.
By the time children enter school, they have learned that gender is a permanent
personal characteristic. At about the same developmental stage, researchers first
observe homophily in play patterns and a tendency for girls to play in smaller
groupsthan boys(see reviewsinSmith-Lovin&McPherson1993, Maccoby1998).
Hallinan and her colleagues have done the most comprehensive studies of gen-
der in young children’s network relationships. Eder & Hallinan (1978) found that
girls are more likely to resolve intransitivity by deleting friendship choices, while
boys are more likely to add them. For example, if A likes B and B likes C, a
young boy would be more likely to add an A–C relation to resolve the intransitiv-
ity, while a young girl would be more likely to drop B as a friend. The Hallinan
results are important primarily because of their implications for the emergence of
cliques and larger network structures. Her data demonstrate how sex barriers to
youthful friendships and these patterns in the resolution of relationship intransitiv-
ity influence the development of social networks. Children are significantly more
likely to resolve intransitivity by deleting a cross-sex friendship than by adding
another cross-sex friendship. In fact, most youths are more likely to delete a same-
sex choice than to resolve the intransitivity by adding a cross-sex one (Tuma &
7Marsden (1988) found no significant social distance effect for race, after taking baseline
and inbreeding into account. The key distinction appears to be same-different, not any more
elaborated form of stratification.
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HOMOPHILY IN SOCIAL NETWORKS 423
Hallinan 1979). These simple, small tendencies toward homophily and sex differ-
ences in resolving problems in the structure of relationships mean that boys and
girls will move toward very different social circles. Their worlds become gender
segregated, with boys in larger, more heterogeneous cliques and girls in smaller,
more homogeneous groups. This tendency is especially marked in the early grades
and abates as adolescents move into the romantic ties of puberty (Shrum et al
1988).
By the time that they are adults, people have friendship and confidant networks
that are relatively sex-integrated (at least when compared to other dimensions like
race, age, and education). People “discuss important matters with” a group of
confidants that are roughly 70% as sex heterogenous as the general population
(Marsden 1987). While 22% of people have no cross-sex confidants, 37% have
networks that are almost perfectly mixed by sex. This pattern is a bit misleading,
however, since close ties contain many kin, and kinship links one to confidants of
the other sex. When Marsden (1987) controlled for kin, he found that among kin
the heterogeneity of networks was very close to the population value, while for
nonkin there was considerable gender homophily. Still, the inbreeding homophily
for sex in confiding networks is considerably less than that for race, education,
and other social dimensions (Marsden 1988).8In contrast, Huckfeldt & Sprague
(1995,p. 195–201)found considerablehomophily inpoliticaldiscussion networks,
with men showing much higher levels of segregation than women; 84% of men
reported discussing politics only with other men.9There may be a tendency for
less intimate, more content-bound relationships to be more gendered than close,
strong ties.
Gender homophily is lower among the young, the highly educated, and Anglos
(as compared with African Americans and Hispanics) (Marsden 1987). This struc-
turing of gender homophily is mirrored in other societies (Blau et al 1991,
Verbrugge 1977) and in more ephemeral relations (Mayhew et al 1995).
Interestingly, the pattern of connections among respondents’ confidants is quite
different for sex than for race/ethnicity. Alters of the same sex are significantly
less likely to be connected than alters that aren’t matched on sex (Louch 2000).
Thispatternsappears because spouses arequite unlikely to knowother-sexfriends.
This is especially true for men, whose wives are especially unlikely to know their
female friends from other foci like work or voluntary organization membership.
While the general population is almost perfectly sex heterogeneous (with men
and women being almost equal-sized groups), most environments where networks
have been studied are not. Work establishments, for example, are highly sex
8Verbrugge (1977) found that sex homophily was stronger than education and religion,
especially among closest friends, where 90% of all men and 68% of all women mentioned
a same-sex person. Verbrugge did not study race in her Altneustadt, German, data.
9Part of the gender difference is evidently a reporting difference between men and women.
When Huckfedlt & Sprague (1995:197–99) looked at political discussion between spouses,
theyfoundthat wivesweremuchmore likelytoreport discussingpoliticswith theirhusbands
than husbands were to report discussing politics with their wives.
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424 MCPHERSON ¥SMITH-LOVIN ¥COOK
segregated (Bielby & Baron 1986, Kalleberg et al 1996 pp. 53–55) as are volun-
tary associations (McPherson & Smith-Lovin 1982, 1986, 1987, Popielarz 1999).
Therefore, it is not surprising that the networks formed in these settings display a
significant amount of baseline homophily on gender. The sex composition of the
establishment, group, and occupational level creates powerful sex differences in
homophily of networks, with the minority sex having much more heterophilous
networks than the majority category members (South et al 1982, 1983, McPherson
& Smith-Lovin 1986, 1987). Researchers have studied this baseline phenomenon
most intensively among upper-level managers and entrepreneurs. Here, the find-
ings are very consistent. Men tend to have more sex homophilous networks than
do women, especially in establishments where they are a strong majority (Ibarra
1992, 1997, Brass 1985). This pattern is especially strong when we consider in-
strumentalorstatus-loaded ties of advice, respect,and mentoring; socio-emotional
ties of friendship and support are much more sex homophilous, in spite of skewed
environments(Ibarra 1992,1997, Lincoln &Miller 1979, Greenberger& Sorenson
1971). Across many cultures and work settings, both men and women use men as
network routes to accomplish tasks and to connect to information in more distant
domains (Aldrich et al 1989, Bernard et al 1988).
AGE The degree of age homophily in networks varies a great deal, depending on
thetype oftiestudied.Homogamyon agein marriageis sotakenfor grantedthat itis
seldomevenstudied (seethe lackofdiscussion inKalmijn 1998).In studiesof close
friendship, homophily on age can be stronger than any other dimension (excepting
perhaps race, which is seldom even studied in these contexts) (Verbrugge 1977,
Fischer 1977, pp. 93–98). Fischer (1977) found that 38% of all Detroit men’s close
friends were within two years of their age; 72% were within eight years. Similarly,
when the ties studied are relatively superficial (like talking about hobbies or work,
orgeneral sociabilityand supportaround the neighborhood),age homophilyis high
(Feld1982). Whenties areclose confidingrelations orinvolveemergencyhelp with
moneyor other services,ties are lessage homophilous becausesignificant numbers
of kin are mentioned (Feld 1984, Marsden 1987, Blau et al 1991). Marsden (1987,
p. 127) found that age heterogeneity in confiding networks was about 60% of
what would be expected by random assortment in the population; eliminating kin
confidants reduces age heterogeneity to less than half of expected. Fischer (1982)
found that nonkin friends were separated by only six years of age, compared to
24 years for nonsibling kin alters.
Age homophily includes a powerful baseline component. The fact that schools
group ages together into classrooms induces strong homophily, although this ten-
dency weakens as children move from early to later grades (Shrum et al 1988).
Age homogeneity of contexts like neighborhoods, work environments, and volun-
tary organizations induces considerable age homophily in both positive ties like
friendship and negative ones like crime (Feld 1982, Sampson 1984).
Age homophilous ties tend to be more close, longer lived (often reflecting the
perseverenceof tiesformed in childhood),to involvea largernumber ofexchanges,
andtobe more personal(Fischer1982). The probability thattwo nonkin confidants
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HOMOPHILY IN SOCIAL NETWORKS 425
will themselves be connected decreases with their absolute age difference (Louch
2000).10 Age-similar dyads are slightly less likely to have multiplex relations,
however (Fischer 1977).11 Evidently this is because people tend to keep in close
touch with same-age childhood friends with whom they share no other current ties.
Marsden (1988) found an interesting patterning of age homophily for different
age categories. In confiding relations, there was both a strong tendency to confide
in someone of one’s own age (especially for the four youngest age categories) and
a social distance effect: The further away someone was in age, the less likely that
theyweresomeone withwhom one“discussed importantmatters.” Therewasmore
distance between the 60+age group and other age groups than there was between
other age categories, perhaps indicating the social importance of retirement and
other institutional processes associated with aging. The over-60 category was the
only age group for which there was significant outbreeding. Older people often
connectwith younger confidants,especially theirchildren(see alsoBlau et al1991,
Burt 1990, 1991).
RELIGION Marriage,friendship,andconfidingrelations showreligioushomophily
inall societieswith religiousdiversity,althoughthe patternis notas typicallystrong
asitis for race and ethnicity(Laumann 1973, Verbrugge 1977, Fischer 1977,1982,
Marsden 1988, Louch 2000). Kalmijn (1998) argues that it appears to be decreas-
ing during the past few decades.12 As with the other forms of homophily, there is
a combination of baseline and inbreeding occurring here. Protestants are likely to
marry and be friends with other Protestants in the United States, because they are
such a large group (Kalmijn 1998, Fischer 1977). Residents of small towns risk
falling away from their religious roots, presumably because suitable coreligionists
are less likely to be available, while residents of larger cities are more likely to
be enveloped in a religious subculture (Fischer 1982). If we look at departures
from these group size effects, however, Protestants show the lowest levels of in-
breeding homophily, while Catholics, those with no religion and “other” religions,
and Jews show higher levels of homophily (in that order) (Fischer 1982, Marsden
1988, Kalmijn 1998). As with race/ethnicity, we see a tendency for inbreeding
homophily to counteract the likelihood that members of smaller categories will
have almost totally outgroup relationships by chance. The Jewish men in Fischer’s
(1977) Detroit sample, for example, have 80% of their friendships with other Jews,
while few would be predicted by random assortment. And 80% of all Jewish mar-
riages are to Jews in this group that makes up less than 2% of the population
(Kalmijn 1998).
Ties between people with the same religion are more likely to be close ties of
giving emergency help, loaning money, giving trusted advice or even therapeutic
10This pattern weakens as the age difference gets very large, probably because of large age
differences in relations among in-laws, mentor-prot´eg´es, etc.
11In another departure from the general pattern, Verbrugge (1984) also found that age
dissimilarity of best friends actually increased their frequency of contact.
12Conservative fundamentalist Protestant groups are the exceptions to this decline.
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426 MCPHERSON ¥SMITH-LOVIN ¥COOK
counseling, while the less intense ties of hobby and work talk often show less
religious homophily (Feld 1984, Marx & Spray 1972). This relationship between
religious similarity and closeness extends even within the family: Men are more
likelyto name their spouses assomeone with whom theydiscuss important matters
(andto namethem first,if theyname thematall), iftheir spouseshares theirreligion
(Liao & Stevens 1994). In relationships of less closeness, religion may not matter
much at all. Bainbridge & Stark (1981) found that among West Coast college stu-
dents, religious attitudes and beliefs were salient only when they were activated by
a social movement or formal organization. Again, fundamentalist students were
more likely to make this dimension a keystone of their friendships. Iannaccone
(1988) reviewed literature differentiating churches and sects, indicating that sects
(which tend to be more conservative, evangelical, and fundamentalist) are a more
total social environment for their members, spawning a larger proportion of their
friendships and social support networks while taking up more of their time. Par-
ents also show greater religious homophily in their network ties than nonparents,
supporting the idea that religious institutions are sought out for children’s benefit
(Fischer 1982). (An alternative hypothesis, of course, is that religious people both
have more same-religion friends and are more likely to have children.)
EDUCATION, OCCUPATION, AND SOCIAL CLASS The dimensions of homophily that
we have discussed up to this point are largely ascribed or strongly inherited from
one’s family of origin. Here, we address dimensions that, in modern industrial
societies, are to a large extent achieved (although still shaped by family origins, of
course).Socialclass of origin oftendetermines neighborhood residence; education
locatespeople in schoolsettings; andoccupationaffectsbothworkplace andvolun-
tary association activity. Therefore, it is not surprising that we find significant ho-
mophilyon theseachievedcharacteristicsas well.Marsden (1987) foundthat about
30% of personal networks were highly homophilous on education, with a stan-
dard deviation of less than one year. On average, respondents’ confiding networks
showedabouthalf theeducational diversityofthe generalpopulation. Thisparallels
Verbrugge’s (1977) results a decade earlier, showing that education, occupation,
and occupational prestige all showed roughly the same levels of homophily as
religion and sex. Louch (2000) found that interconnections among alters were
more likely when they had had the same education too, although this effect was
less strong than for race and religion. Yamaguchi (1990) found that homophily
in education extended to inbreeding bias among the statuses of the friends them-
selves, with one choice predisposing other choices of the same educational level.
Laumann (1973, p. 81–82) found that the occupational structure of Detroit men’s
friendships had at least two dimensions: One was the dominant action of social
status,education,and income, while the otherrepresented a contrast between more
bureaucratic and more entrepreneurial work activities (see also Laumann & Pappi
1976, p. 57–64). Wright (1997, p. 208–22) explored the class structuring of friend-
ships in more detail, finding significant boundaries to friendship across property,
skill, and authority boundaries. The property boundary is the most impermeable
to friendships in most societies (with the notable exception of Sweden).
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HOMOPHILY IN SOCIAL NETWORKS 427
Kinship ties tend to introduce educational and class hetergeneity into confiding
and support networks, for while marriages are quite homophilous on these charac-
teristics (Kalmijn 1998) the cohort differences in educational achievement mean
that many cross-generational links are dissimilar (Marsden 1987). Higher educa-
tion and being male also lead people to have more diverse networks, since these
groups have both homophilous high-status relationships and ties that extend lower
into the educational/occupational status hierarchy (Marsden 1987, Campbell et al
1986, Campbell 1988, Fischer 1982). All educational groups show inbreeding ten-
dencies, as well as a social distance effect: People are both more likely to confide
in others who share their same educational level and become less and less likely
to form such a tie as their difference from others’ achievement increases (Marsden
1988). The edge categories of extremely high and low education show the biggest
inbreeding tendency (Marsden 1988, Kalmijn 1998), with a socially significant
divide between the college-educated and those without college experience and
another major distinction between the white collar and blue collar occupations
(Kalmijn 1998, Hout 1982, Hauser 1982).
Researchers have found educational and occupational homophily in a large
numberof societies, butthere issome indicationthat its levelvariessomewhat from
country to country (Wright 1997, p. 203–22). Blau et al (1991) found roughly the
same level of homophily in a Chinese city as in the United States, but Verbrugge
(1977) found that Altneustadt (German) friendship ties were more structured by
occupation than those in Detroit. Educational homogamy in marriage has been
increasing strongly in the United States, but most countries show no trend and
some show a decrease (Kalmijn 1998). Indications are that it is the operation of
UScolleges asa locus ofmarriage formationand the culturalaspects ofeducational
andoccupational homophily,rather thanthe economicones, thatdrivethe structure.
In spite of the fact that we see strong educational, occupational, and class ho-
mophily in strong ties like marriage and confiding relations, there is some indica-
tion that such similarity is perhaps more important in the less intimate ties of one’s
network. Occupational homophily is one of the few factors that Verbrugge (1977)
found was weaker for best friends than for second and third friends. Louch (2000)
found that education was less likely to create links between confidants than most
other characteristics (religion, race, etc.). Galaskiewicz & Shatin (1981) show that
cooperative ties between community organizations are most likely to be activated
between those with educationally similar backgrounds in turbulent, problematic
times.Schneider et al 1997find strong educationalhomophilyin information flows
about education choices in voucher systems.
NETWORK POSITIONS When networkswithin organizations orsmall communities
are studied, they often display a core-periphery pattern, with a central group of
closely interconnected people and a larger group of people who are less densely
connected to the core and to each other (e.g., Brass 1985). Festinger’s (1950)
classic theory of social comparison posited that people would use as a reference
group those who are similar to them in various ways, including structural position.
More modern network research (Burt 1982, Friedkin 1993) has confirmed this
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428 MCPHERSON ¥SMITH-LOVIN ¥COOK
hypothesis.People who are morestructurally similar tooneanother are morelikely
to have issue-related interpersonal communication and to attend to each other’s
issue positions, which, in turn, leads them to have more influence over one another.
There are powerful homophily effects in who we consider to be the relevant others
in our organizational environment: those to whom we compare ourselves, those
whose opinions we attend to, and simply those whom we are aware of and watch
for signals about what is happening in our environment (Lawrence 2000). While
homophily on structural similarity has focused almost exclusively on influence
and comparison processes, the core-periphery pattern that networks often show
may indicate that other types of advice, friendship, and association respond to this
basis of homophily as well.
BEHAVIOR A long tradition in the literature on adolescence demonstrates the ten-
dencyof teenagerstoassociate withothers who sharetheir behaviorpatterns, either
of achievement or delinquence. Traditionally, these patterns were interpreted as
evidence of peer influence. As your mother always told you, hanging out with the
wrong crowd could get you into trouble. Longitudinal data first became available
in the 1970s, and this led to a rather decisive shift in the interpretation of behav-
ioral homophily. Cohen (1977) and Kandel (1978) demonstrated that both positive
behaviors of school achievement and negative behaviors like smoking marijuana
were homophilous more because of selection into relationships with similar others
than because of behavioral influence within friendship cliques. There also was
a slight tendency for relationships to disband when behavioral similarity did not
support them. Later, Billy et al (1984) showed the same patterns for adolescent
sexual behavior.
Among adults, behavioral homophily has been studied along two dimen-
sions. Verbrugge (1977) noted a mover-stayer pattern in Altneustadt (German)
friendships, with residential stability predicting friendship formation about as
strongly as did sex, nationality, or religion. Knoke (1990) found homophily of
political behavior and practice, with stronger shared political orientations pre-
dicting more behavioral involvement, especially within the context of voluntary
associations.
ATTITUDES, ABILITIES, BELIEFS, AND ASPIRATIONS Having established that homo-
phily exists on a wide array of sociodemographic and behavioral dimensions, we
finally turn to the arena where most people spontaneously recognize that similarity
breeds fellowship: value homophily. An extensive experimental literature in social
psychology established that attitude, belief, and value similarity lead to attraction
and interaction (see review in Huston & Levinger 1978). Homophily on traits like
intelligence was one of the first phenomena studied in the early network literature
(Almack 1922). The classic status attainment literature picked up this assortative
pattern and used it to argue that aspirations for higher educational attainment
were shaped by peer groups (Duncan et al 1968). As with behaviors, however,
the selection into relationships with similar others appears to be a much more
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HOMOPHILY IN SOCIAL NETWORKS 429
powerful force than interpersonal influence within the friendship network (Kandel
1978, Cohen 1977). Much of what appears to be value homophily or influence also
comes from the misperception of friends’ beliefs and attitudes (Jussim & Osgood
1989, Huckfedlt & Sprague 1995); people tend to assume that their friends are
like them, when in fact areas of disagreement simply are not discussed. There
is considerable tendency for adults to associate with those of their own political
orientations (Verbrugge 1977, 1983, Knoke 1990, Huckfedlt & Sprague 1995), but
it unclear whether this homophily is due to actual political similarity or similarity
on other social characteristics that are correlated with political beliefs. At any
rate, selection almost certainly trumps influence or attrition in this domain as
well.
SUMMARY The literature is remarkably consistent across many different rela-
tionships and many different dimensions of similarity: Homophily characterizes
network systems, and homogeneity characterizes personal networks. In diverse
societies, race, and race-like ethnicity create the most stark divides. Sex, age, reli-
gion, and education also strongly structure our relations with others. Occupation,
network position, behaviors, and intrapersonal values also show considerable ho-
mophily, but they seem to be more specific to certain types of networks and/or
derived from the basic facts of sociodemographic homophily. Baseline patterns
strongly shape networks by influencing the opportunity structure for contacts, both
within large populations and within smaller social settings. Inbreeding homophily
oftencomplements baseline, suchthatsmaller categoriesofindividuals whowould
otherwisehavenetworks dominated bythe majority group actually haveassociates
that are much more similar to them than we would predict from the opportunity
structure. We now move on to the sources of this remarkably consistent structural
feature.
CAUSES OF HOMOPHILY: FOCI OF FORMATION,
PROCESSES OF TIE DISSOLUTION
Geography
Perhaps the most basic source of homophily is space: We are more likely to have
contact with those who are closer to us in geographic location than those who are
distant.Zipf(1949) stated the principleas a matter ofeffort: It takesmore energy to
connect to those who are far away than those who are readily available. The classic
community studies illustrated this fact (e.g., Gans 1968; see review in Campbell
1990), although purely local networks are a source more of contacts than close
ties (Wellman 1996) and tend to become less important over time as other types of
homophilytrump merepropinquity (Gans1968, Michaelson1976). Evenfactorsso
seeminglytrivialas thearrangementofstreets(Hampton &Wellman2000,Sudman
1988), dorm halls (Festinger et al 1950), and legislative seating (Calderia &
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430 MCPHERSON ¥SMITH-LOVIN ¥COOK
Patterson 1987) can influence the formation of relatively weak ties (and the poten-
tial for stronger friendship formation).13 Women are more likely than men to form
close ties with neighbors (Moore 1990, p. 729) because they are less likely to be
tied to extralocal foci of tie formation like work and their voluntary associations
are more likely to be geographically local (Fischer & Oliker 1983, McPherson &
Smith-Lovin 1986). Older people also are more constrained by their immediate
geographic environment and have networks that are more reflective of it (Fischer
1982, p. 184).
The advent of new technologies like print, the telegraph, the telephone, and
e-mailmayhave loosened theboundsof geography by loweringthe effort involved
in contact (Kaufer & Carley 1993), but these new modes have certainly not elimi-
nated the old pattern; Verbrugge (1983) still finds that residential proximity is the
singlebest predictor ofhow oftenfriends gettogetherto socialize.Since most high-
tech contacts still reflect contacts that are originally made and sustained through
face-to-face encounters, even ties measured through this mechanism usually show
geographic patterning (Wellman 1996). However, the new technologies may have
allowed people greater latitude to create ties that are homophilous on other di-
mensions (Hampton & Wellman 2000; see review in Wellman et al 1996). In fact,
these technologies seem to have introduced something of a curvilinear relation-
shipbetween physical space andnetwork association, withvery close proximityno
longer being so privileged over intermediate distances but both being considerably
more likely than distant relations. Geographic space also seems more important in
determining the “thickness” of a relationship (its multiplexity and the frequency
of actual contact) than it does in determining the presence of a tie.
The homogeneity of neighborhoods on characteristics that are transmitted by
parents—ethnicity, race, religion, and family background (Lieberson 1980)—
clearly influences the homophily of ties that are formed in this arena as opposed
to organizational foci like schools and workplace, which are organized along dif-
ferent dimensions. Urban areas, with their greater diversity within a moderate
geographic distance, produce networks with higher levels of racial and ethnic het-
erogeneity (Marsden 1987, pp. 128–29). Geographic effects evidently influence
the tendency for people with a farm background to marry others like themselves
(Kalmijn 1998, p. 409). Similarly, the regional distribution of religions (with
Baptists and Methodists concentrated in the South and Catholics in the North-
east) contributes to the religious endogamy observed in marriages (Kalmijn 1998,
p. 408). Blau et al (1984) demonstrated systematically that the composition of an
area with regard to its occupational structure, income structure, industry mix, and
educational distribution all influenced the level of homophily in marriages formed
there.
13Sudman (1988) found a large interaction effect between geographic proximity and the
type of dwelling, with large apartment buildings creating little geographic distance effect
and single family dwellings creating the most. Clearly, architecture and other sociocultural
factors affect the use and influence of space.
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HOMOPHILY IN SOCIAL NETWORKS 431
Family Ties
While geography is the physical substrate on which homophily is built, family
connections are the biosocial web that connect us to those who are simultaneously
similar and different. The prevalence of heterosexual coupling and the roughly
equal likelihood of having male and female children ensures that family connec-
tions will produce high heterogeneity on sex. Generational ties of exchange and
affection also produce much greater age heterophily in the family than occurs in
any other foci of tie formation. In a mobile society where generations often move
to follow educational or occupational opportunities, kin ties often produce rela-
tively close, frequent contacts among those who are at great geographic distance.
Similarly, cohort shifts in the base rate of educational or occupational opportu-
nities create substantial kin-based contacts with different educational and class
levels.
On the other hand, the importance of the marriage bond within families and in
larger society, creates rather dramatic structuring of kinship ties on other dimen-
sions. Family-based ties are much more likely to be same race, same ethnicity, and
same religion. In fact, the tendency to marry within group is so revealing of the un-
derlying importance of dimensions for structuring our society that tracking the rise
or decline of homogamy on a characteristic is an interesting, complex sociological
question (see the debates in Raymo & Xie 2000 and Smits et al 2000).
While the fact that family ties have a somewhat different structure than the
more voluntary, less intense social ties of co-employment, co-membership, or
friendship is interesting, it should not hide the fundamental similarity: (a) family
ties are homophilous on most characteristics, and (b) strong, homophilous ties on
one characteristic may act to induce heterophily on other characteristics. Family
ties, because of their strong affective bonds and slow decay, often allow for much
greater value, attitudinal, and behavioral heterophily than would be common in
more voluntary, easier to dissolve ties formed in the foci discussed below.
Organizational Foci
School, work, and voluntary organizational foci provide the great majority of ties
that are not kin (Louch 2000, p. 53), supporting Feld’s (1981, 1982, 1984) argu-
ment that focused activity puts people into contact with one another to foster the
formation of personal relationships. After the propinquity created by neighbor-
hood play groups, schools are the next major focus of tie formation across the
life course. Shrum et al (1988) found that 88% of all third graders’ friendship
ties are formed in their own grade at school. Tracking within schools assures that
children of similar backgrounds, abilities, and achievement levels are grouped into
the same classes, where homophilous ties can form (Kubitschek & Hallinan 1998,
Hartup & Stevens 1997). Indeed, Neckerman (1996) found that children’s friend-
ships are quite unstable without organizational support. School organizations help
not only to breed ties, but also to maintain them. Some of the homophily in age and
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432 MCPHERSON ¥SMITH-LOVIN ¥COOK
behavioral characteristics induced by school structures survives into adulthood, as
childhood friendships occasionally are maintained in spite of few other connec-
tions. Fischer (1977) found that 20% of Detroit men’s (nonkin) friendships were
formed in childhood.
After school, most people move into a work environment that also segregates
their opportunities for tie formation. The general literature on organizational de-
mography has been reviewed elsewhere (Pfeffer 1983, Reskin et al 1999). Here,
we simply note that a large number of both strong and weak ties are formed at
work [809 out of 4423 close confiding relationships in the General Social Survey,
roughly half of the nonkin ties (Marks 1994)], and that the composition of these
ties is strongly influenced by the composition of the work establishment (Ibarra
1992, 1995, Brass 1985, Feld 1982, see review in Reskin et al 1999). In general,
ties formed among co-workers tend to be more heterogeneous in race and religion
than ties formed elsewhere, and more homogeneous on sex and education be-
cause of the highly segregated character of the workplace on these two dimensions
(Marsden 1990, pp. 402–3).
Recent research has concentrated attention on the role of voluntary associations
in creating interpersonal ties (McPherson & Smith-Lovin 1986, 1987, McPherson
etal1992). While voluntarygroups are probably lessimportant sources of tiesthan
school or work, they are important because they operate over the entire life course,
from childhood to death, and because they represent a unique arena for watch-
ing the strong interplay of structurally induced and choice-produced homophily.
Since voluntary groups are, by definition, less constrained than family, school, or
work (which may be biologically or legally mandated), they represent an excellent
opportunity to examine the co-evolution of groups, ties, and memberships.
There is a structural duality of persons and groups: The fact that groups are
made up of people means that every group creates a set of co-membership ties
among its members (Breiger 1974), and these connections can be used to sample
groupsby sampling from theirmembers in a populationof individuals (McPherson
1982). Larger organizations create proportionally more co-membership ties than
smallerones, ofcourse, because thenumber ofpotential interpersonalrelationships
is (n(n–1)/2), where nis the number of members in the group (McPherson 1983a,
McPherson & Smith-Lovin 1982). Since higher SES people join more groups and
leavethem lessfrequently,theyexperience morevoluntary organizationsover their
life course and have more co-memberships (McPherson 1981, pp. 718–20). Men
also gain more ties from their voluntary organization memberships than women
because they belong to larger groups, on average (McPherson & Smith-Lovin
1982). The extreme gender segregation of the voluntary system leads most co-
membership ties to be sex-homogeneous (McPherson & Smith-Lovin 1986); the
average male membership generates 37 co-membership ties, eight of which are
female, whereas the average female membership generates 29 ties, only 4 of which
are male. All-female groups, in particular, lead women into relationships that are
highly homophilous on age, education, religion, marital status, and work status
(Popielarz 1999a).
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HOMOPHILY IN SOCIAL NETWORKS 433
When we look at ties closer than mere co-membership, we find that many
friendships, confiding relations, and social support ties are formed within volun-
tary groups. Close confiding relations are about as likely to be embedded in vol-
untary groups as they are to be found at work (Marsden 1990, p. 403).14 Feld
(1982) found that 68% of the relationships in Fischer’s (1982) Northern California
Community Study were formed in some type of foci of activity, with roughly a
third of those formed in work and voluntary organizations.
The social homogeneity of most organizational foci creates a strong baseline
homophilyin networksthatare formedthere. Feld (1982)found that organizational
fociproduced tiesthat weretwiceashomogeneousaswouldbe expectedby chance.
Morespecifically,Marsden (1990) foundthat co-membership sourcesreduced age,
race,and especially religious diversityof confidingrelations. McPherson &Smith-
Lovin (1987) showed that the composition of voluntary groups induces strong
homophily in the ties that are formed there, with group size, consolidation of
dimensions, and social diversity within organizations all affecting the extent to
which ties were formed with similar others. In particular, the voluntary groups
induced strong homophily in sex, age, and occupational prestige; Peoples’ choices
of close associates within the groups (inbreeding, in our classification here) were
more important in creating educational homophily. McPherson (1983b) noted
that different types of voluntary groups have specialized demographic structures,
with church, youth, and elderly groups tending to specialize in the age dimension
(and therefore inducing age homophilous co-membership ties), while professional
groups induce educational homophily. Civic groups integrate different age groups,
and groups serving the elderly integrate those with different educational back-
grounds. Hobby groups are the most generalist overall, integrating a wide array of
characteristics (especially occupational statuses).
Researchers have also examined the impact of organizational foci within more
specific institutional domains. Caldeira & Patterson (1987) found that joint com-
mittee memberships had powerful effects inducing friendship, shared attitudes
and information, shared understandings of the legislative role, and behavioral
homophily (voting together) in a state legislature. Cook (2000) found that the
same key variable—shared committee membership—was the most important pre-
dictor of bill co-sponsorship in the United States Congress, even when controlling
for a large number of individual and district characteristics.
Voluntary organizations can also be important in reinforcing the effects of other
typesof ties. Galazkiewicz(1985) found that nonprofitofficers that belongedto the
same professional organizations ended up more proximate in personal networks
and more similar in their evaluation of prospective donors (attitudinal homophily).
Knoke (1990) found that discussing politics with at least one other member of
a voluntary organization strongly boosted a person’s political mobilization both
insidetheorganization and in thelarger community.Davis & Aldrich(2000) found
14These co-membership confidants are more likely to be kin than co-worker confidants,
however.
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434 MCPHERSON ¥SMITH-LOVIN ¥COOK
that co-membership in instrumental organizations (especially when coupled with
intensive organization activity) increased entrepreneur’s odds of gaining access to
resources like expert advice. This was especially true for women entrepreneurs.
The fact that the effect operated more strongly for women may be created by
the fact that women often were seeking help from men with greater experience.
Beggs & Hurlbert (1997) found that female seeker/male contact ties were less
effective than same sex ties in providing support during a job search, unless the
sex heterogeneous tie was reinforced by a shared voluntary organization member-
ship. If reinforced by the organizational context, the nonhomophilous ties were
as effective as same-sex contacts in providing support. Therefore, it appears that
organizational co-membership is capable of reinforcing nonhomophilous ties, to
allow them to operate as homophilous ones would.
Isomorphic Sources: Occupational, Family, and Informal Roles
Early in the modern era of social network analysis, Burt (1982) made the point
that people who occupy similar positions (i.e., have the same role relationships
to similar others) often influence each other in the adoption of innovations. Such
equivalent actors are often linked by direct ties, of course, although Burt argued
thatthe influencecould occur evenwhenthey werenot. If weaccept theproposition
that role occupants are more likely to be similar than randomly chosen people, the
connections between people who occupy equivalent roles will induce homophily
in the system of network ties. Studies illustrating this point have concentrated in
three domains. The most common, by far, are the detailed studies of connections
within the workplace. There also has been some attention to the effect of family
roles and the more intricate study of structurally equivalent actors within informal
networks.
Many studies of the workplace, for example, find that the advice, respect, and
support networks formed there are shaped not just by the composition of the
work establishment as a whole, but even more strongly by the organizational
demography at a person’s own level or job title (Ibarra 1992, 1995, Brass 1985).
Employees are especially likely to have ties to others who occupy their same job,
andoccupationalsexsegregationinducesstrong baselinehomophily.Lazega&Van
Duijin (1997) found that position in the formal structure of a workplace (including
status, seniority, and the functional division of work) influenced the choice of
advisors. Several studies have examined detailed networks of communications
among scientists (perhaps because we know more about the dimensions of their
work). Fuchs (1995) found that status organizes gossip among scientists into a
core-periphery pattern. Judith Blau (1974) found that local contacts among high
energy physicists were strongly structured by whether or not they shared a similar
role within the academy (teaching versus other research roles). Such contacts
also were structured by research accomplishments and specialty even within this
small, elite subfield. Because we know that such stratification in the academy has
demographic parallels, structuring of ties by any of these positional factors will
induce demographic homophily as well.
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HOMOPHILY IN SOCIAL NETWORKS 435
In the world of family life, Fischer & Oliker (1983) found that friendship
contacts are likely to be created as a result of one’s role as spouse. Women’s
networks, in particular, were formed with the other wives that they met through
their husbands. Given significant homogamy in marriage, and the tendency of
men’s friendships to form at work (Marks (1994), friendships formed through this
spousal role are likely to induce considerable levels of homophily. Munch-Rotolo
(2000) showed that the onset of parenthood induced considerable similarity in
the networks of men and women, as they both became more tied to female kin
and other parents with children in their immediate geographic area. Given the
tendency of kin and neighborhoods to stratify contacts in terms of a variety of
social dimensions (see above), this increasing concentration on the two sources of
ties will create substantial racial, ethnic, religious, and class homophily.
A smaller number of researchers have examined the extent to which struc-
tural equivalence in more informal networks induces behavioral or attitudinal
homophily. Calderia & Patterson (1987) found that political leadership roles and
friendship patterns in a state legislature induced considerable homophily of at-
titudes and beliefs. Galaskiewicz (1985) found that similar network positions
induced considerable levels of agreement about potential donors to nonprofits
that he studied.
Cognitive Processes
We have focused overwhelmingly on the structural sources of homophily in our
discussion above because the literature routinely shows the potency of such for-
ces when compared directly with some type of personal choice or selection
(e.g., McPherson & Smith-Lovin 1987). Here, we briefly note the processes that
have historically dominated the research on homophily: the tendency of people
to choose to interact with similar others. The psychology literature has demon-
strated experimentally that attraction is affected by perceived similarity (Huston &
Levinger 1978). Carley (1991) has developed a sociological approach called con-
structuralism that has at its core the assumption that people who share knowledge
with one another are more likely to interact (and, we might extrapolate, form
ties). If demographic similarity tends to indicate shared knowledge (see this ar-
gument developed in Mayhew et al 1995), we would expect people to associate
with similar others for ease of communication, shared cultural tastes (Mark 1999),
and other features that smooth the coordination of activity and communication.
Researchers often have studied this process within adolescent subcultures, where
selection of association among similar others is found to be a much more potent
forcethan socializationwithinthe group(Cohen 1977,Kaplanet al1987, Billyetal
1984).
Selective Tie Dissolution
Most of the review above on sources of homophily has implicitly concentrated on
the creation of ties. Clearly, social ties are usually created in segregated foci of
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436 MCPHERSON ¥SMITH-LOVIN ¥COOK
activity, which induces homogeneous personal networks. Researchers less often
study the process of tie dissolution, since this requires data on associations over
time (see review in Burt 2000).
Hallinan and her colleagues have assembled one of the most impressive sets of
dynamic data, on schoolchildren’s friendship ties over the course of school years.
They find consistently that ties that are cross-sex or cross-race are more likely to
be dropped than ties among demographically similar friends (Hallinan & Williams
1989, Tuma & Hallinan 1979). These nonhomophilous ties are especially likely to
be dropped when they are involved in intransitive friendship patterns. Basically,
homophilous relations help friendships survive other structural challenges. This
patternparallelsthefindingsamong adultsthathomophilybecomesmore important
to tie activation during times of crisis or trouble (Galaskiewicz & Shatin 1981,
Hurlbert et al 2000).
McPherson and his colleagues have studied how ties of co-membership are
affected by similarity to other members of a group. Both strong and weak ties to
others in the group, which are likely to be among similar others, tend to increase
the duration of memberships (McPherson et al 1992). More direct evidence comes
from Popielarz & McPherson (1995), which showed that the closer a member is
to the edge of a group’s niche (i.e., the more s/he is unlike the other members of
the group), the more likely s/he is to leave the group.
Burt (2000) has done a detailed study of tie decay across four years in the
investment banking division of a large financial organization; In this case, a tie
was being involved in regular business dealings with another. He finds that ties
among bankers survive much longer than ties between bankers and those outside
the banker role. There is also a clear core-periphery pattern, such that ties with
the people who are highly ranked in both the formal and informal hierarchy last
longer than those with and among those lower in the hierarchies. Age homophily
also decreased the probability that a tie would dissolve, with this effect being
especially strong for those who are either unusually young or unusually old within
their occupational structures.15
In general, we find that the patterns of tie dissolution mimic those of tie forma-
tion, but perhaps in a somewhat weaker manner. While there is much less evidence
here, homophily seems to affect the probability that a tie will dissolve or decay, net
of other factors (like the liability of newness, embeddedness, structural supports,
etc.). The relative strength of homophily in tie formation and tie dissolution may
be a function of the preeminent importance of structural foci in the tie forma-
tion process. Once ties have been formed in highly segregated organizational and
role foci, their dissolution may be shaped primarily by changes in these support-
ive structures or by cognitive/communication processes. These may be somewhat
15Burt did not find similar gender homophily effects. Instead, women seemed to dissolve
contacts with both men and women at a very high rate. This pattern probably has more to
do with the position of women within this fairly male occupational environment than of
homophily, per se.
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HOMOPHILY IN SOCIAL NETWORKS 437
more idiosyncratic than the highly structured world of tie formation. But, given
the paucity of evidence on tie dissolution, this conclusion may be premature. We
therefore turn now to our recommendations for future research on homophily in
networks.
IMPLICATIONS FOR FUTURE RESEARCH
Need for Studies of Multiplexity
It is striking that 20 years after Fischer’s (1982) classic study of networks in North
California communities, so few large-scale studies investigate the multiple, over-
lapping networks of different types of relationships that his research so admirably
chronicled. If different types of relations are structured by different levels of ho-
mophily on different dimensions, then multiplex relations among individuals may
create systematic, important patterns of cross-cutting social circles. Attention to
this complexity may produce findings as important for the larger issue of the in-
tegration of society as did Peter Blau’s (1977) groundbreaking insights about the
impact of consolidated (correlated) dimensions.
An analogous concern is the operation of overlapping, cross-cutting foci that
mayshape tieformation. Sincewe findthat geographic,organizational androle foci
are powerful structural forces inducing homophily, it makes sense that studying
how these foci interrelate would be important for examining community structure
more generally. Popielarz (1999b), for example, has developed a propositional
theory of how memberships in multiple voluntary organizations can influence the
homophily of networks formed in this domain. The attempts of McPherson and his
colleagues to trace the flow of co-membership ties within a community of com-
peting voluntary organizations has developed a similar theme at the organizational
level (McPherson 1983a, McPherson et al 1992, McPherson & Rotolo 1996). If
foci are where homophilous ties form, it is important to understand in more spe-
cific terms how the organizational structure relates to the personal networks of the
individuals that make up those organizations.
Need for Dynamic Data
Burt (2000) has pointed to the very limited evidence that we have on the dynamics
of networks over time. As with the multiplexity issue above, collecting measures
of even one type of network tie at one point in time for a large, loosely bounded
system is an onerous task;16 this fact limits our ability to study networks over time.
Still, cross-sectional data on networks can never answer the important questions
about the extent to which network patterns, including homophily, are created by
16The social network module of the General Social Survey took approximately 15 minutes
of survey time to elicit information on up to five network alters with one network relation,
with minimal information about the context in which the relationships were formed.
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438 MCPHERSON ¥SMITH-LOVIN ¥COOK
selective tie formation or selective tie dissolution. While we have evidence that
both processes are important, we have little comprehensive information of how
the two processes interrelate17 or about their relative strength of the two processes
are highly tentative.
Several studies have shown that the effects of organizational composition can
last far beyond the actual embeddedness of the individual (Sorenson 2000,
Sparrowe & Popielarz 1995). Only by tracking both the organizational and role
history of the individual along with their personal networks can we see the full
impact of such factors. Analyses of cross-sectional data often leave such long-
term effects of organizational environments misclassified as individual choice or
(more appropriately) as unexplained variance, when in fact they are the systematic
residues of past foci.
Need for Study of the Co-evolution of Foci and Networks
Our final suggestion is, in actuality, a combination of the two themes that we dis-
cuss above’ the need for expanded consideration of multiplexity of both networks
and foci, and the need for dynamic data on changes over time in networks. Carley
(1999) recently has called for an ecology of how social networks evolve, a “socio-
cognitive physics.” While the powerful law-like pattern of homophily in networks
encourages such a call, we argue that the structural sources of homophily will most
likely require a consideration of the co-evolution of social entities like voluntary
organizations, employment establishments, and other social entities that breed ties
along with the study of network change. Focusing more on the organizational lev-
els, researchers have used network homophily in combination with an ecological
model to predict changes over time in the composition of voluntary organizations
and occupations (McPherson & Ranger-Moore 1991, McPherson & Rotolo 1996,
Rotolo & McPherson 2001). We now argue for attention to the analogous prob-
lem on the network side: The ways in which networks evolve over time through
cumulative processes of tie creation and dissolution as they are embedded in a
changing community of multiplex relations spawned by multiple organizational
affiliations. While the need to layer multiple relations over time in connection
with a system of organizations and other foci is a tall order, we have a much more
solid base of empirical knowledge and theory in this domain than in most substan-
tive areas. Further, we have ample evidence that the network phenomena that we
hope to explain are more systematic and orderly than some other areas of social
life. Therefore, Carley’s call for a sociophysics of network ecology may not be
farfetched.
17Even the path-breaking studies that examine dynamic data often look at only one direction
of influence. For example, van Duijn et al (1999) found if homogeneity of friends in terms
of age, marital status or work rose over time, the stability of the relationship rose as well.
They don’t examine whether relationships have a corresponding influence on changes in
work or marital status.
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HOMOPHILY IN SOCIAL NETWORKS 439
ACKNOWLEDGMENTS
Theauthorswould like tothank Peter V. Marsden andClaude S. Fischer forhelpful
comments on earllier drafts of this chapter.
Visit the Annual Reviews home page at www.AnnualReviews.org
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Annual Review of Sociology
Volume 27, 2001
CONTENTS
VIOLENCE AND THE LIFE COURSE: The Consequences of
Victimization for Personal and Social Development, Ross Macmillan 1
Rediscovery of the Family, the Neighborhood, and Culture, Mario Luis 23
CASES AND BIOGRAPHIES: An Essay on Routinization and the Nature
of Comparison, Carol A. Heimer 47
EDUCATION AND STRATIF ICATION IN DEVELOPING
COUNTRIES: A Review of Theories and Research, Claudia Buchmann,
E
mil
y
Hannum 77
THE GREAT AGRICULTURAL TRANSITION: Crisis, Change, and
Social Consequences of Twentieth Century US Farming, Linda Lobao,
K
atherine Me
y
er 103
RELIGIOUS NATIONALISM AND THE PROBLEM OF
COLLECTIVE REPRESENTATION, Ro
g
er Friedland 125
SOCIOECONOMIC STATUS AND CLASS IN STUDIES OF
FERTILITY AND HEALTH IN DEVELOPING , Kenneth A. Bollen,
J
enni
f
er L. Glanville, Gu
y
Stecklov 153
SPORT AND SOCIETY,
R
obert E. Washington, David Karen 187
US SOCIAL POLICY IN COMPARATIVE AND HISTORICAL
PERSPECTIVE: Concepts, Images, Arguments, and Research Strategies,
E
dwin Amenta, Chris Bonastia, Neal Caren 213
IS GLOBALIZATION CIVILIZING, DESTRUCTIVE OR FEEBLE? A
CRITIQUE OF FIVE KEY DEBATES IN THE SOCIAL SCIENCE
LITERATURE,
auro F. Guillén 235
RELIGIOUS PLURALISM AND RELIGIOUS PARTICIPATION, Mark
Chaves, Phili
p
S. Gorski 261
COLLECTIVE IDENTITY AND SOCIAL, Francesca Polletta, James
M
. Jas
p
e
r
283
SOCIAL IMPLICATIONS OF THE INTERNET, Paul DiMaggio, Eszter
H
ar
g
ittai, W. Russell Neuman, John P. Robinson 307
THE SCALE OF JUSTICE: Observations on the Transformation of
Urban Law Practice, John P. Heinz, Robert L. Nelson, Edward O.
L
aumann 337
CONCEPTUALIZING STIGMA,
B
ruce G. Link, Jo C. Phelan 363
SOCIOLOGICAL MINIATURISM: Seeing the Big Through the Small in
Social Psychology, John F. Stolte, Gary Alan Fine, Karen S. Cook 387
BIRDS OF A FEATHER: Homophily in Social Networks, Miller
M
cPherson, L
y
nn Smith-Lovin, James M Cook 415
EARLY TRADITIONS OF AFRICAN-AMERICAN SOCIOLOGICAL
THOUGHT,
A
l
f
ord A. Youn
g
Jr., Donald R. Deskins Jr. 445
HATE CRIME: An Emergent Research Agenda, Donald P. Green,
L
aurence H. McFalls, Jenni
f
er K. Smith 479
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... Each of the four mock tests in Urban World's Phase 2 Prescribe task represented a systematic approach to the selection of 200 agents. The first mock test drew a stratified random sample of agents designed to reflect the age, education, and income distributions of all agents, under the belief that these agentbased characteristics, including homophily (McPherson et al. 2001), might systematically affect friendship networks. The second mock test used a matched sampling approach designed to maximize insight into how other features of the world affected friendship networks, such as the role of location. ...
... This disparity was most evident in the fact that agents did not directly pursue relationships with similar agents but formed relationships with similar agents by seeking out sites of shared interest where they could then meet and, potentially, form a friendship. The former is foundational in sociological understandings of friendship formation (McPherson et al. 2001), while the latter is foundational to geographic understandings of travel patterns (Liu et al. 2015). To grossly exaggerate this distinction, we might say those who built "Urban World" viewed it as a social system where people often focused on the process of choosing where to go next while our team viewed it as a social system where people often focused on the process of choosing friends. ...
Article
Full-text available
The DARPA Ground Truth project sought to evaluate social science by constructing four varied simulated social worlds with hidden causality and unleashed teams of scientists to collect data, discover their causal structure, predict their future, and prescribe policies to create desired outcomes. This large-scale, long-term experiment of in silico social science, about which the ground truth of simulated worlds was known, but not by us, reveals the limits of contemporary quantitative social science methodology. First, problem solving without a shared ontology—in which many world characteristics remain existentially uncertain—poses strong limits to quantitative analysis even when scientists share a common task, and suggests how they could become insurmountable without it. Second, data labels biased the associations our analysts made and assumptions they employed, often away from the simulated causal processes those labels signified, suggesting limits on the degree to which analytic concepts developed in one domain may port to others. Third, the current standard for computational social science publication is a demonstration of novel causes, but this limits the relevance of models to solve problems and propose policies that benefit from the simpler and less surprising answers associated with most important causes, or the combination of all causes. Fourth, most singular quantitative methods applied on their own did not help to solve most analytical challenges, and we explored a range of established and emerging methods, including probabilistic programming, deep neural networks, systems of predictive probabilistic finite state machines, and more to achieve plausible solutions. However, despite these limitations common to the current practice of computational social science, we find on the positive side that even imperfect knowledge can be sufficient to identify robust prediction if a more pluralistic approach is applied. Applying competing approaches by distinct subteams, including at one point the vast TopCoder.com global community of problem solvers, enabled discovery of many aspects of the relevant structure underlying worlds that singular methods could not. Together, these lessons suggest how different a policy-oriented computational social science would be than the computational social science we have inherited. Computational social science that serves policy would need to endure more failure, sustain more diversity, maintain more uncertainty, and allow for more complexity than current institutions support.
... When conducting surveys or interventions, sampling can proceed at contextual and individual levels, as in the Dialysafe cluster randomized controlled trial. Further, social network-based sampling can recruit marginalized participants due to social network homophily [44]-the tendency of people to interact with others similar to themselves. Respondent-driven sampling asks members of marginalized groups to recruit one another [45]. ...
Article
Full-text available
Objectives: There is growing attention to health equity in health informatics research. However, the literature lacks a comprehensive framework outlining critical considerations for health informatics research with marginalized groups. Methods: Literature review and experiences from nine equity-focused health informatics conducted in the United States and Canada. Studies focus on disparities related to age, disability or chronic illness, gender/sex, place of residence (rural/urban), race/ethnicity, sexual orientation, and socioeconomic status. Results: We found four key equity-related methodological considerations. To assist informaticists in addressing equity, we contribute a novel framework to synthesize these four considerations: PRAXIS (Participation and Representation, Appropriate methods and interventions, conteXtualization and structural competence, Investigation of Systematic differences). Participation and representation refers to the necessity for meaningful participation of marginalized groups in research, to elevate the voices of marginalized people, and to represent marginalized people as they are comfortable (e.g., asset-based versus deficit-based). Appropriate methods and interventions mean targeting methods, instruments, and interventions to reach and engage marginalized people. Contextualization and structural competence mean avoiding individualization of systematic disparities and targeting social conditions that (re-)produce inequities. Investigation of systematic differences highlights that experiences of people marginalized according to specific traits differ from those not so marginalized, and thus encourages studying the specificity of these differences and investigating and preventing intervention-generated inequality. We outline guidance for operationalizing these considerations at four research stages. Conclusions: This framework can assist informaticists in systematically addressing these considerations in their research in four research stages: project initiation; sampling and recruitment; data collection; and data analysis. We encourage others to use these insights from multiple studies to advance health equity in informatics.
... Another explanation, particularly for the tendency for URM students to nominate URM peers in Course B, is friendship tie homophily. A host of research suggests that friendship serves as a mechanism for recognition [69,70] and that students tend to form friendships with peers of their same race/ethnicity [71,72]. URM students in Course B, therefore, might have formed friendships with one another and in turn recognized one another as strong in the course. ...
Preprint
Researchers have pinpointed recognition from others as one of the most important dimensions of students' science and engineering identity. Studies, however, have found gender biases in students' recognition of their peers, with inconsistent patterns across introductory science and engineering courses. Toward finding the source of this variation, we examine whether a gender bias exists in students' nominations of strong peers across three different remote, introductory physics courses with varying student populations (varying demographics, majors, and course levels). We also uniquely evaluate possible racial/ethnic biases and probe the relationship between instructional context (whether lecture or laboratory) and recognition. Some of our results replicate previous findings (such as the the association of course grade and small class section enrollment with nominations), while others offer contradictions. Comparing across our three courses and the prior work, results suggest that course level (whether first-year students or beyond-first-year students) might be more associated with a gender bias in peer recognition than other variables. Surprisingly, we also find instances of racial/ethnic biases in favor of students from backgrounds historically underrepresented in science. Finally, we find that the nomination patterns differ when students nominate individuals strong in the lecture material versus laboratory material. This work serves as an important step in determining which courses and contexts exhibit biases in peer recognition, as well as how students' perceptions of one another form in remote teaching environments.
... Here, we see value in examining the role top management team members play in gender diversity. Future research could examine individuallevel factors, such as executives' attributes or experiences, organizational, and environmental factors that may reduce gender homophily (Lazarsfeld & Merton, 1954;McPherson, Smith-Lovin, & Cook, 2001), similarity-attraction biases (Byrne, 1971), and the focus on more symbolic gender diversity. For example, at the individual level, if current TMT members serve as board members on successful, female-led firms or firms with diverse leadership teams, those executives may be more open to greater gender diversity at their home firms. ...
... La proximité sociale se situe et s'observe au niveau des individus.La définition de la proximité sociale se fonde sur la littérature spécifique aux réseaux sociaux.Elle se base sur l'idée que la probabilité que deux personnes entrent en contact augmentera si elles ont des contacts en commun. En outre, se lier avec des partenaires similaires entraîne des coûts moindres aux liens avec des partenaires non similaires(McPherson et al., 2001). La proximité sociale induit qu'une relation peut ne pas être directe et passer par un intermédiaire, membre du réseau social. ...
Thesis
Cette recherche propose une lecture stratégique de l’heuristique des proximités dans le contexte spécifique de la supply chain aéronautique française. Du point de vue théorique, cette étude enrichit les connaissances concernant les théories qui intègrent l’espace comme une variable stratégique dans le modèle d’affaires des firmes. Ainsi, les stratégies de proximités se fondent sur une logique de liens multiples, tandis que les proximités sont des moyens d’action qui facilitent la relation. Cette idée implique de pouvoir mesurer les proximités afin de les identifier, de les suivre et de les modifier. La thèse questionne donc la mesure des proximités. Du point de vue empirique, cette étude investit la filière aéronautique auvergnate composée de sous-traitants de rang 2 et plus et montre, au moyen d’une méthodologie qualitative mobilisant l’approche de l’analyse de contenu, qu’il est possible : (1) d’identifier les proximités et ce qu’elles représentent aux yeux des acteurs, (2) d’observer les effets des proximités, (3) de déterminer l’intensité des proximités par les fréquences d’apparition. En complémentarité, une seconde étude est menée auprès d’un échantillon de sous-traitants de rang 2 et plus insérés dans la supply chain aéronautique française. Nous mettons en lumière au moyen d’une méthodologie quantitative mobilisant l’approche PLS que (4) les échelles de mesure des proximités perçues sont validées dans le contexte de la supply chain aéronautique française (5) et que les stratégies de proximités sont différentes selon la nature de la relation. Cette recherche met en évidence que le management stratégique des proximités dépendra de l’intentionnalité du décideur et son rôle dans la supply chain.
... The homophile was first proposed by Lazarsfeld and Merton in 1954, which suggests people are more inclined to establish relationships with individuals who are like themselves or have the same attributes (McPherson et al., 2001). It is reasonable to assume that homophile is important to the development of learners' interaction. ...
Article
Full-text available
The network is a key concept which has been highly valued in connectivism. Research about the static characteristics of social networks in connectivist learning has been carried out in recent years, however, little knowledge exists regarding the principles of network evolution from a dynamic perspective. This article chose the first connectivist massive open and online course (cMOOC) in China, “Internet plus Education: Dialogue between Theory and Practice” as the research object, using the dynamic analysis method of social networks which is based on stochastic actor-oriented models, to reveal the influence of the individual attributes and network structural attributes on the dynamic evolution of social networks in a cMOOC. We found that: 1) the learners with the same sex, the same social identity, and the same type of behaviour tendency found it much easier to interact with each other; 2) there is a heterogeneous phenomenon with course identity, meaning that compared to communicating with other learners, learners are more inclined to reply to a facilitator; and 3) the reciprocity and transitivity have significant effects on social network evolution. This study is valuable for understanding the network evolution and has implications for the improvement of cMOOC design, in turn improving the online learning experience for cMOOC learners.
... 14 This study examines the religious practices of first-generation Sunni and Shi'a Muslim migrants in Auckland, and explores the process of choosing a mosque as a preferred place of worship, the factors they prioritize, and the significance that engagement with a mosque has in their lives. Employing the theoretical perspective of homophily, or the tendency for individuals to prefer to socialize with others they perceive to be similar, 15 we examine the importance of an individual's own cultural, ethnolinguistic and denominational background in determining their choice of mosque, and logistical considerations that shape their choice. To this end, we address the following research questions: a) What criteria are important for Muslim migrants in the choice of mosque and what role do language and ethnicity play? ...
Article
Full-text available
Abstract 1. Introduction 2. Homophily, Bonding Ties and Bridging Opportunities 3. Methods 4. Results 5. Importance of Frequenting a Mosque 6. Discussion 7. Conclusion Additional information Footnotes Full Article Figures & data Citations Metrics Licensing Reprints & Permissions View PDF View EPUB Abstract In this study, we identify the factors that Muslim migrants in Auckland, New Zealand's gateway city, prioritize when seeking to identify a suitable mosque, and the significance that frequenting a mosque has in their lives. We explore factors related to ethnicity, culture, language, belonging and the intergenerational transmission of religious knowledge and values from the theoretical perspective of homophily, or the tendency of individuals to socialize with others whom they consider to be similar. The importance of ethnolinguistic and cultural homophily is primarily linked to wellbeing, social support and bonding, the intergenerational transmission of beliefs and culture, and spiritual authenticity. Mosque attendance was viewed as a key factor in social integration, connectivity and wellbeing. The lack of suitable mosques for Shi'a was problematized. We discuss the different mosque-related priorities of the first and second generations, and formulate recommendations for catering to the multifarious needs of congregants in a Muslim-minority context.
Article
This paper investigates dynamic changes in instrumental (i.e., work‐related) tie‐seeking patterns and the structure of a communication network following a downsizing event—whereby many employees are simultaneously eliminated from a network. Our analysis spans a two‐year period and applies a resource‐ and network‐change approach to examine how survivors develop revised resource‐acquisition strategies while repositioning themselves after a downsizing. Our results demonstrate that two temporary logics of tie formation—a suspension of within‐unit homophily and a preference for seeking ties with long‐tenured employees—help employees acquire betweenness centrality during the disruption period. Specifically, we find that disruption initiates a transitional period after downsizing in which new tie‐making logics are employed, including seeking out ties with long‐tenured employees and employees outside of one's department. We observed post‐disruption, during the stabilization period after downsizing, where logics used for tie‐making in the disruption period were abandoned, pre‐disruption tie‐making logics were resumed, and betweenness centrality remained relatively constant. We discuss the theoretical and managerial implications of these results and suggest future research directions.
Article
Full-text available
Empirical evidence supports the hypothesis that an individual’s position in an income stratum—more than the absolute income level—determines subjective well-being. However, studies on subjective well-being suffer from a critical methodological weakness: they use exogenously defined reference groups. Our study addresses this point by applying an innovative new survey instrument. We ask respondents to identify individual reference persons for income comparisons. We find that these reference persons come from a range of social groups. Interactions between personality traits and the direction of income comparisons lead to different levels of subjective well-being. This highlights the importance of collecting information on personality traits in research on subjective well-being. We conclude that questions about self-defined individual income comparisons can be a valuable and straightforward addition to future surveys.
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This chapter explores extreme weather event and climate change misinformation on social media. The author reviews a wide variety of studies that explore divergent perceptions of extreme weather and climate change in the United States as well as how misinformation about extreme weather events and climate change is disseminated (and often amplified) via social media. The chapter examines structures and processes of communication within social media platforms as well as individual factors that can lead to polarized views about extreme weather events and climate change. It also compares findings from studies of extreme weather events and/or climate change across various social media platforms (Twitter, Facebook, blogs, and YouTube). Finally, the chapter explores a number of approaches researchers have used to combat extreme weather events and climate change misinformation on social media.
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The general problem may be stated as follows: having given the number of instances respectively in which things are both thus and so, in they are thus but not so, in which they are so but not thus, and in which they are neither thus nor so, it is required to eliminate the general quantitative relativity inhering in the mere thingness of the things, and to determine the special quantitative relativity subsisting between the thusness and the soness of the things.