Student Friendship choices and Ethnic homophily in the classroom

Amalia Alvarez1

1Max Planck Institute for Research on Collective Goods

Abstract The effect of ethnic homophily, i.e. the desire of agents to be connected to similar others, is a persistent feature of, especially in the school context. In this study I use two observations of the complete social network of a cohort of Swedish students (n=115) in a secondary school and analyses the scope of ethnic homophily on segregation and homogeneity, as well as the effect of structural factors such as school's structural organization in classrooms. Sociometric data was collected during a school year and the models presented are based in crosscuts of the friendship network. Homophily in respect to ethnic origin is found in both time points, with students making connections primarily within the ethnic group. Nevertheless, the effect of ethnic homophily seems to decrease between the waves, whereas the effect of structural constraints remains high over time. This hypothesis, as well as the relevance of each effect, is then tested using both network level measures and tie-based measures such as ERGM models. Results suggest that organisational divisions in classrooms play a decisive role in the pattern of friendship connections in the school. These boundaries should be taken into account when conducting research on homophily in friendship networks in the school context. Key words Ethnic homophily, Friendship networks, Inter-ethnic friendship, School segregation, School network

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INTRODUCTION

A notable feature of social networks is their high degree of homogeneity. People who

are similar with respect to many different attributes, ranging from education, attitudes

or occupation, to social status, are more likely to be connected as friends,

acquaintances, or spouses, than are dissimilar people (e.g., Blau, 1977; Marsden, 1987,

1988; McPherson et al., 2001; Verbrugge, 1977). This happens in many contexts such

as school (Shrum, Cheek, & Hunter, 1988), work place (Ibarra, 1992) or couples

(Kalmijn, 1998, 1994). The preference for similar ones, in the absence of other

constraints, leads to individuals choosing their connections based on a similarity of

attributes, a phenomenon known as homophily.

The strength of homophily tendencies varies between attributes, with ethnic origin

being one of the strongest basis for homophily (McPherson et al., 2001). Thus, ethnic

segregation is a persistent feature of friendship networks in general, and in school

settings in particular (Joyner, 2000; Kandel, 1978; Kao & Joyner, 2004; Shrum et al.,

1988). This is a question of broad relevance: ties between the different ethnic groups

can reduce discrimination, decrease implicit and explicit ethnic bias, and increase

minorities’ access to social resources and information (Pettigrew & Tropp, 2000;

Pettigrew, Tropp, Wagner, & Christ, 2011).

Despite the importance of ethnic homophily friendship choices are not only dependent

on the attributes and preferences of the individuals making the choice, but they are also

influenced by the opportunity of contacts, Shared activities and organisational

structures have also been found to affect the patterns of friendships (Feld, 1981, 1982),

because the organisational structure might promote interaction among certain

individuals, thus influencing friendship choices in school (Moody, 2001), and

elsewhere.

The purpose of this study is to investigate students’ possible preference for ethnic

similarity that will result in a majority of friendships being intra-ethnic, and the effect

of the local structural organization of the school (i.e. school classrooms) that will lead

to students choosing to befriend others within their own classroom.

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I first review previous theory and research on homophily. Based on this, different

hypotheses are proposed. The first two hypotheses explore the patterns of ethnic

segregation and homophily in the school in two different time points of the school year

and the effect of the opportunity structure. The third hypothesis examines the

possibility of interplay between ethnic homophily and constraints imposed by the

division of the school in classrooms. If the contact within classrooms fosters friendship

then, the effect of ethnic homophily should diminish over time, whereas the number of

friendship intra classroom should remain stable or increase. This would result in a less

segregated friendship network over time and a reduced effect of ethnicity in the

decision of forming a friendship.

THEORY AND HYPOTHESES

ETHNIC HOMOPHILY AND SCHOOL FRIENDSHIP CHOICES

Friendship homophily is defined as the selection of friends given a motivation to seek

similarity 1 . Homophily is, thus, induced by in-group bias and personal choice

(Kossinets & Watts, 2009; McPherson & Smith-Lovin, 1987, 2001). Ethnicity is one

of the most common attributes defining similarity and group membership (McGuire &

McGuire, 1978) which throughout individuals construct their social identity

(Baumeister & Leary, 1995; Tajfel, 1974; 1978; Turner, 1975) and set the basis for

social interactions. In the presence of homophily, individuals create most of their

connection within their in-group2 (e.g., Girvan & Newman, 2002; Henry, Prałat, &

Zhang, 2011; Palla, Barabási, & Vicsek, 2007; Watts, Dodds, & Newman, 2002). The

reasons for this tendency are diverse: individuals seem to be attracted to similar ones

(Byrne, 1961) or interaction with similar people might be easier due to shared

knowledge and culture (Kalmijn, 1994). In the case of ethnic homophily, for example,

1As the preferred interaction between individuals who share membership in a social category (Wimmer & Lewis, 2010), homophily is a sort of in-group preference (Blau, 1977), and we should think about it as cognitive process, i.e. it refers to ego’s beliefs. Therefore choice homophily is (incorrectly or correctly) based on ego’s beliefs about alter’s attributes. 2 Group membership not only increases the probability of a connection, it might influence in-group favoritism, pro-social behavior, like altruistic cooperation and norm enforcement (Goette et al., 2012; Nowak, 2006; Ostrom & Sedikides, 1992).

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different mechanisms could play a role in the preference for intra-ethnic ties such as

within group similarities derived from a similar cultural background, similar language,

and similar status or prejudice. From a rational choice perspective, what derives is that

establishing a friendship outside one’s ethnic group is costly, in comparison with

befriending people from the in-group (Currarini and Vega-Redondo, 2009; Currarini et

al., 2013).

Empirical research has found a high preference for ethnic similarity in friendship

choices in different social contexts (Wade & Okesola, 2002) and following different

ethnic classification3 (Kao & Joyner, 200, 2004). In the school context researchers

have systematically found significant evidence of homophily between black and whites

in the schools (e.g., DuBois & Hirsch, 1990; Hallinan & Williams, 1989; Kao &

Joyner, 2000, 2004; Shrum, Cheek, & Hunter, 1988). However, in recent years the

field has been enlarged with the incorporation of new categories such as Hispanic and

Asian backgrounds (Carlson, Wilson, & Hargrave, 2003; Iceland, 2004; Quillian &

Campbell, 2003). Studies found persistent high levels of segregation of blacks,

including black Hispanics (i.e. Afro-Latin), from all other ethnic groups (Quillian &

Campbell, 2003).

Research conducted in Europe shows a preference for intra-ethnic friendship in native

students in Germany (Titzmann & Silbereisen, 2009) , as well as for European students

in The Netherlands, Sweden and Germany (Smith, Maas, & van Tubergen, 2014).

Adolescents from the three countries were found to nominate ethnic in-group peers as

friends. Natives were found to persistently show a strong ethnic in-group preference,

whereas, some other ethnic groups were not, such as people with Lebanese origin in

Sweden (Smith et al., 2014).

Ethnic homophily might provide individuals with several advantages, such as increased

mutual support, reduced communication cost or increased reciprocity and cooperation

(Barros, 2007; Nowak, 2006). Nonetheless, homophily can lead to group conflict and

or perpetual inequality (DiMaggio & Garip, 2011, 2012; Ibarra, 1992) by different

mechanisms. First, it can lead to higher levels of prejudice and rigid in-group/out-

group delimitations, what prevents social identification outside the in-group and affect

3 In this study the ethnic classification is based on the student’s parents country of origin.

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students’ ethnic and racial attitudes4 (Tajfel, 1978; Ellison & Powers, 1994; Emerson,

Kimbro & Yancey, 2002). Conversely, ties across different ethnic groups can reduce

prejudice (Allport, 1954; Pettigrew & Tropp, 2000). In the school context, an increased

level of prejudice might lead to a higher level of exclusion affecting, among others,

students’ academic achievement (Kao & Tienda 1998; Kao & Johnson, 2003), and

intensifying school violence (Juvonen, Nishina, & Graham, 2000; Graham & Juvonen,

2002). Furthermore, the patterns of ethnic friendship may be indicative of social

distance between ethnic groups in the future (Joyner & Kao, 2004). As thi pattern

persists over time, homophily might lead to unequal and differential access and return

of social capital (Lin, 1999, 2000; Portes, 1998), therefore perpetuating inequality.

Hence, ethnic homophily might be seen as a mechanism for the persistence of

inequalities or disadvantages of groups (DiMaggio & Garip, 2011, 2012; Lin, 2000)

and has been widely discussed for both migrant and ethnic/racial status (Lin & Dumin,

1986; Lin, 2004), also in Sweden (Behtoui, 2006; Rydgren, 2004)

FRIENDSHIP CHOICES AND OPPORTUNITY STRUCTURE

The importance of homophilous preferences in shaping friendship choices is

unquestionable, yet not the only force at play. Past research has shown that friendship

choices also depend on opportunity structure. Indeed the number of ties between

structurally distant individuals is normally small because people befriend others that

they have the opportunity to meet, thus, preferences for similarity are expected to be

“expressed in the absence of other reasons to form new ties” (Kossinets & Watts, 2009,

p. 436) such as proximity and repeated interaction.

The two mechanisms are not mutually exclusive, but they rather interact. Structural

determinants might intensify or lessen the effect of individual preferences. In the case

of ethnic homophily, for instance, past research concluded that shared activities

increase the likelihood of inter-ethnic ties (Kao & Joyner, 2004), and other findings

suggest that interethnic friendship must be promoted by groups of common interests

(Stark & Flache, 2011), and by the constraints to the meeting opportunity (Blau, 1977;

Feld, 1981, 1982). The divisions in classrooms creates an structure that forces people

4For instance, adolescents within the same group report similar levels of prejudice towards stigmatized ethnic minorities (Kiesner, Maass, Cadinu, & Vallese, 2003)

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to interact, which in turn would reduce prejudice and reduce ethnic segregation and

homophilly, i.e. Contact hypothesis (Allport, 1954). Then, choice homophily as a

mechanism of friendship formation might have a stronger impact where there are no

other constraints that facilitate interaction, as the organisation of students in

classrooms.

THE PRESENT RESEARCH

In this study I present some particularities of special interest for the research of ethnic

homophily in school settings while trying to overcome past limitations. The models are

constructed using data from second-generation immigrant or immigrants with a long

history in the country, thus avoiding biases due to the different stages of the

acculturation process of the individuals. Also, I introduce a ethnic classification that

considers national and cultural links based in wider national and cultural categories, in

the line of newest research such as Smith et al., (2014). This classification tries to be

more encompassing than previous categories such as natives and non-natives or racial

categories. Past research has mainly focused in participation in interest-based groups

and associations, whereas exogenously imposed structural subdivisions, like

classrooms, have remained mostly understudied. The case at hand represents a very

good opportunity to investigate the interplay between the structure of opportunities and

choice homophily.

Finally, the small school setting (n=115 students) allows for network and group level

techniques, as well as tie-based analysis, without the necessity of extremely powerful

computation techniques. Complicated techniques have been a major reason for using

group-based measures even though individual-level measures are known to be better

(Zeng & Xie, 2008). In this study both network level measures as well as tie-based,

exponential random graph models (ERGM), are used to investigate ethnic segregation

and ethnic homophily.

HYPOTHESES

Based on previous findings and theory I expect students in the school might display a

preference to be linked to similar ethnic ones, therefore resulting in a homophilous

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network in respect to ethnic group, as well as ethnic segregation. However friendship

choices might be affected by constraints imposed by the structure, as the division in

classrooms in the school. Hence, the research will analyse two different determinants

of friendship choices in the school: student’s possible motivations to seek ethnic

similarity and its interrelation with homophily induced by structural organization. The

first hypothesis tests whether students in the school display a tendency to befriend

individuals from their own ethnic group, as expected by results in past research.

Hypothesis 1: Similarity with respect to ethnic origin will breed connection in the

school resulting in ethnic segregation in the friendship network.

Hypothesis 2: Students tend to establish friendship within classrooms at all times.

Hypothesis 3: The effect of ethnic homophily in tie formation and ethnic segregation

diminishes between waves.

DATA AND METHODS

DATA

Data was collected from an upper secondary school (grades 10-12) located in one of

Sweden’s most populated urban areas. It comprises the complete friendship network of

students that started grade 10 in 2012, with a total of 115 individuals. Data were

collected5 by means of a survey during the scholar year 2012/13. I exploited two waves

of data. Wave 1 was collected in October at the beginning of the school year (October)

and wave 2 was collected in May at the end of the school year. Between the two times

of data collection the student composition of school changes, with some new students

coming and others quitting the school. The questionnaire included a roster to nominate

friends, as well as sociodemographic information about the students such as sex,

religion or parent’s country of birth. In the roster students could select with “whom

they hang out after school”. Following this data information on the full friendship

network was obtained. The school is divided into 4 classes with similar number of

5 Data was collected by Sara Roman who at that time was a PhD candidate and researcher at Stockholm University. Data was collected with the purpose of serving for her own research.

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students.

Table 1. Number of students by class and wave

Number students Not in sample Class Wave 1 Wave 2 Wave 1 Wave 2

1 27 28 2 3 2 25 19 1 1 3 27 24 0 4 4 24 25 2 1

Total 103 96 5 9

The total number of students included is 103 in wave one and 96 in wave two. Five

students have not joined the school in the first wave and 9 have left before the second

wave. Some students were missing at time of data collection or did not want to

participate. Missing rate is 2,7% in wave 1 and 18% in wave two. Notice that contrary

to the students that were not present in the sample, missing students can still be

nominates as friends. Attribute-based missing information is very low. There is no

missing information in ethnicity or sex, and missing information about religion is

0.04%.

VARIABLE CONSTRUCTION

Friendship definition - A friendship is said to occur between two students, e.g., i and j,

when either j refers i as a friend or vice versa. Because most of the students did not

know each other from before we can assume that initial links are not the result of past

relationships. The network is directed and only some of the links are.

Ethnicity - The country of origin of the parents was used to determine the ethnic origin

of the students so the definition of ethnicity used in this study refers to national origin.

The classification is as follows: (1) students whose parents were born in Africa (sub-

Saharan and horn of Africa) were classified as of African origin; (2) students with

parents born in a country part of the Middle East6 were classified as having middle east

ethnic background; (3) students whose parents were born in Europe7 were classified as

of European background, and finally; (4) a last category was created for students who

6 Middle East countries include: Iran, Irak, Egypt, and Kurdistan. 7 European countries include: Sweden, Iceland, Finland, France, Spain, Poland, and Bosnia.

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could not be classified8. The frequencies of the groups in the two waves are shown in

Table 2.

Table 2. Number of students by ethnic origin

Ethnic background Wave 1 Wave 2

Africa 31 (30.1%) 32 (33.3%) EU 39 (37.9%) 32 (33.3%)

Middle East 21 (20.4% 21 (22.0%) Other 12 11.7%) 11 (11.5%) Total 103 96

The classification was done following the country of origin of the mother. In case of

missing information (0.017%) the country of birth of the father was used. All

ethnicities are present in all the classrooms in a sufficient amount for homophily to be

possible.

ANALYTICAL STRATEGY

In order to measure the network level homogeneity I used the EI index9. The E-I index

measures homogeneity (or segregation) in a network composed by mutually excluded

groups (e.g. the different ethnic origin groups). This measure compares the relative

density of internal connections within a group and the number of connections this

group has to others groups. The index is computed as the number of ties external to the

group minus the number of internal ties, and then divided by the total number of ties in

the network.

The value of the index ranges from 1 to -1 (being 1 totally heterophilous and -1 totally

homophilous). Nevertheless, as recommended in past research (Everett, 2012;

Krackhardt, 1988), it is often helpful to substrate the ratio from 1. The new ratio is

used in the graphs and its values range from 0 to 2, where 0 means total heterophily

and 2 total homophily. The index was implemented using the software UCINET

(Borgatti, 2002, 2013). The significance of the network level index can be tested using

8 Unclassified students are students with born within categories with less than three members. This last group is less informative than the specific categories and, therefore, has been reduced as much as possible. 9 The formula of the EI index is as follows:

𝐸𝐼 𝑖𝑛𝑑𝑒𝑥 =𝐸 − 𝐼𝐸 + 𝐼

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a permutation test. The test provides a rescaled value of the whole network index that

control for density and group sizes. Because the permutation test gives a re-scaled

value that is invariant to size and density, the whole network level E-I index is

comparable between the two networks since it is not affected by group sizes.

To measure the effect of ethnic homophily in tie formation I build an ERGM model

that accounts for individual ethnic attributes, opportunity structure, and relational

mechanisms. ERG models allow us to consider in-group preferences for all the ethnic

groups while taking into account the effects of relative group size, structural effects

and network effects such as triadic closure and reciprocity simultaneously. The ERGM

models control for structural effects and capture relational mechanisms, thus allowing

to disentangling the effect of ethnic homophily from other possible mechanisms.

ERGM specifications. I used a model specification that accounts for the possible

network effects that can influence friendship choices. The term for triadic closure, i.e.

the tendency to befriend the friend of a friend, is the “geometrically weighted edge-

wise shared partner”10 (GWESP) statistic that can accommodate the often observed

tendency of two nodes to share more than one partner, thus controlling for clusters in

the network. A term for reciprocity, i.e. the tendency of two students to nominate each

other, is also added to the model.

ERGM models can account for the relative sized of groups, but they cannot control for

the number of ties or how sociable a group is. In order to control for that sociability

term has been added for every ethnic group. This term controls for the total number of

ties of each group. A homophily term is added to the model for each of the ethnic

groups, as well as for classroom and sex. The homophily terms are dyadic covariates

that take the value of 1 if both nodes belong to the same group and 0 otherwise.

RESULTS

WITHIN CLASSROOMS FRIENDSHIPS

The majority of friendships are made within the classroom: 80% of the ties come from

the same classroom in wave 1, whereas only 73% of the ties are created within

10The geometrical weight expresses the expectation that higher-order triangles are less likely than lower order triangles.

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classrooms in wave 2 (see table 3). The empirical results are in line with the hypothesis

that most of friendships are made within classroom, although, the effect seems to

decrease between the waves. The test for intra-classroom friendship choices shows a

re-scaled E-I index of 1.551 (p.05 SD=.057) compared to an expected value of 0.487.

This means that the majority of nominated friends of a student come from the same

classroom making the network segregated by classrooms.

The effect of classroom persists in wave 2. The re-scaled E-I index for classrooms has

a significant value of 1.439 (p < .05; SD=.053), very similar to the value in wave 1.

This confirms that the effect of organisation in classrooms remains high across waves,

with a majority of friendships coming from the own classroom and that the

organisation in classrooms exerts an important effect in the patterns of friendship.

Table 3. Descriptive network measures

Network attributes Density11 N. of ties Avg. degree w/i classroom ties

Wave 1 0.026 270 5.24 216 (80%) Wave 2 0.031 285 5.94 208 (73%)

E-I INDEX AND SEGREGATION MEASURE

If hypothesis 1 is correct, and similarity with respect to ethnic origin leads to

connection in the school network, then we should expect a bigger number of links

within the in-groups than between groups. This will translates into a significant and

larger than 1 E-I index. In wave 1 the E-I index computed for the whole network takes

a value of 1.05 (p<.05 SD=.065), indicating the presence of homophily in the network.

The expected value for the E-I index is 0.565, so the current value for the index

considerably deviates from expected from the baseline ethnic composition of the

school population. In order to test whether this deviation is statistically significant, a

permutation test was computed. The permutation test (Table 4) with 10000 iterations

shows that the homophily found by the E-I index is significant at the 95% level. This

means that, with a 95% of times, the E-I of the network do not fall in the random

11 Density of the network is defined as the ratio of the observed number of ties to the number of possible ties.

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distribution provided by the permutation test. The results ensure that the distribution of

ties given the groups significantly differs from random. It suggests that the level of

homophily of the network is significantly higher than expected if the connections were

done by chance or if the divisions into ethnic groups did not play a role.

Table 4. Permutation test E-I index wave 1

Obs Min Avg Max SD P>= Ob P<= Ob

Internal 0.502 0.161 0.282 0.424 0.033 0.000 1.000 External 0.498 0.576 0.718 0.839 0.033 1.000 0.000

E-I -0.05 0.151 0.435 0.678 0.065 1.000 0.000 Note- Number of iterations = 10000. E-I Index is significant (p < .05)

The network in wave 3 does not show signs of ethnic segregation. The E-I Index for

the whole network in wave 2 takes a value of 0.892 (SD=.060). The permutation test

shows that the index is not statistically significant, even though it is somewhat bigger

than the expected value. Thus, results suggest that the network in wave 2 is no longer

segregated with respect to ethnic origin or that, at least, results do not vary

significantly from random. Results suggest that ethnic homophily exerts a greater

effect at the beginning of the scholar year, but this effect diminishes over time.

ERGM MODEL

The empirical results presented until now allow us to measure segregation at a network

level. In this section, I present an ERGM model (table 5) to investigate the sources of

tie formation.

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Table 5. ERGM model results

DEPENDENT VARIABLE

WAVE 1 WAVE 2

Network terms

Edges……………………. -5.511*** (0.225) -5.212*** (0.209)

Triadic closure (GWESP). 1.339*** (0.129) 1.472*** (0.117)

Reciprocity……………… 2.080*** (0.256) 0.538** (0.266)

Sex………………………. 0.641*** (0.111) 0.560*** (0.103)

Classroom……………….. 1.297*** (0.133) 1.210*** (0.112)

Sociality terms

Africa..………………….. -0.161 (0.127) -0.158 (0.129)

EU………………………. -0.366** (0.144) -0.157 (0.138)

Middle East……………… -0.223 (0.140) -0.159 (0.135)

Ethnic homophily terms

Africa..………………….. 0.409* (0.225) 0.398* (0.229)

EU………………………. 0.788*** (0.216) 0.525** (0.234)

Middle East……………... 0.726*** (0.257) 0.669** (0.269)

AIC………………………… BIC…………………………

1,631.661 1,718.777

1,887.457 1,972.876

Note- *p<0.1; **p<0.05; ***p<0.01

The terms for network-specific effects, number of edges, triadic closure and

reciprocity, are all significant predictors of tie formation in both waves, and the p-value

is far less than the conventional significance level of .05 cut off. The coefficients in

table 5 are expressed as conditional log-odds. The parameter for edges indicates the

baseline random probability of tie formation if the other model elements are ignored.

Thus, the log-odds of a tie being created are -5.511 in wave 1, which yields a

probability of 0.004 of forming a tie in the network, and -5.212 in wave 2, with a 0.005

probability12. The log-odds that a within classroom friendship will form equals 1.297

in wave 1 and 1.210 in wave 2, which yield probabilities of 0.015 and 0.018

respectively. Likewise, the probability of an ethnic homophilous tie in wave 1 equals 12 p= exp(β)/(1+exp(β)).

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0.009 for the EU group, 0.006 for students of African origin and 0.0083 for students of

the Middle East group. In wave 2 these probabilities are 0.008 for African, 0.0091 for

EU and 0.010 for students from Middle East.

The probabilities of tie formation are higher in wave 2 for all the terms because the

baseline probability of tie formation is higher in wave 2. This is consistent with the

descriptive statistics of the network in both waves that show an increase in the average

degree and density of the network. Nevertheless in order to compare the effect of the

homophily and classroom terms in both waves we should look at the magnitude of the

coefficients. The coefficients of the homophily terms are smaller in wave 2 than in

wave 1. These results are in line with the proposed hypothesis that the effect of ethnic

homophily in tie formation will decrease between the waves. Nonetheless the effect of

being in the same classroom also decreases in wave 2.

The results above show that on the one hand the ethnic segregation decreases over time

and the global effect of the divisions in classrooms remains. On the other hand the

preference for ethnic similarity, albeit less pronounced in wave 2, influences tie

formation in both waves.

DISCUSSION

The main objective of this research was to study ethnic segregation and tie formation

between different ethnic groups in the Swedish school context and the effect of

organisation of the context in classrooms. Results of ethnic homophily at the network-

level and also at the tie level have been presented in this study. The main findings are:

1) using parent’s country of birth as a proxy for ethnic group, the network presents

ethnic segregation, but it decreases between the waves, 2) ethnic homophily affects

friendship nomination, although the effect seems to decrease over time, and 3) there is

a strong tendency to make friendships within the own classroom in both waves, as the

second hypothesis predicted. Results from network level measures seem to be in the

line with hypotheses one and two discussed earlier in the study.

Concerning ethnic homophily the study produced some valuable results. The ERGM

model shows that ethnic homophily influences friendship choices at all times in the

school. In line with previous research students in the school select friends that are

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ethnic similar to them. Results differ across ethnic backgrounds with groups displaying

slightly different patterns of homophily. In the case of this study the picture might be

more complicated to interpret because the categories encompass various countries of

origin. The findings suggest that ethnicity might be less of a barrier to students with

African origin than to European or Middle East backgrounds.

A question posed by the interpretation of the homophily induced by the organisational

structure, i.e. the classrooms, is whether the organisational foci exert stronger effect on

the patterns of friendship in the school than a individual preference for ethnic group.

Results suggest that, due to its salience as a social cue, ethnicity seems to guide

friendship nominations, but the patterns of friendship in the school are affected by the

organisation in classrooms as well as other network effects, because the effect of ethnic

homophily decreases over time whilst the effect of the context remains very strong at

all times. A first, intuitive explanation13 and that the findings in the study seem to

support is that the organisation in classrooms might serve as a constrained opportunity

structure. Classroom creates the social boundaries within individuals are supposed to

establish their social relationship and delimit who can be selected as a friend by

increasing the meeting opportunities of members of the same classroom. One of the

most important conclusions of this study is that is the classroom and not the grade or

the school the real boundaries for friendship making, and this has to be taken into

account in future research. However, to test whether the shared environment and the

repeated interaction within classrooms enhance the likelihood of friendship between

students from different ethnicities, further research is needed.

In concluding, I argue that results in this case study imply that within small schools,

organisation in classrooms is a stronger predictor of connections than ethnic traits,

what means that organisation of the context could bring dissimilar people into contact.

The context serves as a base for expression of preferences. If the context from which

friends are chosen is homogeneous, there will be high levels of ethnic homogeneity,

however, in ethnic diverse settings, the context promotes inter-ethnic friendships.

Factors such as cooperation and increased contact have been found to diminish ethnic

13 From a more economic perspective we can think that creating a new connection is a costly action, people might perceive an incurred cost on creating a connection with someone from a different class. In this sense individuals might just adapt to the context with a cost benefit analysis of friendship formation and will seek similarity only when it is cost-effective (Currarini & Vega-Redondo, 2013; Currarini et al., 2009).

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prejudice and promote inter-ethnic friendships (Allport, 1979; Weigel, Wiser, & Cook,

1975). Even though results in the case at hand cannot ensure that student’s preferences

in respect to ethnic similarity changed, the findings suggest that, at least, the network is

not ethnically segregated in wave 2. To some extent results can inform policies aimed

to decreased ethnic segregation, by bearing in mind that certain context organisations

might encourage inter-ethnic friendship. The study also has some implications for

future research in ethnic homophily in schools. Findings in this study suggest that

classrooms might be always taken into account in the study of homophily in the school,

since this organisation of the context represents the boundaries in which friendship are

created.

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