Abstracts |
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CONNECTIONS 20(1):39-53
©1997 INSNA
Articles and Chapters |
Alpert, C. J.,
and A. B. Kahng. 1997. Splitting an Ordering into a
Partition to Minimize Diameter. Journal
of Classification. 14: 51-74.
Many algorithms can
find optimal bipartitions for various objectives
including minimizing the maximum cluster diameter
("min-diameter"); these algorithms are often
applied iteratively in top-down fashion to derive a
partition P^{k} consisting of k
clusters, with k > 2. Bottom-up
agglomerative approaches are also commonly used to
construct partitions, and we discuss these in terms of a
worst-case performance for metric data sets. Our main
contribution derives from a new restricted partition
formulation that requires each cluster to be an interval
of a given ordering of the objects being
clustered. Dynamic programming can optimally split such
an ordering into partition P^{k}
for a large class of objectives that includes
min-diameter. We explore a variety of ordering heuristics
and show that our algorithm, when combined with an
appropriate ordering heuristic, outperforms traditional
algorithms on both random and non-random data sets. Angle, J. 1996. How the Gamma Law of Income Distribution Appears Invariant Under Aggregation. Journal of Mathematical Sociology. 21(4): 325-58. The Gamma Law of Income
Distribution appears to be a scientific law because the
gamma pdf 1) fits the grange of shapes seen in income
distributions, 2) is parsimonious, 3) appears to be scale
invariant, i.e., to show invariance under population
aggregation, and 4) the gamma pdf's shape parameter
provides a convenient descriptor of the range of shapes
seen in income distributions, allowing the apparent
invariance between education and the shape of the income
distribution to be simply described. The Gamma Law of
Income Distribution cannot, however, be a scientific law
because it is not scale invariant. An unconditional
distribution of income is a mixture, i.e., the weighted
sum, of variously shaped income distributions. People at
different education levels have differently shaped income
distributions. These distributions are well fitted by
gamma pdfs making the correspondent unconditional
distribution a gamma shape mixture. A gamma shape mixture
is not in general a gamma pdf. Aggregating the income
distributions of population segments together can give
rise to gamma shape mixtures. Thus the Gamma Law is not
scale invariant. However, under certain conditions a
gamma shape mixture can be hard to distinguish from GAM
(*, l), the gamma pdf whose shape parameter is *, the
weighted average of the _{i}'s, the shape
parameters of the component gamma pdfs of the mixture.
GAM (*, l) has the same mean as the shape mixture. These
conditions allow the Gamma Law of Income Distribution to
appear to be scale invariant. These conditions occur in
geographically defined populations in the contemporary
U.S. They are 1) the distribution of income conditioned
on education is itself gamma distributed, 2) is invariant
under aggregation, 3) most of the population has attained
an education whose corresponding income distribution is
fitted by GAM (*, l) where _{i} > 1, 4) there
is a close relationship between the shape of the income
distribution and education, and 5) the distribution of
people over education is approximately symmetric,
unimodal, and peaked at its mode. The Gamma Law of
(unconditional) Income Distribution appears to work
because a Gamma Law of Income Conditioned on Education
exists. Banks, D. L., and K. M. Carley. 1996. Models for Network Evolution. Journal of Mathematical Sociology. 21(1-2): 173-96. This paper describes
mathematical models for network evolution when ties
(edges) are directed and the node set is fixed. Each of
these models implies a specific type of departure from
the standard null binomial model. We provide statistical
tests that, in keeping with these models, are sensitive
to particular types of departures from the null. Each
model (and associated test) discussed follows directly
from one or more socio-cognitive theories about how
individuals alter the colleagues with whom they are
likely to interact. The models include triad completion
models, metric models, and the constructural model. We
find that many of these models, in their basic form, tend
asymptotically towards an equilibrium distribution
centered at the completely connected network (i.e., all
individuals are equally likely to interact with all other
individuals); a fact that can inhibit the development of
satisfactory tests. Barkey, K., and R. Van Rossem. 1997. Networks of Contention: Villages and Regional Structure in the Seventeenth-Century Ottoman Empire. American Journal of Sociology. March 102(5): 1345-82. This article analyzes
peasant contention in 17th-century Ottoman villages. The
authors argue that peasant contention results from the
position of the village in the regional structure, with
village-level organization providing the means for
contention The article uses court records to reconstruct
the formal and informal networks within and across
villages in western Anatolia. Under conditions of state
and market expansion, those villages in intermediate
positions in the regional structure tend to experience
the vagaries of these changes more than central or
isolated villages Those intermediate villages are also
most prone to contention Cooperative village organization
is also found to promote contention. Barnes, G. R., P. B. Cerrito, and I. Levi. 1996. Algebraic Structure of the Interaction Semigroup as Related to the Homogeneity of Network. Journal of Mathematical Sociology. 21(4): 295-323. This paper addresses the
development of a semigroup model of social networks. Data
matrices which represent the perceived relationships
between members of a social network are use dot construct
a (possibly infinite data semigroup of derived relations
defined by (real) matrix multiplication. This complex
structure is analyzed by forming interaction semigroups.
These semigroups are homomorphic images of the data
semigroup. The corresponding congruences are generated by
identifying products of finite order which are highly
positively correlated. Several methods of generating the
interaction semigroups are examined and are shown to
generate nonhomomorphic semigroups. For each congruence,
an associated triple of numbers can be defined which may
serve as an indicator of the validity and/or a measure of
the stability of the semigroup model. A series of
hypothetical examples is developed to study how the
algebraic properties of interaction semigroups reflect
and uncover properties of associated networks.
Specifically, relationships between homogeneity of a
network and the algebraic structure of the corresponding
interaction semigroup are addressed. The applicability of
the above techniques to blockmodels is demonstrated. Batchelder, W. H., E. Kumbasar, and J. P. Boyd. 1997. Consensus Analysis of Three-Way Social Network Data. Journal of Mathematical Sociology. 22(1): 29-58. Three-way social network
data occurs when every actor in a social network
generates a digraph of the entire network. This paper
presents a statistical model based on cultural consensus
analysis for aggregating these separate digraphs into a
single consensus digraph. In addition, the model allows
estimation of separate hit and false alarm rates for each
actor that can vary within each actor in different
regions of the digraph. Several standard signal detection
models are used to interpret the hit and false alarm
parameters in terms of knowledge and response bias. A
published three-way data set by Kumbasar, Romney, and
Batchelder (American Journal of Sociology, 1994) is
analyzed, and the model reveals that both response bias
and knowledge decrease with distance from ego. Bearman, P. 1997. Generalized Exchange. American Journal of Sociology. March 102(5): 1383-415. Generalized exchange, in
which sections of a tribe exchange women in a cycle and
thus guarantee social solidarity, was induced from models
of the norms governing classificatory kinship systems. A
block model analysis of one aboriginal tribe yields
sections that serve as marriage classes in a generalized
exchange system, though the norms that govern kinship
would fail to manifest, if followed, a cycle for
exchange. Generalized exchange systems emerge from
inequalities exogenous to the kinship system,
specifically gerontocracy. Models of norms are weak
predictors of actual exchange structures. Models of
relations yield insight into the etiology of systems that
build social solidarity from social exchange. Beggs, J. J., J. S. Hurlbert, and V. A. Haines. 1996. Community Attachment in a Rural Setting: A Refinement and Empirical Test of the Systemic Model. Rural Sociology. 61: 407-26. As they examine the
complex issues currently facing rural America, rural
sociologists draw increasingly on studies of community
attachment. Because this research tradition has
established the superiority of the systemic model, recent
studies in rural and urban settings have focused on the
conceptualization and operationalization of its
components. We introduce four operational refinements to
this model, and we test our refined model with data from
one geographic area in southwest Louisiana. We find that,
although our operational refinements improve our
understanding of community attachment, additional
refinements are necessary. We conclude by exploring the
implications of community attachment studies for attempts
to revitalize community in rural settings. Bonacich, P., and E. J. Bienenstock. 1997. Latent Classes in Exchange Networks: Sets of Positions with Common Interests. Journal of Mathematical Sociology. 22(1): 1-28. While it is known that
positions in exchange networks are interdependent, little
work has been done to develop a systematic procedure to
determine the type and pattern of these
interdependencies. Wording from an insight by Schubik
(1984), this paper proposes a canonical form for such
interdependence. The model does not depend on the
existence of pre-existing categories of complementary
positions, such as buyers and sellers or men and women.
The model uses only network position to create classes of
positions with linked fates. Simulation and experimental
results are presented that support this schema. These
findings lay the groundwork for the study of collusion in
exchange networks: members of latent classes, who share a
common fate, would be likely to form coalitions when free
communication exists. Braun, N. 1996. Why Fix It When It Ain't Broken? A Reply to Henning's Critique. Journal of Mathematical Sociology. 21(4): 379-88. This rejoinder discusses
Henning's arguments against my model for exchange systems
with restricted market access. it also presents an
alternative rational choice model that combines Henning's
central demands with my original modeling idea (according
to which restricted access has effects before the
optimization). This alternative approach yields similar
conclusions as my earlier analysis. A comparison with
Henning's results (which refer to a scenario in which
access restrictions explicitly enter the optimization
program) suggests that the respective model implications
depend crucially on the decision where and how restricted
access is introduced into a model. From this perspective,
Henning's negative assessment of my work is questionable
because, in the absence of empirical evidence, he has no
better rationale for modeling restricted access than I
do. Bulder, Bert, F. Leeuw, and H. Flap. 1996. Networks and Evaluating Public-Sector Reforms. Evaluation. 3(July):261-276. Surveys of client
satisfaction and network analysis of the Dutch Ministry
of the Interior and a semiindependent executive agency in
the Netherlands were used to investigate
relationships between social capital and
government reforms. Results indicated that social
networks greatly contribute to the productivity
of individual employees as well as
organizations. It is argued that well-intentioned
reorganizations or reforms can turn social
capital into "sour" capital, leading to a deterioration
in efficiency, effectiveness, and customer satisfaction. Cheng, R., and G. W. Milligan. 1996. Measuring the Influence of Individual Data Points in a Cluster Analysis. Journal of Classification. 13: 315-35. The problems of measuring
the impact of individual data points in a cluster
analysis is examined. The purpose is to identify those
data points that have an influence on the resulting
cluster partitions. Influence of a single data point is
considered present when different cluster partitions
result from the removal of the element from the data set.
The Hubert and Arabie (1985) corrected Rand index was
used to provide numerical measures of influence of a data
point. Simulated data sets consisting of a variety of
cluster structures and error conditions were generated to
validate the influence measures. The results showed that
the measure of internal influence was 100% accurate in
identifying those data elements exhibiting an influential
effect. The nature of the influence, whether beneficial
or detrimental to the clustering, can be evaluated with
the use of the gamma and point-biserial statistics. Church, A., and Reid Peter. 1996. Urban Power, International Networks and Competition: The Example of Cross-Border Cooperation. Urban Studies. October 33: 1297-318. This paper reviews the military sociology and popular literature on soldier isolation during force-projection operations and the (tele)communication resources available and used to lessen feelings of isolation. During World War 11 and the Cold War era (Korea and Vietnam Wars), soldiers were isolated. Communication with significant others and the larger society was primarily one-way (e.g., via letter mail, Victory-mail, radio, movies, audio tapes, and tape delayed television). During the late-Cold War (e.g., invasion of Grenada, peacekeeping missions, and the invasion of Panama) and more recently during the post-Cold War era (e.g., the Persian Gulf War, Los Angeles riots, and the Somalia relief effort), the diffusion of one-way, and revolution in twoway communication media f e.g., telephones, video tapes, voice-mail, live television, and e-mail) resulted in a continued decrease in isolation for soldiers. Notwithstanding, there is a consistent and salient need among soldiers and families to continue to lessen isolation and separation. Although there has been a revolution in types of communication media (CM) available during force-projections, use across military operations has been evolutionary. In other words, high-tech has not displaced lowtech, but supplemented it. Recognizing that new and old CM are an ever-evolving and important element of the post-Cold War soldiers' experience, the authors stress the importance of social science research in ascertaining the social implications of regulating CM in military and other social institutions. de Leeuw, J., and P. J. F. Groenen. 1997. Inverse Multidimensional Scaling. Journal of Classification. 14: 3-21. For metric
multidimensional scaling much attention is given to
algorithms for computing the configuration for fixed
dissimilarities. Here we study the inverse problem: what
is the set of dissimilarity matrices that yield a given
configuration as a stationary point? Characterizations of
this set are given for stationary points, local minima,
and for full-dimensional scaling. A method for computing
the inverse map for stationary points is presented along
with several examples. Doreian, P., R. Kapuscinzki, D. Krackhardt, and J. Szczypula. 1996. A Brief History of Balance Through Time. Journal of Mathematical Sociology. 21(1-2): 113-31. We present methods for
establishing the amount of reciprocity, transitivity and
group balance (a generalization of structural balance) in
sociometric structures. These methods are applied to the
second time series of sociometric data provided by the
Newcomb (1961) study. The amount of reciprocity was above
chance levels at the outset and showed no systematic
variation thereafter. Transitivity has a very different
time scale. it climbed steadily through the first nine
weeks and remained stable thereafter. While consistent
with chance at the beginning of the study period, it grew
to above chance levels at week 3. Group imbalance
declined throughout the entire period. The reasons for
these different time scales are discussed. Everett, M. G., and S. P. Borgatti. 1996. Exact Colorations of Graphs and Digraphs. Social Networks. 18: 319-31. A coloration is an exact
regular coloration if whenever two vertices are colored
the same they have identically colored neighborhoods. For
example, if one of the two vertices that are colored the
same is connected to three yellow vertices, two white and
red, then the other vertex is as well. Exact regular
colorations have been discussed informally in the social
network literature. However they have been part of the
mathematical literature for sometime, though in a
different format. We explore this concept in terms of
social networks and illustrate some important results
taken from the mathematical literature. In addition we
show how the concept can be extended to ecological and
perfect colorations, and discuss how the CATREGE
algorithm can be extended to find the maximal exact
regular coloration of a graph. Feld, S. L. 1997. Structural Embeddedness and Stability of Interpersonal Relations. Social Networks. 19: 91-95. The amount of structural
embeddedness of a tie between two individuals is defined
as the extent of overlap of social relations between
those two individuals, and presumably reflects the extent
of shared foci of activity that bring these individuals
together with the same others. It is suggested that, in
comparison with other strengths of ties (e.g. strengths
of feelings, and frequencies of interactions), structural
embeddedness: (I) is less under individuals' control, and
therefore (2) tends to be more stable. Analyses of data
on the relationships among male students at one small
liberal arts college in November and April of their first
year in college support the expectation that structural
embeddedness is relatively stable, and tends to have some
effect on other strengths of ties as well as the
continuity of relationships. Flache, A., and M.
W. Macy. 1996. The Weakness of Strong Ties: Collective
Action Failure in a Highly Cohesive Group. Journal
of Mathematical Sociology. 21(1-2):
3-28. Following Homans, exchange
theorists have modeled informal social control as an
exchange of peer approval for compliance with group
obligations. The exchange model predicts higher
compliance in cohesive networks with strong social ties.
However, previous specifications failed to incorporate
bilateral exchange of approval. Computer simulations
using a Bush-Mosteller stochastic learning model show
that bilateral exchanges evolve more readily than
multilateral, causing social control to flow into the
maintenance of interpersonal relationships at the expense
of compliance with group obligations, a structural form
of the "second-order free-rider problem." Frank, Kenneth A. 1996. Mapping Interactions within and between Cohesive Subgroups. Social Networks. 18(2): 93-119. The structure of
interactions and the pattern of influence in an
organization can be characterized in terms of a map of
interactions within and between cohesive subgroups. I
extend the work of Festinger, Schachter and Back (Social
Problems in Informal Groups, 1950 Stanford University
Press) who constructed a map based on the patterns of
communication within and between apartment courts. In
order to generalize Festinger et al.'s approach, I
substitute a posteriori subgroups for Festinger et al.'s
apartment courts, and I replace the distances of a
physical geography with those of a metric
multidimensional scaling. I apply the technique to data
indicating professional discussions among teachers in a
high school. After confirming that discussions are
concentrated within a posteriori subgroups at a level
that is unlikely to have occurred by chance alone, I
construct a map of discussions within and between the
cohesive subgroups. The map allows me to characterize the
process of influence at the teacher and school levels
through which the school responds to external conditions,
and I argue that a map based on blocks of structurally
similar actors does not sustain a comparable
characterization. Frey, C. U., and
C. Rothlisberger. 1996. Social Support in Healthy
Adolescents. Journal of Youth and
Adolescence. 25(1): 17-31.
Social support is examined
in a representative sample of 141 healthy adolescents. By
means of a revised version of the Mannheim Interview on
Social Support, the number, type, perceived adequacy
(satisfaction), and quality (importance) of the social
relationships available were assessed. While peers were
found to provide prime supportive functions in day-to-day
matters, the social support provided by parents has a
stress-buffering effect in emergency situations. The role
of other family members is discussed Differences in
gender and education are moderate. The data suggests the
adequacy of social support and social integration,
contrary to the traditional view of adolescence as a time
of crisis and conflict. Gigone, D., and R. Hastie. 1997. The Impact of Information on Small Group Choice. Journal of Personal and Social Psychology. 72(1): 132-40. The impact of information
on an aggregate decision is directly related to the
number of members of the aggregate who know the
information prior to the group decision. This experiment
obtains this common knowledge effect in small group
choice. Group discussion affects group choice in some
cases, signaled by group choices that
"overturn" the choice of a majority of the
group members. In those overturned majorities, moreover,
the group tended to choose the correct option, leading
group choices to be more accurate than member choices.
Consistent with results comparing individual judgment and
choice, groups pool information less thoroughly and rely
on prominent items of information more heavily when
choosing as compared with estimating. Gil-Mendieta, J., and S. Schmidt. 1996. The Political Network in Mexico. Social Networks. 18: 355-81. The most important
political processes in Mexican politics including
presidential succession since the 1920s have been
conducted within a network whose political rationale has
been political stability. All presidential elections have
been won by a single political party. We analyzed the
role of the network and presidential successions
measuring significant relationships using the system
UCINET IV. We contrasted computer distributions with
historical facts. Applying the structural block model
algorithm we found two well differentiated sub-networks,
one representing a military-based group and the second a
financial-based group. Measuring the network's centrality
is one of the main objectives of network analysis for
understanding concentrations of power and the
distribution of influence in the political system. In
this article we evaluate the maximum node and clique
network index value concentration for the core of the
Mexican network of power. Centrality and power indexes in
the network are presented and their results are discussed
in connection with cohesiveness. Hall, E. J., and E. M. Cummings. 1997. The Effects of Marital and Parent-Child Conflicts on Other Family Members: Grandmothers and Grown Children. Family Relations. 46(2): 135-44. Family conflict may have
pervasive effects, but little is known of effects on
family members outside of the immediate family
environment of parents and minor children. Analogue
methods were used to explore relations between specific
conflict contexts and specific relationships outside of
the immediate family. Grandmothers (N = 32) and grown
children (young adult women, N = 28) responded to
videotaped portrayals of conflict scenarios represented
as occurring in their adult children's, or parents',
families, respectively. While both groups reported
experiencing negative reactions, grandmothers and grown
children reported significantly different patterns of
appraisal, emotional response, dispositions to intervene,
expectancies, and predictions. These results suggest that
the meaning and implications of family conflict are quite
different depending upon an individual's role within the
family. Henning, C. H. C. A. 1996. A Critical Comment on Braun's "Restricted Access in Exchange Systems." Journal of Mathematical Sociology. 21(4): 369-77. In general this comment
tackles the problems and difficulties potentially
combined with an application of formal economic models
and constructs, such as the Walras equilibrium and
microeconomic demand theory, to pure sociological
contexts. In particular, this is done by analyzing a
further attempt, as recently suggested by Braun (1993 and
1994), to extend the well-known Coleman Model by
incorporating the embeddedness of social transactions in
incomplete social network structures. "Pars pro
toto" it is proved that Braun's conceptualization
contains some weakness which imply that fundamental
conclusions drawn in his article have to be revised. Ishii-Kuntz. 1997. Intergenerational Relationships Among Chinese, Japanese, and Korean Americans. Family Relations. 46(1): 23-32. Previous studies that have
focused on Asian American intergenerational relationships
used the cultural concept of filial obligation to explain
an adult child's commitment to his/her elderly parents.
Using data gathered from 628 Chinese, Japanese, and
Korean Americans and their elderly parents, this study
found that such financial and structural factors as an
adult child's income and his/her parent's need for
assistance significantly influenced the frequency of an
adult child's support for his/her parents. The effects of
filial obligation on an adult child's provision of
support for his/her parents change depending on several
of these financial and structural factors. The magnitude
of these relationships varies, however, among three
groups of Asian Americans. It is therefore necessary to
examine interaction effects of cultural, financial, and
structural factors on Asian American intergenerational
relationships as well as the diversity of these
relationships within the Asian American population. Jackson, M. O., and A. Wolinsky. 1996. A strategic model of social and economic networks. Journal of Economic Theory. 71: 44-74. We study the stability and
efficiency of social and economic networks, when
self-interested individuals can form or sever links.
First, for two stylized models, we characterize the
stable and efficient networks. There does not always
exist a stable network that is efficient. Next, we show
that this tension persists generally: to assure that
there exists a stable network that is efficient, one is
forced to allocate resources to nodes that are not
responsible for any of the production. We characterize
one such allocation rule: the equal split rule, and
another rule that arises naturally from bargaining of the
players. Jehn, K. A., and P. P. Shah. 1997. Interpersonal Relationships and Task Performance: An Examination of Mediating Processes in Friendship and Acquaintance Groups. Journal of Personal and Social Psychology. 72(4): 775-90. This study used multiple
methods to examine group processes (information sharing,
morale building, planning, critical evaluation,
commitment, monitoring, and cooperation) that mediate the
effect of relationship level on group performance. The
study uses a 2 by 2 experimental design, crossing
relationship (friendship vs. acquaintance) as a
between-subjects variable and task type (decision making
vs. motor) as a within-subject variable. Fifty-three
3-person groups participated in the study, and data from
4 types of measurement were used to analyze the mediating
processes between relationship level and task
performance. Friendship groups performed significantly
better than acquaintance groups on both decision-making
and motor tasks because of a greater degree of group
commitment and cooperation. Critical evaluation and task
monitoring also significantly increased decision-making
performance, whereas positive communication mediated the
relationship between friendship and motor task
performance. Kirke, D. M. 1996. Social Networks. 18: 333-46. This paper outlines a
method for collecting accurate 'peer' data by using two
name generator and 13 name interpreter questions to
collect 'friend' and 'pal' data from teenagers. The
'peer' data are then used to identify the complete
network and to delineate the naturally existing peer
networks in it. The findings suggest that the concept
'friend' should not be avoided when collecting 'friend'
data. Korenman, S., and S. C. Turner. 1996. Employment Contacts and Minority-White Wage Differences. Industrial Relations. 35(1): 106-22. We study effects of job
contacts on wages in inner-city Boston in 1989 and in the
1982 NLSY. Race/Hispanicity in wages are not explained by
an absence of contacts among minority youths. Rather, in
the Boston data, lower wages of black youths are
explained by lower "returns" to their contacts.
In the NLSY there is little evidence of lower return to
black youths' contacts, but there is evidence of lower
returns to Hispanic youths' contacts. Larrick, R. P., and S. Blount. 1997. The Claiming Effect: Why Players are More Generous in Social Dilemmas Than in Ultimatum Games. Journal of Personal and Social Psychology.: 810-26. The term procedural frames
is introduced and defined as different representations of
structurally equivalent allocation processes. Study 1
compared 2 well-known games, sequential social dilemmas
and ultimatum bargaining, that share the same structure:
Player 1 creates an allocation of a resource and Player 2
decides whether to allow it or deny it. Study 1 found
that Player 1 made more favorable allocations and Player
2 accepted more unfavorable allocations in a social
dilemma frame than in an equivalent ultimatum bargaining
frame. Study 2 revealed the critical determinant was
whether Player 2 had to respond to an allocation by
accepting or rejecting it (as in the ultimatum game) or
by making a claim (as in the social dilemma). Two
additional studies explored how these actions are
perceived. The inconsistency of behavior across
procedural frames raises methodological concerns but
illuminates construal processes that guide allocation. Leenders, R. T. A. J. 1996. Evolution of Friendship and Best Friendship Choices. Journal of Mathematical Sociology. 21(1-2): 133-48. It has been recognized in
the literature that the mechanisms driving friendship
choices differ when different settings are considered. At
the same time, it is likely that different types of
friendships are governed by different mechanisms.
Employing longitudinal sociometric data from classrooms
in elementary schools, it is examined whether gender
similarity, reciprocity, and proximity (joint membership
of study groups) have similar effects on 'friendship' and
'best friendship' choices. The results suggest that
children use loose definitions of 'friendship', as
opposed to their definition of 'best friendship'. The
networks resulting from these different choices are found
to evolve according to (partly) different mechanisms.
This especially holds for the effect of gender
similarity, which is profoundly predominant in the 'best
friend' networks, but loses much of this importance when
'friends' are also considered. Also, 'best friend'
choices are much more stable. Reciprocity of choices is
found to primarily be a by-product of the preference to
choose friends of the same gender, rather than being an
important choice criterion of itself. Leik, R. K., and M. A. Chalkley. 1997. On the Stability of Network Relations Under Stress. Social Networks. 19: 63-74. This paper addresses
possible sources of instability in network relations.
Four distinct sources of observed low auto-correlation
(unreliability of measurement, inherent instability,
systemic change (from endogenous sources), and external
change (from non-system sources)) arc discussed and a
preliminary mathematical model is developed.
Illustrations are provided from current family research
and suggestions arc made for sorting out possible sources
of instability. Even without a complete endogenous model
we demonstrate differential impacts of the distinct
sources of variability. Li, R. M., and S. F. Newcomer. 1996. The Exclusion of Never-Married Women from Chinese Fertility Surveys. Studies in Family Planning. 27(3): 148-54. Never-married women have
been regularly excluded in official national surveys of
fertility in China, even in light of evidence of
increasing premarital sexual activity. Likewise,
never-married women in the United States were
consistently excluded from national fertility surveys
prior to 19820 because of the perceived sensitivity of
questions about contraceptive use and sexual activities.
Data on sexual and fertility behavior from all women of
reproductive age, regardless of marital status, can
provide direct measures of sexual activity and unintended
pregnancies, as well as facilitate modeling of social
networks underlying the sexual transmission of diseases.
China's need for such information, however sensitive,
will become more difficult to ignore given increasing
pressures to attend to the health need of their
never-married but sexually active population. Meulman, J. J. 1996. Fitting a Distance Model to Homogeneous Subsets of Variables: Points of View Analysis of Categorical Data. Journal of Classification. 13: 249-66. An approach is presented
for analyzing a heterogeneous set of categorical
variables assumed to form a limited number of homogeneous
subsets. The variables generate a particular set of
proximities between the objects in the data matrix, and
the objective to the analysis is to represent the objects
in low-dimensional Euclidean spaces, where the distances
approximate these proximities. A least squares loss
function is minimized that involves three major
components: a) the partitioning of the heterogeneous
subsets; b) the optimal quantification of the categories
of the variables, and c) the representation of the
objects through multiple multidimensional scaling tasks
performed simultaneously. An important aspect from an
algorithmic point of view is in the use of majorization.
The use of the procedure is demonstrated by a typical
example of possible application, i.e., the analysis of
categorical data obtained in a free-sort task. The
results of points of view analysis are contrasted with a
standard homogeneity analysis, and the stability is
studied through a Jackknife analysis. Morgan, D. L., M. B. Neal, and P. Carder. 1996. The Stability of Core and Peripheral Networks over Time. Social Networks. 19: 9-25. This article uses data on
'network instability' to show how differences across
multiple measurements on the membership of personal
networks can yield important insights into the nature of
these networks. The data come from a sample of 234 recent
widows, aged 59-85, who completed seven interviews about
their networks over a l-year period. We use these data to
investigate the stability of both overall networks and
individual ties, as well as the linkage between the
stability of individual ties and the stability of the
network's aggregate properties. We find that instability
in these networks is best thought of in terms of an
underlying 'core-periphery' structure, whereby some
network members are likely to be named repeatedly (the
core), while others are relatively unlikely to appear in
any given elicitation of the network (the periphery). We
explore the implications of this core-periphery structure
for cross-sectional elicitations of personal networks. Neto, O. A., and G. W. Cox. 1997. Electoral Institutions, Cleavage Structures, and the Number of Parties. American Journal of Political Science. January 41(1): 149-74. Theory: A classic question in political science concerns what determines the number of parties that compete in a given polity. Broadly speaking, there are two approaches to answering this question, one that emphasizes the role of electoral laws in structuring coalitional incentives, and another that emphasizes the importance of preexisting social cleavages. In this paper, we view the number of parties as a product of the interaction between these two forces, following Powell (1982) and Ordeshook and Shvetsova (1994). Hypothesis: The effective number of parties in a polity should be a multiplicative rather than an additive function of the permissiveness of the electoral system and the heterogeneity of the society. Methods: Multiple regression on cross-sectional aggregate electoral statistics. Unlike previous studies, we (I) do not confine attention to developed democracies; (2) explicitly control for the influence of presidential elections, taking account of whether they are concurrent or nonconcurrent, and of the effective number of presidential candidates; and (3) also control for the presence and operation of upper tiers in legislative elections. Results: The hypothesis is
confirmed, both as regards the number of legislative
parties and the number of presidential parties. O'Toole, L. J. Jr. 1997. Implementing Public Innovations in Network Settings. Administration and Society. May 29(2): 115-38. Practitioners and scholars
have devoted considerable attention in recent years to
initiating public innovations to the relative neglect
of how to ensure the implementation of such efforts.
Executing innovations over the longer term, particularly
in complex network settings, can be expected to be
problematic. And yet networks are likely to be crucial
institutional settings for the implementation of public
innovations. The analytic approach of game theory, used
heuristically, can identify a set of actions useful to
public managers in enhancing prospects that sound
innovations will succeed. The implications of this
inquiry run counter to some of the themes used as mantras
in the recent re-invention discussion and focus attention
on the centrality of institutional infrastructure, trust,
and obligation for innovative success into the future. Peterson, R. S.
1997. A Directive Leadership Style in Group Decision
Making Can Be Both Virtue and Vice: Evidence From Elite
and Experimental Groups. Journal of
Personal and Social Psychology.
72(5): 1107-21. The group dynamics Q-sort
was used to investigate the effects of leader
directiveness in group decision making. Past research on
leadership style has consistently implicated directive
leaders as a chief cause of defective process and poor
outcomes in group decision making. Leader directiveness
was decomposed into 2 components: (a) outcome
directiveness (i.e., the degree to which a leader
advocates a favored solution) and (b) process
directiveness (i.e., the degree to which a leader
regulates the process by which the group reaches a
decision). Process directiveness emerged as a potent
predictor of quality of group process and outcomes.
Outcome directiveness was associated with a much smaller
and less coherent array of group outcomes. These findings
suggest that current prescriptive models of decision
making overemphasize the potential harmful effects of
outcome directiveness. Reed, Janet and Eric Dubow. 1997. Cognitive and Behavioral Predictors of Communication in Mother-Adolescent Dyads. Journal of Marriage and the Family. 59(1): 91-103. This study examines the
relation between mothers' and adolescents' perceptions of
one another's behavior and their actual communication
behavior during a problem-solving task. Forty
mother-adolescent dyads completed self-report and
observational measures of conflict and negative beliefs
regarding the other. Hierarchical multiple regression
analyses indicated that adolescents' negative beliefs
about their mothers significantly contributed unique
variance in predicting adolescent negative communication,
beyond the effects of maternal communication behavior.
Thus, treatment of parent-adolescent conflict should
address adolescents' and parents' perceptions of one
another, as well as their problem-solving behavior. Ridgeway, C. L., and J. W. Balkwell. 1997. Group Processes and the Diffusion of Status Beliefs. Social Psychology Quarterly. 60(1). How are consensual beliefs
about the status-value of individual characteristics
created in a society? A recent theory posits that
inequalities in the distribution of resources in a
population are translated into greater or lesser levels
of consensus via social interaction in small groups.
According to this theory a macro-structural correlation
between resources and a distinguishable individual
difference variable constrains who interacts with whom
and governs the group dynamics of these encounters. It
engenders certain belief-acquisition processes that
create and spread status beliefs about the variable
eventually making them consensual. We constructed a
formal model of this diffusion process that includes the
group interaction effects posited by the theory also the
effects of group size and the unmediated impact of
macro-structural conditions. Calculations based on this
nest integrated formulation support most of the original
theoretical analysis. In addition simulation results
suggest the likelihood that two- to four-person groups
are especially important as creators and spreaders of
status beliefs supporting in a slightly modified fashion
the earlier claim that group processes have the power to
translate macro-structural constraints on actors into
macro-level outcomes. These simulations also clarify
several contingencies and other implications of the
theory not fully apparent in the original formulation. Roberts, J. M. J. 1996. Alternative Approaches to Correspondence Analysis of Sociomatrices. Journal of Mathematical Sociology. 21(4): 359-68. If the usual
correspondence analysis is viewed as a decomposition of
departures from the model of independence, there are
problems in applications to sociomatrices with regard to
the treatment of the diagonal and cell estimates under
independence. Other related techniques from the
literature are more appropriate for analysis of
sociomatrices. The different approaches are used to
analyze a familiar sociomatrix, and the results of the
techniques are compared. Rogerson, P. A. 1997. Estimating the Size of Social Networks. Geographical Analysis. 29(1): 50-63. It is notoriously
difficult to define and estimate the size of individuals'
social networks. Methods are suggested for estimating the
size of such networks, using known rates of mobility
together with survey data on the number of acquaintances
of individuals who have recently moved. Special attention
is given to the likely correlation between mobility rates
and network size. Estimates are found to be consistent
with previous estimates in the literature. The relation
of this approach to multiplicity sampling and to
"the small world problem" is also discussed. Ruan, D., L. C. Freeman, X. Dai, Y. Pan, and W. Zhang. 1997. On the Changing Structure of Social Networks in Urban China. Social Networks. 19: 75-89. This study is a
replication of a survey on personal networks conducted 7
years earlier in Tianjin, China. Comparing the results of
the two surveys reveals a large amount of change. Tianjin
residents now report having more ties to friends and to
associates beyond work and family, and fewer workplace
ties and far fewer family ties. Women have gained on men
in the number of friends, and young people have fewer
workplace ties. These changes at the micro-level are
examined in the light of changes in the Chinese
macro-social structure. Skvoretz, J., K. Faust, and T. J. Fararo. 1996. Social Structure, Networks, and E-State Structuralism Models. Journal of Mathematical Sociology. 21(1-2): 57-76. The method of E-state
structuralism provides dynamic models for the evolution
and development of networks in small groups. Our interest
lies in the kind of social networks that these models
produce. We ask the question of whether such models
produce "interesting" structure from a network
point-of-view, in particular, from the perspective of
Holland and Leinhardt who argue that any network that can
be modeled adequately using only properties of nodes and
dyads has no social structure. We show that E-state
structuralism models are models of social structure in
this technical sense because they assume a bystander
mechanism in the creation of ties. Skvoretz, J., and P. Zhang. 1997. Actor's Responses to Outcomes in Exchange Networks: The Process of Power Development. Sociological Perspectives. 40(2): 183-97. Leading theories of power
in exchange networks make assumptions about actors'
reactions to being included in or excluded from
exchanges. These assumptions, that actors consistently
included increase their demands on others and that actors
consistently excluded decrease their demands, provide the
behavioral mechanism by which structural differences in
position convert into power advantages or disadvantages.
We test these assumptions with data gathered by
experiment from five different networks. We find that
while actors generally respond as assumed, the parameters
of response to inclusion and to exclusion are not
symmetric, depend on the level of experience of the
subjects, and interact both with type of network (strong
power versus weak power) and with network position. Snijders, T. A. B. 1996. Stochastic Actor-Oriented Models for Network Change. Journal of Mathematical Sociology. 21(1-2): 149-72. A class of models is
proposed for longitudinal network data. These models are
along the lines of methodological individualism: actors
use heuristics to try to achieve their individual goals,
subject to constraints. The current network structure is
among these constraints. The models are continuous time
Markov chain models that can be implemented as simulation
models. They incorporate random change in addition to the
purposeful change that follows from the actors' pursuit
of their goals, and include parameters that must be
estimated from observed data. Statistical methods are
proposed for estimating and testing these models. These
methods can also be used for parameter estimation for
other simulation models. The statistical procedures are
based on the method of moments, and use computer
simulation to estimate the theoretical moments. The
Robbins-Monro process is used to deal with the stochastic
nature of the estimated theoretical moments. An example
is given for Newcomb's fraternity data, using a model
that expresses reciprocity and balance. Snijders, T. A. B., and K. Nowicki. 1997. Estimation and Prediction for Stochastic Blockmodels for Graphs with Latent Block Structure. Journal of Classification. 14: 75-100. A statistical approach to a
posteriori blockmodeling for graphs is proposed. The
model assumes that the vertices of the graph are
partitioned into two unknown blocks and that the
probability of an edge between two vertices depends only
on the blocks to which they belong. Statistical
procedures are derived for estimating the probabilities
of edges and for predicting the block structure from
observations of the edge pattern only. ML estimators can
be computed using the EM algorithm, but this strategy is
practical only for small graphs. A Bayesian estimator,
based on Gibbs sampling, is proposed. This estimator is
practical also for large graphs. When ML estimators are
used, the block structure can be predicted based on
predictive likelihood. When Gibbs sampling is used, the
block structure can be predicted from posterior
predictive probabilities. A slide result is that when the
number of vertices tends to infinity while the
probabilities remain constant, the block structure can be
recovered correctly with probability tending to 1. Stokman, F. N., and E. P. H. Zeggelink. 1996. Is Politics Power or Policy Oriented? A Comparative Analysis of Dynamic Access Models in Policy Networks. Journal of Mathematical Sociology. 21(1-2): 77-111. In policy networks actors use access relations to influence preferences of other actors. Establishment and shifts of access relations and their consequences for outcomes of decisions are the main focal points in this paper. Unlike most policy network studies, we therefore do not take the network an its relations as given and constant. Instead we device computer simulation models to account for the dynamics in policy networks. We compare different models and investigate the resulting network structures and predicted outcomes of decisions The choice among the alternative models is made by their correspondence with empirical network structures and actual outcomes of decisions. In our models, we assume that all relevant actors aim at policy outcomes as close as possible to their own preferences. Policy outcomes are determined by the preferences of the final decision makers at the moment of the vote. In general, only a small fraction of the actors takes part in the final vote. Most actors have therefore to rely on access relations for directly or indirectly shaping the preference of the final decision makers. For this purpose actors make access requests to other actors. An access relation is assumed to be established if such a request is accepted by the other. Access relations require time and resources. Actors are therefore assumed to be restricted in the number of access requests that they can make and the number of requests they can accept. Moreover, due to incomplete information and simultaneous actions by other actors, actors have to make simplifying assumptions in the selection of their "best" requests and learn by experience. We devise two base models that correspond to two basic views on the nature of political processes. In the first view politics is seen as power driven. Corresponding to this view, actors aim at access relations with the most powerful actors in the field. They estimate their likelihood of success by comparing their own resources with those of the target actors. Power also determines the order in which actors accept requests. In the second view, policy matters and actors roughly estimate the effects access relations might have on the outcome of decisions. Actors select requests to "bolster" their own preference as much as possible. We will show that these
base models and some intermediate ones result in
fundamentally different network structures and predicted
outcomes. Moreover, we will show that the policy driven
models do fundamentally better than the power driven
models. Suitor, J., and S. Keeton. 1997. Once a Friend, Always a Friend? Effects of Homophily on Women's Support Networks Across a Decade. Social Networks. 19: 51-62. This study uses data
collected on 42 women and 432 members of their social
networks across a 10-year period beginning with the
women's return to school in midlife. The paper addresses
three questions: (1) To what extent did the same
individuals continue to be active members of the women's
social support networks across the decade; (2) to what
extent did educational similarity explain which
individuals continued to be active members of the women's
networks; and (3) did educational similarity explain
patterns of both support and socializing? The analyses
revealed that between one-quarter and one-third of the
associates named as sources of school/work support,
general emotional support or socializing continued to be
named 10 years after the first interview. The analyses
also demonstrated that associates' educational attainment
was important in explaining which individuals continued
to serve as sources of support for school/work; however,
educational attainment was not important in explaining
which associates continued to serve as sources of either
general emotional support or socializing. Thye, S. R., M. J. Lovaglia, and B. Markovsky. 1997. Responses to Social Exchange and Social Exclusion in Networks. Social Forces. 75(3): 1031-47. Various theoretical
accounts of power in social exchange networks have
emerged in recent years. We use a new experimental
setting to test assumptions that appear to be implicit in
all network exchange theories of power: Actor's in
exchange networks increase their demands following social
exchange and concede more resources when excluded. We
also tested for the relative impact of inclusion versus
exclusion and differential responses to multiple exchange
partners give exchange with just one of them. We observed
that the tendency to concede the following exclusion was
significantly greater than the tendency to raise demands
following an exchange. Furthermore, when an actor had
multiple potential exchange partners, the clear tendency
was to demand more from those with whom exchange just
occurred, but not form those excluded. These findings are
discussed in view of current theories of exchange and
commitment. Tourangeau, R., T. W. Smith, and K. A. Rasinski. 1997. Motivation to Report Sensitive Behaviors on Surveys: Evidence from a Bogus Pipeline Experiment. Journal of Applied Social Psychology. 27(3): 209-22. We examined the effects of
a procedure designed to increase motivation to give
accurate reports of socially sensitive behaviors
frequently collected in surveys. Respondents were
assigned at random to a bogus pipeline condition, in
which they were told that inaccurate answers could be
detected by a physiological recording device, or to a
control condition. Respondents in both conditions were
interviewed with a questionnaire that contained 19 items
ranging from smoking and exercise frequency to number of
sexual partners and illicit drug use. While the bogus
pipeline procedure generally increased the reporting of
sensitive behavior, in one instance it reduced the
proportion of respondents who reported a socially
desirable behavior (exercising), indicating that
respondents were motivated to respond accurately and not
just to report more occurrences. Wang, Y., H. Yan, and C. Sriskandarajah. 1996. The Weighted Sum of Split and Diameter Clustering. Journal of Classification. 13: 231-48. In this paper, we propose
a bicriterion objective for clustering a given set of N
entities, which minimizes [ad - (1 - a)s],
where 0 a 1, and d and s are the
diameter and the split of the clustering, respectively.
When a = 1, the problem reduces to minimum diameter
clustering, and when a = 0, maximum split clustering. We
show that this objective provides an effective way to
compromise between the tow often conflicting criteria.
While the problem is NP-hard in general, a polynomial
algorithm with the worst-case time complexity O(N^{2})
is devised to solve bipartitions with respect to diameter
and split, and it can be extended to yield an efficient
divisive hierarchical scheme. An extension of the
approach to the objective [a(d_{1} + d_{2})
- 2(1 - a)s] is also proposed, where d_{1}
and d_{2} are diameters of the two
clusters of a bipartition. Weesie, J., and W. Raub. 1996. Private Ordering: A Comparative Institutional Analysis of Hostage Games. Journal of Mathematical Sociology. Hostage posting (in the
sense of pledging a bond) is a commitment device that
allows for cooperation of rational actors in economic and
social relations with incentive problems, like in the
Prisoner's Dilemma. This paper provides, first, an
informal discussion of hostage posting as a mechanism of
cooperation. We then analyzed noncooperative 2- and
n-person games with complete information where players
can post a hostage prior to their interaction. We compare
rather general hostage 'institutions' that specify the
conditions under which hostages are declared forfeited
and, if forfeited, whether the hostages are transferred
to another player or are lost. The problem of designing
efficient hostage institutions is addressed and solved
for 2-person settings. The minimal institutional
requirement for individually rational hostage posting and
subsequent cooperation is, roughly, that a player's
hostage is forfeited if hostages have been posted by
everyone and if the player deviates unilaterally from
cooperation. Furthermore, the hostages posted have to be
sufficiently valuable, i.e., match the players' costs of
cooperation, and the transaction costs associated with
hostage posting have to be sufficiently low. Wellman, B. 1996. Are Personal Communities Local? A Dumptarian Reconsideration. Social Networks. 18: 347-54. Are local ties important
in personal community networks? Since local ties only
make up a minority of people's active ties, network
analysts have argued for decades that the neighborhood is
not very important. Re-analysis of the Toronto data shows
that when contacts become the unit of analysis instead of
ties, the percentage of local relationships in active
networks nearly doubles. Moreover, when we also take into
account active contacts with coworkers, who like
neighbors are physically proximate, we find that
two-thirds of all contacts are 'local'. As Humpty-Dumpty
has cogently reminded us, a network can be anything we
want it to be. it depends on how we define it. When we
change the definition, the conclusions change too. Wellman, B., R. Yuk-lin, D. Tindall, and N. Nazer. 1997. A Decade of Network Change: Turnover, Persistence and Stability in Personal Communities. Social Networks. 19: 27-50. We analyze changes in
intimate ties in personal community networks. Our data
come from interviews conducted a decade apart with 33
Torontonians. There is much turnover in these networks,
with only 27% of intimate ties persisting. Durable ties
tend to be with intimates who have provided social
support, are infrequent telephone contact, or are kin.
There was almost complete turnover in the networks of
those respondents who got married during the decade. By
contrast, the amount of turnover in networks is not
associated with whether the respondents had children,
moved to a different home, or started/stopped doing paid
work during the decade. Whitmeyer, J. M. 1997. The Power of the Middleman - A Theoretical Analysis. Journal of Mathematical Sociology. 22(1): 59-90. In this article, I present
a technique, multiple general equilibrium analysis
(multiple GEA), based on Coleman's (1990) general
equilibrium analysis (GEA), for determining the
distribution of power among members of a positively
connected network in which middlemen mediate the transfer
of resources. In line with earlier simulation and
experimental studies, multiple GEA indicates that
middlemen actors gain considerable power and resources
from their structural position. Results also show that,
under the assumptions of multiple GEA, actors' relative
power can vary considerably depending on the
configuration of actor interests. Unlike previous uses of
GEA to analyze such networks, the results follow without
needing to use ad hoc factors, or to give middlemen
actors initial control over any resource. Yamaguchi, K. 1996. Power in Networks of Substitutable and Complementary Exchange Relations: A Rational-Choice Model and an Analysis of Power Centralization. American Sociological Review. 61(2): 308-32. In this paper, I introduce
a new measure of power in exchange networks under
substitutable/complementary exchange relations. Although
it is derived from a model based on a modification and
extension of Coleman's model of collective action, the
new measure reflects major characteristics of Emerson and
Cook's power-dependence theory, in which power emerges as
a result of exchange based on actors' benefit-maximizing
actions under network constraints on exchange. In the new
measure, an actor's power depends on the number of
exchange partners interested in the actor's resource, the
extend to which the actor's partners are not interested
or are less interested in others' resources than in the
actor's, the power of the actor's partners as
interdependent correlates, and the consequences of shifts
in demand made by the actor's partners under the
substitutability/complementarity of exchange relations
among their multiple partners. I also show high
consistency between power distributions predicted by the
new measure and corresponding experimental results by
Cook et al. (1983), Yamagishi, Gilmore, and Cook (1988),
and Skvoretz and Willer (1993). Finally, using simulated
exchange network data, I derive an enriched set of
hypotheses about the structural and relational
determinants of power centralization under closely
substitutable exchange relations. Zeggelink, E. P. H., F. N. Stokman, and G. G. Van de Bunt. 1996. The Emergence of Groups in the Evolution of Friendship Networks. Journal of Mathematical Sociology. 21(1-2): 29-55. Friendship networks usually show a certain degree of segmentation: subgroups of friends. The explanation of the emergence of such groups from initially dyadic par friendships is a difficult but important problem. In this paper we attempt to provide a first contribution to the explanation of subgroup formation in friendship networks by using the LS set as a definition for a friendship group. We construct a dynamic individual oriented model of friendship formation and provide preliminary simulation results that give an idea of how to continue the process of explaining group formation. |