BRYONY REICH
https://sites.google.com/site/bryonyreich/home
CONTACT DETAILS
Mailing Address:
Department of Economics
University College London
Drayton House
London WC1H OAX
United Kingdom
Email:
Phone:
b.reich@ucl.ac.uk
+44 20 7679 4696
CURRENT
Postdoctoral fellow, Economics Department, University College London
DOCTORAL STUDIES
2008-2013
2011-2012
PhD Economics, University of Cambridge
Visiting fellow, Economics Department, Harvard University
REFERENCES
Professor Alberto Alesina
Department of Economics
Harvard University
Email: aalesina@harvard.edu
Phone: +1 617 495 8388
Professor Sanjeev Goyal
Department of Economics
University of Cambridge
Email: sg472@cam.ac.uk
Phone: +44 1223 335204
Professor Antonio Cabrales
Department of Economics
University College London
Email: a.cabrales@ucl.ac.uk
Phone: +44 203 108 5229
Professor Jörgen Weibull
Department of Economics
Stockholm School of Economics
Email: jorgen.weibull@hhs.se
Phone: +46 8 736 92 04
PRIOR EDUCATION
2007-2008
MPhil Economics, University of Cambridge
2006-2007
Diploma (BSc equivalent) Economics, University of Cambridge
2002-2006
BSc Mathematics, University of Edinburgh (First Class)
RESEARCH INTERESTS
Applied Theory, Network Theory, Political Economy
RESEARCH
‘The Diffusion of Innovations in Social Networks’ Job Market Paper
This paper determines how different network structures influence the diffusion of innovations. We
develop a model of diffusion where: 1. an individual's decision to adopt a new technology is
influenced by his contacts; and 2. contacts can discuss, coordinate, and make adoption decisions
together. A measure of connectedness, `cohesion', determines diffusion. A cohesive community is
defined as a group in which all members have a high proportion of their contacts within the group.
We show a key trade-off: on one hand, a cohesive community can hinder diffusion by blocking the
spread of a technology into the group; on the other hand, cohesive communities can be particularly
effective at acting collectively to adopt an innovation. We find that for technologies with low
externalities (that require few people to adopt before others are willing to adopt), social structures
with loose ties, where people are not part of cohesive groups, enable greater diffusion. However,
as externalities increase (technologies require more people to adopt before others are willing to
adopt), social structures with increasingly cohesive groups enable greater diffusion. Given that
societal structure is known to differ systematically along this dimension, our findings point to
specialization in technological progress exhibiting these patterns.
‘Melting Pot or Salad Bowl: The Formation of Heterogeneous Communities’ (with Arun Advani)
Submitted
Relatively little is known about what determines whether a heterogenous population ends up in a
cooperative or divisive situation. We develop a theoretical model to understand what social
structures arise in heterogeneous populations. Individuals face a trade-off between cultural and
economic incentives: an individual prefers to maintain his cultural practices, but doing so can
inhibit interaction and economic exchange with those who adopt different practices. We find that a
small minority group will adopt majority cultural practices and integrate. In contrast, minority
groups above a certain critical mass may retain diverse practices and may also segregate from the
majority. The size of this critical mass depends on the cultural distance between groups, the
importance of culture in day to day life, and the costs of forming a social tie. We test these
predictions using data on migrants to the United States in the era of mass migration, and find
support for the existence of a critical mass of migrants above which social structure in
heterogeneous populations changes discretely towards cultural distinction and segregation.
‘Nation-Building’ (with Alberto Alesina) Submitted
Nations stay together when citizens share enough values and preferences and can communicate
with each other. Homogeneity amongst people can be built with education, teaching a common
language, building infrastructure for easier travel, but also by brute force measures such as
prohibiting local cultures. Democracies and dictatorships have different incentives when it comes
to choosing how much and by what means to homogenize the population. We study and compare
homogenization policies under the transition from dictatorship to democracy, in a model where
government location and the size of countries are endogenous. We find that the threat of
democratization provides strong incentives to homogenize. In contrast, the establishment of
democracy is associated with lower homogenization. Historical discussion of several episodes
illustrates our results.
‘Obesity as a Social Equilibrium Phenomenon’ (with Jörgen Weibull)
We develop a mathematical model of obesity in which individuals value consumption but also
have a concern for their body weight, a concern that may be influenced by peers and that may be
hampered by a lack of self-control. Our model is thus focused on the interplay between economic,
social and psychological factors. It is general but yet tractable enough to permit analysis of a range
of factors that have been put forward as relevant to obesity. The model sheds light on stylized facts
about the obesity epidemic of the last thirty years and can be used to simulate policy effects and as
a workhorse in theoretical and empirical research of obesity.
WORK IN PROGRESS
‘War and Nationalism’ (joint with Alberto Alesina and Alessandro Riboni)
PAPER PRESENTATIONS
Barcelona Summer Forum 2015, PET 2015, Alicante 2015, Workshop on Contagion 2015, City
2014, Birkbeck 2014, Cambridge 2014, Oxford 2014, Workshop on Networks in Honour of Matt
Jackson Marseille 2013, SAET 2013, PET 2013, Income Distribution and Macro NBER Summer
Institute 2013, ISNIE 2013, CEPR Public Policy 2013, CTN 2013, ESWC 2010, EEA 2010,
Jerusalem Summer School in Political Economy 2010.
DISCUSSANT
Political Economy group NBER Summer Institute 2013
AWARDS
UK Economic and Social Research Council, Future Research Leaders Grant, 2013-2015
Cambridge Economics Faculty Trust Fund, 2011-2012
Net Institute Summer Research Grant, 2010
ESRC scholarship for PhD, 2008-2011
TEACHING EXPERIENCE
Undergraduate: Instructor, Urban Economics, 2013-2015.
Graduate: Teaching Assistant, Network Theory, 2010, Mechanism Design, 2010, General
Equilibrium, 2009, Contract Theory, 2009, 2010, 2011.
PROFESSIONAL ACTIVITIES
Organizer of reading group on networks and theory, 2009-2010
Referee: American Economic Review, Economic Journal, Journal of Economic Growth, Journal of
Economic Theory, BE Journal of Theoretical Economics
PERSONAL DETAILS
Nationality:
Date of Birth:
Gender:
Languages:
British
23.02.1983
Female
English (native), French (advanced)