Advanced Political Economy
(ECON 3029)
Lecture 27: Current Trends in Politics
–
Political Polarisation
Dr. Emilie Sartre
emilie.sartre@nottingham.ac.uk
emilie.sartre@nottingham.ac.uk
SEM Survey ☺
What did we learn?
• Populism: “A thin-centered ideology that considers society to be ultimately separated
into two homogeneous and antagonistic camps, « the pure people » versus « the corrupt
elite, » and which argues that politics should be an expression of the general will of the
people” (Mudde and Kaltwasser, 2017)
• There are many explaining factors influencing the rise of populism, including:
✓ Cultural factors
• Status loss, cultural backlash, moral values and social capital
• Immigration and its perception
• Internet and Social Media
✓ Economic factors
• Secular trends: Trade globalization and Automation
• Financial crises and Fiscal austerity
• Populism leads to economic consequences (a decrease of GDP by 10% after 15
years), can increase hate crimes, and transform institutions and cultural values
Political Polarisation
Part 3 – Culture, Institutions, and Current Trends in
Political Regimes
A. Culture and Institutions
a) Culture and its persistence over time
b) Interactions between Culture and Institutions
c) Democracy and Growth
B. Current Trends in Politics
a) Political Regimes and Current Trends in Democratic countries
b) The Rise of Populism and its explaining factors
c) The Rise of Populism and its consequences
d) Political Polarisation
Source: Benkler
Lecture 28: Our last lecture in May! A recap lecture
Overview
A. Polarization – Definitions
B. Mass polarization
C. Partisan sorting / elite polarization
D. Affective polarization
E. Geographical polarization
F. Social media and Political polarization
Political polarization – A Definition
❖ The extent to which political opinions/values differ
- Ideologically (Ex: Liberal and conservative opinions)
- Affectively (Ex: Positive/negative emotions regarding parties/party
supporters)
- Geographically (Ex: Red and Blue states in the US)
❖ The process by which this opposition increases over time
Political polarization – A Definition
Can political polarization happen in a multi-party system?
Overview
A. Polarization – Definitions
B. Mass polarization : A debated topic
C. Partisan sorting / Elite polarization
D. Affective polarization
E. Geographical polarization
F. Social media and Political polarization
Mass polarization
• Mass-public polarization is a debated notion
• YES
Abramowitz and Saunders (2008)
• NO
Abrams and Fiorina (2012)
• It all depends on the definition!
Mass polarization in the US
Americans views are mostly single-peaked (Lelkes, 2016; Fiorina et al., 2008)
=> No ideological divergence
Mass polarization in the US
• Americans are not more likely to identify strongly with one party or the other
Mass polarization in the US
• Americans are not more likely to describe less as moderate
Mass polarization in the US ?
• A rise of Ideological consistency (Lelkes, 2016)
1. Sorting
The degree to which ideology matches identity (Levendusky, 2009)
2. Constraint
Correlations btw. issue positions are increasing (Baldassarri and Gelman, 2009)
CONSENSUS ! Among partisans (D/R), there is an increasing correlation between policy
views and partisan identity
It is not considered as mass-public polarization by Fiorina et al. (2008)
But as partisan polarization/party sorting. It is linked with elite
polarization
Mass polarization in the US ?
Mass polarization in the US ?
Mass polarization in the UK ?
• No strong evidence that people’s positions have become more polarized
in the UK (Duffy, Hewlett, McCrae, and Hall – Divided Britain, September
2019)
• After the Brexit referendum, views were particularly polarized
(particularly on immigration)
• But since then, they have found a narrowing of the gap in opinion between
Leavers and Remainers
• Many attitudes and identities that were once polarizing are converging:
health, social care, gender roles, homosexuality, racial discrimination
Overview
A. Polarization – Definitions
B. Mass polarization
C. Partisan sorting / elite polarization
D. Affective polarization
E. Geographical polarization
F. Social media and Political polarization
Elite polarization / Partisan sorting in the US
❖Political parties seem more and more distinct over time in the US
= “Party sorting” (Fiorina, 2016)
Democrats Republicans
(Congress / Senate) Growing Divide (Congress / Senate)
Political Ideology
Liberal Conservative
Elite polarization / Partisan sorting in the US
❖Moderates are disappearing
= “Polarization” (Fiorina, 2016)
Elite polarization / Partisan sorting in the US
❖Political parties seem more and more distinct over time
= “Party sorting” (Fiorina, 2016)
❖Moderates are disappearing in Congress or in Senate
= “Polarization” (Fiorina, 2016)
=> Elite Partisan Polarization
McCarty, Poole and Rosenthal (2008)
At the start of the Cold War:
• United against Communism!
McCarty, Poole and Rosenthal (2008)
❖ The 70s: Two major events
End of bipartisan foreign policies End of bipartisan economic policies
McCarty, Poole and Rosenthal (2008)
• Use roll call votes
A representative or senator votes YES or NO so that the names of members voting on each
side are recorded
McCarty, Poole and Rosenthal (2008)
❖ A simple spatial model on a single policy dimension
• An ideal point can be assigned to all politicians
• The cutpoint divides the representatives who voted yea from those who voted nay
Cutpoint Donald Trump
Joe Biden
One policy
YAY NAY
McCarty, Poole and Rosenthal (2008)
❖ It may be more complex in reality!
1. Deviant votes can happen
Treat them as random events?
2. Majority votes can also happen
3. And several policy dimensions exist
❖ They build the DW-NOMINATE scores (through a multidimensional scaling application)
=> To simplify: –1 is the most liberal position, and +1 is the most conservative.
McCarty, Poole and Rosenthal (2008)
❖ Extreme conservative + Extreme liberal positions are more likely in Congress
McCarty, Poole and Rosenthal (2008)
❖ Parties have become more homogeneous + The difference in the party means has
increased over time
ECON – 1205 Polarization: Elite partisan polarization
McCarty, Poole and Rosenthal (2008)
❖ The moderates are vanishing
Elite polarization / Partisan sorting in the UK?
• Before the Brexit : A strong convergence since the 80’s between the
Labour and Conservative Parties on economic and social welfare policy
(Adams et al., 2011)
=> They find a decline in partisan sorting among the population, between
citizens’ positions and their partisanship
• Still today, there is no strong evidence of partisan sorting in the UK. The
number of people who strongly identify with a political party has declined
• But the Brexit has been polarizing: Party identity becomes less important
than the positioning on the Brexit
Elite polarization / Partisan sorting in the UK?
Remember that elite polarization and party sorting are deeply related
Ex: When candidates are moderates, it is less likely than Democrats and Republicans
are divergent and vice versa
Elite polarization
Ideological consistency / Party sorting / Partisan polarization
Overview
A. Polarization – Definitions
B. Mass polarization
C. Partisan sorting / Elite polarization
D. Affective polarization
E. Geographical polarization
F. Social media and Political polarization
Affective polarization
Affective polarization refers to the extent to which citizens feel more
negatively toward other political parties than toward their own
(Iyengar et al. 2019)
Affective polarization in the US
Iyengar, Sood and Lelkes (2012)
Particularly increasing since the 90s
Multiple causes at stake:
1. Party sorting and affective polarization
2. Electoral campaigns
3. Media and particularly, social media
Affective polarization in the US vs other OECD
countries
Boxell, Gentzkow, Shapiro, 2022
34
Affective polarization in the UK
• Brexit plays a stronger role than political parties in the rise of
affective polarization! (Duffy et al., 2019)
• People on both sides of the Brexit vote dislike the opposing side
(even when they don’t disagree on other salient issues)
• Differentiation: one side views its own position as positive and the other
side’s position as negative
• Perception bias: they don’t perceive the same realities depending on their
Brexit identities
FIGURE 25: Labour ID Conservat ive ID
PERCEIVED
CHARACTERIS- Percept ions of Conservat ive Percept ions of Labour
TICS OF OWN support ers support ers
SIDE AND OTHER
SIDE Intelligent Intelligent
Source: Reproduced Open-minded Open-minded
from Hobolt, Leeper
and Tilley (2018), Honest Honest
‘Divided by the vote’,
p. 17 – based on Selfish Selfish
mean scores on a
1-5 Liker t scale of Hypocritical Hypocritical
agreement from
YouGov survey Closed-minded Closed-minded
conducted in
September 2017. 1 2 3 4 5 1 2 3 4 5
Agreement Agreement
Remainer ID Leaver ID
Percept ions of Leavers Percept ions of Remainers
Intelligent Intelligent
Open-minded Open-minded
Honest Honest
Selfish Selfish
Hypocritical Hypocritical
Closed-minded Closed-minded
1 2 3 4 5 1 2 3 4 5
Agreement Agreement
Overview
A. Polarization – Definitions
B. Mass polarization
C. Partisan sorting / Elite polarization
D. Affective polarization
E. Geographical polarization
F. Social media and Political polarization
Geographical polarization
• Few research on the UK but leave and remain votes were clustered
geographically
Geographical polarization: Only a urban/rural
divide?
• The 2020 Electoral campaign
❖Urban America: Diverse, educated,
productive … and Democrats
❖Rural America: White, dying industries,
stagnation, despair… and Trump supporters
• The description of « Two Americas » is not
very accurate
❖White Americans mainly voted for Trump,
regarding of geography/not (NYT)
❖21% of rural residents are people of color
❖The share of population living under
persistent poverty is larger in urban areas
• This tale may reinforce affective polarization
Geographical polarization
Using exhaustive
registration data, the YES
camp appears to be
winning
(See Brown and Enos, 2020)
Overview
A. Polarization – Definitions
B. Mass polarization
C. Partisan sorting / Elite polarization
D. Affective polarization
E. Geographical polarization
F. Social media and Political polarization
Social media and Political Polarization
• Does social media play an important role in amplifying societal cultural and political divides?
❖Like traditional media, social media helps provide information
❖However, the information provided is much less regulated (no editorial process, less
monitoring)
❖Two major innovations :
1. Online interactions with a social network
Help online communication and coordination – potentially with similar-minded individuals
Enhance binary rapid reaction to some content (like vs. not like)
Can offer a sense of anonymity, invisibility, and reduced accountability
2. Algorithms that impact what type of information users read / view
Social media and Political Polarization
Ex. Twitter’s algorithm :
1. Candidate sourcing (based on in-network sources and out-of-network
sources)
2. Ranking tweets (put at the top the tweets the user is likely to engage with)
3. Filtering tweets (e.g, remove people blocked or muted by the user)
4. Mixing tweets with sponsored content or organic tweets
Social media and Political Polarization
• Social media could enhance echo chambers (Sunstein, 2017)
- Social Media are efficient at sorting users into groups of like-minded
individuals
- The online world can create « cybercascades : » false information can
easily be spread multiple times by the simple press of a button
- They reinforce confirmation bias : the tendency to favor information
that supports users’ prior beliefs or values
- They are used by « polarization entrepreneurs: » (including terrorist
organizations)
He promotes a regulation of social media where users would be
exposed to unchosen and unplanned content
.
Social media and Political Polarization
• Via echo chambers, social media would potentially impact :
- Ideological polarization
- Affective polarization
• Bakshy et al. (2015) examine how 10 million US Facebook users
interact with socially shared news
Social media and Political Polarization
Social media and Political Polarization
Social media and Political Polarization
• But is online political segregation larger than offline political segregation and
face-to-face social interactions?
• Gentzkow and Shapiro (2011) find that ideological segregation of online news is
higher than the segregation of most offline news consumption
• But online segregation is low in absolute terms and lower than the segregation
of face-to-face interactions with neighbors, co-workers or family members
Social media and Political Polarization
Does exposure to social media impact real-life polarization?
• Zhuravskaya et al. (2020) find the scientific literature to be inconclusive. Boxell et
al. (2017) show that the most polarized age groups in society are not the most
likely to use social media
• Several papers show however a positive impact of social media on polarization:
❖Allcott et al. (2020) : Deactivating Facebook during one month decreases
political polarization (and increases subjective well-being!)
❖Yanagizawa-Drott et al. (2024) : Homophilic connections made people use
Facebook more often but socialize less offline – lowering local social capital
and increasing political diversity
Recap
❖ Polarization refers to :
The extent to which political opinions/values differ
- Ideologically (Ex: Liberal and conservative opinions)
- Affectively (Ex: Positive/negative emotions regarding parties/party
supporters)
- Geographically (Ex: Red and Blue states in the US)
The process by which this opposition increases over time
Recap
• There is no strong evidence of mass polarization in the sense of ideological
polarization among citizens (at least in the US or the UK)
• However, party sorting due to elite polarization has happened in the US and we
observe a strong « Brexit sorting » in the UK
• This can fuel affective polarization where society is then divided into camps that
dislike each other. This is an ongoing process in several Western countries
(including the US and the UK)
• Today, social media are presented as fuelling political polarization via echo
chambers. The scientific literature remains inconclusive but recent papers tend
to enhance the positive impact of social media on polarization
