Week 1
● Van Prooijen, The psychology of political polarization: An introduction explains what polarization is,
why it matters, and its connections with overconfidence, intolerance, and motivated reasoning.
● Van Baar and FeldmanHall, The Polarized Mind in Context argues that we need to study the
interaction between people’s cognitive characteristics and their social environments. It also explains
how polarization can appear during attention, language processing, and emotional responses.
1. What is polarization?
Van Prooijen describes political polarization as people becoming strongly attached to their political values
and beliefs, increasing their distance from people with different views. These beliefs often become
moralized: people experience their position as morally right and competing positions as morally wrong.
Strong, moralized attitudes tend to be resistant to change, stable over time, and influential in behavior.
Political disagreement then becomes connected to an “us versus them” distinction.
However, disagreement itself is part of democracy. Van Prooijen distinguishes constructive debate, in which
people discuss different solutions, from conflict focused on defending one’s own side or defeating opponents
at the expense of evidence and cooperation.
2. How can polarization be measured?
The lecture emphasizes that different measures capture different features of polarization. A population
containing many different opinions does not necessarily consist of two opposing camps.
When group membership is unknown, researchers can examine the overall distribution of responses:
Measure What it captures Main limitation
Range / spread The distance between the lowest and It ignores how many people give each response.
highest responses. A few extreme responses can produce a large
range.
Variance / How widely responses are distributed Greater variation can reflect diverse opinions
dispersion around the mean. without clearly separated camps.
Coverage How much of the opinion spectrum is On a questionnaire, every response option may
occupied, including gaps between be used even when distinct camps exist.
clusters.
A bimodal distribution has two peaks: responses cluster around two positions. Range alone cannot tell you
whether such a pattern exists.
For the answer sheet’s police-trust example, the scale runs from 1 to 10. If some respondents choose both
endpoints every year, the range remains 9, even if many more people move toward the extremes. Therefore,
range cannot capture that change.
,When researchers can identify relevant groups, they can examine:
Measure Meaning Direction associated with greater
polarization
Distinctiveness How much the groups’ response Less overlap.
distributions overlap.
Divergence How far apart the groups’ centers are. Greater distance.
Group consensus How similar responses are within each Less within-group variation, when
group. considering opposing groups.
The distinction between these measures matters. Groups can become more internally uniform without their
average positions moving farther apart. Conversely, their averages can move apart while substantial variation
remains within each group.
3. Different types of polarization
Type Main focus What to recognize
Ideological Differences in political beliefs, Groups becoming more entrenched and farther
polarization values, and policy positions. apart in their views.
Affective Feelings and evaluations directed Dislike, distrust, intolerance, and beliefs in one’s
polarization toward political opponents. own group’s moral superiority.
Elite polarization Divisions among political, social, Leaders becoming ideologically more distant or
or economic leaders. expressing hostility toward other groups.
Social Divisions in social circumstances Separation associated with income, wealth,
polarization and social networks. education, health, housing, and opportunities for
contact.
Elite polarization can be ideological or affective. “Elite” identifies whose polarization is being studied;
“ideological” and “affective” identify what kind of division is involved.
Van Prooijen also distinguishes political extremism from populism:
● Political extremism concerns positions at the edges of the political spectrum. In this reading, the
term also includes ordinary citizens with extreme views; it does not automatically imply violence.
● Populism presents society as a conflict between the virtuous people and corrupt elites. Its
dimensions include anti-elitism, people-centrism, and anti-pluralism.
Anti-pluralism means claiming that only one political position represents the people’s true will, denying
legitimacy to competing views. Populism can occur on the left, right, or in the political center, so it is not
synonymous with ideological extremism.
4. Individual characteristics: certainty and cognitive flexibility
,Both readings discuss psychological characteristics associated with polarized beliefs.
Epistemic motivation concerns people’s desire for knowledge, certainty, and an understandable world. A
particularly relevant characteristic is need for closure: wanting clear answers and disliking uncertainty or
ambiguity.
The lecture reports that high need for closure is associated with endorsement of political extremes on both
the left and right. Extreme positions can offer clear principles and simple explanations.
Cognitive flexibility is the ability to switch perspectives, adjust attention, or change a response when
circumstances change. The lecture discusses research by Zmigrod and colleagues using tasks such as card
sorting, remote associations, and generating alternative uses for objects.
Stronger political partisanship at both ends of the spectrum was associated with lower cognitive
flexibility. It is not supported that inflexibility belongs exclusively to conservatives or exclusively to
liberals. It shows an association with stronger partisanship on both sides. It also does not, by itself,
establish whether inflexibility causes stronger partisanship or the reverse.
Van Baar and FeldmanHall additionally discuss the need to belong. Political beliefs can help people
maintain acceptance within a valued group. This creates a connection between individual motivation and the
social environment.
5. Context: social networks, information, and group norms
Van Baar and FeldmanHall define context broadly: it includes social norms, expectations, social pressure,
media habits, and the structure of people’s networks.
The lecture highlights several ways context matters:
● Selective exposure: choosing information that supports existing beliefs.
● Filter bubbles: personalized information selection that repeatedly exposes users to material
consistent with their preferences.
● Echo chambers: social environments in which similar views are repeatedly reinforced.
● Social feedback: learning which opinions and behaviors receive approval or rejection.
The review also discusses information gerrymandering. The structure of a network can give people a
distorted impression of how much support different political positions have. Those impressions can influence
voting decisions.
Its main argument is that cognition and context must be studied together. Individual characteristics alone do
not adequately explain changes in polarization across society. Exposure to a particular environment also does
not affect everyone identically.
The authors propose a framework in which psychological needs influence which environments people select
and how they process information, while those environments reinforce particular beliefs and responses. This
interaction is their central research proposal, rather than a claim that every proposed mechanism has already
been demonstrated.
6. Motivated reasoning: evaluating evidence in a preferred direction
Motivated reasoning occurs when people’s goals or desired conclusions influence how they search for,
interpret, and evaluate information.
Relevant goals include preserving a positive self-image, avoiding discomfort, maintaining a coherent
worldview, and fitting into a social group.
, Van Prooijen describes an asymmetry in evidentiary standards: people more readily accept evidence
supporting their views, while scrutinizing opposing evidence for weaknesses.
The lecture illustrates this with Lord, Ross, and Lepper’s death-penalty study. Supporters and opponents
received the same conflicting research evidence about deterrence. Their prior beliefs shaped their evaluations
of the studies, and exposure to the same material increased the division between their attitudes.
These related concepts are worth distinguishing:
Concept Meaning
Motivated reasoning Reasoning influenced by a desired conclusion or psychological goal.
Confirmation bias Favoring information that supports an existing belief.
Cognitive dissonance Discomfort associated with inconsistency between beliefs, knowledge, or
behavior.
Availability heuristic Judging something using how easily relevant examples come to mind.
Van Baar and FeldmanHall add an important qualification: different interpretations of the same evidence do
not always require motivated reasoning. People can also reach different conclusions because they begin with
different prior beliefs. Their previous environments help shape those starting assumptions.
7. Polarization during attention, language perception, and emotion
The lecture follows the review’s argument that political differences can influence several stages of processing
information.
Attention
The lecture distinguishes:
● Top-down attention: deliberately choosing what to focus on.
● Bottom-up attention: what captures attention more automatically.
For top-down attention, people sometimes give up potential rewards to avoid hearing opposing political
views.
For bottom-up attention, the lecture discusses change blindness: difficulty detecting changes in an image. In
the inequality study, people higher in social dominance orientation, meaning greater preference for group
hierarchy and inequality, detected inequality-related changes more slowly.
The relevant lesson is that beliefs are associated with differences in what people notice, as well as how they
evaluate it afterward.
Language perception
Language understanding depends partly on prior knowledge and expectations. Van Baar and FeldmanHall
explain how political framing and learned associations can shape the meaning people draw from words.
The lecture adds EEG studies showing that political and moral attitudes are reflected in brain responses
during reading:
● Van Prooijen, The psychology of political polarization: An introduction explains what polarization is,
why it matters, and its connections with overconfidence, intolerance, and motivated reasoning.
● Van Baar and FeldmanHall, The Polarized Mind in Context argues that we need to study the
interaction between people’s cognitive characteristics and their social environments. It also explains
how polarization can appear during attention, language processing, and emotional responses.
1. What is polarization?
Van Prooijen describes political polarization as people becoming strongly attached to their political values
and beliefs, increasing their distance from people with different views. These beliefs often become
moralized: people experience their position as morally right and competing positions as morally wrong.
Strong, moralized attitudes tend to be resistant to change, stable over time, and influential in behavior.
Political disagreement then becomes connected to an “us versus them” distinction.
However, disagreement itself is part of democracy. Van Prooijen distinguishes constructive debate, in which
people discuss different solutions, from conflict focused on defending one’s own side or defeating opponents
at the expense of evidence and cooperation.
2. How can polarization be measured?
The lecture emphasizes that different measures capture different features of polarization. A population
containing many different opinions does not necessarily consist of two opposing camps.
When group membership is unknown, researchers can examine the overall distribution of responses:
Measure What it captures Main limitation
Range / spread The distance between the lowest and It ignores how many people give each response.
highest responses. A few extreme responses can produce a large
range.
Variance / How widely responses are distributed Greater variation can reflect diverse opinions
dispersion around the mean. without clearly separated camps.
Coverage How much of the opinion spectrum is On a questionnaire, every response option may
occupied, including gaps between be used even when distinct camps exist.
clusters.
A bimodal distribution has two peaks: responses cluster around two positions. Range alone cannot tell you
whether such a pattern exists.
For the answer sheet’s police-trust example, the scale runs from 1 to 10. If some respondents choose both
endpoints every year, the range remains 9, even if many more people move toward the extremes. Therefore,
range cannot capture that change.
,When researchers can identify relevant groups, they can examine:
Measure Meaning Direction associated with greater
polarization
Distinctiveness How much the groups’ response Less overlap.
distributions overlap.
Divergence How far apart the groups’ centers are. Greater distance.
Group consensus How similar responses are within each Less within-group variation, when
group. considering opposing groups.
The distinction between these measures matters. Groups can become more internally uniform without their
average positions moving farther apart. Conversely, their averages can move apart while substantial variation
remains within each group.
3. Different types of polarization
Type Main focus What to recognize
Ideological Differences in political beliefs, Groups becoming more entrenched and farther
polarization values, and policy positions. apart in their views.
Affective Feelings and evaluations directed Dislike, distrust, intolerance, and beliefs in one’s
polarization toward political opponents. own group’s moral superiority.
Elite polarization Divisions among political, social, Leaders becoming ideologically more distant or
or economic leaders. expressing hostility toward other groups.
Social Divisions in social circumstances Separation associated with income, wealth,
polarization and social networks. education, health, housing, and opportunities for
contact.
Elite polarization can be ideological or affective. “Elite” identifies whose polarization is being studied;
“ideological” and “affective” identify what kind of division is involved.
Van Prooijen also distinguishes political extremism from populism:
● Political extremism concerns positions at the edges of the political spectrum. In this reading, the
term also includes ordinary citizens with extreme views; it does not automatically imply violence.
● Populism presents society as a conflict between the virtuous people and corrupt elites. Its
dimensions include anti-elitism, people-centrism, and anti-pluralism.
Anti-pluralism means claiming that only one political position represents the people’s true will, denying
legitimacy to competing views. Populism can occur on the left, right, or in the political center, so it is not
synonymous with ideological extremism.
4. Individual characteristics: certainty and cognitive flexibility
,Both readings discuss psychological characteristics associated with polarized beliefs.
Epistemic motivation concerns people’s desire for knowledge, certainty, and an understandable world. A
particularly relevant characteristic is need for closure: wanting clear answers and disliking uncertainty or
ambiguity.
The lecture reports that high need for closure is associated with endorsement of political extremes on both
the left and right. Extreme positions can offer clear principles and simple explanations.
Cognitive flexibility is the ability to switch perspectives, adjust attention, or change a response when
circumstances change. The lecture discusses research by Zmigrod and colleagues using tasks such as card
sorting, remote associations, and generating alternative uses for objects.
Stronger political partisanship at both ends of the spectrum was associated with lower cognitive
flexibility. It is not supported that inflexibility belongs exclusively to conservatives or exclusively to
liberals. It shows an association with stronger partisanship on both sides. It also does not, by itself,
establish whether inflexibility causes stronger partisanship or the reverse.
Van Baar and FeldmanHall additionally discuss the need to belong. Political beliefs can help people
maintain acceptance within a valued group. This creates a connection between individual motivation and the
social environment.
5. Context: social networks, information, and group norms
Van Baar and FeldmanHall define context broadly: it includes social norms, expectations, social pressure,
media habits, and the structure of people’s networks.
The lecture highlights several ways context matters:
● Selective exposure: choosing information that supports existing beliefs.
● Filter bubbles: personalized information selection that repeatedly exposes users to material
consistent with their preferences.
● Echo chambers: social environments in which similar views are repeatedly reinforced.
● Social feedback: learning which opinions and behaviors receive approval or rejection.
The review also discusses information gerrymandering. The structure of a network can give people a
distorted impression of how much support different political positions have. Those impressions can influence
voting decisions.
Its main argument is that cognition and context must be studied together. Individual characteristics alone do
not adequately explain changes in polarization across society. Exposure to a particular environment also does
not affect everyone identically.
The authors propose a framework in which psychological needs influence which environments people select
and how they process information, while those environments reinforce particular beliefs and responses. This
interaction is their central research proposal, rather than a claim that every proposed mechanism has already
been demonstrated.
6. Motivated reasoning: evaluating evidence in a preferred direction
Motivated reasoning occurs when people’s goals or desired conclusions influence how they search for,
interpret, and evaluate information.
Relevant goals include preserving a positive self-image, avoiding discomfort, maintaining a coherent
worldview, and fitting into a social group.
, Van Prooijen describes an asymmetry in evidentiary standards: people more readily accept evidence
supporting their views, while scrutinizing opposing evidence for weaknesses.
The lecture illustrates this with Lord, Ross, and Lepper’s death-penalty study. Supporters and opponents
received the same conflicting research evidence about deterrence. Their prior beliefs shaped their evaluations
of the studies, and exposure to the same material increased the division between their attitudes.
These related concepts are worth distinguishing:
Concept Meaning
Motivated reasoning Reasoning influenced by a desired conclusion or psychological goal.
Confirmation bias Favoring information that supports an existing belief.
Cognitive dissonance Discomfort associated with inconsistency between beliefs, knowledge, or
behavior.
Availability heuristic Judging something using how easily relevant examples come to mind.
Van Baar and FeldmanHall add an important qualification: different interpretations of the same evidence do
not always require motivated reasoning. People can also reach different conclusions because they begin with
different prior beliefs. Their previous environments help shape those starting assumptions.
7. Polarization during attention, language perception, and emotion
The lecture follows the review’s argument that political differences can influence several stages of processing
information.
Attention
The lecture distinguishes:
● Top-down attention: deliberately choosing what to focus on.
● Bottom-up attention: what captures attention more automatically.
For top-down attention, people sometimes give up potential rewards to avoid hearing opposing political
views.
For bottom-up attention, the lecture discusses change blindness: difficulty detecting changes in an image. In
the inequality study, people higher in social dominance orientation, meaning greater preference for group
hierarchy and inequality, detected inequality-related changes more slowly.
The relevant lesson is that beliefs are associated with differences in what people notice, as well as how they
evaluate it afterward.
Language perception
Language understanding depends partly on prior knowledge and expectations. Van Baar and FeldmanHall
explain how political framing and learned associations can shape the meaning people draw from words.
The lecture adds EEG studies showing that political and moral attitudes are reflected in brain responses
during reading:
