Opinion polarization is on the rise, causing concerns for the openness of
public debates. Additionally, extreme opinions on different topics often show
significant correlations. The dynamics leading to these polarized ideological
opinions pose a challenge: How can such correlations emerge, without assuming
them a priori in the individual preferences or in a preexisting social
structure? Here we propose a simple model that qualitatively reproduces
ideological opinion states found in survey data, even between rather unrelated,
but sufficiently controversial, topics. Inspired by skew coordinate systems
recently proposed in natural language processing models, we solidify these
intuitions in a formalism of opinions unfolding in a multidimensional space
where topics form a non-orthogonal basis. Opinions evolve according to the
social interactions among the agents, which are ruled by homophily: two agents
sharing similar opinions are more likely to interact. The model features phase
transitions between a global consensus, opinion polarization, and ideological
states. Interestingly, the ideological phase emerges by relaxing the assumption
of an orthogonal basis of the topic space, i.e. if topics thematically overlap.
Furthermore, we analytically and numerically show that these transitions are
driven by the controversialness of the topics discussed, the more controversial
the topics, the more likely are opinion to be correlated. Our findings shed
light upon the mechanisms driving the emergence of ideology in the formation of
opinions.

本文提出了一种基于多维空间，通过社会交互和共性原则的思想演化模型，解释了意见形成的意识形态现象，通过越来越具有争议性的主题，人们倾向于和相似观点的人互动，从而导致了意识形态的出现。