Opinion dynamics of rational agents

Summary

Social media and other online communities are a maelstrom of competing ideas, memes and opinions. As these communities become a more and more central part of our social and political lives, identifying how and why some ideas spread and some don’t is crucial to understanding how the online world influences what we believe, what we do and how we vote.

Models of opinion dynamics typically treat the spread of ideas like an epidemic, with individuals becoming ‘infected’ with a certain opinion and then passing it on to others. Indeed, observing how beliefs and opinions spread on social media it can often seem as though people have little control over which beliefs they adopt, and which they pass on. However, people are not simply passive recipients and vectors for ideas; expressing themselves online is a decision, and one that they make so as to accomplish their goals, whether conscious or not.

This is a mathematical programme of research that will be based on probability theory, especially Bayesian inference and optimisation. Stochastic processes, networks and game theory are also likely to be important. Applicants should be able to evidence a solid background in statistics and probability, and scientific programming. You will also engage with work from biology, psychology and sociology that provides a context for understanding human sociality, motivations and cognitive processes.

In this project you will develop models of opinion dynamics based on the idea that the expression of ideas, opinions and beliefs is a choice made by rational agents in pursuit of specific goals. You will join a research team focused on understanding the collective behaviour of humans and animals in terms of rational decision-making theory. This PhD project will extend on previous and ongoing work [1, 2] by considering:

(i) The expression of an opinion as a decision. How does the expressed opinion relate to an agent’s true beliefs? What do people seek to accomplish by expressing it? What do we all want from our social media activity?

(ii) What can we learn from social media and other online groups? What is the relationship between the truth and collective opinions online? How much should online opinion influence policy?

(iii) How can problems with social media be tamed? Is there a role for ‘fact checking’? How can recommendation algorithms help or damage collective wisdom? Is more or less connectivity better for our online communities?

This work is related to ongoing projects in the group: Collective behaviour of cognitive agents; Rationality and reasoning beyond the individual

References:

1. RP Mann (2018) Collective decision making by rational individuals. Proceedings of the National Academy of Sciences
2. RP Mann (2022) Collective decision-making under changing social environments among agents adapted to sparse connectivity. Collective Intelligence.

Applicants to research degree programmes should normally have at least a first class or an upper second class British Bachelors Honours degree (or equivalent) in an appropriate discipline. The criteria for entry for some research degrees may be higher, for example, several faculties, also require a Masters degree. Applicants are advised to check with the relevant School prior to making an application. Applicants who are uncertain about the requirements for a particular research degree are advised to contact the School or Graduate School prior to making an application.

The minimum English language entry requirement for research postgraduate research study is an IELTS of 6.0 overall with at least 5.5 in each component (reading, writing, listening and speaking) or equivalent. The test must be dated within two years of the start date of the course in order to be valid. Some schools and faculties have a higher requirement.