The behavioural sciences, social sciences and humanities can bring us new insights into our political behaviour, such as how and why emotions, values, identity and reason affect how we think, talk and take decisions on political issues. Misperception and disinformation: our thinking skills are challenged by today’s information environment and make us vulnerable to disinformation. We need to think more about how we think. Motivated reasoning makes people resist evidence that runs against their beliefs. Misinformed people do not think of themselves as ignorant – they hold facts which they believe to be true. False news, particularly political is diffused ‘significantly farther, faster, deeper and more broadly than the truth’. Corrections do lead to more accurate assessments of the facts although generally do not change people’s views. Collective intelligence: science can help us re-design the way policymakers work together to take better decisions and prevent policy mistakes. Thinking collectively can significantly improve the quality of political decisions but only if collaborative processes are carefully designed. Only if all critical information, unique knowledge and expertise are shared can collective intelligence be achieved and groupthink or polarisation avoided. Psychological safety is essential for the sharing of critical information, ideas, questions and dissenting opinions. Emotions: we can’t separate emotion from reason. Better information about citizens’ emotions and greater emotional literacy could improve policymaking. Emotions are just as essential to decision-making as logical reasoning and as likely to enhance rationality as to subvert it. Angry people are less likely to seek information and more likely to adopt a closed mind while anxiety may lead to a deeper processing of information. Sensing citizens’ emotions more effectively could better guide policy choices. Learning to integrate and use emotions, rather than trying to suppress them could improve decision-making and collaboration in government. Values and identities drive political behaviour but are not properly understood or debated. Political decisions are strongly influenced by group identity, values, worldviews, ideologies and personality traits. Political polarisation is on the rise and a new form of cultural, rather than economic, polarisation has emerged, with the far right opposed to immigration and multiculturalism. Values strongly influence not only our political behaviour but also our perceptions about facts. Framing, metaphor and narrative: facts don’t speak for themselves. Framing, metaphors and narratives need to be used responsibly if evidence is to be heard andunderstood. There is no such thing as a neutral frame; something is included at the expense of something else. The ways in which policy problems are framed can substantially influence beliefs. It is not the side with the most or best facts that wins an argument, but the one that provides the most plausible scenario that feels intuitively reliable, communicated by a perceived credible source. Trust and openness: the erosion of trust in experts and in government can only be addressed by greater honesty and public deliberation about interests and values. Trustworthiness depends on expertise, honesty shared interests and values. The ideal of value-free science is more complex in reality: values may enter at several stages of the process. This does not mean that science cannot be trusted but that there is a need to be more transparent about the role of values in science. Opening evidence to public scrutiny is crucial to maintain scientific authority. Deliberative democracy and citizen engagement can be effective responses to the loss of trust in democratic institutions. Evidence-informed policymaking: the principle that policy should be informed by evidence is under attack. Politicians, scientists and civil society need to defend this cornerstone of liberal democracy. The framing of a policy problem is a political rather than technical issue that determines what research is needed, what evidence counts and what should be ignored. The commitment to evidence-informed policy cannot be taken for granted. Partisan leadership in highly polarised political environments undermines the capacity of governments to use evidence effectively. There are extensive barriers to the use of evidence – scientists and policymakers have different norms, cultures, languages, misaligned incentives, understanding of time and budget constraints. A well-designed evidence-informed policy system would include knowledge brokers and boundary organisations between scientists and policymakers. The principle of informing policy through evidence could be recognised as a key accompaniment to the principles of democracy and the rule of law.