A number of commentators have argued that we are in a "post-truth" world [1], where there is a "circuitous slippage between facts or alt-facts, knowledge, opinion, belief, and truth" [2], that has led to a politicisation of the validity of scientific knowledge. Of course, science and politics have never been entirely separate, as science is often organised, funded, and institutionalised through public policy. Whilst political culture has historically been dominated by normative matters of civil rights and law, political economy, and economic policy, there is an increasing component of "post-truth politics". This sort of politics engages in appeal to emotion, talking-points, short news cycles etc., the strength of which is sufficiently relevant that the Oxford dictionary chose "post-truth" as "word of the year" in 2016 [3], which also occurred in Germany with the word "Postfaktisch" by the Gesellschaft für deutsche Sprache (GfdS) [4]. A post-truth environment has a profound importance for the survival of democratic governance, public representation, policies, and consequences.
It might be tempting to look to something like schizophrenia for an explanation, as people who endure this mental illness commonly experience conspiracy theories as part of their internal fantasy. This also ties into with common expressions of grandiosity among such people; e.g., "Unlike me, the 'sheeple' have been duped by the mass media; they need to 'wake up'!". However even casting the widest possible net, considering schizophrenia as a continuum rather than a category (we are all schizophrenic to a degree), or as epigenetic [5] rather than genetic (particular environments encourage existing and heritable genetic expressions in the phenotype), this can only provide a partial explanation at best.
Instead, the social psychology of prejudice could have greater explanatory power. From the outset, it is acknowledged that whilst prejudices are often harmful (including a post-truth environment) they arise from mental processes that are usually beneficial. The ability of the human mind to abstract and generalise from specifics provides us efficient guidance in thought and behaviour, known as a schema [6]. Noting similarities and differences in generalised situations leads to the development of discrimination between the situations and the assignment of stereotypes among people. This can result in prejudicial thoughts and actions in the literal sense of "pre-judgment", which overlooks the particulars of the situation or the person as an individual. This often occurs when the person expressing the prejudice is operating with incomplete information (i.e., they lack diverse experience) or have been provided incorrect information (e.g., from other sources, such as the media), and especially when the two are combined.
Does this apply to the post-truth political environment and doubt in the veracity of considered, researched, and reviewed scientific investigations? When looking at the ingredients of prejudice, that is, lack of experience and provision of false information, certainly the former is inevitable to a degree. Not everyone has is a practicing scientist, or has a science degree, let alone having a practicing qualification in the particular subject of discussion. Nevertheless, even a person without qualification can trust the review process and admit their own ignorance in a subject, respecting the considered opinions of those who engage in such work as their profession. This is certainly the case in trades (e.g., plumbing, electrical, automotive mechanics, etc). What is different is the number of people who no longer seem to have this trust and have sought alternative explanations for their information, through both mainstream and social media.
An inevitable question is raised is why do people trust or seek such alternative explanations? Looking at social and evolutionary psychology of prejudice, our beliefs come firstly from emotional responses which are strongly correlated to the more, primal and subconscious emotional parts of our brain that provide mechanisms for quick decision-making. As a sapient species, we have heuristics for pattern-recognition and as a conscious species, these emotions and heuristics mix with our socially-derived needs especially confirmation of being part of the same "in-group" as our peers [7]. The great issue is that the human brain, like all others, is an imperfect organ. The brain rewards us not on the basis of whether we are right or wrong, but rather whether our opinions confirm with those whom we've surrounded ourselves with and with our pre-existing beliefs and prejudices. The very pattern-generating heuristics that serve us so well to make logical elaborations also serves to believe things without appropriate evidence.
Under these circumstances encouraging aggressive partisanship and discouraging rational consideration of facts in favour of these emotional loyalties, is encouraged for particular political purposes through mass psychographic data (e.g., Cambridge Analytica, AggregateIQ [8], GTV Media Group [9]), which in itself makes for an interesting distinction between the existence of actual conspiracies (i.e., the deliberate use of media to promote things that are untrue for political purposes) and conspiracy theories (i.e., claims of definite conspiracies but with weak evidence) [10]. In addition, there is another important item for consideration; conspiracy theorists usually have some factual statements in their arsenal of beliefs but have elaborated far beyond what is true and what is fiction [11]. The "theory" is the part that has been elaborated, not the facts.
Because such beliefs are primarily emotional, rather than appealing to the critical reasoning faculties of the recently evolved parts of the brain, appeals to evidence will be discounted by a visceral reaction that most people have against being wrong. The cognitive dissonance between the evidence and the belief usually causes many people to strengthen their loyalty to the belief and the in-group, rather than admit error [12]. The provision of transparent, factual information, is absolutely necessary of course (especially for those who are neutral on a subject, or as a resource for those inclined towards a factual orientation) but in many cases it is not sufficient in itself to sway an individual's opinion, and certainly not in the short-term. However, it does seem that our ability to reason has a socially argumentative function, rather than an individual one. That is when we engage in debate ("somebody is wrong on the Internet") we seek to convince ourselves, as much as our interlocutor, when raising points for validity; the real effect it has is on third-party observers. Whilst an individual should learn and train their critical thinking skills, putting those to practise involves engaging in public discourse. In this is carried out, there is cause for optimism that not just the "post-truth" political culture can be broken down, but so too can the irrational loyalties and tribal divisions that divide us.
References
[1] Keyes, Ralph. The Post-Truth Era: Dishonesty and Deception in Contemporary Life. St. Martin's, 2004
[2] Biesecker, B.A. "Guest Editor's Introduction: Toward an Archaeogenealogy of Post-truth". Philosophy & Rhetoric. 51 (4): 329, 2018 doi:10.5325/philrhet.51.4.0329
[3] Flood, Alison. "'Post-truth' named word of the year by Oxford Dictionaries". The Guardian, 15 November 2016.
https://www.theguardian.com/books/2016/nov/15/post-truth-named-word-of-t...
[4] "Postfaktisch" ist Wort des Jahres 2016, Der Spiegel, 9 December, 2016
https://www.spiegel.de/kultur/gesellschaft/wort-des-jahres-2016-postfakt...
[5] Smigielski, Lukasz., Jagannath, Vinita., Rössler, Wulf., et al. Epigenetic mechanisms in schizophrenia and other psychotic disorders: a systematic review of empirical human findings., Molecular Psychiatry, 25, 1718–1748, 2020
[6] Shahghasemi, E. Cultural Schema Theory. The International Encyclopedia of Intercultural Communication. 1–9, 2017.
http://onlinelibrary.wiley.com/doi/10.1002/9781118783665.ieicc0019/full
[7] Novella, Steven., Your Deceptive Mind: A Scientific Guide to Critical Thinking Skills, The Great Courses, 2012
[8] Lloyd Hardy, How Dominic Cummings Hacked the EU Referendum, June 8, 2020
https://www.linkedin.com/pulse/how-dominic-cummings-hacked-eu-referendum...
[9] Hui¸ Echo., Cohen, Hagar. "They once peddled misinformation for Guo Wengui and Steve Bannon. Now they're speaking out", Australian Broadcasting Commision, November 1st, 2020
https://www.abc.net.au/news/2020-11-01/behind-the-scenes-of-the-guo-and-...
[10] McConnachie, James., Tudge, R. The Rough Guide To Conspiracy Theories, Rough Guides, 2008
[11] Basu, T., How to talk to conspiracy theorists - and still be kind, MIT Technology Review, July 15, 2020
https://www.technologyreview.com/2020/07/15/1004950/how-to-talk-to-consp...
[12] Mercier, Hugo., Sperber, Dan. The Enigma of Reason, Harvard University Press, 2017