Wednesday, October 10, 2018

Our beliefs blind us to the logical validity of political arguments

There's an interesting post on the British Psychological Society's Research Digest blog that looks at how good we are at judging the logical validity of political arguments when we already have beliefs about the issue in question.

It reports research by Vladimíra Čavojová at the Slovak Academy of Sciences and her colleagues, who recruited 387 participants (mainly university students) in Slovakia and Poland.

The researchers first assessed the students' views on abortion, which is a topical and contentious issue in both countries. They then presented them with 36 syllogisms – formal logical arguments that come in the form of three statements. The students had to judge whether the third statement, the conclusion of the argument, followed logically from the first two.

Some of the syllogisms were on neutral subjects, but others had a conclusion that was relevant to the abortion debate - some were pro-life and some were pro-choice.

The Research Digest post says:
Čavojová and her team found that the participants’ existing attitudes to abortion interfered with their powers of logical reasoning – the size of this effect was modest but statistically significant. 
Mainly the participants had trouble accepting as logical those valid syllogisms that contradicted their existing beliefs, and similarly they found it difficult to reject as illogical those invalid syllogisms that conformed with their beliefs. This seemed to be particularly the case for participants with more pro-life attitudes.
One intriguing point is that this bias was actually higher among students with previous experience of training in logic.*

The researchers suggest their results "show why debates about controversial issues often seem so futile”.

* Formal logic, like chess opening theory and the Romanov Tsars of Russia, is one of the things I used to know a fair bit about but have now largely forgotten.


Anonymous said...

Surely the main reason that some political issues are so controversial is that they _don't_ just involve proceeding logically from axioms to conclusions. Politics involves differences of opinion about how the world should be run, not just a choice of which group of managers will be most efficient or which measures will achieve a set of goals everyone already agrees on.

David Evans said...

Actually, Anonymous' comment is a perfect example of the illogical behaviour that the research has identified. He/she disagrees and so constructs a simple but irrelevant aphorism that denies its validity, rather than consider whether it could be true and why it might be very important.

I suggest a good read on this sort of thing would be "Thinking, Fast and Slow." It clearly shows how massively sub optimal most human decision making can be unless it is forcibly made objective. This is why private sector decision making is so much better than public sector - the private sector has a business case with numbers and measurable objectives, the public sector produces business cases based on feelings and unmeasurable values.

This is most important within a single political movement which should share the same goal (say for example to build and safeguard a free open and fair society). In this case an important possible scenario could be: We have just got into coalition, do we accept lots of stuff at the start that our coalition partners want but rather goes against what people are expecting of us (in the expectation that our partners will later will stick to their side of the bargain and allow us to deliver more of what we promised later), or do we insist that they give to us at the start as well (because the electoral consequences could be so bad that we are massacred year after year and become a party so small we are unable to safeguard that society)?

Phil Beesley said...

David Evans: "It clearly shows how massively sub optimal most human decision making can be..."

To me, that statement appears subjective. Contrast with the David Evans observation about "a perfect example of the illogical behaviour..."