Do you rationally evaluate the arguments you disagree with?

In a polarized society it can be extremely difficult to convince others with our arguments, and it often seems that discussions are useless. Why does it happen?

Psychology helps us to understand a little better the reasons for this type of problem, for example, by showing that regardless of political inclinations most people are very motivated to protect their views .

A  new article  published in the  Journal of Cognitive Psychology  tested people’s ability to assess the logic of formal arguments (syllogisms) that confirmed or contradicted their views on abortion. Vladimíra Čavojová and his colleagues at the Slovak Academy of Sciences have demonstrated yet another impressive piece of evidence of how our reasoning ability may be impaired by biases .

How the study was done

387 participants in Slovakia and Poland, mostly university students, analyzed their views on abortion, a very current and controversial topic in both countries. The researchers introduced participants to 36 syllogisms. See examples below:

Examples of valid and invalid syllogisms (free translation)



  • All mastiffs are dogs.
  • Some mastiffs are black.
  • Some of the things that are black are dogs.


  • All mastiffs are dogs.
  • Some dogs are black.
  • Some of the things that are black are mastiffs.



  • All fetuses must be protected.
  • Some fetuses are human beings.
  • Some human beings must be protected.


  • All fetuses are human beings.
  • Some human beings must be protected.
  • Some of those that must be protected are fetuses.



  • All women’s rights must be supported.
  • Some of women’s rights are abortions.
  • Some abortions must be supported.


  • All abortions are women’s rights.
  • Some of the rights of women must be supported.
  • Some of the things that must be supported are abortions.


The challenge in the study was to determine whether the third statement of each syllogism logically followed the first two (assumed to be true premises). It is a test of pure logical reasoning, and participants were instructed to consider the first two statements to be true. To succeed in the task, it was necessary to evaluate only the logic, disregarding their own beliefs, previous knowledge and personal opinions .

Conclusions: we don’t think so objectively

According to Čavojová and his colleagues, the participants’ logical reasoning was interfered with by their opinions about abortion. Mainly, the participants found it difficult to accept valid syllogisms that contradicted their beliefs as logical, and found it difficult to reject valid syllogisms that confirmed their beliefs as illogical.

You can easily think: “but this business is very difficult, it could be that nobody really understood what this business of logic is”. The fact is that, curiously, this “bias on my side” was greater among participants with previous experience or training in logic!

“Our results show why debates on controversial issues often seem so futile,” said the researchers. “Our values ​​can blind us to recognize the same logic in our opponent’s arguments if the values ​​underlying those arguments offend ours.”

This is just one of several studies in psychology that demonstrate how flawed our reasoning can be, and how difficult it is to evaluate evidence and arguments objectively. Other research shows that:

  • many of us  overestimate our knowledge
  • the effects of fake news on the trial can be difficult to correct
  • we believe in false facts  due to the effect of continuous influence
  • we tend to see our own theories as accurate
  • our brains treat opinions we agree with as facts
  • when facts seem to contradict our beliefs, we seek unfailing arguments

It all shows that thinking objectively is difficult for most people. We are often not as rational and impartial as we think.

You might also want to know about:

by Abdullah Sam
I’m a teacher, researcher and writer. I write about study subjects to improve the learning of college and university students. I write top Quality study notes Mostly, Tech, Games, Education, And Solutions/Tips and Tricks. I am a person who helps students to acquire knowledge, competence or virtue.

Leave a Comment