By Christian Jarrett

In a post-truth world of alternative facts, there is understandable interest in the psychology behind why people are generally so wedded to their opinions and why it is so difficult to change minds.

We already know a lot about the deliberate mental processes that people engage in to protect their world view, from seeking out confirmatory evidence (the “confirmation bias“) to questioning the methods used to marshal contradictory evidence (the scientific impotence excuse).

Now a team led by Anat Maril at the Hebrew University of Jerusalem report in Social Psychological and Personality Science that they have found evidence of rapid and involuntarily mental processes that kick-in whenever we encounter opinions we agree with, similar to the processes previously described for how we respond to basic facts.

The researchers write that “their demonstration of such a knee-jerk acceptance of opinions may help explain people’s remarkable ability to remain entrenched in their convictions”.

The background to this involves something you’ve probably heard of, the Stroop Effect – how we’re slower to name the ink colour of colour-denoting words when the word meaning doesn’t match the ink, like RED written in blue ink. The Stroop Effect occurs because our brains rapidly and involuntarily process the colour meaning of the word, which interferes with our processing of the ink colour.

A while back, psychologists showed there’s a similar phenomenon for facts (they called it the “Epistemic Stroop Effect”) – we’re quicker to verify that factual, than non-factual, statements are spelled correctly, suggesting that our rapid discernment of factual accuracy interacts with our judgment about spelling (even though the factual accuracy of the statements is irrelevant to the spelling task).

Now, across four studies, Maril and her team have found that something similar occurs for opinions. They composed 88 opinion statements, written in Hebrew, that covered politics, personal tastes and social issues, such as “The internet has made people more isolated” or “The internet has made people more sociable”. They presented dozens of Israeli participants with versions of these statements that were grammatical or not (e.g. the gender or use of singular/plural were incorrect) and the participants’ task was to indicate as rapidly as possible whether the grammar was correct. Later, the participants were shown all the statements again and asked to indicate whether they agreed with them.

The key finding was that participants were quicker to identify statements as grammatically correct when they agreed with the opinion expressed in the statement, compared with when they disagreed (there was no difference for time taken to identify ungrammatical statements as ungrammatical). This was the case even though their agreement with the opinion expressed in the statements was irrelevant to the grammatical task at hand. “The results demonstrate that agreement with a stated opinion can have a rapid and involuntary effect on its cognitive processing,” the researchers said, which is similar to the epistemic Stroop Effect observed for facts.

In their final study, the researchers created a variation of the task that required participants to indicate whether statements (e.g. “coriander is tasty” or “coriander is disgusting”) indicated something positive or negative. For statements that they agreed with, participants were faster to answer “yes”, whether they were identifying that the statement was positive or identifying that it was negative. The researchers said this confirms that we have a rapid, involuntary cognitive bias is for answering in the affirmative to semantic questions about opinion statements that we agree with (ruling out effects of fluency or unfamiliarity that might have confounded the results for judging the grammar of statements in the earlier studies).

“The current findings suggest that despite adults’ understanding of the notion of subjectivity, they may react to opinion-incongruent statements as if they were factually incorrect,” the researchers said, adding, “The distinction between factual truths and opinions held to be true is pivotal for rational discourse. However this distinction may apparently be somewhat murky within human psychology.”

More generally they said their paradigm provided “an addition to the social psychologists’ tool kit” that could be used as a new way to explore implicitly held opinions (providing an alternative to the implicit association test, for example). Further research could also explore whether the effect described here is moderated by factors like stress or peer pressure, or individual characteristics like one’s political leanings.

—That’s My Truth: Evidence for Involuntary Opinion Confirmation

Christian Jarrett (@Psych_Writer) is Editor of BPS Research Digest