Oliver Sacks sent me his recent editorial review of an imaging study by Sam Harris and colleagues. Harris is more familiar for his attacks on religious fundamentalism in his books, “End of Faith” and “Letter to a Christian Nation,” but has resumed his graduate work in cognitive neuroscience.
The study that appeared in the Annals of Neurology is really interesting. Very briefly they had participants judge statements from seven different categories (autobiographical, mathematical, geographical, religious, ethical, semantic and factual). Each was designed to be “clearly true, false or undecidable.” For example,
Mathematical
(2+6) + 8 = 16
62 can be evenly divided by 9
1.257= 32608.5153
Factual
Most people have 10 fingers and 10 toes
Eagles are common pets
The Dow Jones Industrial Average rose by 1.2% last Tuesday.
What they found was that there were two separable patterns of brain activity for assenting and dissenting statements. Assenting statements preferentially activated the ventromedial prefrontal cortex associated with emotional regions whereas dissent activated the more dorsal regions associated with executive functions. In other words, it is emotionally gratifying to agree with statements whereas dissent involves dissonance.
This reminds me of the confirmation bias that one finds operating in psychology. We tend to preferentially process information that is consistent with our inherent beliefs. Harris and other’s findings are more radical suggesting that we are inclined to acceptance of statements rather dismissal which could be a mechanism for the power of accepting other people’s testimony.
This is an intriguing idea. Certainly early in development children have a strong “Yes” bias in response to questioning. Behaviourally we are more inclined to compliance than dissent.
However, I have a couple of quibbles with the study – they collapsed across all categories for true and false statements but how can you have a clearly true religious statement. The one cited in the paper is “A personal God exists, just as the Bible describes.” But that is a belief whereas the others are factually verifiable. So just because one gets a neurological marker for judging factually correct statements that triggers for certainty, one cannot say the same applies to beliefs.
Spinoza’s conjecture is that in understanding statements, it is much easier to accept a statement as a truth than it is to reject it as false. I think that is correct but as Francis Bacon pointed, “Man prefers to believe what he prefers to be true.” So we are not simply gullible blank slates for memes. Still it is a really interesting line of enquiry.
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“Intriguingly, they note, the strongest emotional
reactions were observed in association with dissent or disbelief, which activated bilateral areas of the anterior insula, a region thought to be involved in reactions of disgust. “The acceptance or rejection of propositional truth claims,” they write, “appear to be governed in part by the same regions that govern the pleasantness of tastes and odors.””
..wow, now here is something that utterly stuns me, and excites me to no end.
That Harris did a study as simple as this and gets such conclusions is freaking genius.
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