Some people are incurable contrarians or imperturbable logicians. But most of us, whether we like it or not, allow other people's opinions and advice to color our own experiences and opinions. Have you found that restaurant to really be as good as people say it is?

New findings suggests that a person's willingness to coolly consider the facts gleaned from their own experience—apart from others' previous verbal suggestions—might be based in large part on genetics.

It has been known and frequently demonstrated that "people will distort what they experience to be perceived as more consistent with what they thought already," Michael Frank, of the Brown Institute for Brain Science at Brown University, and a collaborator in the new research, said in a prepared statement. Even researchers can fall prey to confirmation bias, thinking they have discovered what they actually had expected to find  in the noise of data.

So, why do we often struggle to accept our own impressions if they contradict what we've been told to expect? The disconnect occurs in part because these two types of information, the abstract and the experiential, are processed in different parts of the brain. Advice ("go to that Italian restaurant") is filtered, along with other higher-level cognition, in the prefrontal cortex. Experience ("that Italian restaurant is usually mediocre"), on the other hand, is lodged in a more primitive region of the brain, the striatum.

Although perhaps we should be more inclined to stick with what our gut (or tastebuds) has learned from personal experience, most people tend to lean on what their prefrontal cortex—i.e. outside instruction—has to say for more time than they rationally should.

"Maintaining instructions in the prefrontal cortex changes the way that the striatum works," Bradley Doll, a researcher at Brown, said in a prepared statement. "It biases what people learn about the contingencies they are actually experiencing," noted Doll, who coauthored a new paper detailing the results, which published online April 19 in The Journal of Neuroscience.

People's willingness to let advice color their experience hinges at least in part on the neurotransmitter dopamine, which is associated with pleasure, reward and learning. The researchers pinpointed one gene in particular, COMT, that seems to play a role in a person's inclination to learn from his or her own experiences. Individuals in the study with different alleles of this gene had differing propensities to be biased by outside advice in interpreting their own experiences.

Frank, Doll and colleague Kent Hutchinson tested more than 70 adults on a computer-based learning program. Subjects had to learn which symbols were most likely to be classified as the "correct" answer. The correlation was based on probability, rather than strict correlation, creating a gray area in which subjects had to weigh their past experiences with each symbol. In some tests, people were given advice about which symbols were correct most often—but this advice sometimes proved to be incorrect.

People with an exceptional ability to spot inaccurate instructions and start making decisions using their own experience tended to have the Val/Val version of the gene, whereas those who needed "greater confidence" that their experience was telling them to jettison earlier advice were more likely to have the Met allele.

Overall, the researchers concluded, "these findings suggest that the striatal learning process is modulated by prior expectations, and that the resulting associative weights cannot be easily 'undone' after the prior is rejected." So that might mean you have to order many bowls of substandard pasta before you finally admit to yourself that a much-lauded Italian restaurant isn't actually all that great.

Of course, it's certainly easier—and less painful—to learn to avoid a hot plate by being told to do so, and we've likely evolved to take this into account, prizing the prefrontal cortex's retained instructions. "This phenomenon of confirmation bias might actually just be a byproduct of a system that tries to be more efficient with the learning process," Frank said.

But the human mind is rarely satisfied with simple instruction, as instruction—and advice—often turn out to be wrong. And what's a few burnt fingertips in the grand scheme of independent thought?

Image courtesy of iStockphoto/Yuri_Arcurs