Ask a bride before walking down the aisle “How likely are you to get divorced?” and most will respond “Not a chance!” Tell her that the average divorce rate is close to 50 percent, and ask again. Would she change her mind? Unlikely. Even law students who have learned everything about the legal aspects of divorce, including its likelihood, state that their own chances of getting divorced are basically nil. How can we explain this?

Psychologists have documented human optimism for decades. They have learned that people generally overestimate their likelihood of experiencing positive events, such as winning the lottery, and underestimate their likelihood of experiencing negative events, such as being involved in an accident or suffering from cancer. Informing people about their statistical likelihood of experiencing negative events, such as divorce, is surprisingly ineffective at altering their optimistic predictions, and highlighting previously unknown risk factors for diseases fails to engender realistic perceptions of medical vulnerability. How can people maintain their rose-colored views of the future in the face of reality? Which neural processes are involved in people’s optimistic predictions?

To answer these questions we have investigated optimism by using a recent, burgeoning approach in neuroscience: Describing neural activity related to complex behavior with the simple concept of “prediction errors.” Prediction errors are the brain’s way of keeping track of how well it is doing at predicting what is going to happen in the future.

The concept of prediction errors was initially put forward in research on artificial intelligence. By now, scientists have used the basic concept of prediction errors in several domains and have come up with various ways of describing prediction errors in mathematical equations. Let me give you the basics without any mathematics: Imagine your granny tells you that she will give you some money next time she visits. You estimate how much money she will give you, maybe 10, maybe 100 dollars depending on how rich (and generous) your granny is. When she gives you the money you will not only be happy about the money but you will also see how much your prediction differed from what you actually got; in other words, you calculate a prediction error. Knowing this prediction error will help you to estimate how much money you will get the next time your granny comes along. It’s an essential part of learning, and the brain is doing it all the time.

How have neuroscientists employed the idea of prediction errors to study brain activity? In dozens of studies, researchers have looked for and identified brain regions that are related to the calculation of prediction errors. They do this in various ways, but the typical experiment consists of having participants gamble for money on computerized versions of slot machines. At the same time, participants’ brains are monitored in functional magnetic resonance imaging (fMRI) scanners.

Interestingly, similar patterns of brain activity seem to be at play when participants gamble for money and when they engage in complex social interactions. For example, in our everyday life, we often have to track how good or bad the advice of another person is. Timothy Behrens and colleagues from Oxford University used prediction errors to model how humans incorporate advice from social partners into their decisions. Participants repeatedly had to choose which one of two options would yield a higher reward. Before they made their decision, they saw which option another person would advise them to choose. So participants had to form prediction errors for two types of information: non-social (how rewarding are the two options) and social (how good is the other person’s advice). The two kinds of prediction errors were processed in a similar fashion, suggesting conceptual links between processing social and non-social information.

3 Comments

1. 1. Michael M 03:19 PM 1/15/12

   It appears that association is a significant process through which memory derives supporting evidence:
   We add evidence which supports our cognitions at this moment, and fail to dredge up events producing results counter to our desires.
   
   Over and over, whether in private plans and reveries, politics, marriage, hopes for lotteries, we appear to create a partial personality supporting our most recent, most emotional experience, wishes, desires, beliefs.
   Social psychologists have repeatedly shown that we refuse to entertain cognitive dissonance, and this phenomenon is key to further experiment.
   
   The trait the author discusses is certainly neurohormonal, and obviously highly plastic in that we entertain chaotically conflicting beliefs at alternate times, should we have not developed such cognitive protection.
   Remember the brain-mapping studies of cat hearing, in which the neuroimaging showed complete shutdown of response to the aural experiment when the cat(s) became aware of rodents in the lab?
   
   Neuromodulation is adaptive, signalling losers of contests to reduce their output of testosterone; likely this effect kept key ancestors alive to reproduce when later out of range of winners.
   
   As readers may know, it is likely that most of our later-evolved brain areas were social adaptations. The complexity of our many, many slightly differing neurotransmitters were possibly the microevolutionary adaptations for social success.
   
   The newlywed is eager to socially succeed, in spite of what reservations she may have hidden from herself when proposed to by the most socially dominant suitor she could attract. Love (as a descriptive factor of long-term loyalty, and attendant behaviors and cognitions) may not be a part of the wedding at all, as social success veils reservations,at least until oxytocin is no longer produced in sufficient quantities to overcome negative experience.
   
   It is more complex than this, yet we must look to the most outstanding cognitive and behavioral activators for indications -she's not going to tell us about reservations she is convincing herself are not real while walking down that aisle.

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2. 2. Petra 03:38 PM 1/15/12

   Facts on divorce rates, messy divorces and so forth are poor benchmarks for understanding why any persons marriage may fail. Most do not understand no one ever knows anyone, even when married for decades; living compatibility in marriage must be discovered and in time with age we become someone else and very different from who we were when we married; yet we don't know what we may become.
   
   But as we weigh factors in predicting if one might have a successful and happy marriage much is left to emotional decision, not based upon far to many unknown elements and individual events which will test any relationship. Even persons who lived together for years have discovered once legally committed to each other the couple behaves differently, thus it's not a good test of sustainability either.
   
   Overall, most fail to understand we should take off the rose colored glasses and see a person who may hold our physical, emotional and financial lives in their hands. Yet, we trust without ever doing a background check on them and assume everything we see and hear is the truth. Assumptions are poor indicators in sorting out fact from fiction. Yet, chemistry trumps logical thought and in that no statistics seem to make a difference. In that it seems we humans love to be charmed.

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3. 3. okburt75 11:32 AM 1/16/12

   The author didn't say if the participants, in the study on changing estimating positive or negative experiences when presented with actual statistics, were undergraduates or mature adults. If undergrads, then the results need to be taken with a grain of salt as their frontal lobes are not fully wired.

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