In two or three hundred years life on earth will be unimaginably beautiful, astounding. Man needs such a life and if it hasn’t yet appeared, he should begin to anticipate it, wait for it, dream about it, prepare for it.
Anton Pavlovich Chekhov
In a study, published in Current Biology, researchers have confirmed an important role for dopamine in how human expectations are formed and how people make complex decisions. It also contributes to an understanding of how pleasure expectation can go awry. The study has found human beings are hard-wired to be optimistic, even in the face of a darker reality. Scientists led by Dr Tali Sharot at the University College London studied a group of people who were told they were likely to experience something bad. The results found most people stayed highly optimistic. And the researchers say the study shows why people are often foolhardy, naive or overly ambitious.
“We tend to learn more from positive information about the future,” Dr Sharot said.
The research team, which included Dr Tamara Shiner and Professor Ray Dolan, examined estimated pleasure of future events before and after the administration of a drug called L-DOPA which is known to enhance dopamine function in the brain and is commonly used to treat patients with Parkinson’s disease.
The 61 study participants were asked to rate their expectations of happiness if they were to holiday at each of 80 destinations, from Thailand to Greece. They were then given L-DOPA or a placebo and asked to imagine holidaying in those destinations.
The following day participants had to pick between a series of paired destinations that they had initially assigned with equal ratings, one member of the pair was imagined under L-DOPA the day before and the other under placebo. Finally, they rated the full set of 80 destinations again.
Ratings for particular destinations increased after they were imagined under L-DOPA’s influence. That increase also affected the participants’ selections the following day. Dr Sharot added: “We had reason to believe that dopamine would enhance expectations of pleasure in humans, but were surprised at the strength of this effect. The enhancement lasted at least 24 hours and was evident in almost 80 per cent of the subjects.”
The study builds on earlier work by Dr Sharot and colleagues, which used brain imaging as participants imagined holiday destinations. An area of the brain called the striatum tracked expectations and the scientists found that they could take that signal and predict what the participants would choose. The authors believed this was dopamine at work and set up this study to further explore its role.
“The reason is that regions of the front of your brain are very good at tracking and coding for positive information about the future.” said Dr Sharot ”When you get negative information about the future, the frontal lobes don’t code that information as efficiently.”
In some of her early studies, Sharot asked participants to recall past memories. She was surprised by the inaccuracy of their recollections. Using brain imaging technology, she found that the same brain structures that are engaged when we recollect the past are called upon when we think of the future. Recollection, therefore, is a reconstructive process, not a video-like rerun of past events. It is thus susceptible to inaccuracy.
“Understanding healthy optimism is important because optimism is related to mental and physical health and to success. We can have people who are not necessarily depressed but have different levels of optimism,” said Dr Sharot.
The researchers said they examined how the brain generates what some scientists call the human “optimism bias.”
“Humans expect positive events in the future even when there is no evidence to support such expectations,” the researchers wrote in the journal Nature.
“For example, people expect to live longer and be healthier than average, they underestimate their likelihood of getting a divorce, and overestimate their prospects for success on the job market,” they wrote.
Dr Sharot is also the author of a book, The Optimism Bias, which eloquently explains how the human brain is hard-wired for optimism.
According to Sharot’s research in optimism and memory, humans are hard-wired for optimism. Sharot speculates that optimism served an evolutionary purpose because positive expectations of the future enhanced the probability of survival. Sharot claims that optimism can be destructive if we cannot realistically predict what will happen in the future. For example, law students who were well briefed on the statistics that 50% of all marriages end in divorce were still quite convinced their upcoming marriages would last “until death do us part.”
Sharot also claims that optimism is functional in the sense that it defends us from feeling hopeless about the future, thus reducing stress and anxiety and enhancing motivation to act and be productive. There are parts of our brain that evolved to give us the capacity to envision ourselves in the future. They enable us to plan ahead, saving food and money, which can ensure our future security. Both prospective thinking and optimism work hand in hand to propel people forward.
“Now it doesn’t mean that we don’t remember positive or negative information, it just means that we take positive [information] about the future in order to update our beliefs,” she said.
“For example, if we learn that the probability of suffering from a certain disease is actually less than what we expected, we take that information and we update that belief of how likely we are to suffer a medical disease.
“But if we get negative information about the future, for example, everyone knows that divorce rates are about 50 per cent, we don’t take that information as relevant to us and don’t change or estimate on how likely we are to get divorced.” Even in the face of mounting negative information about the likelihood of illness, accident or even heartbreak, people still cling to the positive. ”It’s some sort of denial. We think that we will be okay. This is not going to happen to us. You can say it’s some sort of denial,” Dr Sharot said.
Sharot asserts that health and progress are more likely when our brains over-predict future happiness and success. “The tendency for positive predictions to create positive outcomes (whether subjective or objective) is rooted in fundamental rules governing the way the mind perceives, interprets and alters the work it encounters.” The mind has a tendency to try to transform predictions into reality because people’s behavior is influenced by their own subjective perceptions of reality. Thus the self-fulfilling prophecy becomes a cause of the event rather than just a forecast of the future.
People with a higher likelihood for depression tend to be negatively biased, interpreting everyday events as more negative more often. According to Sharot, antidepressants do not directly enhance people’s moods. They actually change the cognitive bias. This is why it takes time for antidepressants to change perceptions, attention, and memory and thereby alter someone’s emotional state.
Sharot cites research that suggests that a gene coding for serotonin function affects a person’s likelihood of suffering depression – but only after experiencing a very stressful life event like death of a loved one, unemployment, or divorce. Perhaps this genetic predisposition makes a person less resistant to stressors, similar to a weakened immune system. Perhaps it also heightens physiological response to stressful situations. If so, it may well be that resilience training and practices that redirect cognitive bias toward the positive, can, in fact, protect against depression.
“You might not buy insurance, and when we talk about financial markets, what happens is the optimism bias of all of the individuals come together into a bubble and actually a bias that is much, much bigger, and in that situation it can be ever more dangerous.” Sharot says the research also provides insights into mental illness.
Having completed the above, it seems remiss to end this here, this research is so interconnected with previous – and doubtless, future – research:
Sharot also co-authored another impressive paper – published in science- Following the Crowds: Brain Substrates of Long-Term Memory Conformity; in which she outlines Human memories susceptibility to social influence. Researchers examined how socially induced memory errors are generated in the brain. The researchers looked at two forms of memory/conformity – private and public conformity – they looked at the differeing recollection and retention of persistant memory.
In private conformity, an individuals recollection might be genuinely altered by social influence, resulting in long lasting, persistent memory errors. Even when social influence is removed, individuals will persist in claiming erroneous memory as a part of their own experience. Private conformity can be considered a bona fide memory change.
In public conformity, individuals may choose outwardly to comply, providing an account that fits that of others, inwardly however they maintain certitude in their own original memory. Memory errors in public conformity are transient and are dispelled with the subsidence of socially transferred information.
Of note is the researchers statement that “private and public memory conformity are often behaviorally indistinguishable, they reflect different cognitive processes” The researchers search for a physical course of mnemonic functions is profound to say the least. To put focus on this needle in a heystack hunt; the search deep within the medial temporal lobes via fMRI, for 2 distinct physical reactions to 2 behaviorally indistinguishable forms of memory is, well, simply mind bend bending.
As the researcherss note, while the influence of social pressure on memory is well known, with many instances of subjects who abandon true memories in favour of false ones, “the underlying neurobiology of this process is unknown.”
In the study, participants watched a documentary film in small groups. Three days later, they returned to the lab individually to take a memory test, answering questions about the film. They were also asked how confident they were in their answers.
They were later invited back to the lab to retake the test. This time, the subjects were also given supposed answers of the others in their film-viewing group (along with social-media-style photos) while being scanned in a functional MRI – fMRI – that revealed their brain activity.
Planted among these were false answers to questions the volunteers had previously answered correctly and confidently. The participants conformed to the group on these “planted” responses, giving incorrect answers nearly 70% of the time.
To determine if their memory of the film had actually undergone a change, the researchers invited the subjects back to the lab later to take the memory test once again, telling them that the answers they had previously been fed were not those of their fellow film watchers, but random computer generations.
Some of the responses reverted back to the original, correct ones, but get this: despite finding out the scientists messed with their minds, close to half of their responses remained erroneous, implying that the subjects were relying on false memories implanted in the earlier session.
An analysis of the fMRI data showed a strong co-activation and connectivity between two brain areas: the hippocampus and the amygdala. Social reinforcement could act on the amygdala to persuade our brains to replace a strong memory with a false one, the researchers suggest. the study showed that this active brain signature was present when private conformity was occurring, but not when public conformity prevailed.
“The amygdala plays a key role in social and emotional processing, modulating memory related hippocampal activity. It is strategically placed for this function, having rich anatomical connections with the hippocampal complex – the anterior hippocampus in particular – as well as with neocortical areas. The amygdala is thus a prime candidate for mediating social effects on memory, most likely involving its interactions with other brain regions.”
In their conclusion, the researchers caution: “Altering memory in response to group influence may produce untoward effects. For example, social influence such as false propaganda can deleteriously affect individuals’ memory in political campaigns and commercial advertising and impede justice by influencing eyewitness testimony.”
However, the researchers speculate that “memory conformity may also serve an adaptive purpose, because social learning is often more efficient and accurate than individual learning. For this reason, humans may be predisposed to trust the judgment of the group, even when it stands in opposition to their own original beliefs.”
source: Dr Tali Sharot: The Optimism Bias
source: current biology