1. When making decisions, monkeys use different brain areas to weigh value and availability

    September 16, 2017 by Ashley

    From the Cell Press press release:

    There are many calculations at play in our minds when we make a decision, whether we are aware of them or not. Seventeenth-century mathematician Blaise Pascal first introduced the idea of expected value, which is reached by multiplying the value of something (how much it’s wanted or needed) with the probability that we might be able to obtain it. Now some very 21st century research is showing for the first time in monkeys which parts of the brain are involved in the two-pronged decision-making process that determines this expected value. The study appears August 30 in Neuron.

    “For a long time we thought that representations of value and probability were being evaluated in the same, single part of the brain,” says Peter Rudebeck, an assistant professor of neuroscience and psychiatry at the Icahn School of Medicine at Mount Sinai and the lead author of the new study. “What’s exciting here is that we’re showing that it’s being done in two different parts of the brain, which are separate both functionally and anatomically.”

    The researchers focused on two areas of the brain, the orbital frontal cortex (OFC) and the ventrolateral prefrontal cortex (VLPFC). Studies of people who have had their OFCs damaged due to injury or disease have indicated that injuries to that region of the brain resulted in impaired decision-making abilities. “But when we tried to duplicate this effect experimentally in monkeys by creating lesions in their OFCs, we didn’t see the same result,” Rudebeck explains.

    Further examination revealed that the difference came from how much of the brain was damaged. “When surgeons remove a tumor from the OFC, they remove not only the gray matter, the cortex of the brain, but will also inadvertently affect the white matter, which carries the connections between different parts of the brain,” he says. “We knew the VLPFC sits right next to the OFC, so we decided to look at that as well.”

    Two sets of experiments were devised: the first looked at how the monkeys weighed probability when making decisions, and the second looked at how they weighed value.

    In the first set, monkeys played a sort of slot machine game, where they were shown images on a touch screen and had to determine which image was most likely to get them a reward — a banana-flavored pellet. The researchers periodically changed the probability, but the control monkeys were able to adjust their choices accordingly. Animals with OFC and VLPFC lesions were then given the same task: those with OFC lesions performed the same as the control animals, whereas the monkeys with VLPFC lesions lost the ability to track probability.

    In the second set of experiments, the monkeys had a choice of two rewards when they played a game — peanuts or M&Ms. These rewards were hidden under objects that the monkeys had previously learned predicted either of the two rewards. Because monkeys generally like peanuts and M&Ms equally, they turn over objects overlying peanuts and M&Ms at the same rate. But to shift the value toward one treat over the other, in favor of the peanuts, the monkeys were given M&Ms immediately before the experiment. Having already had their fill of M&Ms, the control monkeys favored the objects overlying peanuts, as expected. Those with VLPFC lesions had the same inclination. The monkeys with OFC lesions, however, showed a preference for the objects overlying M&Ms.

    “We’ve known for a long time that these two parts of the brain are highly interconnected,” Rudebeck says. “They both send connections to another area of the frontal lobe, the ventromedial prefrontal cortex (VMPFC). Imaging studies with fMRI suggested that the VMPFC may be where choices ultimately get made.”

    The investigators tested this in a separate set of experiments, where they induced lesions in that area. “The animals were able to make a decision based on probability or value alone, but when they had to combine the two, they were less able to do that,” Rudebeck concludes. “This lines up with what we’ve seen in humans, because we know that people who have brain damage in that area also have trouble with making decisions.”


  2. Chronic lack of sleep increases risk-seeking

    September 12, 2017 by Ashley

    From the University of Zürich press release:

    Young adults have a natural sleep requirement of about 9 hours a day on average, older adults 7.5 hours. Many people in western societies, however, get considerably less sleep. According to studies, about one-third of the persons surveyed in several industrial countries reported too little sleep. If a young adult sleeps less than 8 hours a night, increased attention deficits occur, which can lead to considerable negative consequences. In sleep clinics there is an increasing number of healthy people who are suffering from the negative consequences of insufficient sleep.

    Not enough sleep leads to riskier decision-making

    Researchers at the University of Zurich and the University Hospital Zurich have now identified a further critical consequence of a chronic lack of sleep: increased risk-seeking. The sleep and neuroeconomics scientists studied the risk behavior of 14 healthy male students aged from 18 to 28 years. If the students slept only 5 hours a night for a week, they displayed clearly riskier behavior in comparison with a normal sleep duration of about 8 hours. Twice a day, they had to choose between obtaining a specified amount of money paid out with a given probability or playing it safe with a lower amount of money paid out for sure. The riskier the decision, the higher the possible prize — but also the risk of getting nothing.

    Riskier behavior remains unnoticed

    While a single sleepless night had no effect on risk-seeking, 11 of 14 of the subjects behaved significantly and increasingly riskier as the week of a reduced sleep duration went on. An additional finding is particularly alarming: The students assess their risk-taking behavior to be the same as under regular sleep conditions. “We therefore do not notice ourselves that we are acting riskier when suffering from a lack of sleep,” emphasizes Christian Baumann, professor of neurology and the head of the Clinical Research Priority Programs (CRPP) “Sleep and Health” at UZH. According to the authors of the study, we should therefore all strive for a sufficient sleep duration — especially political and economic leaders who make wide-reaching decisions daily. “The good news is,” Baumann says, “that, in the high-powered world of managers, getting enough sleep is increasingly being seen as desirable.”

    Lack of recovery in important regions of the brain

    For the first time, the researchers have proven that a low depth of sleep in the right prefrontal cortex is directly connected with higher risk-seeking behavior. This part of the cerebral cortex has already been associated with risk-taking behavior in earlier studies. “We assume that behavioral changes occur for anatomical-functional reasons to some extent as a result of the right prefrontal cortex not being able to recover properly due to a chronic lack of sleep,” Baumann concludes.


  3. High moral reasoning associated with increased activity in the human brain’s reward system

    September 10, 2017 by Ashley

    From the University of Pennsylvania School of Medicine press release:

    Individuals who have a high level of moral reasoning show increased activity in the brain’s frontostriatal reward system, both during periods of rest and while performing a sequential risk taking and decision making task according to a new study from researchers at the Perelman School of Medicine, the Wharton School of the University of Pennsylvania, Shanghai International Studies University in Shanghai, China and Charité Universitätsmediz in Berlin, Germany. The findings from the study, published this month in Scientific Reports, may help researchers to understand how brain function differs in individuals at different stages of moral reasoning and why some individuals who reach a high level of moral reasoning are more likely to engage in certain “prosocial” behaviors — such as performing community service or giving to charity — based on more advanced principles and ethical rules.

    The study refers to Lawrence Kohlberg’s stages of moral development theory which proposes that individuals go through different stages of moral reasoning as their cognitive abilities mature. According to the researchers, Kohlberg’s theory implies that individuals at a lower level of moral reasoning are more prone to judge moral issues primarily based on personal interests or adherence to laws and rules, whereas individuals with higher levels of moral reasoning judge moral issues based on deeper principles and shared ideals.

    The researchers’ previous work found an association between high levels of moral reasoning and gray matter volume, establishing a critical link between moral reasoning and brain structure. This more recent study sought to discover whether a link exists between moral reasoning and brain function.

    In this study, the researchers aimed to investigate whether the development of morality is associated with measurable aspects of brain function. To answer this question, they tested moral reasoning in a large sample of more than 700 Wharton MBA students, and looked at the brain reward system activity in a subset of 64 students, both with and without doing a task. According to Hengyi Rao, PhD, a research assistant professor of Cognitive Neuroimaging in Neurology and Psychiatry in the Perelman School of Medicine and senior author of the study, the team observed considerable individual differences in moral development levels and brain function in this relatively homogeneous and well-educated MBA group of subjects.

    “It is well established in the literature that the brain reward system is involved in moral judgment, decision making, and prosocial behavior. However, it remains unknown whether brain reward system function can be affected by stages of moral development,” Rao said. “To our knowledge, this study is the first to demonstrate the modulation effect of moral reasoning level on human brain reward system activity. Findings from our study provide new insights into the potential neural basis and underlying psychological processing mechanism of individual differences in moral development. ”

    The finding of increased brain reward system activity in individuals at a high level of moral reasoning suggests the importance of positive motivations towards others in moral reasoning development, rather than selfish motives. These findings also support Kohlberg’s theory that higher levels of moral reasoning tend to be promotion and other-focused (do it because it is right) rather than prevention or self-focused (do not do it because it is wrong).

    “Our study documents brain function differences associated with higher and lower levels of moral reasoning. It is still unclear whether the observed brain function differences are the cause or the result of differential levels of moral reasoning,” explained Diana Robertson, PhD, a James T. Riady professor of Legal Studies and Business Ethics at the Wharton School and a co-author of the study. “However, we believe that both factors of nurture, such as education, parental socialization and life experience, and factors of nature, like biological or evolutionary basis, the innate capacities of the mind, and the genetic basis may contribute to individual differences in moral development.”

    The researchers say future studies could expand on this work by assessing to what extent individual differences in moral reasoning development depend on in-born differences or learned experience, and whether education can further promote moral reasoning stage in individuals even past the age at which structural and functional brain maturation is complete.


  4. People favor highly reviewed products, even when they shouldn’t

    September 4, 2017 by Ashley

    From the Association for Psychological Science press release:

    When we’re trying to decide which cell phone case to buy or which hotel room to book, we often rely on the ratings and reviews of others to help us choose. But new research suggests that we tend to use this information in ways that can actually work to our disadvantage.

    The findings, published in Psychological Science, a journal of the Association for Psychological Science, indicate that people tend to favor a product that has more reviews, even when it has the same low rating as an alternative product.

    “It’s extremely common for websites and apps to display the average score of a product along with the number of reviews. Our research suggests that, in some cases, people might take this information and make systematically bad decisions with it,” says researcher Derek Powell of Stanford University, lead author on the study.

    “We found that people were biased toward choosing to purchase more popular products and that this sometimes led them to make very poor decisions,” he explains.

    As opportunities to buy products and services online multiply, we have greater access than ever before to huge amounts of first-hand information about users’ experiences.

    “We wanted to examine how people use this wealth of information when they make decisions, and specifically how they weigh information about other people’s decisions with information about the outcomes of those decisions,” says Powell.

    Looking at actual products available on Amazon.com, Powell and colleagues Jingqi Yu (Indiana University Bloomington), Melissa DeWolf and Keith Holyoak (University of California, Los Angeles) found no relationship between the number of reviews a product had and its average rating. In other words, real-world data show that a large number of reviews is not a reliable indicator of a product’s quality.

    With this in mind, the researchers wanted to see how people would actually use review and rating information when choosing a product. In one online experiment, 132 adult participants looked at a series of phone cases, presented in pairs. The participants saw an average user rating and total number of reviews for each phone case and indicated which case in each pair they would buy.

    Across various combinations of average rating and number of reviews, participants routinely chose the option with more reviews. This bias was so strong that they often favored the more-reviewed phone case even when both of the options had low ratings, effectively choosing the product that was, in statistical terms, more likely to be low quality.

    A second online experiment that followed the same design and procedure produced similar results.

    “By examining a large dataset of reviews from Amazon.com, we were able to build a statistical model of how people should choose products. We found that, faced with a choice between two low-scoring products, one with many reviews and one with few, the statistics say we should actually go for the product with few reviews, since there’s more of a chance it’s not really so bad,” Powell explains. “But participants in our studies did just the opposite: They went for the more popular product, despite the fact that they should’ve been even more certain it was of low quality.”

    The researchers found that this pattern of results fit closely with a statistical model based on social inference. That is, people seem to use the number of reviews as shorthand for a product’s popularity, independent of the product’s average rating.

    According to Powell, these findings have direct implications for both retailers and consumers:

    “Consumers try to use information about other people’s experiences to make good choices, and retailers have an incentive to steer consumers toward products they will be satisfied with,” he says. “Our data suggest that retailers might need to rethink how reviews are presented and consumers might need to do more to educate themselves about how to use reviews to guide their choices.”


  5. Do video game players make the best unmanned pilots?

    September 3, 2017 by Ashley

    From the University of Liverpool press release:

    New research from the University of Liverpool highlights the usefulness of Video Game Players (VGPs) as unmanned aircraft operators.

    The move to significant automation has been a feature of aviation over the last 40 years. Unmanned Aerial Systems (UAS) operations, commonly known as a aircraft which are unmanned, have outpaced current training regimes resulting in a shortage of qualified UAS pilots.

    In an effort to address this problem researchers from the University’s Institute of Psychology, Health and Society, led by Dr Jacqueline Wheatcroft, and the Department of Mechanical, Materials and Aerospace Engineering (Dr Mike Jump), explored the suitability of three potential UAS groups; VGPs, private pilots and professional pilots.

    The participants, 60 in total, all took part in a simulated civilian cargo flight to enable the researchers to assess their levels of accuracy, confidence and confidence-accuracy judgements (W-S C-A).

    The participants made 21 decision tasks, which varied across three levels of danger/ risk.

    As danger increased levels of confidence, accuracy and the relationship between how accurate the decision was and the level of confidence applied to those decisions decreased.

    The dangerousness of the decision also affected how confident participants were when choosing to intervene or rely on the automation; confidence was lower when the operator chose to intervene.

    Professional pilots and VGPs exhibited the highest level of decision confidence, with VGPs maintaining a constant and positive W-S C-A relationship across decision danger/risk.

    All groups showed higher levels of decision confidence in decisions controlled by the UAS in comparison to decisions where the operator manually intervened.

    Dr Jacqueline Wheatcroft, said: “Understanding which potential supervisory group has the best skills to make the best decisions can help to improve UAS supervision. Overall, video game players were less overconfident in their decision judgements.

    “The outcome supports the idea that this group could be a useful resource in UAS operation.”


  6. Study looks at what goes on when a relationship is being questioned

    September 2, 2017 by Ashley

    From the University of Utah press release:

    Knowing whether to stay in or leave a romantic relationship is often an agonizing experience and that ambivalence can have negative consequences for health and well-being.

    Now a new study offers insights into what people are deliberating about and what makes the decision so difficult, which could help therapists working with couples and stimulate further research into the decision-making process.

    The study, led by U psychology professor Samantha Joel, was published in Social Psychology and Personality Science. Co-authors were Geoff MacDonald and Elizabeth Page-Gould of the University of Toronto.

    “Most of the research on breakups has been predictive, trying to predict whether a couple stays together or not, but we don’t know much about the decision process — what are the specific relationship pros and cons that people are weighing out,” Joel said.

    In the first phase of the study, the researchers recruited three samples of people — including people who were in the midst of trying to decide whether to break up or not — to participate in an anonymous survey.

    Participants were asked open-ended questions about their specific reasons for both wanting to stay and leave a relationship.

    That yielded a list of 27 different reasons for wanting to stay in a relationship and 23 reasons for wanting to leave.

    The stay/leave factors were then converted into a questionnaire that was given to another group of people who were trying to decide whether to end a dating relationship or marriage. Those dating had been together for two years on average, while married participants reported relationships that averaged nine years.

    In both studies, general factors considered as the individuals deliberated what to do were similar.

    At the top of the stay list: emotional intimacy, investment and a sense of obligation. At the top of the leave list: issues with a partner’s personality, breach of trust and partner withdrawal.

    Individuals in both dating and married situations gave similar reasons for wanting to leave a relationship.

    But the researchers found significant differences in stay reasoning between the two groups.

    Participants who were in a dating relationship said they were considering staying based on more positive reasons such as aspects of their partner’s personality that they like, emotional intimacy and enjoyment of the relationship. Those who were married gave more constraint reasons for staying such as investment into the relationship, family responsibilities, fear of uncertainty and logistical barriers.

    And about half of the participants said they had reasons to both stay and leave, indicating ambivalence about their relationships.

    “What was most interesting to me was how ambivalent people felt about their relationships. They felt really torn,” Joel said. “Breaking up can be a really difficult decision. You can look at a relationship from outside and say ‘you have some really unsolvable problems, you should break up’ but from the inside that is a really difficult thing to do and the longer you’ve been in a relationship, the harder it seems to be.”

    Most people, Joel said, have standards and deal breakers about the kind of person they want to date or marry but those often go out the window when they meet someone.

    “Humans fall in love for a reason,” Joel said. “From an evolutionary perspective, for our ancestors finding a partner may have been more important than finding the right partner. It might be easier to get into relationships than to get back out of them.”


  7. Communicating in a foreign language takes emotion out of decision-making

    September 1, 2017 by Ashley

    From the University of Chicago press release:

    If you could save the lives of five people by pushing another bystander in front of a train to his death, would you do it? And should it make any difference if that choice is presented in a language you speak, but isn’t your native tongue?

    Psychologists at the University of Chicago found in past research that people facing such a dilemma while communicating in a foreign language are far more willing to sacrifice the bystander than those using their native tongue. In a paper published Aug. 14 in Psychological Science, the UChicago researchers take a major step toward understanding why that happens.

    “Until now, we and others have described how using a foreign language affects the way that we think,” said Boaz Keysar, the UChicago psychology professor in whose lab the research was conducted. “We always had explanations, but they were not tested directly. This is really the first paper that explains why, with evidence.”

    Through a series of experiments, Keysar and his colleagues explore whether the decision people make in the train dilemma is due to a reduction in the emotional aversion to breaking an ingrained taboo, an increase in deliberation thought to be associated with a utilitarian sense of maximizing the greater good or some combination of the two.

    “We discovered that people using a foreign language were not any more concerned with maximizing the greater good,” said lead author Sayuri Hayakawa, a UChicago doctoral student in psychology. “But rather, were less averse to violating the taboos that can interfere with making utility-maximizing choices.”

    The researchers, including Albert Costa and Joanna Corey from Pompeu Fabra University in Barcelona, propose that using a foreign language gives people some emotional distance and that allowed them to take the more utilitarian action.

    “I thought it was very surprising,” Keysar said. “My prediction was that we’d find that the difference is in how much they care about the common good. But it’s not that at all.”

    Studies from around the world suggest that using a foreign language makes people more utilitarian. Speaking a foreign language slows you down and requires that you concentrate to understand. Scientists have hypothesized that the result is a more deliberative frame of mind that makes the utilitarian benefit of saving five lives outweigh the aversion to pushing a man to his death.

    But Keysar’s own experience speaking a foreign language — English — gave him the sense that emotion was important. English just didn’t have the visceral resonance for him as his native Hebrew. It wasn’t as intimately connected to emotion, a feeling shared by many bilingual people and corroborated by numerous lab studies.

    “Your native language is acquired from your family, from your friends, from television,” Hayakawa said. “It becomes infused with all these emotions.”

    Foreign languages are often learned later in life in classrooms, and may not activate feelings, including aversive feelings, as strongly.

    The problem is that either the “more utilitarian” or the “less emotional” process would produce the same behavior. To help figure out which was actually responsible, the psychologists worked with David Tannenbaum, a postdoctoral research fellow at the University of Chicago Booth School of Business at the time of the research and now an assistant professor at the University of Utah.

    Tannenbaum is an expert at a technique called process dissociation, which allows researchers to tease out and measure the relative importance of different factors in a decision process. For the paper, the researchers did six separate studies with six different groups, including native speakers of English, German and Spanish. Each also spoke one of the other languages, so that all possible combinations were equally represented. Each person was randomly assigned to use either his or her native language or second language throughout the experiment.

    Participants read an array of paired scenarios that varied systematically in key ways. For example, instead of killing a man to save five people from death, they might be asked if they would kill him to save five people from minor injuries. The taboo act of killing the man is the same, but the consequences vary.

    “If you have enough of these paired scenarios, you can start gauging what are the factors that people are paying attention to,” Hayakawa said. “We found that people using a foreign language were not paying any more attention to the lives saved, but definitely were less averse to breaking these kinds of rules. So if you ask the classic question, ‘Is it the head or the heart?’ It seems that the foreign language gets to the heart.”

    The researchers are next looking at why that is. Does using a foreign language blunt people’s mental visualization of the consequences of their actions, contributing to their increased willingness to make the sacrifice? And do they create less mental imagery because of differences in how foreign language use affects which memories come to mind?

    The researchers are also starting to investigate whether their lab results apply in real-world situations where the stakes are high. A study Keysar’s team is initiating in Israel looks at whether the parties in a peace negotiation assess the same proposal differently if they see it in their own language or the language of their negotiating partner. And Keysar is interested in looking at whether language can be usefully considered in decisions made by doctors speaking a foreign language.

    “You might be able to predict differences in medical decision-making depending on the language that you use,” he said. “In some cases you might prefer a stronger emotional engagement, in some you might not.”


  8. Well-designed visual aids improve risk understanding

    August 17, 2017 by Ashley

    From the University of Oklahoma press release:

    A University of Oklahoma professor, Edward T. Cokely, shows that informed decision making depends on the ability to accurately evaluate and understand information about risk in a newly published study in the scientific journal Human Factors. A state-of-the-science review of the literature concludes that visual aids are beneficial for diverse people with different levels of numeracy and graph literacy. Cokely identifies five categories of practical, evidence-based guidelines for the evaluation and design of visual aids.

    “It is striking to see how effective visual aids can be for diverse people facing complex, life-changing decisions, including physicians, patients and their families,” Cokely said.

    Cokely, Presidential Research Professor and associate professor of psychology, in the OU Department of Psychology and National Institute of Risk and Resilience, collaborated with Rocio Garcia-Retamero, University of Granada in Spain, on the review of “how to” build visual aids that promote understanding and good decision making. Data for the study covered research from January 1995 to April 2016, and 36 publications provided data on 27,885 diverse participants from 60 different countries, concluding that well-designed visual aids tend to be highly effective tools for improving informed decision making among diverse decision makers.

    Cokely and Garcia-Retamero reviewed literature concentrated in health and medical decision making that included findings on the link between skills and quality outcomes. Next, the researchers presented findings on the psychological, social and technological factors which shape the influence of numeracy on risk literacy, decision making and health outcomes. Lastly, they presented a review of research investigating the influence of skills on the benefits of visual aids.

    Visual aids are graphical representations of numerical expressions of probability and include icon arrays, bar and line charts and others and have been used to communicate risk information. However, not all visual aids are equally effective. Visual aids provide an efficient means of risk communication when they are transparent — that is, when they promote unbiased risk understanding and evaluation. This means the visual aid is well defined and accurately and clearly represents the essential risk information. Researchers then focused on individual differences in two relevant skills: numeracy and graph literacy. Numeracy, the ability to use mathematical skills to solve everyday problems, including statistical numeracy, has been found to be one of the strongest single predictors of general decision-making skill and risk literacy. Graph literacy is the ability to evaluate and extract data and meaning from graphical representations of numerical information — another essential component of risk literacy.

    A review of static visual aids to improve risk literacy and promote healthy behavior focused on studies involving people with different levels of numeracy that included a control condition, which compared visual aids with numerical information in written text. Eighty-eight percent of the studies showed static visual aids tend to be beneficial. Static visual aids were helpful for people with low numeracy as long as they had moderate-to-high graph literacy.

    One theme that emerged across some studies is that, on average, “less is more.” Very simple icon arrays including clear explanations to convey the meaning of information can improve understanding. People with different levels of numeracy and graph literacy like, trust and prefer simple icon arrays. These icon arrays offer an efficient means of reaching individuals with different levels of numeracy and graphic literacy. A simple training in the use of icon arrays maximizes potential benefits and reaches vulnerable groups of people with limited graph literacy.

    Visual aids improve accuracy of risk understanding in part because they increase the likelihood that people deliberate more about the relevant risks and trade-offs. Because visual aids cause relatively robust changes in risk understanding by shaping and fine-tuning knowledge representation in long-term memory, visual aids also tend to give rise to more enduring changes in attitudes and behavioral intentions, which can directly affect decision making and healthy behavior. Based on all relevant, available scientific data from the last 20 years, findings indicate that icon arrays tend to be the best “all purpose” type of visual aids.


  9. In witnessing the brain’s ‘aha!’ moment, scientists shed light on biology of consciousness

    August 10, 2017 by Ashley

    From the Zuckerman Institute at Columbia University press release:

    Columbia scientists have identified the brain’s ‘aha!’ moment — that flash in time when you suddenly become aware of information, such as knowing the answer to a difficult question. Today’s findings in humans, combined with previous research, provide compelling evidence that this moment — this feeling of having decided — pierces consciousness when information being collected by the brain reaches a critical level. The results of this study further suggest that this piercing of consciousness shares the same underlying brain mechanisms known to be involved in making far simpler decisions. Importantly, this study offers new hope that the biological foundations of consciousness may well be within our grasp.

    This research was reported in Current Biology.

    “The vast majority of thoughts circling in our brains happen below the radar of conscious awareness, meaning that even though our brain is processing them, we are not aware,” said Michael Shadlen, MD, PhD, a Principal Investigator at Columbia’s Mortimer B. Zuckerman Mind Brain Behavior Institute and the paper’s senior author. “How some of that information bubbles to the level of consciousness, however, remains an unsolved mystery. But now, we’ve found a way to observe that moment in real time, and then apply those findings to our understanding of consciousness itself.”

    For Dr. Shadlen, the most complex thoughts that the human brain can experience — such as love, grief, guilt or morality — can be ultimately be boiled down to a series of decisions, made by the brain, to engage with the outside world. He has spent his career working to understand how signals sent by the brain’s billions of cells result in such decisions. In so doing, he hopes to unravel the mechanisms that underlie the brain’s most complex abilities.

    In 2008, Dr. Shadlen and colleagues found that when asked to make a challenging decision, the brain does not use all the available information before deciding. This is not because the brain is unable to do so, but rather because at a certain point, the brain thinks it has all the information it needs. There is a mechanism in the brain that says “enough is enough.”

    “For us, this then begged a question,” recalled Dr. Shadlen, who is also a professor of neuroscience at Columbia University Medical Center and an investigator at the Howard Hughes Medical Institute. “Could the moment when the brain believes it has accumulated enough evidence be tied to the person’s awareness of having decided — that important ‘aha!’ moment?”

    To find out, the researchers asked five human participants to watch dots on a computer screen that moved like grains of sand blowing in the wind. The participants were then asked whether the dots seemed to be blowing to the right or to the left.

    Placed in the center of the screen was a clock. Once the dots’ motion ended and after a brief delay, participants chose which direction the dots had traveled. Using a controversial technique known as mental chronometry, the participants were asked to move the clock handle backwards to the time they felt they had become aware that they knew the answer. The participants repeated this action over many trials and levels of difficulty.

    “The moment in time indicated by the participants — this mental chronometry — was entirely subjective; it relied solely on their own estimation of how long it took them to make that decision,” said Dr. Shadlen. “And because it was purely subjective, in principle it ought to be unverifiable.”

    But by incorporating this new data with decades of previous research on the brain mechanisms of decision making, the team devised a clever way to verify whether the time reported by the participants was an accurate reflection of having actually decided.

    “If the time reported to us by the participants was valid, we reasoned that it might be possible to predict the accuracy of the decision,” Dr. Shadlen explained. “We incorporated a kind of mathematical trick, based on earlier studies, which showed that the speed and accuracy of decisions was tied together by the same brain function.”

    Previous research by Dr. Shadlen and others had uncovered how the process of making a decision plays out at the level of individual cells in the brain. By combining this knowledge with the mathematical trick, the team could scientifically validate that the participants’ subjective reporting — their feeling of having decided — was indeed an accurate reflection of the brain’s decision-making process.

    “Essentially, the act of becoming consciously aware of a decision conforms to the same process that the brain goes through to complete a decision, even a simple one — such as whether to turn left or right,” said Dr. Shadlen.

    While preliminary, this study raises the possibility that a deep understanding the human brain’s most complex thoughts and feelings, once solely under the purview of philosophy, may soon be understood in terms of biology as well.

    “Some people think that the nitty gritty of neuroscience is far from the highfalutin stuff that a philosopher would consider,” said Dr. Shadlen. “But rest assured, explaining these concepts — whether it’s ethics, consciousness anything else — in terms of neuroscience isn’t explaining them away. Instead, I would argue that it is helping to bring the biological study of the brain closer to the philosophical study of the mind.”


  10. How do people decide: Should I go, stay, drink?

    by Ashley

    From the Research Society on Alcoholism press release:

    Many studies of alcohol use disorders (AUDs) use tasks that involve monetary rewards or losses to examine individual decision-making vis-à-vis alcohol and other substance use. Yet drinking typically occurs in specific social and incentive contexts that do not involve economic decision-making. This study examined decisions about attending, and drinking in, hypothetical drinking/social contexts wherein several different incentive and disincentive options were provided to the individual.

    Researchers used community advertisements to recruit 434 adults (240 men, 194 women), between 18 and 30 years of age, who varied widely in lifetime alcohol use as well as antisocial problems. Using a computer screen, all participants were presented with six different hypothetical scenarios of drinking at a party; incentives involved party-time fun activities and disincentives involved next-day responsibilities.

    Antisocial symptoms were associated with a reduced sensitivity to potentially negative consequences of drinking, while alcohol problems were associated with a greater sensitivity to the rewarding aspects of partying. Next-day responsibility disincentives had substantial effects on discouraging decisions about attendance, even for those with many alcohol problems. The authors contend that there is value in directly assessing drinking-related decisions in different hypothetical contexts, and in assessing decisions about attendance at risky drinking events and drinking-amount decisions while there.