Friday, November 16, 2018

Self driving cars will have to decide who should live and who should die.

Johnson points to a collaboration by Awad et al. that explored the moral dilemmas faced by autonomous vehicles. They designed an experimental platform (The Moral Machine Website) that gathered 40 million decisions in ten languages from millions of people in 233 countries and territories. A few clips from Johnson's summary:
The study...identified a few preferences that were strongest: People opt to save people over pets, to spare the many over the few and to save children and pregnant women over older people. But it also found other preferences for sparing women over men, athletes over obese people and higher status people, such as executives, instead of homeless people or criminals. There were also cultural differences in the degree, for example, that people would prefer to save younger people over the elderly in a cluster of mostly Asian countries.
Outside researchers said the results were interesting, but cautioned that the results could be overinterpreted. In a randomized survey, researchers try to ensure that a sample is unbiased and representative of the overall population, but in this case the voluntary study was taken by a population that was predominantly younger men. The scenarios are also distilled, extreme and far more black-and-white than the ones that are abundant in the real world, where probabilities and uncertainty are the norm.
“The big worry that I have is that people reading this are going to think that this study is telling us how to implement a decision process for a self-driving car,” said Benjamin Kuipers, a computer scientist at University of Michigan, who was not involved in the work.
“Building these cars, the process is not really about saying, ‘If I’m faced with this dilemma, who am I going to kill.’ It’s saying, 'If we can imagine a situation where this dilemma could occur, what prior decision should I have made to avoid this?” Kuipers said.
And here is a TEDxCambridge talk by Iyad Rahwan "The Social Dilemma Of Driverless Cars"

Thursday, November 15, 2018

Biomarkers of inflamation are lower in people with more positive emotions

Fron Ong et al.:
There is growing evidence that inflammatory responses may help to explain how emotions get “under the skin” to influence disease susceptibility. Moving beyond examination of individuals’ average level of emotion, this study examined how the breadth and relative abundance of emotions that individuals experience — emodiversity — is related to systemic inflammation. Using diary data from 175 adults aged 40 to 65 who provided end-of-day reports of their positive and negative emotions over 30 days, we found that greater diversity in day-to-day positive emotions was associated with lower circulating levels of inflammation (indicated by IL-6, CRP, fibrinogen), independent of mean levels of positive and negative emotions, body mass index, anti-inflammatory medications, medical conditions, personality, and demographics. No significant associations were observed between global or negative emodiversity and inflammation. These findings highlight the unique role daily positive emotions play in biological health. (PsycINFO Database Record (c) 2018 APA, all rights reserved)

Wednesday, November 14, 2018

New longevity vitamins?

Well known senior biochemist Bruce Ames (b. 1928) suggests an array of compounds should be added to the list of essential vitamins that maintain health and enhance longevity:
It is proposed that proteins/enzymes be classified into two classes according to their essentiality for immediate survival/reproduction and their function in long-term health: that is, survival proteins versus longevity proteins. As proposed by the triage theory, a modest deficiency of one of the nutrients/cofactors triggers a built-in rationing mechanism that favors the proteins needed for immediate survival and reproduction (survival proteins) while sacrificing those needed to protect against future damage (longevity proteins). Impairment of the function of longevity proteins results in an insidious acceleration of the risk of diseases associated with aging. I also propose that nutrients required for the function of longevity proteins constitute a class of vitamins that are here named “longevity vitamins.” I suggest that many such nutrients play a dual role for both survival and longevity. The evidence for classifying taurine as a conditional vitamin, and the following 10 compounds as putative longevity vitamins, is reviewed: the fungal antioxidant ergothioneine; the bacterial metabolites pyrroloquinoline quinone (PQQ) and queuine; and the plant antioxidant carotenoids lutein, zeaxanthin, lycopene, α- and β-carotene, β-cryptoxanthin, and the marine carotenoid astaxanthin. Because nutrient deficiencies are highly prevalent in the United States (and elsewhere), appropriate supplementation and/or an improved diet could reduce much of the consequent risk of chronic disease and premature aging.
By the way, Ames is a co-founder of Juvenon, a company that markets anti-aging supplements.

Tuesday, November 13, 2018

Are we getting too hysterical about the dangers of artificial intelligence?

It is certainly true that A.I. might take away the current jobs of people like lawyers and radiologists who scan data looking for patterns, or those who are now doing tasks that can be accomplished by defined algorithms. A series of articles, such as those by and about Yuval Harari, predict that most of us will become a human herd manipulated by digital overlords that know more about us than we know about ourselves.  These have to be taken very seriously. (See, for example "Watch Out Workers, Algorithms Are Coming to Replace You — Maybe,"Tech C.E.O.s Are in Love With Their Principal Doomsayer," and "Why Technology Favors Tyranny")

However, there are arguments that one fear - that machines having a general flexible human like intelligence really similar or even superior to our own will render common humans obsolete - is not yet even remotely realistic. The current deep learning algorithms sifting deep data for patterns and connections work at the level of our unconscious cognition, and don't engage context, ambiguity, and alternative scenarios in the way that our cognitive apparatus can. One can find some solace in how easy it is to fool A.I. sophistical pattern recognition systems (see "Hackers easily fool artificial intelligence") and how hapless A.I. systems are in dealing with the actual meaning of what they are doing, or why they are doing it (See "Artificial Intelligence Hits the Barrier of Meaning". Intelligence is a measure of ability to achieve a particular aim, to deploy novel means to attain a goal, whatever it happens to be, the goals are extraneous to the intelligence itself. Being smart is not the same as wanting something. Any level of intelligence — including superintelligence — can be combined with just about any set of final goals — including goals that strike us as stupid.

One clip from the last link noted above, a choice quote from A.I. researcher Pedro Domingos:
People worry that computers will get too smart and take over the world, but the real problem is that they’re too stupid and they’ve already taken over the world.

Monday, November 12, 2018

Even a 10 minute walk can boost your brain

From Suwabe et al.:

Our previous work has shown that mild physical exercise can promote better memory in rodents. Here, we use functional MRI in healthy young adults to assess the immediate impact of a short bout of mild exercise on the brain mechanisms supporting memory processes. We find that this brief intervention rapidly enhanced highly detailed memory processing and resulted in elevated activity in the hippocampus and the surrounding regions, as well as increased coupling between the hippocampus and cortical regions previously known to support detailed memory processing. These findings represent a mechanism by which mild exercise, on par with yoga and tai chi, may improve memory. Future studies should test the long-term effects of regular mild exercise on age-related memory loss.
Physical exercise has beneficial effects on neurocognitive function, including hippocampus-dependent episodic memory. Exercise intensity level can be assessed according to whether it induces a stress response; the most effective exercise for improving hippocampal function remains unclear. Our prior work using a special treadmill running model in animals has shown that stress-free mild exercise increases hippocampal neuronal activity and promotes adult neurogenesis in the dentate gyrus (DG) of the hippocampus, improving spatial memory performance. However, the rapid modification, from mild exercise, on hippocampal memory function and the exact mechanisms for these changes, in particular the impact on pattern separation acting in the DG and CA3 regions, are yet to be elucidated. To this end, we adopted an acute-exercise design in humans, coupled with high-resolution functional MRI techniques, capable of resolving hippocampal subfields. A single 10-min bout of very light-intensity exercise (30%V˙O2peak) results in rapid enhancement in pattern separation and an increase in functional connectivity between hippocampal DG/CA3 and cortical regions (i.e., parahippocampal, angular, and fusiform gyri). Importantly, the magnitude of the enhanced functional connectivity predicted the extent of memory improvement at an individual subject level. These results suggest that brief, very light exercise rapidly enhances hippocampal memory function, possibly by increasing DG/CA3−neocortical functional connectivity.

Friday, November 09, 2018

Facebook language predicts depression in medical records.

Eichstaedt et al., suggest that analysis of language used by consenting individuals in their social media accounts could provide a depression assessment that complements existing screening and monitoring procedures:
Depression, the most prevalent mental illness, is underdiagnosed and undertreated, highlighting the need to extend the scope of current screening methods. Here, we use language from Facebook posts of consenting individuals to predict depression recorded in electronic medical records. We accessed the history of Facebook statuses posted by 683 patients visiting a large urban academic emergency department, 114 of whom had a diagnosis of depression in their medical records. Using only the language preceding their first documentation of a diagnosis of depression, we could identify depressed patients with fair accuracy [area under the curve (AUC) = 0.69], approximately matching the accuracy of screening surveys benchmarked against medical records. Restricting Facebook data to only the 6 months immediately preceding the first documented diagnosis of depression yielded a higher prediction accuracy (AUC = 0.72) for those users who had sufficient Facebook data. Significant prediction of future depression status was possible as far as 3 months before its first documentation. We found that language predictors of depression include emotional (sadness), interpersonal (loneliness, hostility), and cognitive (preoccupation with the self, rumination) processes. Unobtrusive depression assessment through social media of consenting individuals may become feasible as a scalable complement to existing screening and monitoring procedures.

Thursday, November 08, 2018

Advancing front of old-age human survival

Zuo et al. examine the probabilities of death at ages past 65 years for males and females in developed countries; that is, they consider individuals in each year who are alive at age 65 y and thereafter experience death rates for that year. They conclude that an advancing old-age front characterizes old-age human survival in 20 developed countries. The long-term speed of the advancing front is ≃0.12 y per calendar year, about 3 y per human generation. Thus, the front implies that, e.g., age 68 y today is equivalent, in terms of mortality, to age 65 y a generation ago. Their finding of a shifting front in the percentiles of death at old age is consistent with some patterns of shifts in old-age mortality hazards.
Old-age mortality decline has driven recent increases in lifespans, but there is no agreement about trends in the age pattern of old-age deaths. Some argue that old-age deaths should become compressed at advanced ages, others argue that old-age deaths should become more dispersed with age, and yet others argue that old-age deaths are consistent with little change in dispersion. However, direct analysis of old-age deaths presents unusual challenges: Death rates at the oldest ages are always noisy, published life tables must assume an asymptotic age pattern of deaths, and the definition of “old-age” changes as lives lengthen. Here we use robust percentile-based methods to overcome some of these challenges and show, for five decades in 20 developed countries, that old-age survival follows an advancing front, like a traveling wave. The front lies between the 25th and 90th percentiles of old-age deaths, advancing with nearly constant long-term shape but annual fluctuations in speed. The existence of this front leads to several predictions that we verify, e.g., that advances in life expectancy at age 65 y are highly correlated with the advance of the 25th percentile, but not with distances between higher percentiles. Our unexpected result has implications for biological hypotheses about human aging and for future mortality change.

Wednesday, November 07, 2018

The human herd and its digital overlords.

We've been seeing articles about the downside of young children and teenagers using digital social platforms, and the family conflicts resulting from trying to restrict smartphone use among teenagers. Several recent NYTimes articles note striking class differences in screen use between rich and less affluent households - the rich are reducing screen use in their home and private schools, while public schools are promoting digital tablet use. The Silicon Valley technologists who know know how smart phones really work don't want their own children anywhere near them.

For a chilling vision of our future if we continue the current trajectory I recommend the article by Yuval Harari in the August issue of the Atlantic. He suggests that most humans run the risk of becoming similar to domesticated animals, with only a small elite training their children to maintain the expertise and competence required to run the whole show. From his concluding paragraphs:
...if we want to prevent the concentration of all wealth and power in the hands of a small elite, we must regulate the ownership of data...Unfortunately, we don’t have much experience in regulating the ownership of data, which is inherently a far more difficult task than regulating land or machines...The race to accumulate data is already on, and is currently headed by giants such as Google and Facebook and, in China, Baidu and Tencent. So far, many of these companies have acted as “attention merchants”—they capture our attention by providing us with free information, services, and entertainment, and then they resell our attention to advertisers. Yet their true business isn’t merely selling ads. Rather, by capturing our attention they manage to accumulate immense amounts of data about us, which are worth more than any advertising revenue. We aren’t their customers—we are their product.
Ordinary people will find it very difficult to resist this process. At present, many of us are happy to give away our most valuable asset—our personal data—in exchange for free email services and funny cat videos. But if, later on, ordinary people decide to try to block the flow of data, they are likely to have trouble doing so, especially as they may have come to rely on the network to help them make decisions, and even for their health and physical survival.
Nationalization of data by governments could offer one solution; it would certainly curb the power of big corporations. But history suggests that we are not necessarily better off in the hands of overmighty governments. So we had better call upon our scientists, our philosophers, our lawyers, and even our poets to turn their attention to this big question: How do you regulate the ownership of data?
Currently, humans risk becoming similar to domesticated animals. We have bred docile cows that produce enormous amounts of milk but are otherwise far inferior to their wild ancestors. They are less agile, less curious, and less resourceful. We are now creating tame humans who produce enormous amounts of data and function as efficient chips in a huge data-processing mechanism, but they hardly maximize their human potential. If we are not careful, we will end up with downgraded humans misusing upgraded computers to wreak havoc on themselves and on the world.
If you find these prospects alarming—if you dislike the idea of living in a digital dictatorship or some similarly degraded form of society—then the most important contribution you can make is to find ways to prevent too much data from being concentrated in too few hands, and also find ways to keep distributed data processing more efficient than centralized data processing. These will not be easy tasks. But achieving them may be the best safeguard of democracy.

Tuesday, November 06, 2018

Might tribal conflict fatigue lead to a contagion of civility and kindness ?

A majority of both republicans and democrats express dismay over the current state of our civil discourse. Continuously stoked arousal of our brains' fear and anger systems is debilitating - a public health crisis. One wonders (hopes) whether that at some point the pendulum will slowly start to swing the other way, with people starting to perceive that the other tribes do not actually present an existential threat, and that starting to feel more civility and kindness toward "the other" can provide a major relief for stress. In this vein, I want to point to several articles on means of enhancing kindness. Schiffman asks "Can Kindness Be Taught?" and points to the Kindness Curriculum developed for preschoolers by the Center for Healthy Minds at the University of Wisconsin, as well to other programs. Zaki describes work on Kindness Contagion showing that witnessing kindness inspires kindness, causing it to spread like a virus. Petrow's article on kindness contagion discusses Zaki's work, as well as that of others, and Bornstein writes on "Recovering the (Lost) Art of Civility."

Monday, November 05, 2018

Core mechanisms undermining liberal democracy.

Because of the overwhelming number of (slightly hysterical) articles appearing on how our society is coming unhinged, I have become reluctant to do posts on the almost perfect storm that is spinning our political order, as well as that of other liberal democracies, out of control. Still, I want to point to two articles that make very central core points.

A liberal democracy requires that it’s diverse groups be able to tolerate each other. In “The Neuroscience of Hate Speech” psychiatrist Richard Friedman describes how Trump’s hate and fear-mongering targeted at non-white males can goad deranged people to action. Stoking anger and fear turns on stress hormones like cortisol and norepinephrine, and engages the amygdala, the brain center for threat. Feeling defensive and threatened facilitates violence towards, and dehumanization of, those supposedly presenting the threat. “So when someone like President Trump dehumanizes his adversaries, he could be putting them beyond the reach of empathy, stripping them of moral protection and making it easier to harm them..”

Max Fisher notes a common theme among the liberal democracies trending towards authoritarian populism (Hungary, Brazil, and now Germany) even though popular backlash is against different issues (corruption and crime in Brazil, immigration and European union problems in Hungary and Germany).
Maybe Brazil’s election, along with the rest of the populist trend, represents something more disruptive than a single wave with a single point of origin. Research suggests it exemplifies weaknesses and tensions inherent to liberal democracy itself — and that, in times of stress, can pull it apart…When institutions fall short…voters can grow skeptical of the entire idea of accruing power to bureaucrats and elites…the trouble often starts when members of a particular social group believe their group is declining in status relative to others. 
When that happens, voters tend to reject that system in all but name and follow their most basic human instincts toward older styles of government: majoritarian, strong-fisted, us-versus-them rule.
Human beings are tribal by nature. Our instincts are to put our group first and see ourselves as locked in competition with other groups. Liberal democracy, which promises that everyone gains when rights are protected for all, asks us to suppress those impulses.
But this is no easy ask. And tribal instincts tend to come to the fore in times of scarcity or insecurity, when our capacity for lofty ideals and long-term planning is weakest.

Friday, November 02, 2018

A review of body effects of mindfulness meditation

I point to a review by Jill Suttie, "Five Ways Mindfulness Meditation Is Good for Your Health." because it has a number of useful links to research articles - with the usual cautions about 'preliminary" data and inadequate controls - suggesting beneficial effects of mindfulness meditation on heart function, immune responses, cell aging, psychological pain, and decreasing cognitive decline from aging or Alzheimer's.

Thursday, November 01, 2018

Are you holding your breath?

As I was doing some homework on techniques of coping with stress, I came across an old MindBlog post which I pass on again, below. It was part of what motivated me to do the web/lecture "Are you holding your breath? - Structures of arousal and calm" Here is the repost:

I notice - if I am maintaining awareness of my breathing - that the breathing frequently stops as I begin a skilled activity such as piano or computer keyboarding. At the same time I can begin to sense an array of unnecessary (and debilitating) pre-tensions in the muscle involved. If I just keep breathing and noticing those tensions, they begin to release. (Continuing to let awareness return to breathing when it drifts is a core technique of mindfulness meditation). Several sources note that attending to breathing can raise one's general level of restfulness relative to excitation, enhancing parasympathetic (restorative) over sympathetic (arousing) nervous system activities. These personal points make me feel like passing on some excerpts from a recent essay which basically agrees with these points: "Breathtaking New Technologies," by Linda Stone, a former Microsoft VP and Co-Founder and Director of Microsoft's Virtual Worlds Group/Social Computing Group. It is a bit simplistic, but does point in a useful direction.
I believe that attention is the most powerful tool of the human spirit and that we can enhance or augment our attention with practices like meditation and exercise, diffuse it with technologies like email and Blackberries, or alter it with pharmaceuticals...but... the way in which many of us interact with our personal technologies makes it impossible to use this extraordinary tool of attention to our advantage...the vast majority of people hold their breath especially when they first begin responding to email. On cell phones, especially when talking and walking, people tend to hyper-ventilate or over-breathe. Either of these breathing patterns disturbs oxygen and carbon dioxide balance...breath holding can contribute significantly to stress-related diseases. The body becomes acidic, the kidneys begin to re-absorb sodium, and as the oxygen and CO2 balance is undermined, our biochemistry is thrown off.

The parasympathetic nervous system governs our sense of hunger and satiety, flow of saliva and digestive enzymes, the relaxation response, and many aspects of healthy organ function. Focusing on diaphragmatic breathing enables us to down regulate the sympathetic nervous system, which then causes the parasympathetic nervous system to become dominant. Shallow breathing, breath holding and hyper-ventilating triggers the sympathetic nervous system, in a "fight or flight" response...Some breathing patterns favor our body's move toward parasympathetic functions and other breathing patterns favor a sympathetic nervous system response. Buteyko (breathing techniques developed by a Russian M.D.), Andy Weil's breathing exercises, diaphragmatic breathing, certain yoga breathing techniques, all have the potential to soothe us, and to help our bodies differentiate when fight or flight is really necessary and when we can rest and digest.

I've changed my mind about how much attention to pay to my breathing patterns and how important it is to remember to breathe when I'm using a computer, PDA or cell phone...I've discovered that the more consistently I tune in to healthy breathing patterns, the clearer it is to me when I'm hungry or not, the more easily I fall asleep and rest peacefully at night, and the more my outlook is consistently positive...I've come to believe that, within the next 5-7 years, breathing exercises will be a significant part of any fitness regime.

Wednesday, October 31, 2018

The evolution of overconfidence

Johnson and Fowler on the crucial role of overconfidence in human success:
Confidence is an essential ingredient of success in a wide range of domains ranging from job performance and mental health to sports, business and combat. Some authors have suggested that not just confidence but overconfidence—believing you are better than you are in reality—is advantageous because it serves to increase ambition, morale, resolve, persistence or the credibility of bluffing, generating a self-fulfilling prophecy in which exaggerated confidence actually increases the probability of success. However, overconfidence also leads to faulty assessments, unrealistic expectations and hazardous decisions, so it remains a puzzle how such a false belief could evolve or remain stable in a population of competing strategies that include accurate, unbiased beliefs. Here we present an evolutionary model showing that, counterintuitively, overconfidence maximizes individual fitness and populations tend to become overconfident, as long as benefits from contested resources are sufficiently large compared with the cost of competition. In contrast, unbiased strategies are only stable under limited conditions. The fact that overconfident populations are evolutionarily stable in a wide range of environments may help to explain why overconfidence remains prevalent today, even if it contributes to hubris, market bubbles, financial collapses, policy failures, disasters and costly wars.

Tuesday, October 30, 2018

Self-care and finding personal peace in today's socio-political climate.

In Fort Lauderdale, FL, and now in Austin TX, I have organized discussion groups that meet regularly to discuss new topics and ideas. The Florida group named itself “The Roundtable” while the Austin group calls itself the “Austin Rainbow Forum.” The topic for the next Austin meeting, appropriate to the age of Trump, is “Self-care and finding personal peace in today's socio-political climate.”

The topic reminded me of a relevant talk I worked up some years ago titled “Are you holding your breath? - Structures of arousal and calm.” The talk describes downstairs and upstairs systems in our brain that regulate our arousal.

I thought I would show here a summary of part IV of that talk (parts of the summary, absent the context of the whole talk will seem a bit cryptic), and also show edited text that goes with part B. 1. dealing with the importance of our self construal in how we deal with stress. The link to the talk given above takes you to the whole package…

There are two broad categories of upstairs to downstairs, or top down regulators,  one emphasizing biased self construal (B. 1., middle list to the left) the other attempting more unbiased self observation (B2, right list) So, to start with the first:

It seems clear that most of us are completely unequipped to function without a vast array of positive delusions about our abilities, our futures, etc.  There is a large literature on this. Dan Dennett and McKay have just written a treatise in Brain and Behavioral Science that examines possible evolutionary rationales for mistaken beliefs, bizarre delusions, instances of self-deception, etc., they conclude that  only positive illusions meet their criteria for being adaptive.

Johnson and his colleagues have produced an evolutionary model suggesting that overconfidence maximizes individual fitness and that populations tend to become overconfident as long as benefits from contested resources are sufficiently large compared with the cost of competition. Unbiased strategies are only stable under limited conditions.  Maybe this is why overconfidence prevails, even as it contributes to market bubbles, financial collapses, policy failures, disasters and costly wars.

Most people report they are above average drivers and typically place themselves higher many scales than they really are. 70% of high schoolers rate, and, according to themselves,  a spectacular 94% of college professors possess teaching abilities that are above average.

In predicting the future we overestimate the likelihood of positive events, and underestimate the likelihood of negative one. Underestimate our chances getting divorced, being in a car accident, having cancer. We expect to live longer, be more successful, have more talented kids,  than objective measures would warrant. This is officially named the optimism bias, and it is one of the most consistent, prevalent, and robust biases documented in psychology and behavioral economics.

People update their beliefs more in response to information that is better than expected than to information that is worse,  and Dolan’s lab has actually found this reflected in activity in the prefrontal area that tracks estimation errors.  Highly optimistic individuals show reduced tracking of estimation errors that called for negative updates.   In other words, optimism is tied to a selective update failure and diminished neural coding of undesirable information regarding the future.

Our experience of the world is a mixture of stark reality and comforting illusion. We can't spare either. We might think of people as having a psychological immune system [on prezi list] that defends the mind against unhappiness like the physical immune system defends the body from illness.  Defense needs to be good, but not too good - somewhere between “I’m perfect and everyone is against me” and “I’m a loser and I ought to be dead.”

We engage in a wide array of mental gymnastics to salvage our self-esteem rather than owning up to our mistakes.    Recall the famous “mistakes were made” comment regarding the U.S. charging into the Iraq war.

One way to negotiate aging is to deny it, not spend give a lot of mental space to self fulling personal or societal expectations of decline. You can argue that psychological neoteny, retaining youthful attitudes and behaviors, is quite adaptive, especially in old folks, because it might help preserve plasticity of mind and personality that is very useful in ever-changing modern life.

Achievement is usually enhanced by having an inflated view of one’s abilities, which can also lead to working harder to live up to this enhanced self-image.  Students who exaggerate their current grade point averages are more motivated towards education and have higher calming parasympathetic activation when discussing academics.

If we generate a construal of ourselves as powerful, rested, and competent this can dial the blood pressure and sympathetics down and parasympathetics up.   A self construal of being powerless has the opposite effect.  Changes in immune status and inflammatory processes correlate with this transition.  Actually, our brain links to our immune system via the vagus nerve.

One's role in a hierarchy, or relative position in a gradient of personal helplessness to power, is a fundamental determinant of individual well being in both animal and human societies. Subordinate individuals show more chronic stress, anxiety-like behaviors, and susceptibility to disease.  This was most strikingly shown in a well known study on British civil servants.

So, as a summary: self deception can be useful and adaptive as long as it is not wildly inappropriate.  It can enhance vitality and motivate performance, yet enough realism should be retained to avoid straining to do what can not be done.

Monday, October 29, 2018

DNA variants linked to same sex behavior.

Michael Price and Jocelyn Kaiser report from the annual meeting of the American Society of Human Genetics in San Diego:
How genes influence sexual orientation has sparked debate for at least a quarter-century. But geneticists have had only a handful of underpowered studies to address a complex, fraught, and often stigmatized area of human behavior. Now, the largest-ever study of the genetics of sexual orientation has revealed four genetic variants strongly associated with what the researchers call nonheterosexual behavior. Some geneticists are hailing the findings as a cautious but significant step in understanding the role of genes in sexuality. Others question the wisdom of asking the question in the first place.
Andrea Ganna, a research fellow with the Broad Institute in Cambridge, Massachusetts, and Harvard Medical School in Boston, and colleagues examined data from hundreds of thousands of people who provided both DNA and behavioral information to two large genetic surveys, the UK Biobank study and the private genetics firm 23andMe. They analyzed DNA markers from people who answered either “yes” or “no” to the question, “Have you ever had sex with someone of the same sex?” In total, they identified 450,939 people who said their sexual relationships had been exclusively heterosexual and 26,890 people who reported at least one homosexual experience.
In Ganna’s talk yesterday at the annual meeting of the American Society of Human Genetics here, he emphasized that the researchers were cautious about exploring sexual behavior that is still illegal in many countries, and that they tried to frame their questions carefully “to avoid a fishing expedition.” The team, which includes behavioral scientists, preregistered their research design and also met regularly with members of the lesbian, gay, bisexual, transgender, or questioning (LGBTQ) community to discuss and share results. Ganna acknowledged that what they call “nonheterosexual behavior” includes “a large spectrum of sexual experiences, that go from people who engage exclusively in same-sex behavior to those who might have experimented once or twice.”
The researchers performed a genome-wide association study (GWAS) in which they looked for specific variations in DNA that were more common in people who reported at least one same-sex sexual experience. They identified four such variants on chromosomes seven, 11, 12, and 15, respectively.
Two variants were specific to men who reported same-sex sexual experience. One, a cluster of DNA on chromosome 15, has previously been found to predict male-pattern baldness. Another variant on chromosome 11 sits in a region rich with olfactory receptors. Ganna noted that olfaction is thought to play a large role in sexual attraction.
A much smaller 1993 study, which used a different kind of association technique known as a genetic linkage study, had suggested a stretch of DNA on the X chromosome was linked to inherited homosexuality. In the new GWAS, that stretch was not found to be associated with the reported same-sex behavior. But the lead author of the earlier study, Dean Hamer, then of the National Institutes of Health in Bethesda, Maryland, praised the new work. “It's important that attention is finally being paid [to the genetics of sexual orientation] with big sample sizes and solid institutions and people,” he said. “This is exactly the study we would have liked to have done in 1993.”
The four newly identified genetic variants also were correlated with some mood and mental health disorders. Both men and women with the variants were more likely to have experienced major depressive disorder and schizophrenia, and women were more likely to have bipolar disorder. Ganna stressed that these findings should not be taken to mean that the variants cause the disorders. Instead, it “might be because individuals who engaged in nonheterosexual behavior are more likely to be discriminated [against], and are more likely to develop depression,” he said.
Ganna noted that the correlation with schizophrenia and risk-taking behavior was more pronounced in the UK Biobank participants, who tend to skew older than those in the 23andMe group. That could be because older generations faced more sexual discrimination than younger ones, Ganna said, noting that environment likely plays a significant role in which traits wind up correlating with sexual orientation.
Overall, he said the findings reinforce the idea that human sexual behavior is complex and can’t be pinned on any simple constellation of DNA. “I’m pleased to announce there is no ‘gay gene,’” Ganna said. “Rather, ‘nonheterosexuality’ is in part influenced by many tiny genetic effects.” Ganna told Science that researchers have yet to tie the genetic variants to actual genes, and it’s not even clear whether they sit within coding or noncoding stretches of DNA. Trying to pin down exactly what these DNA regions do will be among the team’s difficult next steps.
“It’s an intriguing signal,” he said. “We know almost nothing about the genetics of sexual behavior, so anywhere is a good place to start.”..He added that the four genetic variants could not reliably predict someone’s sexual orientation. “There’s really no predictive power,” he said.
Given the complexity of human sexual behavior, much of which is not captured in the study questions, biomedical informatics graduate student Nicole Ferraro from Stanford University in Palo Alto, California, questioned the work’s utility. She and fellow biomedical sciences grad student Kameron Rodrigues said the study didn’t do enough to explore the nuances of how one’s sexual identity differs from sexual behavior, and they worried that the study could be used to stigmatize members of the LGBTQ community. “It just seems like there’s no benefit that can come from this kind of study, only harm,” Rodrigues said.
The abstract for Ganna’s talk referenced another provocative result: Heterosexual people who possess these same four genetic variants tend to have more sexual partners, suggesting associated genes might confer some mating advantage for heterosexuals. That could help explain why these variants might stick around in populations even if people attracted to the same sex tend to have fewer children than heterosexuals. Ganna did not touch on that finding in his talk, citing lack of time.
That was probably a wise choice, geneticist Chris Cotsapas at the Yale School of Medicine said, because the evolutionary implications haven’t been firmed up. “People are going to oversimplify it to say, ‘Gay genes help straight people have more sex,’ and it’s really not that simple,” he said.
Overall, the findings were “very carefully, cautiously presented,” Cotsapas said, and represent a good start for geneticists charting the complexities of human sexuality.

Friday, October 26, 2018

Diffusion in networks and the virtue of burstiness

From Akbarpour and Jackson:

The contagion of disease and the diffusion of information depend on personal contact. People are not always available to interact with those around them, and the timing of people’s activities determines whether people have opportunities to meet and transmit a germ, idea, etc., and ultimately whether widespread contagion or diffusion occurs. We show that, in a simple model of contagion or diffusion, the greatest levels of spreading occur when there is heterogeneity in activity patterns: Some people are active for long periods of time and then inactive for long periods, changing their availability only infrequently, while other people alternate frequently between being active and inactive. This observation has policy implications for limiting contagious diseases as well as promoting diffusion of information.
Whether an idea, information, or infection diffuses throughout a society depends not only on the structure of the network of interactions, but also on the timing of those interactions. People are not always available to interact with others, and people differ in the timing of when they are active. Some people are active for long periods and then inactive for long periods, while others switch more frequently from being active to inactive and back. We show that maximizing diffusion in classic contagion processes requires heterogeneous activity patterns across agents. In particular, maximizing diffusion comes from mixing two extreme types of people: those who are stationary for long periods of time, changing from active to inactive or back only infrequently, and others who alternate frequently between being active and inactive.

Thursday, October 25, 2018

Musicians' enhanced auditory perception depends on the instrument they play.

Professionally trained musicians show enhanced auditory perception of music. Krishnan et al. show that this expertise is modulated by the instrument played by the musician:
Studies of classical musicians have demonstrated that expertise modulates neural responses during auditory perception. However, it remains unclear whether such expertise-dependent plasticity is modulated by the instrument that a musician plays. To examine whether the recruitment of sensorimotor regions during music perception is modulated by instrument-specific experience, we studied nonclassical musicians—beatboxers, who predominantly use their vocal apparatus to produce sound, and guitarists, who use their hands. We contrast fMRI activity in 20 beatboxers, 20 guitarists, and 20 nonmusicians as they listen to novel beatboxing and guitar pieces. All musicians show enhanced activity in sensorimotor regions (IFG, IPC, and SMA), but only when listening to the musical instrument they can play. Using independent component analysis, we find expertise-selective enhancement in sensorimotor networks, which are distinct from changes in attentional networks. These findings suggest that long-term sensorimotor experience facilitates access to the posterodorsal “how” pathway during auditory processing.

Wednesday, October 24, 2018

Seeing something that is not there - our brain retroactively constructs our reality.

Two new illusions found by Stiles et al. (open source) report two new multimodal illusions in which sound influences visual perception. Their abstract, followed by one of the demonstrations:
Neuroscience investigations are most often focused on the prediction of future perception or decisions based on prior brain states or stimulus presentations. However, the brain can also process information retroactively, such that later stimuli impact conscious percepts of the stimuli that have already occurred (called “postdiction”). Postdictive effects have thus far been mostly unimodal (such as apparent motion), and the models for postdiction have accordingly been limited to early sensory regions of one modality. We have discovered two related multimodal illusions in which audition instigates postdictive changes in visual perception. In the first illusion (called the “Illusory Audiovisual Rabbit”), the location of an illusory flash is influenced by an auditory beep-flash pair that follows the perceived illusory flash. In the second illusion (called the “Invisible Audiovisual Rabbit”), a beep-flash pair following a real flash suppresses the perception of the earlier flash. Thus, we showed experimentally that these two effects are influenced significantly by postdiction. The audiovisual rabbit illusions indicate that postdiction can bridge the senses, uncovering a relatively-neglected yet critical type of neural processing underlying perceptual awareness. Furthermore, these two new illusions broaden the Double Flash Illusion, in which a single real flash is doubled by two sounds. Whereas the double flash indicated that audition can create an illusory flash, these rabbit illusions expand audition’s influence on vision to the suppression of a real flash and the relocation of an illusory flash. These new additions to auditory-visual interactions indicate a spatio-temporally fine-tuned coupling of the senses to generate perception.

Tuesday, October 23, 2018

An average person can recognize 5,000 faces.

Jenkins et al. recruited 25 undergraduate or postgraduate students at the University of Glasgow and the University of Aberdeen (15 female, 10 male; mean age 24, age range 18–61 years). They were given 1 hour to list as many faces from their personal lives as possible, and then another hour to do the same with famous faces, like those of actors, politicians, and musicians. To figure out how many additional faces people recognized but were unable to recall without prompting, they showed the participants photographs of 3441 celebrities, including Barack Obama and Tom Cruise. To qualify as “knowing” a face, the participants had to recognize two different photos of each person. Here is a video done by Science Magazine to describe the work:

Monday, October 22, 2018

What is the last question?

After 20 years, the annual question exercise seems to have run out of steam. John Brockman, author of "The Third Culture" and the guru who has led the effort, says:
After twenty years, I’ve run out of questions. So, for the finale to a noteworthy Edge project, can you ask "The Last Question"?
Two hundred and eightyfour respondents offer single sentence questions. Scrolling through these, I pull out a few that strike me, sometimes suggesting my immediate flippant answer to the question:
Are complex biological neural systems fundamentally unpredictable? (Yes)
Are the simplest bits of information in the brain stored at the level of the neuron? (No)
Does consciousness reside only in our brains? (No)
Can consciousness exist in an entity without a self-contained physical body? (Yes)
Is there a fundamental difference between the biological world and the physical world? (No)
Will some things about life, consciousness, and society necessarily remain unseen? (Yes)
Will we soon cease to care whether we are experiencing normal, augmented, or virtual reality? (Yes)
Is our brain fundamentally limited in its ability to understand the external world? (Yes)
And, finding myself running out of steam only a quarter of the way through the list, I zoom to the end and find Robert Sapolsky's question:
Given the nature of life, the purposeless indifference of the universe, and our complete lack of free will, how is it that most people avoid ever being clinically depressed?