Know This

by Mr. John Brockman

  Formerly, any commonalities among a stroll in the park, the turbulence of a river, the revolution of a carriage wheel, the trajectory of a cannon ball, or the paths of the planets seemed preposterous. It was Newton who found the underlying generalities that explained each of them (and so much more) at a fundamental level.

  Now comes a similarly audacious pursuit, to subsume under general principles, perhaps even laws, the essence of intelligence wherever it’s found. “Truth is ever to be found in simplicity, and not in the multiplicity and confusion of things,” Newton said. As far as intelligence goes, we are pre-Newtonian. Commonalities of intelligence shared by cells, dolphins, plants, birds, robots, and humans seem, if not preposterous, at least far-fetched.

  Yet rich exchanges among artificial intelligence, cognitive psychology, and the neurosciences, for a start, aim exactly toward Newton’s “truth in simplicity,” those underlying principles (maybe laws) that will connect these disparate entities together. The pursuit’s formal name is computational rationality. What is it exactly, we ask? Who, or what, exhibits it?

  The pursuit is inspired by the general agreement in the sciences of mind that intelligence arises not from the medium that embodies it—whether biological or electronic—but the way interactions among elements in the system are arranged. Intelligence begins when a system identifies a goal, learns (from a teacher, a training set, or an experience), and then moves on autonomously, adapting to a complex, changing environment. Another way of looking at this is that intelligent entities are networks, often hierarchies, of intelligent systems—humans certainly among the most complex but congeries of humans even more so.

  The three scientists postulate that three core ideas characterize intelligence. First, intelligent agents have goals and form beliefs and plan actions that will best reach those goals. Second, calculating ideal best choices may be intractable for real-world problems, but rational algorithms can come close enough (“satisfice” in Herbert Simon’s term) and incorporate the costs of computation. Third, these algorithms can be rationally adapted to the entity’s specific needs—either offline, through engineering or evolutionary design, or online, through meta-reasoning mechanisms that select the best strategy on the spot for a given situation.

  Though barely begun, the inquiry into computational rationality is already large and embraces multitudes. For example, biologists now talk easily about cognition, from the cellular to the symbolic level. Neuroscientists can identify computational strategies shared by both humans and animals. Dendrologists can show that trees communicate with each other (slowly) to warn of nearby enemies, like wood beetles: Activate the toxins, neighbor.

  The humanities themselves are comfortably at home here too, although it’s taken many years for most of us to see that. And of course here belongs artificial intelligence, a key illuminator, inspiration, and provocateur.

  It’s news now; it will stay news because it’s so fundamental; its evolving revelations will help us see our world, our universe, in a completely new way. And for those atremble at the perils of superintelligent entities, surely understanding intelligence at this fundamental level is one of our best defenses.

  Neuro-News

  Noga Arikha

  Historian of ideas; author, Napoleon and the Rebel

  Science is never fixed in place: It must always move forward, and in that sense it is always “news.” What makes science news in a journalistic sense, however, tends to be biased by current concerns, economic interests, and popular fears and hopes.

  It is no surprise that research into the brain, in particular, continues to be the focus of much media attention—not only for the obvious reason of its central role in the very fabric of evolved life and of its infinite complexity but also because of the strong need to understand the biological bases of human behavior. This has led to many excessively positive claims for, and overinterpretations of, necessarily partial, provisional findings about brain mechanisms. The prefix “neuro” now twists into pseudoscientific shape all aspects of human behavior, from aesthetics to economics, as if the putative cerebral correlates for all that we do explained to us what we are. There are worthwhile and important avenues to explore here, but reports in the mainstream media hardly do justice to their scientific, methodological, and conceptual complexity.

  Yet truly newsworthy neuroscience does get reported. The publication in a June 2015 issue of Nature of the discovery of a lymphatic system within the central nervous system is hugely important and was acknowledged as such in more mainstream venues. ScienceDaily titled its report of the discovery “Missing link found between brain, immune system; major disease implications,” with the blurb, “In a stunning discovery that overturns decades of textbook teaching, researchers have determined that the brain is directly connected to the immune system by vessels previously thought not to exist. The discovery could have profound implications for diseases from autism to Alzheimer’s to multiple sclerosis.”

  We might need to take with a few grains of salt this last sentence—the sort of claim that reflects wishful thinking rather than actual reality, typical of what constitutes fast-burning “news.” On the other hand, few discoveries do “overturn decades of textbook teaching”—and this one probably does. The fact that established teaching can be overturned is important in itself; it’s easy to forget that most work goes on within given frameworks on the basis of assumptions rather than with an eye to the need for questioning those assumptions. This particular discovery emphasizes at last the need to understand connections between the nervous and immune systems, and can only promote the development of the burgeoning field of neuroimmunology. Precisely because of the specialized nature of research and clinical care, brain facts tend to be understood apart from body facts, in a Cartesian fashion, as if one were really apart from the other. This piece of news reminds us that we can understand one only as an aspect of the other, and that we need to take seriously, in scientific terms, phenomena such as the placebo and nocebo effects and the role of the psyche in the evolution of mental and physical disease generally. And in turn, this shows that what we take to be scientific news—that is, news about our understanding of the world and ourselves—is a function of what we expect.

  Microbial Attractions

  Pamela Rosenkranz

  Artist

  Sterility is not considered healthy anymore. Medicine is shifting from an antibiotic to a probiotic approach, and the idea of hygiene is becoming an organization of contamination, as opposed to disinfection. Not long ago, it was determined that the placenta is not sterile after all. The growing fetus was earlier believed to thrive in an absolutely clean bubble; instead, it seems to be confronted with germs through the filter of its mother’s biological system and building its future immune system from the very start of cell division.

  There are trillions of viruses, bacteria, fungi, and parasites thriving in each of us right now. Around 2 pounds of our body weight consists of what are popularly called bugs. Many of the microbiotic organisms are ancient. The most feared are viruses like Ebola or HIV, bacteria like Streptoccocus, and parasites like rabies. But next to the few fast and furious scary exceptions, most of the common organisms are easy for our immune system to deal with—even when they’re pathogenic. New research suggests that many of them are actually keeping us healthy; they seem to be “training” our immune system.

  The term “microbiome” was coined in the 1990s, but research is still beginning to sort the good from the bad. This community of organisms is so manifold and complex that we speak of a sea, a forest, a new natural world to be discovered within us. The main idea so far is that the more diversity—not just in the environment we live in but also in the environment that lives within us—the better.

  One simple clinical treatment that has turned into a substantial new industry is fecal transplants from healthy to sick people. It has been shown to heal the colon from an overgrowth of Clostridium difficile, a bacteria that often cannot be cured by antibiotics. It has he
lped obese people lose weight. And as it turns out that the gut is fundamentally intertwined with our brain, it influences our psychological sanity.

  Current research suggests that certain bacterial cultures cause anxiety, depression, and even Alzheimer’s, while others might help alleviate these ailments. But the effects on our mental state seem even more shockingly direct, if we take toxoplasmosis as an example: This neuroactive parasite influences one of the most existential of our feelings—sexual attraction.

  We, along with mice and other mammals, are only intermediary hosts; cats are its main target. In this unconscious ménage a trois, the parasite wants the mouse to be attracted to the cat, so Toxoplasma gondii travels up to the region of the mouse’s brain where sexual arousal occurs and there it prompts the mouse to react positively rather than negatively to cat pheromones and approach the cat instead of fleeing—so that the cat can much more easily catch and ingest it. Once inside that cat, the parasite has reached its goal: It can reproduce.

  Humans are part of its scheme in more abstract ways. Those who carry it are attracted to scents that originate from cat pheromones (this scent can be found in many perfumes—allegedly, Chanel No. 5, for instance). About 30 percent of the global population is infected—quite a target group! Apparently, this segment of humanity is also more prone to involvement in car accidents, and female carriers are known to acquire more designer clothes.

  We tend to see sexuality as one of the main markers of our individuality, but not only does our own biological system react to sexual attractions in ways we can’t control but there are also parasites that can neurologically influence, or possibly even direct, our behavior. It’s a provocative and difficult topic, and it challenges the fundamental understanding of what it means to be human.

  We are in constant exchange with our germs. We shake hands, kiss, have sex, travel, use toilets, go to parties, churches. Now there’s research about how religion, as a social factor, might be entangled in that complicated communal sharing of microbial organisms. When we come together, what do we really exchange? Might it be that our need for social interaction is also influenced by the secret powers of microbes?

  The Epidemic of Absence

  Matt Ridley

  Science writer; Fellow, Royal Society of Literature and the Academy of Medical Sciences; author, The Evolution of Everything

  As Stewart Brand acutely says, most of the things that dominate the news are not really new: Love, scandal, crime, and war come round again and again. Only science and invention deliver truly new stuff, like double helixes and search engines. In this respect, the new news from science that most intrigues me is that we may have a way to explain why certain diseases are getting worse as we get richer. We are defeating infectious diseases, slowing or managing many diseases of aging, like heart disease and cancer, but we are faced with a growing epidemic of allergy, autoimmunity, and things like autism. Some of it is due to more diagnosis, some of it is no doubt hypochondria, but there does seem to be a real increase in these kinds of problems.

  Take hay fever. It is plainly a modern disease, far more common in urban, middle-class people than it used to be in peasants or still is in subsistence farmers in Africa. There’s good timeline data on this, chronicling the appearance of allergies as civilization advances, province by province or village by village. And there’s good evidence that what causes this is the suppression of parasites. You can see this happen in Eastern Europe and in Africa in real time: Get rid of worms and a few years later children start getting hay fever. Moises Velasquez-Manoff chronicles this in glorious detail in his fine book An Epidemic of Absence.

  This makes perfect sense. In the arms race with parasites, immune systems evolved to “expect” to be down-regulated by parasites, so they overreact in their absence. A good balance is reached when parasites try down-regulating the immune system, but it turns rogue when there are no parasites. And the obvious remedy works: Ingest worms and you rid yourself of hay fever. Though it’s probably not worth it—worms are no fun.

  But how many of our modern diseases are caused by this problem, an impoverished ecology not just of parasites but of commensal and symbiotic microorganisms too? Do kids today in the rich world have unbalanced gut flora after an upbringing of obsessive hygiene? Probably. How many diseases and disorders are the consequence of this? More than we think, I suspect—multiple sclerosis, obesity, anorexia, perhaps even autism.

  There’s a fascinating recent study by Jeffrey Gordon’s group at Washington University School of Medicine, St. Louis, showing that if you take the gut flora from an obese person and introduce it into a mouse with no gut flora, the mouse puts on weight faster than does another mouse with gut flora introduced from the obese person’s non-obese twin. That’s a well-designed experiment.*

  So a big new thing in science is that we are beginning to understand the epidemic of absence.

  Bugs R Us

  Nina Jablonski

  Evan Pugh University Professor of Anthropology, Penn State University; author, Living Color: The Biological and Social Meaning of Skin Color

  Ignaz Semmelweis changed our world when, back in 1847, he decided to start washing his hands after he performed an autopsy and before he delivered a baby. When Semmelweis worked in a Viennese obstetric hospital, the germ theory of disease and the concept of “infection” were unknown. Postpartum infections due to “childbed fever” killed a high percentage of women who gave birth in hospitals. Semmelweis knew that there was something in and around dead bodies that had the potential to cause disease, and so he decided to follow the practice of midwives and wash his hands before delivering a baby. Fewer mothers died, and Semmelweis knew he was onto something. During his lifetime, his innovation was rejected by fellow male physicians, but within decades, evidence from doctors and scientists in other parts of Europe proved him right. Small organisms like bacteria caused disease, and taking simple precautions like hand-washing could lower disease risk.

  Thanks to Semmelweis and his intellectual descendants, we follow a range of routines from boiling water and avoiding tropical ice cubes to near-fanatical levels of hand sanitizing, in order to reduce the chances of getting sick because of the nasty bugs in our environment.

  We have known for a long time that our bodies harbor lots of “normal” flora, but until about a decade ago few people studied them. We focused on Semmelweis’s disease-causing bacteria, which we cultured in petri dishes so that we could identify and kill them. The rest of our microbial residents were thought to be pretty much harmless baggage and were ignored.

  The introduction of new methods of identifying diverse communities of organisms from their DNA alone (including such innovations as high-throughput DNA sequencing) changed all that, and we began to realize the magnitude of what we had been missing. The world of critters living in and on us was soon discovered to be a vast and complex one, and it mattered.

  Since 2008, when the Human Microbiome Project officially started, hundreds of collaborating scientists have illuminated the nature and effects of the billions of bacteria that are part of our normal healthy bodies. There isn’t one human microbiome; there are many. There is a microbiome in our hair, one up our nostrils, another in our vaginas, several lavishly differentiated on the vast real estate of our skin, and a veritable treasure trove in our gut, thanks to diligent subcontractors in the esophagus, stomach, and colon.

  This great menagerie undergoes changes as we age, so that some of the bacteria that were common and apparently harmless when we were young start to bother us when we’re old, and vice versa. The taxonomic diversity and census of our resident bacteria are more than just subjects of scientific curiosity; they matter greatly to our health. The normal bacteria on our skin, for instance, are essential to maintaining the integrity of the skin’s barrier functions. Many diseases—psoriasis, obesity, inflammatory bowel disease, some cancers, even cardiovascular disease—are associated with shifts in our microbiota.

  While it’s too early to tell if
the changing bacteria are the cause or the result of these afflictions, the discovery of robust associations between bacterial profiles and disease states opens the door for new treatments and targeted preventive measures. The body’s microbiota also affect and are affected by the body’s epigenome, the chemical factors influencing gene expression. Thus, the bugs on us and in us are controlling the normal action of genes in the cells of our bodies, and changes in the proportions or overall numbers of bacteria affect how our cells work and respond to stress.

  Let’s stop thinking about our bodies as temples of sinew and cerebrum, and instead as evolving and sloshing ecosystems full of bacteria that are regulating our health in more ways than we could ever imagine. As we learn more about our single-celled companions in the coming years, we’ll take probiotics for curing acute and chronic diseases, we’ll undertake affirmative action to maintain diversity of our gut microflora as we age, and we’ll receive prescriptions for increasingly narrow-spectrum antibiotics to exterminate only the nastiest of the nasties when we have a serious acute infection. Hand sanitizers and colon cleansing will probably be with us for some time, but it’s best just to get used to it now: Bugs R us.

  Fecal Microbiota Transplants

  Joichi Ito

  Director, MIT Media Lab

  Although we have been talking about the microbiome for years, news about our microbial friends was huge this year. We have known for some time that the microbes in our gut were important for our health, but recently studies are beginning to show that the gut biome is even more important than we thought.