Friday, April 21, 2017

A.I. better at predicting heart attacks, learns implicit racial and gender bias.

Lohr notes a study that suggest we need to develop and "A.I. index" analogous to the Consumer Price Index, to track the pace and spread of artificial intelligence technology. Two recent striking finding in this field:

 Weng et al. show that AI is better at predicting heart attacks from routine clinical data on risk factors than human doctors are. Hutson notes that the best The best of the four A.I. algorithms tried — neural networks — correctly predicted 7.6% more events than the American College of Cardiology/American Heart Association (ACC/AHA) method (based on eight risk factors—including age, cholesterol level, and blood pressure, that physicians effectively add up), and it raised 1.6% fewer false alarms.

Caliskan et al. show that machines can learn word associations from written texts and that these associations mirror those learned by humans, as measured by the Implicit Association Test (IAT). In large bodies of English-language text, they decipher content corresponding to human attitudes (likes and dislikes) and stereotypes. In addition to revealing a new comprehension skill for machines, the work raises the specter that this machine ability may become an instrument of unintended discrimination based on gender, race, age, or ethnicity. Their abstract:
Machine learning is a means to derive artificial intelligence by discovering patterns in existing data. Here, we show that applying machine learning to ordinary human language results in human-like semantic biases. We replicated a spectrum of known biases, as measured by the Implicit Association Test, using a widely used, purely statistical machine-learning model trained on a standard corpus of text from the World Wide Web. Our results indicate that text corpora contain recoverable and accurate imprints of our historic biases, whether morally neutral as toward insects or flowers, problematic as toward race or gender, or even simply veridical, reflecting the status quo distribution of gender with respect to careers or first names. Our methods hold promise for identifying and addressing sources of bias in culture, including technology.

Thursday, April 20, 2017

Study suggests social media are not contributing to political polarization.

Bromwich does an interesting piece on increasing political polarization in the US. The number of the 435 house districts in the country competitive for both parties has decreased from 90 to 72 over the past four years. It has been commonly assumed that internet social media are a major culprit driving polarization, because they make it easier for people to remain in their own tribal bubbles. The problem with this model is that the increase in political polarization has been seven times higher among older Americans (who are least likely to use the internet) than among adults under 40 (see Boxell et al.). An explanatory factor has to make sense equally across demographics.

Wednesday, April 19, 2017

How to feel good - and how feeling good can be bad for you.

In case you feel like another click,  I pass on these two self-helpy feel-good or happiness bits, in the common list form ...

First, a bit from Scelfo noting a Martin Seligman recipe for well being:

1. Identifying signature strengths;
2. Finding the good;
3. Practicing gratitude;
4. Responding constructively.

And second, Five way feeling good can be bad for you:

1. When you’re working on critical reasoning tasks.
2. When you want to judge people fairly and accurately.
3. When you might get taken advantage of.
4. When there’s temptation to cheat.
5. When you’re empathizing with suffering.

Tuesday, April 18, 2017

Scratching is contagious.

The precis from Science Magazine, followed by the abstract:
Observing someone else scratching themselves can make you want to do so. This contagious itching has been observed in monkeys and humans, but what about rodents? Yu et al. found that mice do imitate scratching when they observe it in other mice. The authors identified a brain area called the suprachiasmatic nucleus as a key circuit for mediating contagious itch. Gastrin-releasing peptide and its receptor in the suprachiasmatic nucleus were necessary and sufficient to transmit this contagious behavior.
Socially contagious itch is ubiquitous in human society, but whether it exists in rodents is unclear. Using a behavioral paradigm that does not entail prior training or reward, we found that mice scratched after observing a conspecific scratching. Molecular mapping showed increased neuronal activity in the suprachiasmatic nucleus (SCN) of the hypothalamus of mice that displayed contagious scratching. Ablation of gastrin-releasing peptide receptor (GRPR) or GRPR neurons in the SCN abolished contagious scratching behavior, which was recapitulated by chemogenetic inhibition of SCN GRP neurons. Activation of SCN GRP/GRPR neurons evoked scratching behavior. These data demonstrate that GRP-GRPR signaling is necessary and sufficient for transmitting contagious itch information in the SCN. The findings may have implications for our understanding of neural circuits that control socially contagious behaviors.

Monday, April 17, 2017

Is "The Stack" the way to understand everything?

When the Apple II computer arrived in 1977, I eagerly took its BASIC language tutorials and began writing simple programs to work with my laboratory’s data. When Apple Pascal, based on the UCSD Pascal system, arrived in 1979 I plunged in and wrote a number of data analysis programs. Pascal is a structured programming language, and I soon found myself structuring my mental life around its metaphors. Thus Herrman’s recent article on “the stack” has a particular resonance with me. Some clips:
…the explanatory metaphors of a given era incorporate the devices and the spectacles of the day…technology that Greeks and Romans developed for pumping water, for instance, underpinned their theories of the four humors and the pneumatic soul. Later, during the Enlightenment, clockwork mechanisms left their imprint on materialist arguments that man was only a sophisticated machine. And as of 1990, it was concepts from computing that explained us to ourselves..
We don’t just talk intuitively about the ways in which people are “programmed” — we talk about our emotional “bandwidth” and look for clever ways to “hack” our daily routines. These metaphors have developed right alongside the technology from which they’re derived…Now we’ve arrived at a tempting concept that promises to contain all of this: the stack. These days, corporate managers talk about their solution stacks and idealize “full stack” companies; athletes share their recovery stacks and muscle-building stacks; devotees of so-called smart drugs obsessively modify their brain-enhancement stacks to address a seemingly infinite range of flaws and desires.
“Stack,” in technological terms, can mean a few different things, but the most relevant usage grew from the start-up world: A stack is a collection of different pieces of software that are being used together to accomplish a task.
An individual application’s stack might include the programming languages used to build it, the services used to connect it to other apps or the service that hosts it online; a “full stack” developer would be someone proficient at working with each layer of that system, from bottom to top. The stack isn’t just a handy concept for visualizing how technology works. For many companies, the organizing logic of the software stack becomes inseparable from the logic of the business itself. The system that powers Snapchat, for instance, sits on top of App Engine, a service owned by Google; to the extent that Snapchat even exists as a service, it is as a stack of different elements. …A healthy stack, or a clever one, is tantamount (the thinking goes) to a well-structured company…On StackShare, Airbnb lists over 50 services in its stack, including items as fundamental as the Ruby programming language and as complex and familiar as Google Docs.
Other attempts to elaborate on the stack have been more rigorous and comprehensive, less personal and more global. In a 2016 book, “The Stack: On Software and Sovereignty,” the professor and design theorist Benjamin Bratton sets out to, in his words, propose a “specific model for the design of political geography tuned to this era of planetary-scale computation,” by drawing on the “multilayered structure of software, hardware and network ‘stacks’ that arrange different technologies vertically within a modular, interdependent order.” In other words, Bratton sees the world around us as one big emerging technological stack. In his telling, the six-layer stack we inhabit is complex, fluid and vertigo-inducing: Earth, Cloud, City, Address, Interface and User. It is also, he suggests, extremely powerful, with the potential to undermine and replace our current conceptions of, among other things, the sovereign state — ushering us into a world blown apart and reassembled by software. This might sound extreme, but such is the intoxicating logic of the stack.
As theory, the stack remains mostly a speculative exercise: What if we imagined the whole world as software? And as a popular term, it risks becoming an empty buzzword, used to refer to any collection, pile or system of different things. (What’s your dental care stack? Your spiritual stack?) But if tech start-ups continue to broaden their ambitions and challenge new industries — if, as the venture-capital firm Andreessen-Horowitz likes to say, “software is eating the world” — then the logic of the stack can’t be trailing far behind, ready to remake more and more of our economy and our culture in its image. It will also, of course, be subject to the warning with which Daugman ended his 1990 essay. “We should remember,” he wrote, “that the enthusiastically embraced metaphors of each ‘new era’ can become, like their predecessors, as much the prison house of thought as they first appeared to represent its liberation.”

Friday, April 14, 2017

Anterior temporal lobe and the representation of knowledge about people

Anzellotti frames work by Wang et al.:
Patients with semantic dementia (SD), a neurodegenerative disease affecting the anterior temporal lobes (ATL), present with striking cognitive deficits: they can have difficulties naming objects and familiar people from both pictures and descriptions. Furthermore, SD patients make semantic errors (e.g., naming “horse” a picture of a zebra), suggesting that their impairment affects object knowledge rather than lexical retrieval. Because SD can affect object categories as disparate as artifacts, animals, and people, as well as multiple input modalities, it has been hypothesized that ATL is a semantic hub that integrates information across multiple modality-specific brain regions into multimodal representations. With a series of converging experiments using multiple analysis techniques, Wang et al. test the proposal that ATL is a semantic hub in the case of person knowledge, investigating whether ATL: (i) encodes multimodal representations of identity, and (ii) mediates the retrieval of knowledge about people from representations of perceptual cues.
The Wang et al. Significance and Abstract statements:

Knowledge about other people is critical for group survival and may have unique cognitive processing demands. Here, we investigate how person knowledge is represented, organized, and retrieved in the brain. We show that the anterior temporal lobe (ATL) stores abstract person identity representation that is commonly embedded in multiple sources (e.g. face, name, scene, and personal object). We also found the ATL serves as a “neural switchboard,” coordinating with a network of other brain regions in a rapid and need-specific way to retrieve different aspects of biographical information (e.g., occupation and personality traits). Our findings endorse the ATL as a central hub for representing and retrieving person knowledge.
Social behavior is often shaped by the rich storehouse of biographical information that we hold for other people. In our daily life, we rapidly and flexibly retrieve a host of biographical details about individuals in our social network, which often guide our decisions as we navigate complex social interactions. Even abstract traits associated with an individual, such as their political affiliation, can cue a rich cascade of person-specific knowledge. Here, we asked whether the anterior temporal lobe (ATL) serves as a hub for a distributed neural circuit that represents person knowledge. Fifty participants across two studies learned biographical information about fictitious people in a 2-d training paradigm. On day 3, they retrieved this biographical information while undergoing an fMRI scan. A series of multivariate and connectivity analyses suggest that the ATL stores abstract person identity representations. Moreover, this region coordinates interactions with a distributed network to support the flexible retrieval of person attributes. Together, our results suggest that the ATL is a central hub for representing and retrieving person knowledge.

Thursday, April 13, 2017

Lying is a feature, not a bug, of Trump’s presidency.

PolitiFact rates half of Trump’s disputed public statements to be completely false. Adam Smith points out that Trump is telling…
“blue” lies—a psychologist’s term for falsehoods, told on behalf of a group, that can actually strengthen the bonds among the members of that group…blue lies fall in between generous “white” lies and selfish “black” ones.
…lying is a feature, not a bug, of Trump’s campaign and presidency. It serves to bind his supporters together and strengthen his political base—even as it infuriates and confuses most everyone else. In the process, he is revealing some complicated truths about the psychology of our very social species.
…while black lies drive people apart and white lies draw them together, blue lies do both: They help bring some people together by deceiving those in another group. For instance, if a student lies to a teacher so her entire class can avoid punishment, her standing with classmates might actually increase.
A variety of research highlights...
...a difficult truth about our species: We are intensely social creatures, but we’re prone to divide ourselves into competitive groups, largely for the purpose of allocating resources. People can be “prosocial”—compassionate, empathic, generous, honest—in their groups, and aggressively antisocial toward outside groups. When we divide people into groups, we open the door to competition, dehumanization, violence—and socially sanctioned deceit.
If we see Trump’s lies not as failures of character but rather as weapons of war, then we can come to understand why his supporters might see him as an effective leader. To them, Trump isn’t Hitler (or Darth Vader, or Voldemort), as some liberals claim—he’s President Roosevelt, who repeatedly lied to the public and the world on the path to victory in World War II.
...partisanship for many Americans today takes the form of a visceral, even subconscious, attachment to a party group...Democrats and Republicans have become not merely political parties but tribes, whose affiliations shape the language, dress, hairstyles, purchasing decisions, friendships, and even love lives of their members.
...when the truth threatens our identity, that truth gets dismissed. For millions and millions of Americans, climate change is a hoax, Hillary Clinton ran a sex ring out of a pizza parlor, and immigrants cause crime. Whether they truly believe those falsehoods or not is debatable—and possibly irrelevant. The research to date suggests that they see those lies as useful weapons in a tribal us-against-them competition that pits the “real America” against those who would destroy it.
Perhaps the above clips will motivate you read Smith's entire article, which goes on to discuss how anger fuels lying, and suggests some approaches to defying blue lies.

Wednesday, April 12, 2017

How exercise calms anxiety.

Another mouse story, as in the previous post, hopefully applicable to us humans. Gretchen Reynolds points to work of Gould and colleagues at Princeton showing that in the hippocampus of mice that have been in a running regime not only are new excitatory neurons and synapses generated, but also inhibitory neurons are more likely to become activated to dampen the excitatory neurons, in response to stress. This was a long term running response, because running mice were blocked from exercise for a day before stress testing in a cold bath that showed them to be less reactive to the cold than sedentary mice.
Physical exercise is known to reduce anxiety. The ventral hippocampus has been linked to anxiety regulation but the effects of running on this subregion of the hippocampus have been incompletely explored. Here, we investigated the effects of cold water stress on the hippocampus of sedentary and runner mice and found that while stress increases expression of the protein products of the immediate early genes c-fos and arc in new and mature granule neurons in sedentary mice, it has no such effect in runners. We further showed that running enhances local inhibitory mechanisms in the hippocampus, including increases in stress-induced activation of hippocampal interneurons, expression of vesicular GABA transporter (vGAT), and extracellular GABA release during cold water swim stress. Finally, blocking GABAA receptors in the ventral hippocampus, but not the dorsal hippocampus, with the antagonist bicuculline, reverses the anxiolytic effect of running. Together, these results suggest that running improves anxiety regulation by engaging local inhibitory mechanisms in the ventral hippocampus.

Tuesday, April 11, 2017

The calming effect of breathing.

Sheikhbahaei1 and Smith do a Perspective article in Science on the work of Yackle et al. in the same issue. The first bit of their perspective, followed by the Yackle et al. abstract:
Breathing is one of the perpetual rhythms of life that is often taken for granted, its apparent simplicity belying the complex neural machinery involved. This behavior is more complicated than just producing inspiration, as breathing is integrated with many other motor functions such as vocalization, orofacial motor behaviors, emotional expression (laughing and crying), and locomotion. In addition, cognition can strongly influence breathing. Conscious breathing during yoga, meditation, or psychotherapy can modulate emotion, arousal state, or stress. Therefore, understanding the links between breathing behavior, brain arousal state, and higher-order brain activity is of great interest...Yackle et al. identify an apparently specialized, molecularly identifiable, small subset of ∼350 neurons in the mouse brain that forms a circuit for transmitting information about respiratory activity to other central nervous system neurons, specifically with a group of noradrenergic neurons in the locus coeruleus (LC) in the brainstem, that influences arousal state. This finding provides new insight into how the motor act of breathing can influence higher-order brain functions.
The Yackle et al. abstract:
Slow, controlled breathing has been used for centuries to promote mental calming, and it is used clinically to suppress excessive arousal such as panic attacks. However, the physiological and neural basis of the relationship between breathing and higher-order brain activity is unknown. We found a neuronal subpopulation in the mouse preBötzinger complex (preBötC), the primary breathing rhythm generator, which regulates the balance between calm and arousal behaviors. Conditional, bilateral genetic ablation of the ~175 Cdh9/Dbx1 double-positive preBötC neurons in adult mice left breathing intact but increased calm behaviors and decreased time in aroused states. These neurons project to, synapse on, and positively regulate noradrenergic neurons in the locus coeruleus, a brain center implicated in attention, arousal, and panic that projects throughout the brain.

Monday, April 10, 2017

Brain correlates of information virality

Scholz et al. show that activity in brain areas associated with value, self and social cognition correlates with internet sharing of articles, reflecting how people express themselves in positive ways to strengthen their social bonds.

Why do humans share information with others? Large-scale sharing is one of the most prominent social phenomena of the 21st century, with roots in the oldest forms of communication. We argue that expectations of self-related and social consequences of sharing are integrated into a domain-general value signal, representing the value of information sharing, which translates into population-level virality. We analyzed brain responses to New York Times articles in two separate groups of people to predict objectively logged sharing of those same articles around the world (virality). Converging evidence from the two studies supports a unifying, parsimonious neurocognitive framework of mechanisms underlying health news virality; these results may help advance theory, improve predictive models, and inform new approaches to effective intervention.
Information sharing is an integral part of human interaction that serves to build social relationships and affects attitudes and behaviors in individuals and large groups. We present a unifying neurocognitive framework of mechanisms underlying information sharing at scale (virality). We argue that expectations regarding self-related and social consequences of sharing (e.g., in the form of potential for self-enhancement or social approval) are integrated into a domain-general value signal that encodes the value of sharing a piece of information. This value signal translates into population-level virality. In two studies (n = 41 and 39 participants), we tested these hypotheses using functional neuroimaging. Neural activity in response to 80 New York Times articles was observed in theory-driven regions of interest associated with value, self, and social cognitions. This activity then was linked to objectively logged population-level data encompassing n = 117,611 internet shares of the articles. In both studies, activity in neural regions associated with self-related and social cognition was indirectly related to population-level sharing through increased neural activation in the brain's value system. Neural activity further predicted population-level outcomes over and above the variance explained by article characteristics and commonly used self-report measures of sharing intentions. This parsimonious framework may help advance theory, improve predictive models, and inform new approaches to effective intervention. More broadly, these data shed light on the core functions of sharing—to express ourselves in positive ways and to strengthen our social bonds.

Friday, April 07, 2017

Three sources of cancer - the importance of “bad luck”

Tomasetti and Vogelstein raised a storm by claiming several years ago that 65% of the risk of certain cancers is not due to inheritance or environmental factors, but rather to mutations linked to stem cell division in the cancerous tissues examined. Now they have provided further evidence that this is not specific to the United States. Here is a summary of, and the abstract from, their more recent paper:

Cancer and the unavoidable R factor
Most textbooks attribute cancer-causing mutations to two major sources: inherited and environmental factors. A recent study highlighted the prominent role in cancer of replicative (R) mutations that arise from a third source: unavoidable errors associated with DNA replication. Tomasetti et al. developed a method for determining the proportions of cancer-causing mutations that result from inherited, environmental, and replicative factors. They found that a substantial fraction of cancer driver gene mutations are indeed due to replicative factors. The results are consistent with epidemiological estimates of the fraction of preventable cancers.
Cancers are caused by mutations that may be inherited, induced by environmental factors, or result from DNA replication errors (R). We studied the relationship between the number of normal stem cell divisions and the risk of 17 cancer types in 69 countries throughout the world. The data revealed a strong correlation (median = 0.80) between cancer incidence and normal stem cell divisions in all countries, regardless of their environment. The major role of R mutations in cancer etiology was supported by an independent approach, based solely on cancer genome sequencing and epidemiological data, which suggested that R mutations are responsible for two-thirds of the mutations in human cancers. All of these results are consistent with epidemiological estimates of the fraction of cancers that can be prevented by changes in the environment. Moreover, they accentuate the importance of early detection and intervention to reduce deaths from the many cancers arising from unavoidable R mutations.

Thursday, April 06, 2017

How "you" makes meaning.

Orvell et al. do some experiments on our use of the generic “you” rather than the first-person pronoun “I.”
“You” is one of the most common words in the English language. Although it typically refers to the person addressed (“How are you?”), “you” is also used to make timeless statements about people in general (“You win some, you lose some.”). Here, we demonstrate that this ubiquitous but understudied linguistic device, known as “generic-you,” has important implications for how people derive meaning from experience. Across six experiments, we found that generic-you is used to express norms in both ordinary and emotional contexts and that producing generic-you when reflecting on negative experiences allows people to “normalize” their experience by extending it beyond the self. In this way, a simple linguistic device serves a powerful meaning-making function.

Wednesday, April 05, 2017

Religiosity and social support

I found this article by Eleanor Power to be an interesting read. Here is her abstract:.
In recent years, scientists based in a variety of disciplines have attempted to explain the evolutionary origins of religious belief and practice1. Although they have focused on different aspects of the religious system, they consistently highlight the strong association between religiosity and prosocial behaviour (acts that benefit others). This association has been central to the argument that religious prosociality played an important role in the sociocultural florescence of our species. But empirical work evaluating the link between religion and prosociality has been somewhat mixed. Here, I use detailed, ethnographically informed data chronicling the religious practice and social support networks of the residents of two villages in South India to evaluate whether those who evince greater religiosity are more likely to undertake acts that benefit others. Exponential random graph models reveal that individuals who worship regularly and carry out greater and costlier public religious acts are more likely to provide others with support of all types. Those individuals are themselves better able to call on support, having a greater likelihood of reciprocal relationships. These results suggest that religious practice is taken as a signal of trustworthiness, generosity and prosociality, leading village residents to establish supportive, often reciprocal relationships with such individuals.

Tuesday, April 04, 2017

Wiser than than the crowd.

In a summary in Nature Human Behavior, Kousta points to work by Prelec et al. The summary:
The notion that the average judgment of a large group is more accurate than that of any individual, including experts, is widely accepted and influential. This ‘wisdom of the crowd’ principle, however, has serious limitations, as it is biased against the latest knowledge that is not widely shared.
Dražen Prelec and colleagues propose an alternative principle — the ‘surprisingly popular’ principle — that requires people to answer a question and also predict how others will answer it. By selecting the answer that is more popular than people predict, the surprisingly popular algorithm outperforms the wisdom of crowds. To understand why it works, think of a scenario where the correct answer is mostly known by experts. While those who do not know the correct answer will incorrectly predict that their answer will be the most popular, those who know the correct answer — the experts — also know it is not widely known and hence will predict that the incorrect answer will prevail. The authors formalize and test the surprisingly popular principle in a series of studies that demonstrate that it yields more accurate answers than an algorithm relying on the ‘democratic vote’.
Polling people for their views as well as their predictions of the views of others offers a powerful tool for allowing expert knowledge to win out when popular views are incorrect.

Monday, April 03, 2017

Several takes on extending our lives.

In spite of the fact that I am unsympathetic to efforts to extend our lifespan, I want to pass on several recent articles on the effort. Tad Friend does an excellent article on Silicon Valley money supporting a variety of different efforts to let us attain eternal life,  Baar et al. find that an anti-aging protein that causes the apoptosis (death) of senescent cells reverses symptoms of aging,  Li et al. show that NAD+ directly regulates protein-protein interactions which may protect against cancer, radiation, and aging; and Rich Handy points to several pieces of research, one by Baar et al. on a peptide that restores fitness, hair density, and renal function in fast and naturally aged mice.