Trigger warnings and ‘safety-ism’ don’t work.

Mark Manson does an engaging "Mindf*ck Monday Newsletter from Sept. 7" that I recommend you have a look at. It cites a meta-analysis by Brigland et al. that shows that trigger warning don't work, in some cases they may make things worse. Their abstract:

Trigger warnings, content warnings, or content notes are alerts about upcoming content that may contain themes related to past negative experiences. Advocates claim that warnings help people to emotionally prepare for or completely avoid distressing material. Critics argue that warnings both contribute to a culture of avoidance at odds with evidence-based treatment practices and instill fear about upcoming content. Recently, a body of psychological research has begun to investigate these claims empirically. We present the results of a meta-analysis of all empirical studies on the effects of these warnings. Overall, we found that warnings have no effect on affective responses to negative material nor on educational outcomes (i.e., comprehension). However, warnings reliably increase anticipatory affect. Findings on avoidance were mixed, suggesting either that warnings have no effect on engagement with material, or that they increase engagement with negative material under specific circumstances. Limitations and implications for policy and therapeutic practice are discussed.

Manson also discusses the dying fad of "safety-ism" noted by Jonathan Haidt and Greg Lukianoff in their book "The Coddling of the American Mind," and makes the point that...

The human mind is antifragile—that is, it gains from discomfort and strain. That means to grow stronger, the human mind needs to regularly be confronted with difficult and upsetting experiences to develop stability and serenity for itself.

Neural synchronization predicts marital satisfaction

From Li et al.:  

Significance

Humans establish intimate social and personal relationships with their partners, which enable them to survive, successfully mate, and raise offspring. Here, we examine the neurobiological basis of marital satisfaction in humans using naturalistic, ecologically relevant, interpersonal communicative cues that capture shared neural representations between married couples. We show that in contrast to demographic and personality measures, which are unreliable predictors of marital satisfaction, neural synchronization of brain responses during viewing of naturalistic maritally relevant movies predicted higher levels of marital satisfaction in couples. Our findings demonstrate that brain similarities that reflect real-time mental responses to subjective perceptions, thoughts, and feelings about interpersonal and social interactions are strong predictors of marital satisfaction and advance our understanding of human marital bonding.

Abstract

Marital attachment plays an important role in maintaining intimate personal relationships and sustaining psychological well-being. Mate-selection theories suggest that people are more likely to marry someone with a similar personality and social status, yet evidence for the association between personality-based couple similarity measures and marital satisfaction has been inconsistent. A more direct and useful approach for understanding fundamental processes underlying marital satisfaction is to probe similarity of dynamic brain responses to maritally and socially relevant communicative cues, which may better reflect how married couples process information in real time and make sense of their mates and themselves. Here, we investigate shared neural representations based on intersubject synchronization (ISS) of brain responses during free viewing of marital life-related, and nonmarital, object-related movies. Compared to randomly selected pairs of couples, married couples showed significantly higher levels of ISS during viewing of marital movies and ISS between married couples predicted higher levels of marital satisfaction. ISS in the default mode network emerged as a strong predictor of marital satisfaction and canonical correlation analysis revealed a specific relation between ISS in this network and shared communication and egalitarian components of martial satisfaction. Our findings demonstrate that brain similarities that reflect real-time mental responses to subjective perceptions, thoughts, and feelings about interpersonal and social interactions are strong predictors of marital satisfaction, reflecting shared values and beliefs. Our study advances foundational knowledge of the neurobiological basis of human pair bonding.

How nature nurtures

MindBlog has passed on a number of articles on how exposure to nature reduces stress (see a sample list below). Here is a further contribution from Sudimac et al., who show amygdala activity decreases as the result of a one-hour walk in nature:

Since living in cities is associated with an increased risk for mental disorders such as anxiety disorders, depression, and schizophrenia, it is essential to understand how exposure to urban and natural environments affects mental health and the brain. It has been shown that the amygdala is more activated during a stress task in urban compared to rural dwellers. However, no study so far has examined the causal effects of natural and urban environments on stress-related brain mechanisms. To address this question, we conducted an intervention study to investigate changes in stress-related brain regions as an effect of a one-hour walk in an urban (busy street) vs. natural environment (forest). Brain activation was measured in 63 healthy participants, before and after the walk, using a fearful faces task and a social stress task. Our findings reveal that amygdala activation decreases after the walk in nature, whereas it remains stable after the walk in an urban environment. These results suggest that going for a walk in nature can have salutogenic effects on stress-related brain regions, and consequently, it may act as a preventive measure against mental strain and potentially disease. Given rapidly increasing urbanization, the present results may influence urban planning to create more accessible green areas and to adapt urban environments in a way that will be beneficial for citizens’ mental health.

A few previous MindBlog posts on this topic:

Blue Mind - looking at water improves your health and calm 

Pictures of green spaces make you happier. 

More green space in childhood, fewer psychiatric disorders in adulthood.

Machine learning is translating the languages of animals

Anthes does an article on how machine learning is being used to eavesdrop on naked mole rats, fruit bats, crows and whales — and to communicate back. Some edited clips:

Machine-learning systems, which use algorithms to detect patterns in large collections of data, have excelled at analyzing human language, giving rise to voice assistants that recognize speech, transcription software that converts speech to text and digital tools that translate between human languages.

...this technology can be deployed to decode animal communication, working towards finding a Google Translate for animals, using machine-learning algorithms to identify when squeaking mice are stressed or why fruit bats are shouting. Even more ambitious projects are underway — to create a comprehensive catalog of crow calls, map the syntax of sperm whales and even to build technologies that allow humans to talk back.

...machine-learning algorithms can spot subtle patterns that might elude human listeners...these programs can tell apart the voices of individual animals, distinguish between sounds that animals make in different circumstances and break their vocalizations down into smaller parts, a crucial step in deciphering meaning.

...the technology could also be deployed for the benefit of animals, helping experts monitor the welfare of both wild and domestic fauna. Scientists also said that they hoped that by providing new insight into animal lives, this research might prompt a broader societal shift. Many pointed to the galvanizing effect of the 1970 album “Songs of the Humpback Whale,” which featured recordings of otherworldly whale calls and has been widely credited with helping to spark the global Save the Whales movement...many scientists said they hoped these new, high-tech efforts to understand the vocalizations of whales — and crows and bats and even naked mole rats — will be similarly transformative, providing new ways to connect with and understand the creatures with whom we share the planet.

Lasting improvements in seniors’ working and long-term memory with repetitive neuromodulation

From Grover et al., an open source article in which details of their transcranial alternating current stimulation (tACS) protocols are given:

The development of technologies to protect or enhance memory in older people is an enduring goal of translational medicine. Here we describe repetitive (4-day) transcranial alternating current stimulation (tACS) protocols for the selective, sustainable enhancement of auditory–verbal working memory and long-term memory in 65–88-year-old people. Modulation of synchronous low-frequency, but not high-frequency, activity in parietal cortex preferentially improved working memory on day 3 and day 4 and 1 month after intervention, whereas modulation of synchronous high-frequency, but not low-frequency, activity in prefrontal cortex preferentially improved long-term memory on days 2–4 and 1 month after intervention. The rate of memory improvements over 4 days predicted the size of memory benefits 1 month later. Individuals with lower baseline cognitive function experienced larger, more enduring memory improvements. Our findings demonstrate that the plasticity of the aging brain can be selectively and sustainably exploited using repetitive and highly focalized neuromodulation grounded in spatiospectral parameters of memory-specific cortical circuitry.

The sex of human experimenters influences mouse behaviors and neural responses.

As I was scanning a recent nature neuroscience table of contents, the title of this item elicited an immediate “What the f…..?” reaction, so I had to click on it. I had not been aware that mice are aversive to the scent of male versus female human experimenters. Here is the Georgiou et al. abstract:

We show that the sex of human experimenters affects mouse behaviors and responses following administration of the rapid-acting antidepressant ketamine and its bioactive metabolite (2R,6R)-hydroxynorketamine. Mice showed aversion to the scent of male experimenters, preference for the scent of female experimenters and increased stress susceptibility when handled by male experimenters. This human-male-scent-induced aversion and stress susceptibility was mediated by the activation of corticotropin-releasing factor (CRF) neurons in the entorhinal cortex that project to hippocampal area CA1. Exposure to the scent of male experimenters before ketamine administration activated CA1-projecting entorhinal cortex CRF neurons, and activation of this CRF pathway modulated in vivo and in vitro antidepressant-like effects of ketamine. A better understanding of the specific and quantitative contributions of the sex of human experimenters to study outcomes in rodents may improve replicability between studies and, as we have shown, reveal biological and pharmacological mechanisms.

A 2020 MindBlog anti-aging experiment whose results I forgot to report to MindBlog readers.

How embarassing. While doing a scan of posts on aging to update my Jan. 2018 talk "How Much Can We Change Our Aging?" talk, I pulled up a post from Wed. Oct. 14, 2020 describing an experiment to test the effects of trying alpha-ketoglutarate (meant to promote mitochondrial metabolism) as a dietary supplement. I did not follow up on my promise to report and side effects in an addendum to the post. I have now done that, and below paste in the amended text:

I've done a bit more reading on alpha-ketoglutarate, a natural component of the Krebs biochemical cycle that generates body energy and whose levels normally decline with aging. It was the subject of a recent post pointing to studies indicating the positive effects of its supplementation on health and longevity in mice.  So...I have started taking 300 mg capsules of the stuff with my other breakfast supplements. I decided to pass on the pricey 'Rejuvant Life Tabs', containing 1000 mg and offered by Ponce de Leon Health, a company set up by some of the researchers, and instead got the compound from Kirkman, one of the supplement providers. I'm inclined not to be too paranoid about their sending sawdust instead of the real product.  I noted that I could buy the >98% pure dry powder from the Sigma-Aldrich company, the supplier my biochemisty lab used for over 30 years, but decided the hassle of dealing with bulk powder wasn't worth it.  The compound is quite acidic, so best taken as the Calcium or Magnesium salt and with a meal.  I had an unhappy tummy when I tried it without food.  

I will continue taking the compound, will report imagined positive or negative effects as addenda to this post.  Undesirable side effects will lead me to discontinue the supplement, as was the case with my 2010 (Acetyl L-carnitine, alpha-lipoic acid, and the B-vitamin biotin) and 2016 (pterostilbene and nicotinamide riboside) self experiments.  The latter, like a 2008 experiment with resveratrol was terminated because of increasing arthritic symptoms. The 2008 post had 33 comments reporting negative effects resveratrol.

And, a necessary comment regarding Ponce de Leon Health and other purveyors of life extension elixirs:

You're gonna die..there is compelling evidence that none of us will make it past ~120 years of age.   

ADDENDUM... added 9/1/2022 Apologies for spacing out for almost two years.... I took 300 mg capsules of alpha-ketoglutarate with breakfast for one week in early Nov. 2020. It caused acid reflux and increasing hand arthritis over the week. Both side effects vanished after a week off the supplement. I had observed the hand arthritis side effect also in my resveratrol experiment.

How the internet has fueled our current cultural stagnation.

I pass on some of Michelle Goldberg's description of a forthcoming book by W. David Marx, “Status and Culture: How Our Desire for Social Rank Creates Taste, Identity, Art, Fashion, and Constant Change,” and suggest you read her whole essay.

Marx posits cultural evolution as a sort of perpetual motion machine driven by people’s desire to ascend the social hierarchy. Artists innovate to gain status, and people unconsciously adjust their tastes to either signal their status tier or move up to a new one. As he writes in the introduction, “Status struggles fuel cultural creativity in three important realms: competition between socioeconomic classes, the formation of subcultures and countercultures, and artists’ internecine battles.”

Marx uses the rise of avant-garde compose John Cage after his first major orchestral piece premiered at Lincoln Center in 1964, as an example the introduction of a radical new perspective that would most likely be impossible today.

“There was a virtuous cycle for Cage: His originality, mystery and influence provided him artist status; this encouraged serious institutions to explore his work; the frequent engagement with his work imbued Cage with cachet among the public, who then received a status boost for taking his work seriously,” writes Marx. For Marx, this isn’t a matter of pretension. Cachet, he writes, “opens minds to radical propositions of what art can be and how we should perceive it.”

The internet, Marx writes in his book’s closing section, changes this dynamic. With so much content out there, the chance that others will recognize the meaning of any obscure cultural signal declines. Challenging art loses its prestige. Besides, in the age of the internet, taste tells you less about a person. You don’t need to make your way into any social world to develop a familiarity with Cage — or, for that matter, with underground hip-hop, weird performance art, or rare sneakers.

...people are, obviously, no less obsessed with their own status today than they were during times of fecund cultural production. It’s just that the markers of high social rank have become more philistine...When the value of cultural capital is debased, it makes “popularity and economic capital even more central in marking status...there’s “less incentive for individuals to both create and celebrate culture with high symbolic complexity.” ...We live in a time of rapid and disorienting shifts in gender, religion and technology. Aesthetically, thanks to the internet, it’s all quite dull.

Non-duality as a platform for experiencing daily life.

I pass on abstracted edited clip from a recent podcast conversation between Sam Harris and M.I.T philosopher Kierna Setiya on “Philosophy and the Good Life” which has a succinct definition of what Harris takes non-duality or ‘having no self’ to mean, and how experiencing this can lead to a surprising kind of equanimity and even eudemonia, as well as solving a very wide class of psychological problems. I suggest that MindBlog readers who enjoy this subject matter also have a look back at my March 22 post, titled "Points on having a self and free will."

There can be confusion over what is meant by no-self in various meditative traditions. It’s not the claim that people are illusions, or that you can’t say anything about the psychological or biological continuity of a person. It’s not mysterious that we wake up today as ourselves and not someone else. These are not the puzzles being addressed.

The core insight, the illusion that is cut through, conceptually and experientially, is our apparent normal default condition of feeling like there is a subject in the center of experience. Most people don’t merely feel identical to experience, they feel like they are having an experience, they feel like they are appropriating their experience from some point - very likely in their heads - the witness, the thinker of thoughts, the willer of will, the guy in the boat who has free will, who can decide what to think and do next. That’s the default state for almost everybody, and commonplace as it is, it is a peculiar point of view. It doesn’t make a lot of sense, particularly biological sense. It’s not the same thing as feeling identical to our bodies, because we usually don’t feel identical to our bodies, we feel like we are subjects who have bodies, there is a kind of Cartesian dualism that is intuitive. People are ‘common sense dualists.’ As a matter of experience there is this feeling that “I am a subject behind my face.” “I” have a body, am a subject who is thinking, internal to the body, has a body. It is the final representation of the subject that is the illusion.

To put this in neurological terms, let’s just say for the sake of argument at all of this is just neurophysiological events in the brain delivering these representations. It is plausible that any one of these processes can be interrupted, so that you can cease to faithfully or coherently represent a world. You can suddenly go blind, may not be able to name living things but still be able to name tools, suddenly not be able to perceive motion or location, those things can break apart. All kinds of things can be disrupted for the worse certainly. But what these contemplative traditions have recognized is that certain things can be disrupted or brought to a halt for the better. The thing that can interrupt the usual cascade of mediocrity and suffering psychologically speaking is this representation of self as subject in the middle of experience.

You can cease to construct a subject that is internal to the body. What remains in that case is a sense that mind is much vaster than it was a moment ago, because it is no longer confined to the sense that there is this central thinker of thoughts. There is a recognition that thoughts arise all by themselves, just as sounds do, no one is authoring your thoughts - you certainly aren’t. The sense that you are is what it feels like to be identified with this next spontaneously arising thought.

So, you loose sense that you are on the edge of your life, looking over your own shoulder, appropriating experience and what you can feel very vividly here is a real unity. emptyness, non-duality of subjects and objects, such that there is really just experience. This is not a new way of thinking about yourself in the world, this is a ceasing to identify with thought. This is making no metaphysical claims about how this relates to matter or the universe.

As as matter of experience you can feel identical to experience itself. You are not standing on the river bank watching things go by, you are the river, and that solves a very wide class of problems, psychologically speaking, with respect to suffering. And, it does land one in a surprising kind of equanimity and even eudemonia (well being) that may seem counter intuitive in the midst of the cacophony of daily life. But again, it’s not about the negation of personhood, it is just a recognition that as a matter of experience there is just experience, and the feeling that there is an experiencer is yet more experience, so that if you just drop back… there is just everything in its own place.

Eye movements are related to the contents of consciousness in REM (rapid eye movment) sleep

Senzai and Scanziani have recorded head direction cells in the anterior dorsal nucleus of the thalamus in mice during wake and sleep. The direction and amplitude of eye movements encoded the direction and amplitude of the heading of mice in their virtual environment during REM sleep. It was possible to predict the actual heading in the real and virtual world of the mice during wake and REM sleep, respectively, using saccadic eye movements. Their abstract:

Since the discovery of rapid eye movement (REM) sleep, the nature of the eye movements that characterize this sleep phase has remained elusive. Do they reveal gaze shifts in the virtual environment of dreams or simply reflect random brainstem activity? We harnessed the head direction (HD) system of the mouse thalamus, a neuronal population whose activity reports, in awake mice, their actual HD as they explore their environment and, in sleeping mice, their virtual HD. We discovered that the direction and amplitude of rapid eye movements during REM sleep reveal the direction and amplitude of the ongoing changes in virtual HD. Thus, rapid eye movements disclose gaze shifts in the virtual world of REM sleep, thereby providing a window into the cognitive processes of the sleeping brain.

Is History History?

I recommend that you read Bret Stephens fascinating NYTimes piece. Some clips:

The End of History was supposed to have happened back in 1989, the year the Berlin Wall fell and Francis Fukuyama announced the conclusive triumph of liberal democracy. We know how that thesis worked out. But what happens when the other kind of History — academic, not Hegelian — starts to collapse?...That’s a question that James H. Sweet, a professor of history at the University of Wisconsin, Madison, and the president of the American Historical Association, tried to raise earlier this month in a column titled “Is History History?” for the organization’s newsmagazine. It didn’t go well...Sweet’s core concern in the piece was the “trend toward presentism” — the habit of weighing the past against the social concerns and moral categories of the present.

Sweet was immediately attacked by the cancel culture of left-wing academics and felt obliged to issue an apology. Stevens notes that

...the larger shame is that Sweet had important things to say in his thoughtful column — things that the reaction to the column (and the reaction to the reaction) now risk burying...Between 2003 and 2013, a dwindling number of history Ph.D.s, he noted, were going to students doing work on topics preceding 1800. At the same time, historians were producing works that “collapse into the familiar terms of contemporary debates,” particularly those connected to identity politics.....“This new history,” he wrote, “often ignores the values and mores of people in their own times, as well as change over time, neutralizing the expertise that separates historians from those in other disciplines.”

...Sweet was warning that historians risked doing an injustice both to their own profession as well as to the past itself by falling victim to “the allure of political relevance.” His main example came from a recent visit to the Elmina Castle in Ghana..which has become a kind of shrine for African Americans seeking a place to memorialize enslaved ancestors...Sweet says as a historian of Africa, “less than 1 percent of the Africans passing through Elmina arrived in North America” — most...ended up in Brazil or the Caribbean. And those who were enslaved were often first brought to Elmina by other African brokers who promoted the slave trade just as cruelly and greedily as the Europeans with whom they did business.

That does nothing to diminish the evil of the trade, much less its relevance to America’s past and present...But it helps put it into a global context in which the roles of victim and victimizer seldom fall neatly along a color line. If that challenges current orthodoxy, it’s only because that orthodoxy is based on a simplistic understanding of history. The proper role of the historian is to complexify, not simplify; to show us historical figures in the context of their time, not reduce them to figurines that can be weaponized in our contemporary debates.

Above all, historians should make us understand the ways in which the past was distinct. This shouldn’t prevent us from making moral judgments about it. But we can make better judgments, informed by the knowledge that our forebears rarely acted with the benefit (or burden) of our assumptions, expectations, experiences and values. There’s a lesson in humility in that, as well as a reminder that we are only actors in time whose most cherished ideas may eventually seem strange, and sometimes abhorrent, to our descendants.

Sweet's column...

— which bent over backward to showcase his liberal bona fides — ignited the usual progressive furies. Anyone looking for further confirmation that modern academia has become a fundamentally ideological and coercive exercise masquerading as a scholarly and collegial one need have looked no further. It will be interesting to see if Sweet manages to hold on to his post as the American Historical Association’s president...If people are wondering how history ends, maybe this is how: when a scholarly discipline tries to turn itself into something it isn’t, making itself increasingly irrelevant in its desperate bid for relevancy.

Animals (including us) conjure model-based structures from random events

Superstitious learning is usually thought to be accounted for by conditioned association, but Jin et al. now show that monkeys can develop more complex cognitive structures independent of reinforcement:  

Significance

Past studies on learning and decision-making usually rely on the assumption that the task is learnable. However, humans and other animals often infer spurious relationships from coincidental associations, and it is unknown if this could be achieved without reward conditioning. Here, we exposed monkeys to sets of images that had a hidden hierarchical order and to unordered sets that lacked an underlying structure. Monkeys treated the unordered sets as if they had a hierarchical order even under reward schedules that incentivized random choices. The results cannot be explained by simple associative mechanisms that account for other types of spurious learning, suggesting that when presented with random events animals conjure elaborate model-based structures.

Abstract

Humans and other animals often infer spurious associations among unrelated events. However, such superstitious learning is usually accounted for by conditioned associations, raising the question of whether an animal could develop more complex cognitive structures independent of reinforcement. Here, we tasked monkeys with discovering the serial order of two pictorial sets: a “learnable” set in which the stimuli were implicitly ordered and monkeys were rewarded for choosing the higher-rank stimulus and an “unlearnable” set in which stimuli were unordered and feedback was random regardless of the choice. We replicated prior results that monkeys reliably learned the implicit order of the learnable set. Surprisingly, the monkeys behaved as though some ordering also existed in the unlearnable set, showing consistent choice preference that transferred to novel untrained pairs in this set, even under a preference-discouraging reward schedule that gave rewards more frequently to the stimulus that was selected less often. In simulations, a model-free reinforcement learning algorithm (Q-learning) displayed a degree of consistent ordering among the unlearnable set but, unlike the monkeys, failed to do so under the preference-discouraging reward schedule. Our results suggest that monkeys infer abstract structures from objectively random events using heuristics that extend beyond stimulus–outcome conditional learning to more cognitive model-based learning mechanisms.

Increasingly good artificial intelligence (A.I.) is offering us promise and peril.

I want to pass on a few items from my list of putative MindBlog posts on A.I. 

The first derives from an series of emails on A.I. sent to the listserve of the "Chaos and Complex Systems Discussion Group" at Univ. of Wisconsin, Madison, that I attended until my move to Austin Tx. They point to the kerfuffle started by suspended Google engineer Blake Lemoine over whether one of the company's experimental AIs called LaMDA had achieved sentience, and How belief in AI sentience is becoming a problem.

(By the way, If you want to set up your own chatbot for self therapy, that won't collect and sell personal info you may divulge to it, visit https://replika.com/.... I actually tried it out, was underwhelmed by its responses, so deleted my account.)

An article by Kevin Roose on the potentials and risks of A.I. is worth reading.  One amazing feat of A.I. has been solving the "protein-folding problem," which I (as a trained biochemist) have been following for over 50 years.

This summer, DeepMind announced that AlphaFold (an A.I. system descended from the Go-playing one) had made predictions of the three-dimensional structures of proteins from their one-dimensional amino acid sequences for nearly all of the 200 million proteins known to exist — producing a treasure trove of data that will help medical researchers develop new drugs and vaccines for years to come. Last year, the journal Science recognized AlphaFold’s importance, naming it the biggest scientific breakthrough of the year.

Here are a few further clips:

Even if the skeptics are right, and A.I. doesn’t achieve human-level sentience for many years, it’s easy to see how systems like GPT-3, LaMDA (language models) and DALL-E 2 (generating images from language descriptions) could become a powerful force in society. In a few years, the vast majority of the photos, videos and text we encounter on the internet could be A.I.-generated. Our online interactions could become stranger and more fraught, as we struggle to figure out which of our conversational partners are human and which are convincing bots. And tech-savvy propagandists could use the technology to churn out targeted misinformation on a vast scale, distorting the political process in ways we won’t see coming.

Ajeya Cotra, a senior analyst with Open Philanthropy who studies A.I. risk, estimated two years ago that there was a 15 percent chance of “transformational A.I.” — which she and others have defined as A.I. that is good enough to usher in large-scale economic and societal changes, such as eliminating most white-collar knowledge jobs — emerging by 2036...But in a recent post, Ms. Cotra raised that to a 35 percent chance, citing the rapid improvement of systems like GPT-3.

Because of how new many of these A.I. systems are, few public officials have any firsthand experience with tools like GPT-3 or DALL-E 2, nor do they grasp how quickly progress is happening at the A.I. frontier...we could end up with a repeat of what happened with social media companies after the 2016 election — a collision of Silicon Valley power and Washington ignorance, which resulted in nothing but gridlock and testy hearings...big tech companies investing billions in A.I. development — the Googles, Metas and OpenAIs of the world — need to do a better job of explaining what they’re working on, without sugarcoating or soft-pedaling the risks.