Friday, September 24, 2021

Asymptomatic infection is the pandemic’s dark matter

Fisman and Tuite do a commentary on the article by Sah et al. (open source) that includes a great graphic showing how estimated asymptomatic COVID can be biased in two different ways. I pass on first the graphic and its explanation, and then the Sah et al. significance statement. The bottom line of their meta-analysis is that more than one-third of infections are truly asymptomatic, with greater asymptomaticity in children compared with the elderly:
The... authors address two important biases in the study of asymptomatic infection in their study and note that failure to address these biases distorts estimates of asymptomaticity. The first bias is an ascertainment effect associated with studies including symptomatic index cases in their estimates. The second bias is introduced when studies capture populations of infected individuals at a single time point, which means that presymptomatic individuals (symptomatic cases whose latent period has ended but who have not yet entered the symptomatic stage) are misclassified as asymptomatic. In their review, the authors find that failure to adjust for these biases results in a predictable underestimation of the frequency of asymptomatic infection in the former case, and overestimation of asymptomaticity in the latter.
These biases, and their effects, are described in Fig. 1 (click to enlarge). The circles at the left-hand side of the figure make up a hypothetical population of infected individuals, with a true prevalence of asymptomatic infection (blue circles) of around 33%. If this population attracts notice as a result of an outbreak with notable illness, we may be more likely to sample symptomatic index cases, creating sample A. By contrast, if we are able to sample the population systematically, and obtain a representative sample of infectives, we will create sample B. If we ascertain the prevalence of symptoms at a single point in time, we will misclassify presymptomatic individuals (diagonally shaded circles) as asymptomatic. This will lead to overestimation of the prevalence of asymptomatic infection. In the diagram, 4/9 (44%) of the sample are “asymptomatic” at the first time point in sample A, while 6/9 (67%) are “asymptomatic” in sample B; both samples provide an overestimate of the true probability of asymptomatic infection. If we allow time to pass so that presymptomatic individuals become symptomatic, the probability of asymptomatic infection in sample A drops to 1/9 (11%), a marked underestimate. However, in sample B, the probability declines to 3/9 (33%), which reflects the true underlying probability of asymptomatic infection in the source population.
The Sah et al. significance statement:
Asymptomatic infections have been widely reported for COVID-19. However, many studies do not distinguish between the presymptomatic stage and truly asymptomatic infections. We conducted a systematic review and meta-analysis of COVID-19 literature reporting laboratory-confirmed infections to determine the burden of asymptomatic infections and removed index cases from our calculations to avoid conflation. By analyzing over 350 papers, we estimated that more than one-third of infections are truly asymptomatic. We found evidence of greater asymptomaticity in children compared with the elderly, and lower asymptomaticity among cases with comorbidities compared to cases with no underlying medical conditions. Greater asymptomaticity at younger ages suggests that heightened vigilance is needed among these individuals, to prevent spillover into the broader community.

Wednesday, September 22, 2021

Is self awareness a mirage?

David Brooks does a brief psychological essay - a sequel to one described in MindBlog's Sept. 10 post.
One of the most unsettling findings of modern psychology is that we often don’t know why we do what we do...We have a conscious self, of course, the voice in our head, but this conscious self has little access to the parts of the brain that are the actual sources of judgment, problem-solving and emotion. We know what we’re feeling, just not how and why we got there...we also don’t want to admit how little we know about ourselves, so we make up some story, or confabulation.
Mary Pipher, the legendary therapist and author of “Reviving Ophelia” ...prefers “what, when, where and how” questions: When do you notice feelings of inferiority? Basically, she wants clients to become closer observers of their own behavior.....Maybe the best way to see yourself is to get out of the deceptive rumination spirals of your own self-consciousness and to think about yourself in the third person...Dan McAdams, the Northwestern scholar who specializes in how people tell their life stories...doubts that we can ever really know why we do anything, so we are compelled to fall back on narratives or what he calls “personal myths.”...some stories are better than others. Stories that are closer to “what really happened” are more reliable than ones that are distorted by self-flattery and self-affirmation... Americans, McAdams has found, tend to tell redemption stories...I was rising, I faltered, I came back better.
Lori Gottlieb, the author of “Maybe You Should Talk to Someone.” She also sees therapy as a form of story-editing. But she is much more optimistic that we can actually get down to the sources of our behavior...You have to understand the “why,” so you can recognize the behavior when it’s happening again and address what’s causing you to behave as you do.
Epley, the "Mindwise" author, stressed that we can attain true wisdom and pretty good self-awareness by looking at behavior and reality in the face to create more accurate narratives, and highlighted the importance of humility in life... recognizing that we don’t have privileged access to our minds, toneing down our self-confidence and realizing don’t know other people as well as we think we do.”

Monday, September 20, 2021

Secure human attachment can promote support for climate change mitigation

From Misa et al.

Significance

Attachment theory focuses on the primal form of emotional bonding between humans. Attachment is conceptualized as an innate behavioral system aimed at safeguarding against potential threats by assuring proximity to caring and supportive others. When individuals feel securely attached (thus feeling less threatened in most situations), the activation of the caregiving behavioral system (concern for others) is facilitated. With this research, we show that priming attachment security influences how much people care about and accept climate change via an increased empathy for humanity. Furthermore, we demonstrate that this activation bypasses the resistance of politically conservative individuals to mitigate climate change. Overall, we show that attachment security–based stimuli can inform intervention and policymaking strategies to help fight climate change.
Abstract
Attachment theory is an ethological approach to the development of durable, affective ties between humans. We propose that secure attachment is crucial for understanding climate change mitigation, because the latter is inherently a communal phenomenon resulting from joint action and requiring collective behavioral change. Here, we show that priming attachment security increases acceptance (Study 1: n = 173) and perceived responsibility toward anthropogenic climate change (Study 2: n = 209) via increased empathy for others. Next, we demonstrate that priming attachment security, compared to a standard National Geographic video about climate change, increases monetary donations to a proenvironmental group in politically moderate and conservative individuals (Study 3: n = 196). Finally, through a preregistered field study conducted in the United Arab Emirates (Study 4: n = 143,558 food transactions), we show that, compared to a message related to carbon emissions, an attachment security–based message is associated with a reduction in food waste. Taken together, our work suggests that an avenue to promote climate change mitigation could be grounded in core ethological mechanisms associated with secure attachment.

Monday morning tonic - A modern folk song about your brain

Ryan Stotland, a song writer from Montreal, has pointed me to a few of his engaging pieces, and I pass on one of them to you. It rhapsodizes about what different parts of our brains do... (not to worry, if you're a regular MindBlog reader, that the facts presented are phrenological oversimplifications that are a bit out of date.) 

 

Friday, September 17, 2021

How social mindfulness and prosociality vary across the globe

From Van Doesum et al. (open source) I pass on the abstract, one figure, and a clip of the discussion: Significance
Cooperation is key to well-functioning groups and societies. Rather than addressing high-cost cooperation involving giving money or time and effort, we examine social mindfulness—a form of interpersonal benevolence that requires basic perspective-taking and is aimed at leaving choice for others. Do societies differ in social mindfulness, and if so, does it matter? Here, we find not only considerable variation across 31 nations and regions but also an association between social mindfulness and countries’ performance on environmental protection. We conclude that something as small and concrete as interpersonal benevolence can be entwined with current and future issues of global importance.
Abstract
Humans are social animals, but not everyone will be mindful of others to the same extent. Individual differences have been found, but would social mindfulness also be shaped by one’s location in the world? Expecting cross-national differences to exist, we examined if and how social mindfulness differs across countries. At little to no material cost, social mindfulness typically entails small acts of attention or kindness. Even though fairly common, such low-cost cooperation has received little empirical attention. Measuring social mindfulness across 31 samples from industrialized countries and regions (n = 8,354), we found considerable variation. Among selected country-level variables, greater social mindfulness was most strongly associated with countries’ better general performance on environmental protection. Together, our findings contribute to the literature on prosociality by targeting the kind of everyday cooperation that is more focused on communicating benevolence than on providing material benefits.  
Distribution of means for Social Mindedness (SoMi), (click to enlarge)
In the end, what best explains the general picture? Considering all findings, we suggest that SoMi may be conceptualized as a specific and effective expression of social capital, a comprehensive perspective on society with important implications for its development and functioning (30). Following one of the definitions, the economic function of social capital is to diminish the costs of formal coordination tasks by using informal social communication channels. From a relational perspective, such capital materializes through social interactions that include low-cost cooperation. Requiring no monetary or otherwise effortful investments to acknowledge, confirm, and promote high-trust social relationships, SoMi would be specifically set up to do so; the socially mindful person signals benevolence and trustworthiness. A promising connection with social capital is also suggested in the ranking of our locations: Japan, highest on the SoMi list, is traditionally known for stressing the value of social capital, and ranks 12th (of 180) on the Global Sustainable Competiveness Index social capital world index, while Indonesia, lowest on the SoMi list, ranks 70. A simple bivariate correlation without corrections learns that SoMi and social capital scores are associated at r (30) = 0.56, P = 0.002. Although quantifying social capital is difficult, this is corroborated by the relations we found between SoMi and the ensemble of variables lead by EPI and followed by economic indices (GDP, GNI, and Gini), rule of law, power distance, individual and generalized trust, and civic cooperation (tendency only), which all in their own way have been connected to presence and development of social capital. Future research could develop this.

Wednesday, September 15, 2021

Domestic dogs: Born human whisperers

Vignieri does a summary of recent work by  Bray et al. and Salomans et al. in Current Biology

 
The closest relative to dogs, “man’s best friend,” is the wolf, a wily predator that generally avoids human interaction. For decades, researchers and dog owners have wondered how the leap to domestication occurred. The main hypothesis invoked very early selection for wolves that “liked”—or least tolerated—humans, and the connection strengthened from there. However, there is still some debate about whether the degree to which dogs interact and communicate with humans is a learned trait. Two recent studies appear to close the book on this learning hypothesis. Bray et al. looked at about 400 puppies and found that at this young age and without much human interaction, they were adept at following human gestures and positively responded to high-pitched “puppy talk.” Further, there was variation in these responses with an association between relatedness and social communication skills, which supports a genetic driver. Salomons et al. compared dog and wolf puppies and found no difference in general cognitive responses, but much greater responsiveness to human gestures and eye contact, in dog puppies. Importantly, this happened even though the dog pups had received less actual human interaction than did the wolf pups. These studies confirm that dogs’ interest in communication with humans is an evolved trait unique to their lineage.

Monday, September 13, 2021

The 31st First Annual Ig Nobel Ceremony -

I pass on this Science.org summary of the virtual awards ceremony.
Musical cats, upside-down rhinos, and submarine cockroaches took the gold last night at the 31stst annual Ig Nobel Prize ceremony—an awards show honoring research that “makes people laugh, then think.” Although the pandemic kept the ceremony virtual for a second year, organizers made the best of the format. Nobel laureates, including Frances Arnold (chemistry, 2018) and Eric Maskin (economics, 2007), “handed” awardees their prizes—self-assembled 3D paper gears printed with pictures of teeth. This year’s theme was “engineering.”
The biology prize—one of 10 awards—went to a series of studies on the purrs, trills, tweedles, murmurs, meows, yowls, and other sounds cats seem to use to communicate their desires to humans. Cat vocalization researcher Susanne Schötz at Lund University has been hard at work cracking the “cat code” with her collaborators since 2011, handing the microphone to cats to analyze what felines mean when they meow.
Schötz was honored for several papers, including one on how well humans interpret cat “meowsic.” She reported that when cats want food from their owners, their sounds tend to rise in pitch at the end. If the cats are anxious about a trip to the vet, however, they drop their pitch. When she played meows for a group of 30 humans, she found they guessed the cats’ feelings from intonation alone the majority of the time. Cat owners were the best guessers, showing that when it comes to cats, practice makes purrfect.
Other prizes went to research on animals that reached for the sky and dove under the sea. The transportation prize honored researchers who determined that the best way to transport a rhinoceros by helicopter is upside down. This technique has been vital to conservationists who move large animals such as rhinos and elephants to keep them safe from poachers or maintain genetic diversity. During the ceremony, the honorees assured Nobel laureate Richard Roberts (physiology or medicine, 1993) that they’d tested the technique on themselves before trying it on rhinos. Roberts maintained that if he ever had to be transported to a safer place, “I hope not to be doing it upside down.”
The entomology prize highlighted one of the most fraught human-animal relationships: the ongoing battle between humans and cockroaches. For this prize, the awards committee dug deep into the archives for a study from 1971 titled, “A new method of cockroach control on submarines.” Retired U.S. Navy Cmdr. John Mulrennan Jr. accepted the award for developing a new technique for getting rid of cockroaches on navy submarines using a pesticide called dichlorvos after the ethylene oxide gas previously used made someone sick. “The Navy was happy at the time,” he noted in his acceptance speech, although he doesn’t know whether it still uses his technique.
Other awards included the physics prize, for an analysis of why people in crowds don’t constantly run into each other, and the kinetics prize, for a study answering why they sometimes do (the answer: cellphones). The ecology prize went to an analysis of bacteria that hitch a ride on used chewing gum, the peace prize went to a test of how effectively beards protect faces from punches (they soften the blow), and the medicine prize went to a study of whether orgasms can serve as an effective nasal decongestant. (They can, but the effects only last about 1 hour.) Winners also received a fake 10 trillion Zimbabwean dollar bill from Marc Abrahams, editor of the Annals of Improbable Research and host of the ceremony.
Dispersed throughout the night were several “24/7” talks, in which researchers gave full technical descriptions of a scientific topic in 24 seconds followed by a simple explanation in seven words. (“Coffee drinking: good, good for you … maybe!”) To round out the proceedings, scientists and opera singers performed an original three-act miniopera called A Bridge Between People. Its plot revolved around children bringing together angry adults by building tiny suspension bridges between them.
Abrahams ended the night by expressing his hope that everyone could be together in person next year, and by delivering his traditional signoff: “If you didn’t win an Ig Nobel Prize tonight—and especially if you did—better luck next year.”

Friday, September 10, 2021

You Are Not Who You Think You Are

I want to point to the NYTimes piece by polymath David Brooks that does a nice summary of several themes that have been emphasized in MindBlog posts - on the recent work of Barrett, Friston, Hoffman, Johnson, and others. He touches on several areas in which our understanding of how our minds work has been completely transformed by work and ideas over just the past 10 years. I suggest you read the whole article and click on links to the articles he references. Here are a few clips:
You may think you understand the difference between seeing something and imagining it. When you see something, it’s really there; when you imagine it, you make it up. That feels very different...It turns out, reality and imagination are completely intermixed in our brain...the separation between our inner world and the outside world is not as clear as we might like to think.
...most of seeing is making mental predictions about what you expect to see, based on experience, and then using sensory input to check and adjust your predictions. Thus, your memory profoundly influences what you see...The conversation between senses and memory produces a “controlled hallucination,” which is the closest we can get to registering reality.
...humans have come up with all sorts of concepts to describe different thinking activities: memory, perception, emotion, attention, decision-making. But now, as scientists develop greater abilities to look at the brain doing its thing, they often find that the activity they observe does not fit the neat categories our culture has created, and which we rely on to understand ourselves...Barrett of Northeastern University argues that people construct emotions and thoughts, and there is no clear distinction between them...emotions assign value to things, so they are instrumental to reason, not separate from or opposed to it.
...there is no such thing as disembodied understanding. Your neural, chemical and bodily responses are in continual conversation with one another, so both understanding and experiencing are mental and physical simultaneously...When faced with a whole person...we shouldn’t think that they can be divided into a ‘mind’ and a ‘body.
...You realize that neither the term ‘decision-making’ nor the term ‘attention’ actually corresponds to a thing in the brain...the concepts at the core of how we think about thinking need to be radically revised...neuroscientists spent a lot of time trying to figure out what region of the brain did what function. (Fear is in the amygdala!) Today they also look at the ways vast networks across the brain, body and environment work together to create comprehensive mental states. Now there is much more emphasis on how people and groups creatively construct their own realities, and live within their own constructions.

Wednesday, September 08, 2021

Ageing yields improvements as well as declines across attention and executive functions

Interesting work from Verissimo et al.:
Many but not all cognitive abilities decline during ageing. Some even improve due to lifelong experience. The critical capacities of attention and executive functions have been widely posited to decline. However, these capacities are composed of multiple components, so multifaceted ageing outcomes might be expected. Indeed, prior findings suggest that whereas certain attention/executive functions clearly decline, others do not, with hints that some might even improve. We tested ageing effects on the alerting, orienting and executive (inhibitory) networks posited by Posner and Petersen’s influential theory of attention, in a cross-sectional study of a large sample (N = 702) of participants aged 58–98. Linear and nonlinear analyses revealed that whereas the efficiency of the alerting network decreased with age, orienting and executive inhibitory efficiency increased, at least until the mid-to-late 70s. Sensitivity analyses indicated that the patterns were robust. The results suggest variability in age-related changes across attention/executive functions, with some declining while others improve.

Monday, September 06, 2021

A test of plasticity-based cognitive training in treating mild traumatic brain injury

A study from Mahncke et al. (open source) shows that using a computerized cognitive training program that I have mentioned in previous MindBlog posts (BrainHQ, Posit Science) improves cognitive function in people with mild traumatic brain injury. Here is their abstract:
Clinical practice guidelines support cognitive rehabilitation for people with a history of mild traumatic brain injury (mTBI) and cognitive impairment, but no class I randomized clinical trials have evaluated the efficacy of self-administered computerized cognitive training. The goal of this study was to evaluate the efficacy of a self-administered computerized plasticity-based cognitive training programmes in primarily military/veteran participants with a history of mTBI and cognitive impairment. A multisite randomized double-blind clinical trial of a behavioural intervention with an active control was conducted from September 2013 to February 2017 including assessments at baseline, post-training, and after a 3-month follow-up period. Participants self-administered cognitive training (experimental and active control) programmes at home, remotely supervised by a healthcare coach, with an intended training schedule of 5 days per week, 1 h per day, for 13 weeks. Participants (149 contacted, 83 intent-to-treat) were confirmed to have a history of mTBI (mean of 7.2 years post-injury) through medical history/clinician interview and persistent cognitive impairment through neuropsychological testing and/or quantitative participant reported measure. The experimental intervention was a brain plasticity-based computerized cognitive training programme targeting speed/accuracy of information processing, and the active control was composed of computer games. The primary cognitive function measure was a composite of nine standardized neuropsychological assessments, and the primary directly observed functional measure a timed instrumental activities of daily living assessment. Secondary outcome measures included participant-reported assessments of cognitive and mental health. The treatment group showed an improvement in the composite cognitive measure significantly larger than that of the active control group at both the post-training [+6.9 points, confidence interval (CI) +1.0 to +12.7, P = 0.025, d = 0.555] and the follow-up visit (+7.4 points, CI +0.6 to +14.3, P = 0.039, d = 0.591). Both large and small cognitive function improvements were seen twice as frequently in the treatment group than in the active control group. No significant between-group effects were seen on other measures, including the directly-observed functional and symptom measures. Statistically equivalent improvements in both groups were seen in depressive and cognitive symptoms.

Friday, September 03, 2021

Babbling bats

An interesting piece from Fernandez et al.:
Babbling is a production milestone in infant speech development. Evidence for babbling in nonhuman mammals is scarce, which has prevented cross-species comparisons. In this study, we investigated the conspicuous babbling behavior of Saccopteryx bilineata, a bat capable of vocal production learning. We analyzed the babbling of 20 bat pups in the field during their 3-month ontogeny and compared its features to those that characterize babbling in human infants. Our findings demonstrate that babbling in bat pups is characterized by the same eight features as babbling in human infants, including the conspicuous features reduplication and rhythmicity. These parallels in vocal ontogeny between two mammalian species offer future possibilities for comparison of cognitive and neuromolecular mechanisms and adaptive functions of babbling in bats and humans.

Wednesday, September 01, 2021

The neuroinflammation collection: a review of neuro-immune crosstalk

Irani et al. (open source) offer a compact and concise review that highlights publications in Brain over the past several years as a focal point to offer a vision of how anticipated developments in neuroinflammation are likely to impact our understanding of key elements of neurology, and lead to new treatments. They offer some nice summary graphics, and organize their presentation around several areas: 

-Prototypical autoimmune-mediated conditions

-Neurodegeneration 

-Multiple sclerosis and CNS neoplasia 

-Inflammation in cerebrovascular disease 

-Harnessing innate immune responses in the brain