It’s possible that I shall make an ass of myself. But in that case one can always get out of it with a little dialectic. I have, of course, so worded my proposition as to be right either way (K.Marx, Letter to F.Engels on the Indian Mutiny)
Saturday, June 26, 2021
Babies can see things that adults cannot
Visual perception changes drastically in the second half of the first year of life
IMAGE: NEW RESEARCH SHOWS THAT INFANTS YOUNGER THAN 7 MONTHS CAN PERCEIVE OBJECTS THAT OLDER INFANTS AND ADULTS CANNOT SEE BECAUSE OF A PHENOMENON CALLED "VISUAL BACKWARD MASKING. " view more
CREDIT: CHUO UNIVERSITY, LAIMAN
We can generally recognize an object, even if it is presented for a very brief time. However, if another object appears immediately following the first object, the perception on the first object is impaired such that we do not notice its existence. This perceptual phenomenon, called "visual backward masking," is used in vision science to study how visual perception is processed in the brain. Interestingly, this phenomenon occurs even if the second object does not spatially overlap the first object, such as a contour or four dots surrounding the object.
The occurrence of this phenomenon is assumed to be due to a disruption of "feedback processing." When we see something, visual information is serially processed from lower to higher visual areas in the brain in a bottom-up manner. However, top-down feedback processing, in which visual signals are sent back from higher to lower areas, also plays a critical role in visual perception. Visual backward masking is thought to occur owing to interference with feedback processing.
"We applied backward masking to infants aged 3-8 months to examine the development of feedback processing," says Yusuke Nakashima, a postdoctoral fellow at Chuo University in Tokyo and the study's lead author. "Recent studies in vision science revealed the importance of feedback processing in visual perception, but its development is poorly understood."
To test whether backward masking occurs in infants, the researchers presented images of faces on a computer screen and measured the length of time that infants spent looking at them. As infants tend to look longer at faces, researchers can test whether infants perceive faces by measuring their looking time. The faces were presented in two ways. In one condition, a face was followed by a mask image, in which infants would not see the face if backward masking occurred. In another condition, nothing appeared after the face; thus, infants would be able to see the face.
The researchers found that infants aged 7-8 months could not see faces followed by the mask, indicating that backward masking occurred, similar to adults. In contrast, infants aged 3-6 months could perceive faces even when the faces were followed by the mask image, indicating that masking did not occur and that younger infants could see faces that older infants could not.
"These results suggest that feedback processing is immature in infants younger than 7 months," says Nakashima. "That is, younger infants do not have feedback processing that backward masking should interfere, and thus, masking is ineffective for them." The results of the study demonstrated that the mechanisms for visual perception change drastically in the second half of the first year of life, from the bottom-up system to the system incorporating top-down processing.
The results also showed that objects that can be perceived in early infancy become imperceptible during development. "This might seem counterintuitive," says Masami Yamaguchi, a professor at Chuo University. "Instead, important visual abilities would be acquired by the maturation of feedback processing."
For example, feedback processing is essential for robustly perceiving ambiguous visual images, such as occluded objects. "Younger infants whose feedback processing is immature might perceive the external world ambiguously," says Yamaguchi. "In return for susceptibility to visual masking, we acquire the ability to robustly perceive ambiguous visual scenes."
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Paper: Nakashima Y., Kanazawa S., & Yamaguchi M. K. "Perception of invisible masked objects in early infancy" Proceedings of the National Academy of Sciences of the United States of America, 118 (27), e2103040118.
Toronto, ON - Despite research showing associations between anabolic steroid use and criminal offending, the possibility of a similar association between legal performance-enhancing substance use, such as creatine, and criminal offending remained unknown. A new study published online in the journal Drug and Alcohol Dependence now shows that both forms of performance-enhancing substance use is longitudinally associated with criminal offending among U.S. adults.
The study, which analyzed a sample of over 9,000 U.S. participants from the National Longitudinal Study of Adolescent Health (Add Health), highlights the need for more research on performance-enhancing substances to understand the complex social problems associated with their use.
"This is the first study to identify relationships between legal performance-enhancing substance use and criminal offending," says lead author Kyle T. Ganson, PhD, MSW, assistant professor at the University of Toronto's Factor-Inwentash Faculty of Social Work. "This finding is acutely salient because these substances are easily accessible and commonly used, particularly among young people."
The study highlights the importance of clinical professionals screening for performance-enhancing substance use and assessing patterns of criminal offending among young people.
"We need more research to identify effective prevention and intervention techniques to ensure that we reduce the use of these substances, as well as curtail any connection with criminal offending," says co-author Jason M. Nagata, MD, MSc, assistant professor at the University of California, San Francisco's Department of Pediatrics.
"The associations found in this study are likely explained by an intersection of behavioral, psychological, and sociocultural influences," says Ganson. "We therefore need to target this problem from a multitude of angles, including clinically and via public health and policy interventions."
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Ganson, K.T., Testa, A., Jackson, D.B., & Nagata, J.M. (2021). Performance-Enhancing Substance Use and Criminal Offending: A 15-Year Prospective Cohort Study. Drug and Alcohol Dependence, https://doi.org/10.1016/j.drugalcdep.2021.108832
Edible Cholera vaccine made of powdered rice proves safe in phase 1 human trials
Study points towards role of gut microbiome in vaccine effectiveness
IMAGE: RESEARCHERS AT THE UNIVERSITY OF TOKYO HAVE ANNOUNCED THE SUCCESSFUL RESULTS OF THE PHASE 1 CLINICAL TRIAL OF A NEW TYPE OF VACCINE TO PROTECT AGAINST CHOLERA AND TRAVELERS' DIARRHEA.... view more
CREDIT: IMAGE BY DR. HIROSHI KIYONO, CC BY 4.0
A new vaccine to protect against deadly cholera has been made by grinding up genetically modified grains of rice. The first human trial has shown no obvious side effects and a good immune response. Researchers based at the University of Tokyo and Chiba University have published the peer-reviewed results of the Phase 1 clinical trial of the vaccine, named MucoRice-CTB, in The Lancet Microbe.
Vaccine manufacturing has made enormous strides in 2020, spurred on by COVID-19. However, the complexity of mRNA-based SARS-CoV-2 vaccines has highlighted the value of inoculations that can be made, transported and stored cheaply and without refrigeration.
The MucoRice-CTB vaccine is stable at room temperature from start to finish.
"I'm very optimistic for the future of our MucoRice-CTB vaccine, especially because of the dose escalation results. Participants responded to the vaccine at the low, medium and high doses, with the largest immune response at the highest dose," said Professor Hiroshi Kiyono, D.D.S., Ph.D., from the Institute of Medical Science at the University of Tokyo who leads the MucoRice project. Dr. Kiyono is also a faculty member at Chiba University in Japan and the University of California, San Diego, in the U.S.
Thirty volunteers received a placebo and groups of 10 volunteers received a total of four doses spaced every two weeks of either 3 milligrams (mg), 6 mg or 18 mg each of the vaccine. Tests two and four months after receiving the last dose revealed that volunteers who responded to the vaccine had IgA and IgG antibodies - two types of proteins the immune system produces to fight infections - specific to cholera toxin B (CTB). Participants who received a higher dose of vaccine were more likely to have CTB-specific antibodies.
An independent review board found no evidence of significant side effects.
Growing a new type of vaccine Vibrio cholerae bacteria is spread most often by drinking water contaminated with sewage. Without medical attention, cholera can kill in mere hours due to diarrhea with severe dehydration. Cholera infects 1.3 million to 4 million people and causes 21,000 to 143,000 deaths each year, according to the World Health Organization.
There are four modern needle-free cholera vaccines, all of which are given as drops on the tongue, but require cold storage and are made from whole killed or live-attenuated (weakened) cholera cells;https://www.fda.gov/media/98688/download).
The new cholera vaccine grows in genetically modified Japanese short-grain rice plants that produce a nontoxic portion of CTB that can be recognized by the immune system. CTB is similar in structure to a toxin made by some types of disease-causing E. coli bacteria, so cholera vaccines often provide cross protection against travelers' diarrhea.
Researchers grow the rice plants in a purpose-built, indoor hydroponic farm that meets WHO good manufacturing practice standards for medicines, which ensures that the vaccine remains uncontaminated and that the plants are isolated from the natural environment.
The plants produce the CTB subunit in their seeds, the edible grains of rice, and store the antigens in droplets called protein bodies with membranes made of fat.
"The rice protein bodies behave like a natural capsule to deliver the antigen to the gut immune system," said Dr. Kiyono.
Other medicines have been grown in plants, most often in the leaves - including treatments for Ebola, lymphoma and flu - but the drugs have to be extracted and purified before being used. The grain-based aspect of the MucoRice system avoids those extra steps, the need for cold storage, and protects the antigens as they travel through the harsh acid of the stomach.
When the plants are mature, the rice is harvested and ground into a fine powder, then sealed in aluminum packets for storage. When people are ready to be vaccinated, the powder is mixed with about 90 milliliters (1/3 U.S. cup) of liquid and then drunk. Researchers have only tested the vaccine using saline (a salt solution equivalent to body fluids), but they expect it would work equally well with plain water.
Immunity through the gut is strong, but complicated by the microbiome
"The beautiful part of our vaccine is that it wisely uses the body's mucosal immune system through the gut for the induction of antigen-specific antibodies," said Dr. Kiyono.
MucoRice-CTB enters the body through intestinal mucosal membranes, mimicking a natural way of encountering and responding to germs. Stimulating the mucosal immune system produces two classes of antibodies that identify germs and target them for removal, IgG and IgA. Vaccines that are injected under the skin or into a muscle generally increase only IgG, not IgA, antibodies.
Volunteers who responded to MucoRice-CTB had their highest blood levels of antigen-specific IgG and IgA after eight to 16 weeks.
However, 11 of the 30 volunteers who received the vaccine showed low or no measurable immune response. All study volunteers reported never traveling outside of Japan, so it is unlikely that they had any previous exposure or natural immunity to V. cholerae or pathogenic E. coli.
"When we saw those data about the 11 low and nonresponders, we thought maybe gut microflora have an influence on the outcome of the immune response," Dr. Kiyono recalled.
The microflora or microbiome is the community of microorganisms that live in our bodies and either benefit us or are harmless. It is well accepted that the microflora of the digestive system influence health and immunity, but scientists are just beginning to understand the precise mechanisms of the relationship.
Extensive genetic analysis of all volunteers' fecal samples identified the thousands of bacterial species living in volunteers' intestines.
"In simplified terms, high responders had more diversified microflora, and in the low-responder group, diversity was much narrower," said Dr. Kiyono.
Researchers cautioned that the small size of the Phase 1 study - giving the vaccine to only 30 healthy Japanese male volunteers - means the relevance and prevalence of nonresponders is still unclear and that the total difference in microflora diversity was subtle. However, the results do hint at the larger role of microflora in vaccine effectiveness.
"It's all speculation right now, but maybe higher microflora diversity creates a better situation for strong immune response against oral vaccine," said Dr. Kiyono.
The link between the gut microbiome and vaccine effectiveness has been previously revealed by the unfortunate fact that most vaccines are developed in industrialized nations and some are then less effective when delivered in developing countries. Mucosal vaccines, including oral vaccines against polio and cholera, seem especially prone to this disparity. Most scientific theories to explain the phenomenon focus on chronic intestinal inflammation linked to poor sanitation. (https://doi.org/10.1186/1741-7007-8-129)
"Probably for every vaccination right now, even injected vaccines, we should think of the immune status of the individual based on the condition of their microflora," said Dr. Kiyono.
It remains to be seen how microflora diversity will impact the global effectiveness of the new MucoRice edible vaccine system compared to other oral vaccines' records.
For now, the researchers plan to work with partners in the pharmaceutical industry to bring MucoRice-CTB into the next phase of clinical trials in Japan and overseas.
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Research Publication
Yoshikazu Yuki, Masanori Nojima, Osamu Hosono, Hirotoshi Tanaka, Yasumasa Kimura, Takeshi Satoh, Seiya Imoto, Satoshi Uematsu, Shiho Kurokawa, Koji Kashima, Mio Mejima, Rika Nakahashi-Ouchida, Yohei Uchida, Takanori Marui, Noritada Yoshikawa, Fumitaka Nagamura, Kohtaro Fujihashi, Hiroshi Kiyono. 24 June 2021. Assessment of Oral MucoRice-CTB vaccine for the safety and microbiota-dependent immunogenicity in humans: A Randomized Trial. The Lancet Microbe.
The University of Tokyo is Japan's leading university and one of the world's top research universities. The vast research output of some 6,000 researchers is published in the world's top journals across the arts and sciences. Our vibrant student body of around 15,000 undergraduate and 15,000 graduate students includes over 4,000 international students. Find out more at http://www.u-tokyo.ac.jp/en/ or follow us on Twitter at @UTokyo_News_en.
Funders
Japan Agency for Medical Research and Development (AMED), Ministry of Education, Culture, Sports, Science and Technology (MEXT), Science and Technology Research Partnership for Sustainable Development (SATREPS)
AI used to predict unknown links between viruses and mammals
IMAGE: NETWORKS OF OBSERVED AND PREDICTED ASSOCIATIONS BETWEEN WILD AND SEMI-DOMESTICATED MAMMALIAN HOSTS AND KNOWN VIRUS SPECIES. view more
CREDIT: DR MAYA WARDEH
A new University of Liverpool study could help scientists mitigate the future spread of zoonotic and livestock diseases caused by existing viruses.
Researchers have used a form or artificial intelligence (AI) called machine-learning to predict more than 20,000 unknown associations between known viruses and susceptible mammalian species. The findings, which are published in Nature Communications, could be used to help target disease surveillance programmes.
Thousands of viruses are known to affect mammals, with recent estimates indicating that less than 1% of mammalian viral diversity has been discovered to date. Some of these viruses such as human and feline immunodeficiency viruses have a very narrow host range, whereas others such as rabies and West Nile viruses have very wide host ranges.
"Host range is an important predictor of whether a virus is zoonotic and therefore poses a risk to humans. Most recently, SARS-CoV-2 has been found to have a relatively broad host range which may have facilitated its spill-over to humans. However, our knowledge of the host range of most viruses remains limited," explains lead researcher Dr Maya Wardeh from the University's Institute of Infection, Veterinary and Ecological Sciences.
To address this knowledge gap, the researchers developed a novel machine learning framework to predict unknown associations between known viruses and susceptible mammalian species by consolidating three distinct perspectives - that of each virus, each mammal, and the network connecting them, respectively.
Their results suggests that there are more than five times as many associations between known zoonotic viruses and wild and semi-domesticated mammals than previously thought. In particular, bats and rodents, which have been associated with recent outbreaks of emerging viruses such as coronaviruses and hantaviruses, were linked with increased risk of zoonotic viruses.
The model also predicts a five-fold increase in associations between wild and semi-domesticated mammals and viruses of economically important domestic species such as livestock and pets.
Dr Wardeh said: "As viruses continue to move across the globe, our model provides a powerful way to assess potential hosts they have yet to encounter. Having this foresight could help to identify and mitigate zoonotic and animal-disease risks, such as spill-over from animal reservoirs into human populations."
Dr Wardeh is currently expanding the approach to predict the ability of ticks and insects to transmit viruses to birds and mammals, which will enable prioritisation of laboratory-based vector-competence studies worldwide to help mitigate future outbreaks of vector-borne diseases.
IMAGE: AFRICAN SAVANNA ELEPHANT TEMBO, AT THE SAN DIEGO ZOO, WAS ONE OF THE ELEPHANT PARTICIPANTS IN THE STUDY. view more
CREDIT: LISA BARRETT
Just as humans have their own individual personalities, new research in the Journal of Comparative Psychology shows that elephants have personalities, too. Moreover, an elephant's personality may play an important role in how well that elephant can solve novel problems.
The article was written by Lisa Barrett and Sarah Benson-Amram in the University of Wyoming's Animal Behavior and Cognition Lab, led by Benson-Amram. It may be viewed here.
The authors of the paper tested 15 Asian elephants and three African savanna elephants in three zoos across the country -- the San Diego Zoo, the Smithsonian's National Zoological Park and the Oklahoma City Zoo -- with the help of elephant caretakers.
Previous work from Barrett and Benson-Amram demonstrated that Asian elephants can use water as a tool to solve a novel problem -- and reach a tasty marshmallow reward -- in what's called the floating object task. This time, the authors designed new novel tasks, as well as personality tests, for the elephants.
"We took a comprehensive approach by using three different problem-solving tasks and three types of personality assessments to determine if individual personality played a role in which elephants were able to solve these tasks," Barrett says. "Since we couldn't give the elephants a personality test like the ones you're familiar with online, we had to think creatively."
The authors developed novel object tests, in which they presented the elephants with an unfamiliar object, a mylar balloon, a burned log and the scent of a predator (lion or hyena), and recorded the elephants' responses. You can watch videos of the novel object trials: balloon, burned log and urine. They also asked elephant caretakers to fill out a survey about the personalities of the animals in their care; and, finally, they observed the elephants interacting with one another in their zoo habitats.
From those assessments, Barrett and Benson-Amram learned that the surveys and observations were the most reliable methods to get at elephant personality. Overall, Barrett and Benson-Amram measured traits such as active, affectionate, aggressive, defiant, excitable, mischievous, shy and sociable, which have been studied in other animals as well.
"We were eager to see if the personality traits we uncovered through the surveys and observations predicted success on novel problem-solving tasks," Benson-Amram says. "The elephants had an opportunity to solve each task three times, and we measured if they learned to solve faster over time, and then we traced their success back to their personality type."
The three problem-solving tasks included the trap tube task, which is a common test used with primates but which had never been presented outside of primates before. You can watch videos of the problem-solving trials: boxed ball, rod ball and trap tube.
Barrett and Benson-Amram found that elephants did learn to solve two out of the three tasks faster over time, even though the elephants only received three trials on each task. Traits including aggressiveness and activity were important predictors of problem-solving overall, but the personality traits measured did not significantly predict learning ability.
This study makes connections between two sources of individual variation, personality and cognition, in threatened species. One reason it is important to examine problem-solving in elephants is that they are faced with new problems that they need to solve regularly in the wild. For example, if certain traits enable elephants to overcome novel problems, elephants may be more likely to invade farmland and contribute to human-elephant conflict. With more research, managers can predict which elephants might overcome or habituate to deterrents, and managers can devote more resources to tracking elephants.
The authors call for more work on different forms of personality assessments to determine which methods would be best for management of zoo and wild elephants.
"Research with free-ranging elephants can extend this study to determine which personality traits are most important for solving novel problems that elephants experience in the wild," says Barrett, a 2020 graduate of UW's Program in Ecology and the Department of Zoology and Physiology.
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Actively addressing inequalities promotes social change
UMass Amherst social scientist part of global research team studying group interactions
IMAGE: LINDA TROPP, PROFESSOR OF SOCIAL PSYCHOLOGY AT UMASS AMHERST, LED THE MULTINATIONAL STUDY IN THE U.S. view more
CREDIT: UMASS AMHERST
What does it take for people to commit to take action to promote social equality? And how might this differ for people from advantaged and disadvantaged groups?
An international team, including Linda Tropp at the University of Massachusetts Amherst and researchers in 23 countries, finds more mutual support for social change among advantaged and disadvantaged groups when inequality is actively addressed and the psychological needs of each group are met. The new research, led by the University of Zurich (UZH), was published in the Journal of Personality and Social Psychology.
"What this research is showing is that people on both sides really need to acknowledge that they have different motivations and concerns when they interact with each other," says co-author Tropp, the lead researcher in the U.S. who has examined how members of different groups experience intergroup contact for more than 20 years.
Prior research has shown that advantaged groups prefer to discuss commonalities among groups rather than differences between groups, at the same time as they desire to feel accepted and not be labeled as biased. But if members of socially disadvantaged groups simply have pleasant, positive exchanges with people who are not themselves targets of discrimination, they may emerge from those contact experiences even less committed to fighting for social justice and improving their own group's social position.
As first author Tabea Hässler of UZH says, "They get the deceptive impression that their own group no longer suffers so much discrimination... It is therefore important that social inequalities and discrimination between different social groups are actively addressed and named." This helps to meet the needs of disadvantaged group members, such as racial minorities and LGBTIQ+ individuals, who are motivated to have a voice and feel empowered in their relations with advantaged groups.
Each group's psychological needs are therefore an important part of the equation. "If contact situations are structured where members of disadvantaged groups or minority groups feel empowered, that they have a voice and are being listened to and heard, that's the time when contact with members of advantaged groups may support their interest in collective action to challenge the status quo," says Tropp, professor of social psychology at UMass Amherst.
Similarly, when members of majority groups "feel welcome as allies in that cause and not presumed to be racist, then that can bolster their willingness to use some of their time and energy to try to promote social equality," she says.
To gather their data, 43 researchers around the world conducted a survey with more than 11,000 individuals from a range of identity groups, including heterosexual individuals and members of sexual or gender minorities, migrants and members of their respective host societies, as well as indigenous groups and religious minorities.
"Overall, our findings suggest that contact across group boundaries fosters social change when it meets the targeted needs of disadvantaged and advantaged groups," says Johannes Ullrich, professor of social psychology at UZH.
Tropp says one next step is to help prepare members of advantaged groups to engage in difficult conversations about power relations and discrimination.
"To the extent that the advantaged engage in those conversations with disadvantaged groups, talking about the structural inequalities that do exist and need to be addressed, then it's likely that both members of disadvantaged groups as well as advantaged groups will be more prepared to engage in efforts to challenge the inequalities that we have in our society," she says.
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People across the world favor paid parental leave, study finds
Americans are also supportive, but with some caveats
COLUMBUS, Ohio - Although the United States is the only wealthy nation that doesn't guarantee paid leave to mothers or fathers after the arrival of a new child, Americans endorse providing paid time off for parents nearly as much as people from other countries.
About 82% of Americans support paid maternity leave, just slightly less than the 86% who support it in 26 wealthy nations, a new study shows.
Where Americans differ from the rest of the world is that they are less supportive of government funding for paid leaves, prefer shorter leave times and are less supportive of paid leave for fathers.
"We find marked differences in how Americans want paid leave administered compared to the rest of the world - but very similar desires to have leave available," said Chris Knoester, co-author of the study and associate professor of sociology at The Ohio State University.
Knoester conducted the study with Richard Petts, professor of sociology at Ball State University, and Amelia Li, a doctoral student in sociology at Ohio State. Their findings were published this week in the International Journal of Comparative Sociology.
The researchers analyzed data from 35,488 people who participated in the International Social Survey Programme 2012. The participants come from 26 wealthy countries, including the United States, that belong to the OECD, the Organisation for Economic Co-Operation and Development.
Overall, the study found high levels of support for paid leave across the developed world, as well as support for relatively long paid leave periods and government funding for the time off, Knoester said.
Worldwide, about 75% of people wanted government support for paid maternity leave. In a previous study the authors published in Social Science Research, they found that about half wanted it for paternity leave.
Support for government funding was much lower in the United States - about half endorsed it for maternity leave, and only a third wanted it for paternity leave. And very few Americans wanted government funding leave by itself, Knoester said. Most wanted the government and private employers to share the costs.
"This may be a major reason why we don't have more widespread and generous leave offered in the United States, even though most people support it," he said.
"If we don't have leave provided through the federal government, we get what we have now, which is a patchwork of states and employers offering different leave policies."
Americans also didn't want as much paid leave as did those from other countries in the survey. People in the United States wanted about four months of leave allocated to new parents. Worldwide, people supported close to 13 months.
Support for paid leave for fathers is lower than for maternity leave, both in the United States and in the rest of the countries surveyed.
Overall, about 60% of people surveyed wanted paid paternity leave, compared to just over half of Americans.
While a lack of support for government funding may be one reason why the U.S. is the only major country without paid maternity leave, there are other reasons, the researchers said.
In another new study by the researchers, forthcoming in Sociological Focus, findings showed that older white people with more conservative political views in the United States were least supportive of paid parental leave.
"These tend to be the people in the elite positions in our society who make those policy decisions about paid leave," Li said. "That makes it difficult to enact leave policies."
Petts noted another reason why political elites in the United States may be less supportive of government-supported leave.
"These are the people who already largely have access to paid leave through their employers. They would not directly benefit from it, because they already have it," Petts said.
"It is a story of the haves and the have-nots."
The international study also showed other factors that affect people's support of paid leave.
As expected, women were generally more likely to support paid leave and wanted longer time off.
Also, people who were strong supporters of traditional gender roles, in which men focus on paid work and women focus on the home and family, were less supportive of paid leave than people who advocated more egalitarian gender roles.
"Relatedly, when people endorse both members of a couple working, they are more supportive of paid leave and this shows up particularly for support of paid leave for fathers in the U.S.," Knoester said.
In addition, individuals who felt more conflict between their home and job responsibilities were more likely to endorse paid leave.
While the survey that this study was based on was done 10 years ago, the researchers said more recent surveys suggest people's views have not changed much. If anything, people may have become slightly more supportive of paid leave, particularly in the United States.
"We are still seeing very high support of paid maternity leave, and there are some indications that support for paternity leave has increased since 2012," Knoester said.
In addition, signs point toward more Americans being in favor of government support of parental leave. Nine states and Washington, D.C., have enacted paid parental leave programs. Last November, Colorado voters passed a ballot measure that allows for up to 12 weeks of leave.
"I would never have guessed that the kind of measure enacted in Colorado would pass in the U.S. It suggests Americans are becoming more open to government support," Petts said.
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Association of Childcare Facility Closures With Employment Status of US Women vs Men During the COVID-19 Pandemic
In the US, policy responses to COVID-19 have varied across states, with some states requiring closures of childcare facilities to reduce population mobility and contact among households. Such policies may have been associated with reductions in the growth rate of the pandemic but may also have had unintended consequences. Women perform more unpaid labor than men in couples with children.1 Because of these inequities, negative outcomes associated with lack of childcare options, such as reductions in hours worked, may be concentrated among working mothers. A study in Italy2 found that the amount of household labor remained greater for women during the early period of the COVID-19 pandemic. We investigated the association between childcare facility closures and employment status among women vs men with children during the first year of the COVID-19 pandemic (January to December 2020) in the US.
Methods
For this cross-sectional study, we obtained employment and demographic data from the Integrated Public Use Microdata Series, Current Population Survey from January to December 2020. The number of deaths from COVID-19 per month was obtained from the Johns Hopkins Coronavirus Resource Center.3 Childcare closure data were obtained from the COVID-19 US State Policy Database.4 Our unit of observation was the person-month, restricted to individuals aged 18 to 64 years in households with children. This study was deemed to be exempt from review and informed consent by the Boston University institutional review board because it involved nonhuman subjects research. The study followed the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) reporting guideline.
We used a triple differences approach with a linear probability model to estimate the association between childcare facility closures and overall changes in employment stratified by sex. Interrupted time series models were then used to assess changes in employment by race/ethnicity, sex, and state childcare facility closure status. Models controlled for individual-level demographic characteristics (eg, age, family size) and state-level COVID-19 case loads, with fixed effects for industry, occupation, month, state, and household. We controlled for race/ethnicity to improve model precision and stratify our findings. We used Stata, version 16-MP (StataCorp LLC) for statistical analysis. Additional information is given in the eMethods in the Supplement.
Results
This study included 48 920 individuals (13 307 in states with childcare closures and 35 613 in states without closures), of whom 24 452 (49.98%) were women and 24 648 (50.02%) were men; the mean SD age was 43.3 (9.6) years. The sample comprised 165 158 individual-months, including 44 925 individual-months in 15 states that closed childcare facilities by April 2020. All closures were rescinded by June 2020. Employment decreased for both men and women beginning in April 2020 (Figure). Estimates from the triple differences analysis showed that compared with men, the likelihood of a women being employed was −2.6 percentage points (95% CI, −4.3 to −1.0 percentage points) in closure states while closures were in effect. Nationally, this equated to a reduction of approximately 611 000 workplace positions among 23.5 million working mothers.5 Estimates were similar when controlling for the number of adults (vs men) in the household and greater when restricting to households with children younger than 6 years (−3.3 percentage points; 95% CI, −6.2 to −0.5% percentage points).
Interrupted time series models indicated that the largest differences in employment were observed in households with Hispanic and Black individuals, although differential estimates by sex in closure states were greatest in households with Hispanic and White individuals (Table). In a falsification test for households without children, there was no association of sex with employment status (estimate, −0.8 percentage points; 95% CI, −2.2 to 0.4 percentage points), and there was also no association in a test for households with only children of middle school age (11 years to <18 years) (estimate, −1.1 percentage points; 95% CI, −3.5 to 1.3 percentage points).
Estimates from the interrupted time series model for hours worked were greater for both men (−3.9; 95% CI, −4.9 to −3.0) and women (−5.8; 95% CI, −6.5 to −5.0) in closure states than for those in nonclosure states (men: −3.5 [95% CI, −4.2 to −2.8]; women −4.3 [95% CI, −5.2 to −3.5]). Women in closure states had a differential reduction of approximately 1 hour worked unconditional on employment.
Discussion
In this cross-sectional analysis, state-level childcare facility closures were associated with greater reductions in employment among women compared with men. This association was limited to parents of children younger than 6 years. Our results comport with prior estimates6; however, the longer study period allowed us to evaluate whether these associations dissipated by December 2020. We also found that the sex-differential associations were strongest in households with White and Hispanic individuals. In addition, we observed a differential association of sex with hours worked.
Our study has several limitations. First, we could not observe actual childcare service use. Second, because of our observational study design, all findings should be treated as associations. Third, other simultaneously enacted policies (eg, business closures) may have moderated the primary associations, but such policies were not included in this study.
Labor market outcomes may differ by sex, and well-intentioned policies may exacerbate existing inequities. Our findings suggest that additional policy interventions to support women in families with children are needed.
Corresponding Author: Yevgeniy Feyman, BA, Department of Health Law, Policy, and Management, Boston University School of Public Health, 715 Albany St, Talbot Bldg. T2-West, Boston, MA 02118 (yfeyman@bu.edu).
Author Contributions: Mr Feyman and Dr Griffith had full access to all of the data in the study and take responsibility for the integrity of the data and the accuracy of the data analysis.
Concept and design: All authors.
Acquisition, analysis, or interpretation of data: Feyman, Griffith.
Drafting of the manuscript: All authors.
Critical revision of the manuscript for important intellectual content: Feyman, Griffith.
Statistical analysis: Feyman, Griffith.
Obtained funding: Griffith.
Administrative, technical, or material support: Fener.
Supervision: Griffith.
Conflict of Interest Disclosures: None reported.
Funding/Support: This study was supported by grant K12 HS026395 (Dr Griffith) from the Agency for Healthcare Research and Quality.
Role of the Funder/Sponsor: The Agency for Healthcare Research and Quality had no role in the design and conduct of the study; collection, management, analysis, and interpretation of the data; preparation, review, or approval of the manuscript; and decision to submit the manuscript for publication.
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