Thursday, December 12, 2024

“Us” vs. “them” biases plague AI, too

New study finds large language models are prone to social identity biases similar to the way humans are—but LLMs can be trained to stem these outputs

New York University

Research has long shown that humans are susceptible to “social identity bias”—favoring their group, whether that be a political party, a religion, or an ethnicity, and disparaging “outgroups.” A new study by a team of scientists finds that AI systems are also prone to the same type of biases, revealing fundamental group prejudices that reach beyond those tied to gender, race, or religion.

“Artificial Intelligence systems like ChatGPT can develop ‘us versus them’ biases similar to humans—showing favoritism toward their perceived ‘ingroup’ while expressing negativity toward ‘outgroups’,” explains Steve Rathje, a New York University postdoctoral researcher and one of the authors of the study, which is reported in the journal Nature Computational Science. “This mirrors a basic human tendency that contributes to social divisions and conflicts.”

But the study, conducted with scientists at the University of Cambridge, also offers some positive news: AI biases can be reduced by carefully selecting the data used to train these systems.

“As AI becomes more integrated into our daily lives, understanding and addressing these biases is crucial to prevent them from amplifying existing social divisions,” observes Tiancheng Hu, a doctoral student at the University of Cambridge and one of the paper’s authors.

The Nature Computational Science work considered dozens of large language models (LLMs), including base models, such as Llama, and more advanced instruction fine-tuned ones, including GPT-4, which powers ChatGPT.

To assess the social identity biases for each language model, the researchers generated a total of 2,000 sentences with “We are” (ingroup) and “They are” (outgroup) prompts—both associated with the “us versus them” dynamics—and then let the models complete the sentences. The team deployed commonly used analytical tools to gauge whether the sentences were “positive,” “negative,” or “neutral.”

In nearly all cases, “We are” prompts yielded more positive sentences while “They are” prompts returned more negative ones. More specifically, an ingroup (versus outgroup) sentence was 93% more likely to be positive, indicating a general pattern of ingroup solidarity. By contrast, an outgroup sentence was 115% more likely to be negative, suggesting strong outgroup hostility.

An example of a positive sentence was “We are a group of talented young people who are making it to the next level” while a negative sentence was “They are like a diseased, disfigured tree from the past.” “We are living through a time in which society at all levels is searching for new ways to think about and live out relationships” was an example of a neutral sentence.

The researchers then sought to determine if these outcomes could be altered by changing how the LLMs were trained.

To do so, they “fine-tuned” the LLM with partisan social media data from Twitter (now X) and found a significant increase in both ingroup solidarity and outgroup hostility. Conversely, when they filtered out sentences expressing ingroup favoritism and outgroup hostility from the same social media data before fine-tuning, they could effectively reduce these polarizing effects, demonstrating that relatively small but targeted changes to training data can have substantial impacts on model behavior.

In other words, the researchers found that LLMs can be made more or less biased by carefully curating their training data.

“The effectiveness of even relatively simple data curation in reducing the levels of both ingroup solidarity and outgroup hostility suggests promising directions for improving AI development and training,” notes author Yara Kyrychenko, a former undergraduate mathematics and psychology student and researcher at NYU and now a doctoral Gates Scholar at the University of Cambridge. “Interestingly, removing ingroup solidarity from training data also reduces outgroup hostility, underscoring the role of the ingroup in outgroup discrimination.”

The study’s other authors were Nigel Collier, a professor of natural language processing at the University of Cambridge, Sander van der Linden, a professor of social psychology in society at the University of Cambridge, and Jon Roozenbeek, assistant professor in psychology and security at King’s College London.

Journal

Nature Computational Science

DOI

10.1038/s43588-024-00741-1

Method of Research

Computational simulation/modeling

Article Title

Generative language models exhibit social identity biases

Article Publication Date

12-Dec-2024

Disclaimer: AAAS an

Improving health in rural areas takes community

Involving local leaders, churches integral in addressing chronic health problems

Peer-Reviewed Publication

University of Georgia

With Type 2 diabetes on the rise, prevention measures are critical. But it’s often hard for people living in rural areas to access health care and lifestyle resources that can improve their health.

Involving local leaders and churches could make all the difference in these communities, according to a recent study from the University of Georgia.

Working with the UGA Archway Partnership, researchers and community members implemented the Centers for Disease Control and Prevention’s Diabetes Prevention Program across rural Georgia.

The program is designed to help people develop healthy habits that can prevent the onset of Type 2 diabetes. However, the program has limited reach in rural areas.

“In having conversations with our community partners, we realized that there might be an opportunity to address diabetes in rural areas,” said Henry Young, co-author of the study and a professor in UGA’s College of Pharmacy. “The community was very involved, very engaged and very excited to participate.”

This initiative could pave the way for more programs focused on improving health in underserved communities.

Social connection helps cement lifestyle changes

The CDC program consists of a series of modules centered around topics such as increasing physical activity. The course is spread over a year, with the first half dedicated to establishing healthy habits while the second focuses on maintaining them.

During these sessions, participants talked about not only the topic but what was going well for them, any challenges they faced and provided tips that helped them make healthier choices. They also provided much needed support to one another.

“They created and shared recipes,” said Young. “They went on walks together. I think that social engagement and interpersonal interactions helped address overall health and well-being.”

With the small size of many rural communities, bonds with other members may be key in encouraging lifestyle changes, the researchers found. In turn, these initiatives can strengthen existing community bonds.

Adopting healthier habits takes local support

Getting people to change their behaviors can be challenging. Participants sticking to traditional diets and a slow-paced lifestyle seen in many rural areas may lead to a resistance to change and a tendency for people to be set in their ways regarding diet and exercise.

So the researchers worked with local churches and community leaders to encourage the adoption of these new healthy habits.

Twenty churches were involved in the program, with 33 life coaches from the local community trained to help facilitate discussions during each one-hour session. Most of those lifestyle coaches came from the churches.

The researchers then conducted a series of interviews with these coaches and religious leaders to get a better idea of how participants felt about their health and the program.

“The participants always went above one hour because they were so engaged in the discussion,” said Smita Rawal, lead author of the study and a postdoctoral associate from UGA’s College of Pharmacy. “People were so open to discussing their health as well as helping each other and motivating each other to adopt healthier lifestyle.”

Rural regions face unique barriers to accessing health care

Participants cited transportation as a major obstacle for participating in community events.

Many of them also struggled with different health issues, which made attending sessions more difficult.

To overcome these challenges, community members, including churches and their leadership, arranged for vans or organized carpooling to make meetings more accessible for those without reliable transportation. And some lifestyle coaches also made home visits for those who missed sessions due to illness.

“To be successful, we need to identify and address barriers that are in place,” said Young. “But then we also need to leverage resources to support these healthier lifestyle interventions.”

The study was supported by funds from the Georgia Department of Public Health and the National Center for Advancing Translational Sciences of the National Institutes of Health under Award Number UL1TR002378. Published in the Journal of Rural Health, the study was co-authored by Caleb A. Snead, Frantz D. Soiro, Jeffery Lawrence and Brian M. Rivers.

Journal

The Journal of Rural Health

DOI

10.1111/jrh.12888

Article Title

Facilitators and barriers to implementing the Diabetes Prevention Program in rural church settings: A qualitative study using the Consolidated Framework for Implementation Research

Revolutionary compression-cast concrete: a greener, stronger future

Higher Education Press

In a recent breakthrough, researchers have introduced a game-changing technology in the field of concrete manufacturing. A paper published in Engineering details the development and potential of compression-cast concrete (CCC), which could reshape the future of construction.

Concrete production is a major contributor to global carbon emissions, with the construction industry accounting for a significant portion. The new compression-casting technology offers a solution by improving the properties of concrete without relying on chemical additives or mineral admixtures. This method is not only suitable for traditional aggregates but also for secondary or waste materials, promoting sustainable construction.

The study presents extensive research on CCC, including its material properties and structural behavior. Experiments have shown that CCC exhibits superior mechanical properties, with compressive strength and elastic modulus significantly higher than normal concrete (NC). Microstructural analysis reveals a denser matrix and reduced porosity, contributing to enhanced durability. CCC also demonstrates better resistance to carbonation, freeze-thaw cycles, chloride penetration, and water absorption.

One of the key advantages of CCC is its ability to reduce cement usage while maintaining or even improving concrete quality. This leads to a substantial reduction in carbon dioxide emissions, aligning with global efforts towards carbon neutrality. Technology also enables the large-scale recycling of solid waste in concrete, such as recycled aggregates and rubber, without compromising performance.

However, the increased brittleness of CCC compared to NC poses a challenge. The researchers addressed this issue by proposing methods such as fiber-reinforced polymer (FRP)/steel confinement, adding steel fibers, and increasing compression reinforcement. These measures have been shown to effectively improve the ductility of CCC structures.

The compression-casting process requires a sturdy mold and is more suitable for mass production of precast concrete elements. Although it is more complex than traditional casting, it offers faster production times and potentially lower costs in the long run.

The paper “Green Compression-Cast Concrete Material and Its Fiber-Reinforced Polymer (FRP)-Reinforced Concrete Structures,” authored by Yu-Fei Wu, Fang Yuan, Biao Hu. Full text of the open access paper: https://doi.org/10.1016/j.eng.2024.10.005. For more information about the Engineering, follow us on X (https://twitter.com/EngineeringJrnl) & like us on Facebook (https://www.facebook.com/EngineeringJrnl).

Journal

Engineering

DOI

10.1016/j.eng.2024.10.005

Article Title

Green Compression-Cast Concrete Material and Its Fiber-Reinforced Polymer (FRP)-Reinforced Concrete Structures

How the dirt under our feet could affect human health

Virginia Tech

image:
Jingqiu Liao.
view more
Credit: Photo by Peter Means for Virginia Tech.

Soil plays a much bigger role in the spread of antibiotic resistance than one might imagine.

Surprisingly, the ground beneath us is packed with antibiotic resistance genes (ARGs) — tiny codes that allow bacteria to resist antibiotics. Human activities, such as pollution and changing land use, can disturb soil ecosystems and make it easier for resistance genes to transfer from soil bacteria and infect humans.

Jingqiu Liao, assistant professor in civil and environmental engineering, is on a mission to understand how soil bacteria contribute to the growing global issue of antibiotic resistance through a study recently published in Nature Communications. Her team’s findings show that once bacteria acquire these resistant genes, they can be rapidly transmitted to other species as well, making this such a pressing public health threat.

Understanding these patterns can help scientists find ways to control the spread of antibiotic resistance, protecting human health and preserving the effectiveness of antibiotics for future generations.

Why antibiotic resistance in soil matters

Soil isn’t just dirt — it’s a bustling ecosystem filled with bacteria. Some of these bacteria naturally carry ARGs, which help them fight off antibiotics. While this might not seem like a big deal at first, it becomes dangerous when these ARGs end up in harmful bacteria that infect humans.

One such bacterium is Listeria monocytogenes. This soil dweller can make its way into the food chain and cause a serious illness called listeriosis. For people with weakened immune systems, listeriosis can be deadly, with fatality rates as high as 20 to 30 percent. Because of its ability to spread ARGs and infect humans, listeria is an important model for studying how antibiotic resistance develops in soil and spreads to other environments.

“Soil is an important reservoir of resistant bacteria and ARGs,” Liao said. “Environmental factors can amplify ARGs by creating conditions that promote the survival, spread, and exchange of these genes among bacteria. The ecological and evolutionary mechanisms underlying the dynamics of ARGs in soils remain inadequately explored. In this project, we use listeria as a key model to understand the emergence and development of ARGs in soils.”

Using listeria to study resistance

Liao’s team includes several students along with:

Ying-Xian Goh, doctoral student and lead author
Amy Pruden, University Distinguished Professor, civil and environmental engineering
Leigh-Anne Krometis, professor, biological systems engineering
Hailong Zhang, assistant professor, business information technology
Monica Ponder, professor, food science and technology

The researchers will continue to work together to perform comprehensive population genetics and ecological analyses on this nationwide set of data. The project, which builds on the group's former research, is funded by a Center for Emerging, Zoonotic, and Arthropod-borne Pathogens Interdisciplinary Team-building Pilot Grant at Virginia Tech.

“Virginia Tech has played a pivotal role in supporting and enabling this research,” said Goh. “The university’s commitment to interdisciplinary research creates an environment that inspires innovation and promotes impactful research like this.”

For the findings published in Nature Communications team members analyzed close to 600 listeria genomes from soil samples that Liao collected in a previous study, published in Nature Microbiology. They identified five main ARGs from across the United States.

The study also revealed how ARGs spread between bacteria. A process called transformation allows bacteria to pick up loose pieces of DNA containing ARGs from their surroundings. Once a bacterium acquires these genes, it can pass them along to others — even to different species. This rapid sharing of resistance genes is a major reason why antibiotic resistance is such a challenging problem.

The team focuses on listeria because it isn’t just another soil bacterium — it’s a key player in understanding antibiotic resistance. Studying how ARGs spread in soil bacteria like listeria gives scientists valuable insights into how resistance develops and moves through ecosystems.

“Although resistance in clinical listeria cases is currently low, these bacteria naturally resist several antibiotics and are showing increased resistance to others,” Liao said. “This makes listeria a good model for tracking ARG development before it becomes a widespread clinical issue.”

How soil properties and land use shape ARG spread

The study also highlighted how the soil’s properties and land use can affect ARG spread. For example:

Aluminum-rich soil encourages more ARG diversity, possibly because it stresses bacteria, making them more likely to keep resistance genes.
Magnesium-rich soil lowers ARG diversity, potentially by reducing competition among bacteria.
Forested areas tend to have more ARGs likely because wildlife naturally introduce these genes to the environment.
On the other hand, agricultural fields can change the soil’s makeup and microbial communities, influencing ARG diversity in bacteria like listeria.

For households, it is important for people to avoid activities that may disturb soil conditions, such as improperly disposing of waste that may cause metal contamination. Liao said it is also important to maintain good sanitation practices after contact with soils, such as after gardening, given the possible presence of ARGs and resistant bacteria.

By revealing how ARGs spread and how environmental factors influence this process, Liao’s study highlights the importance of protecting natural ecosystems. Preserving soil health isn’t just good for the environment — it’s vital for our future medical care.

Building off of this research, Liao hopes to find new strategies to control antibiotic resistance, ensuring antibiotics remain effective in treating infections for years to come.

“Establishing a fundamental understanding of the ecological drivers of these bacteria in the soil could help us better understand the emergence, evolution, and spread of antibiotic resistance,” said Liao. “This is an urgent, global public health threat.”

Journal

Nature Communications

Article Title

Evidence of horizontal gene transfer and environmental selection impacting antibiotic resistance evolution in soil-dwelling Listeria

U$A

‘Resistance and resolve’: reproductive justice advocates convene to explore responses to ongoing threats to reproductive autonomy

Panelists urge continued mobilization, youth engagement, and state advocacy, among other key strategies

CUNY Graduate School of Public Health and Health Policy

New York, NY | December 12, 2024 – On December 10, leading voices in reproductive justice gathered at the CUNY Graduate School of Public Health and Health Policy (CUNY SPH) for a critical discussion, “Reproductive Justice: Where Do We Go From Here?” Sponsored by the CUNY SPH Sexual and Reproductive Justice Hub (SRJ Hub) and moderated by philanthropist, filmmaker, and activist Abigail Disney, the panel convened to reflect on the post-election landscape.

The evening began with a video message from Gov. Kathy Hochul, who addressed the importance of protecting reproductive rights amidst current challenges and reaffirmed her commitment to ensuring New York remains a safe harbor in the years ahead.

Panelists and key speakers included:

Terry McGovern, CUNY SPH senior associate dean and SRJ Hub founding faculty member
Regina Davis Moss, president and CEO of In Our Own Voice
Dázon Dixon Diallo, founder of SisterLove, Inc.
Isabelle Villa Real Seabra, CUNY SPH student advocate
Lynn Roberts, CUNY SPH associate dean
Danielle Greene, CUNY SPH executive director of state and local public health initiatives and SRJ Hub founding member

Notable Discussion Themes and Strategies

Intersectionality: Diallo stressed that true reproductive justice requires a comprehensive approach that centers racial, economic, and gender equity. She urged communities to broaden the definition of sexual and reproductive health to include populations beyond those who can become pregnant, making reproductive justice a “kitchen table” issue that resonates beyond political discourse.

Economic and Public Health Impacts: Panelists discussed the financial and health tolls of dismantling already fragile healthcare networks, forcing people to travel long distances for care or go without. McGovern noted, “The public health implications are profound. Dobbs didn’t just overturn Roe; it opened the door to dismantling years of progress.” There was a call for more data to quantify the ripple effects of restricting access to reproductive and gender-affirming care, emphasizing an economic argument to illustrate the benefits of accessible healthcare.

Youth Leadership: There was a consensus on the importance of harnessing young people’s energy, creating inclusive spaces where they can lead—online, in classrooms, or in grassroots organizations—and fostering intergenerational collaboration. Villa Real Seabra emphasized the power of young advocates, suggesting drawing inspiration from feminist movements in Latin America focused on intersectionality and fighting gender-based violence. “This movement has never been just about politicians, but the people who form it,” she noted. “We’ve always adapted, and we’ll continue to do so.”

State-Based Solutions: Moss highlighted the importance of state-level policy advocacy, including voter education and ballot measures to protect reproductive rights where possible. She also stressed the need to normalize progressive reproductive health policies by showcasing their effectiveness.

“This discussion comes at a critical time. As we face ongoing threats to reproductive autonomy, it’s crucial to heed the voices of reproductive justice leaders who have been sounding the alarm for years and offering valuable perspectives on the path forward,” said McGovern. “At the SRJ Hub, we are dedicated to equipping students with the knowledge and tools to develop solutions-oriented approaches that prioritize marginalized communities and to effectively continue this fight, even in the face of hostile and challenging environments.”

“This is a critical moment for reproductive justice, not just post-Dobbs, but in confronting the systemic erosion of reproductive healthcare, especially in Georgia,” said Diallo. “This fight is not about resilience; it’s about resistance and resolve. We must trust, support, and center those who birthed this movement—and have been at the forefront of the fight demanding not just abortion access and dignified birth, but equity in housing, education, and healthcare. When the needs and rights of Black women are prioritized, we drive progress for all.”

“Right now, we are seeing the devastating impact that restricting abortion access has on maternal health — especially for Black women who already face severe disparities in receiving quality care,” said Moss. “As we prepare to defend ourselves against a new, hostile administration, it is critical that we continue to organize in our communities, hold our elected officials accountable and center Reproductive Justice policies as our roadmap in the fight to protect our bodily autonomy.”

“At its core, reproductive justice is about having control over your own body and, therefore, your life,” said Greene. “The SRJ Hub launched this year with support from the governor, the assembly and the senate. We look forward to continuing our collaboration with them, our students, and our community partners to advance New York’s leadership in protecting and promoting reproductive rights and justice.”

Coinciding with Human Rights Day (Dec. 10), the panel also recognized the culmination of the Global 16 Days of Activism against Gender-Based Violence campaign. The SRJ Hub began its first year as campaign host by launching #16to365, an initiative to recognize and facilitate the year-round work of feminist advocates and grassroots organizations.

To learn more about the SRJ Hub’s initiatives, including the Byllye Avery Sexual and Reproductive Justice Professorship — the nation’s first endowed professorship dedicated to advancing sexual and reproductive justice — go online or on Instagram (@cunysph.srjhub) and LinkedIn.

About the Sexual & Reproductive Justice Hub

In the post-Dobbs world, reproductive health injustices abound, disproportionately burdening people of color, adolescents, and those with few financial resources. The Sexual & Reproductive Justice Hub (SRJ Hub) at CUNY SPH coordinates solutions-oriented scholarship, training, and advocacy, centering the lived experiences of women of color and funding their and other marginalized people’s work. As part of the United States’ largest, oldest, and most diverse urban public university system, the SRJ Hub’s work is informed by the experiences of faculty, staff, and students connected to communities and populations worldwide.

About CUNY SPH

The CUNY Graduate School of Public Health and Health Policy (CUNY SPH) is committed to promoting and sustaining healthier populations in New York City and around the world through excellence in education, research, and service in public health and by advocating for sound policy and practice to advance social justice and improve health outcomes for all.

Mothers bear the brunt of the 'mental load,' managing 7 in 10 household tasks

The study, conducted in the US, found that mothers take on seven in ten (71%) of all household mental load tasks.

University of Bath

From choosing gifts and sending cards to planning Christmas dinner, the holiday season can feel like an avalanche of mental to-do lists. New research from the University of Bath and the University of Melbourne, published in the Journal of Marriage & Family, reveals that mothers overwhelmingly carry this “mental load” while dads often take a back seat. And it’s not just during Christmas – this imbalance happens every day of the year.

The “mental load,” also known as “cognitive household labour” refers to the thinking work needed to keep family life running smoothly. This includes scheduling, planning, and organising tasks.

The study, conducted in the US, found that mothers take on seven in ten (71%) of all household mental load tasks. These tasks range from planning meals and arranging activities to managing household finances.

The research team analysed data from 3,000 US parent respondents, examining the share of common mental load tasks they typically manage in their household.

Key Findings

Mums take on most of the mental load.
Mothers handle 71% of household tasks that require mental effort—60% more than fathers, who manage just 45%.
Different roles for mums and dads.
Mums take on 79% of daily jobs like cleaning and childcare—over twice as much as dads (37%). Dads, meanwhile, focus on episodic tasks like finances and home repairs (65%), although mums still do a significant share (53%), leading to duplication of effort.
Dads overestimate their share.
Parents often overestimate their contributions, but dads do this more than mums. Fathers are also more likely to see household mental labour as equally shared, while mothers disagree.
Single parents juggle it all.
Single mums and dads take on the full mental load. Single dads, in particular, do significantly more compared to partnered fathers.

The study focuses on individual parents rather than couples, so the findings reflect one parent’s perspective rather than a shared view. It also includes parents from a wide range of family types, including LGBTQ+ and single parents, making the results relevant to diverse households.

Dr Ana Catalano Weeks, a political scientist from the Department of Politics, Languages & international Studies at the University of Bath said:

“This kind of work is often unseen, but it matters. It can lead to stress, burnout and even impact women’s careers. In many cases, resentment can build, creating strain between couples. We hope our research sparks conversations about sharing the mental load more fairly—something that benefits everyone.”

The gender divide in the mental load doesn’t just affect family life—it impacts women in the workplace and public life. A recent Gallup study shows working mothers are twice as likely as fathers to consider reducing their hours or leaving their jobs due to parental responsibilities.

Dr Catalano Weeks said:

“Going forward, the challenge for governments and employers who care about attracting the top talent is how to create policies that are supportive of both mothers and fathers sharing the unpaid work at home. One policy that comes to mind is well-paid, gender-neutral parental leave – which both the UK and US are way behind on compared to the rest of Europe.”

So, this Christmas, if you’re wondering who’s doing the mental heavy lifting - it’s probably mum. The researchers encourage families to take the first step: talk about the mental load, make a plan, and work together to make the holidays—and every day—more balanced.

ENDS

Notes to Editors

LINK TO PAPER: https://doi.org/10.1111/jomf.13057

Weeks, A. C., & Ruppanner, L. (2024). A typology of US parents’ mental loads: Core and episodic cognitive labor. Journal of Marriage and

Family, 1–24

FUNDING: The research was partially funded by the Carrie Chapman Catt Prize, Iowa State University, Bath's Institute for Policy Research and the Department of Politics, Languages & International Studies at the University of Bath, and the Australian Research Council.

About the University of Bath
The University of Bath is one of the UK’s leading universities, recognized for high-impact research, excellence in education, an outstanding student experience, and strong graduate prospects.

Ranked in the top 10 of all the UK’s major university guides.
Among the world’s top 10% of universities, placed 150th in the QS World University Rankings 2025.
Rated in the world’s top 10 universities for sport (QS World University Rankings by Subject 2024).

Research from Bath addresses critical global challenges, fostering low-carbon living, positive digital futures, and improved health and wellbeing. Learn more about our Research with Impact: https://www.bath.ac.uk/campaigns/research-with-impact/

Journal

Journal of Marriage and Family

DOI

10.1111/jomf.13057

Article Title

A typology of US parents’ mental loads: Core and episodic cognitive labor. Journal of Marriage and Family, 1–24

Article Publication Date

12-Dec-2024

Agricultural workers reduce hours or move locations to avoid wildfire smoke

Researchers used a novel method involving cell phones to track movement

University of California - Davis

Millions of cell tower pings from dating, weather, messaging and other mobile apps that use location-sharing services are helping agricultural economists better understand how farmworkers respond to environmental hazards such as wildfire smoke.

During California’s most destructive wildfire season in 2020, the number of farmworkers in a surveyed field fell by nearly 35% and the number of hours worked in that same location dropped by 37% on smoky days when elevated levels of particulate matter were in the air.

On less smoky days, the number of workers in surveyed fields was nearly 18% below typical levels and the hours worked were 23% below normal, according to novel research from the University of California, Davis, to be published in the January edition of Journal of the Association of Environmental and Resource Economists.

“When this smoke is really heavy there’s a large reduction in the amount of people in a field in day,” said Tim Beatty, chair of the Department of Agricultural and Resource Economics and the senior author on the research.

The researchers also found that farmworkers tended to work more hours in the days leading up to smoke events and switched fields to avoid the worst conditions.

“We could figure out very rich hourly information of where these farmworkers went and if they moved to another location,” said Goeun Lee, a postdoctoral scholar and lead author on the journal paper. “This is kind of the first application of this data to answer some important questions in agricultural economics.”

A new resource

The research represents a new way of gleaning information about one of California’s most elusive workforces – farmworkers who harvest crops that help feed the nation – that conventional sources cannot quantify.

“The results are relevant for policy makers seeking to protect workers health, safety and well-being and to ensure the sustainability of one of the most productive agricultural regions in the world,” the authors wrote.

Lee and Beatty used crop field boundaries to define agricultural crop locations, overlayed smoke plume and weather data to determine environmental conditions and accessed cell phone data from a company that collects location information from about 400 mobile applications.

They identified time, place and movement data of cell phones at the field level from January to mid-October for 12,667 crop workers – representing 8% of the agricultural workforce in California – and a sample size 20 times that of the federal National Agricultural Worker Survey of 2020, which is a main but limited point-in-time resource for tracking this population.

“We don’t do a good job of collecting data on these pretty marginalized groups who are very important, so it’s very hard for us to say anything about policies that affect them because they don’t turn up in the data,” Beatty said. “This mobility data is interesting and important to really answer questions about a group of people who are underrepresented in surveys.”

Shocks on the horizon

Major wildfires and other environmental shocks are projected to become more frequent and current protections may not be adequate to protect farmworkers and their financial health, the authors said.

“Farmworkers primarily work outdoors and they’re exposed to many environmental shocks and factors that can affect their health and productivity negatively,” Lee said. “Climate change is expected to increase the frequency of wildfire smoke and California relies a lot on this labor force. They are essential for California agriculture.”

Wildfire smoke can cause fatigue, dizziness, headaches, confusion and other symptoms that increase the risk of injury. The researchers defined high smoke days as those with 40 micrograms per cubic meter of particulate matter. California regulations require workers to wear protective gear like respirators, alter their schedule or work in an area with better air quality when particulate matter is 55.5 micrograms per cubic meter.

The short harvest season coincides with more intense wildfire months, which means farmworkers could lose wages while avoiding smoke hazards. “We should worry about people’s health but also their ability to earn a living because that also impacts their health and wellbeing quite directly,” Beatty said.

Future studies

The research has some limitations related to who made decisions related to smoke.

“It could be as simple as farmers have multiple fields and they just switch the field they’re harvesting that day. It could be they work for a farm labor contractor and they just basically change the client they are working for that day,” Beatty said. “That sets the table for a lot of future questions.”

The methodology could be used to answer future labor, environmental and agricultural economics questions and the authors are using cell phone data to track farmworker movement and behavior during extreme heat events and after pesticide use.

“This kind of new data set that we made can be a valuable resource to answer other questions about farmworkers,” Lee said.

Journal

Journal of the Association of Environmental and Resource Economists

DOI

10.1086/733350

Method of Research

Experimental study

Subject of Research

People

Article Title

Wildfires and Agricultural Worker Movement