Dementia: Why we find it difficult to stay awake in the day and sleep at night?

Study Suggests Tau Tangles, Not Amyloid Plaques, Drive Daytime Napping That Precedes Dementia

Researchers and caregivers have noted that excessive daytime napping can develop long before the memory problems associated with Alzheimer’s disease begin to unfold. Prior studies have considered this excessive daytime napping to be compensation for poor nighttime sleep caused by Alzheimer’s-related disruptions in sleep-promoting brain regions, while others have argued that the sleep problems themselves contribute to the progression of the disease. But now UC San Francisco scientists have provided a striking new biological explanation for this phenomenon, showing instead that Alzheimer’s disease directly attacks brain regions responsible for wakefulness during the day.

two people talk in a lab
Lea Grinberg (right), MD, PhD, the senior study author

The new research demonstrates that these brain regions (including the part of the brain impacted by narcolepsy) are among the first casualties of neurodegeneration in Alzheimer’s disease, and therefore that excessive daytime napping – particularly when it occurs in the absence of significant nighttime sleep problems – could serve as an early warning sign of the disease. In addition, by associating this damage with a protein known as tau, the study adds to evidence that tau contributes more directly to the brain degeneration that drives Alzheimer’s symptoms than the more extensively studied amyloid protein.

“Our work shows definitive evidence that the brain areas promoting wakefulness degenerate due to accumulation of tau – not amyloid protein – from the very earliest stages of the disease,” said study senior author Lea T. Grinberg, MD, PhD, an associate professor of neurology and pathology at the UCSF Memory and Aging Center and a member of the Global Brain Health Institute and UCSF Weill Institute for Neurosciences.

Wakefulness Centers Degenerate in Alzheimer’s Brains

In the new study, published August 12, 2019, in Alzheimer’s & Dementia: The Journal of the Alzheimer’s Association, lead author Jun Oh, a Grinberg lab research associate, and colleagues precisely measured Alzheimer’s pathology, tau protein levels and neuron numbers in three brain regions involved in promoting wakefuless from 13 deceased Alzheimer’s patients and seven healthy control subjects, which were obtained from the UCSF Neurodegenerative Disease Brain Bank.

Compared to healthy brains, Oh and colleagues found that the brains of Alzheimer’s patients had significant tau buildup in all three wakefulness-promoting brain centers they studied – the locus coeruleus (LC), lateral hypothalamic area (LHA), and tuberomammillary nucleus (TMN) – and that these regions had lost as many as 75 percent of their neurons.

portrait on Jun Oh.
Jun Oh, lead author of the study. 

“It’s remarkable because it’s not just a single brain nucleus that’s degenerating, but the whole wakefulness-promoting network,” Oh said. “Crucially this means that the brain has no way to compensate because all of these functionally related cell types are being destroyed at the same time.”

Oh and colleagues also studied brain samples from seven patients with progressive supranuclear palsy (PSP) and corticobasal disease (CBD), two distinct forms of neurodegenerative dementia caused by tau accumulation. In contrast to the Alzheimer’s disease brains, wakefulness-promoting neurons appeared to be spared in the PSP and CBD brains, despite comparable levels of tau buildup in these tissue samples.

“It seems that the wakefulness-promoting network is particularly vulnerable in Alzheimer’s disease,” Oh said. “Understanding why this is the case is something we need to follow up in future research.”

Studies Point to Role of Tau Protein in Alzheimer’s Symptoms

The new results are in line with an earlier study by Grinberg’s group which showed that people who died with elevated levels of tau protein in their brainstem – corresponding to the earliest stages of Alzheimer’s disease – had already begun to experience changes in mood, such as anxiety and depression, as well as increased sleep disturbances.

“Our new evidence for tau-linked degeneration of the brain’s wakefulness centers provides a compelling neurobiological explanation for those findings,” Grinberg said. “It suggests we need to be much more focused on understanding the early stages of tau accumulation in these brain areas in our ongoing search for Alzheimer’s treatments.”

These studies add to a growing recognition among some researchers that tau buildup is more closely linked to the actual symptoms of Alzheimer’s than the more widely studied amyloid protein, which has so far failed to yield effective Alzheimer’s therapies.

For instance, another recent study by the Grinberg lab measured tau buildup in the brains of patients who died with different clinical manifestations of Alzheimer’s disease, including variants that involved language impairment or visual problems instead of more typical memory loss. They found that differences in local tau burden in these patients’ brains closely matched their symptoms: patients with language impairments had more tau accumulation in language related brain areas than in memory regions, while patients with visual problems had higher tau levels in visual brain areas.

“This research adds to a growing body of work showing that tau burden is likely a direct driver of cognitive decline,” Grinberg said.

Increased focus on the role of tau in Alzheimer’s suggests that treatments currently in development at UCSF’s Memory and Aging Center and elsewhere that directly tackle tau pathology have the potential to improve sleep and other early symptoms of Alzheimer’s disease, in addition to holding a key to slowing the progress of the disease overall, the authors say.

Authors: See study online for full list of authors.

Funding: This study was supported by The Rainwater Foundation and grants from the National Institutes of Health (R01AG064314, R01AG060477, P50AG023501, P01AG019724, K24AG053435), the Global Brain Health Institute, and the São Paulo Research Foundation (FAPESP).

Disclosures: The authors declare no conflicts of interest.

The University of California, San Francisco (UCSF) is exclusively focused on the health sciences and is dedicated to promoting health worldwide through advanced biomedical research, graduate-level education in the life sciences and health professions, and excellence in patient care. It includes UCSF Health, which comprises three top-ranked hospitals, as well as affiliations throughout the Bay Area.

Source
August 2019| The Regents of The University of California – Alzheimer’s Disease Destroys Neurons that Keep Us Awake By Nicholas Weiler

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Apathy: The forgotten symptom of dementia

Press Release
July 2019| University of Exeter – Apathy: The forgotten symptom of dementia

Apathy is the most common neuropsychiatric symptom of dementia, with a bigger impact on function than memory loss – yet it is under-researched and often forgotten in care.

photo of elderly man sitting on wooden chair outside house
Photo by weedlyr on Pexels.com

A new study has found that apathy is present nearly half of all people with dementia, with researchers finding it is often distinct from depression.

Although common, apathy is often ignored as it is less disruptive in settings such as care homes than symptoms like aggression. Defined by a loss of interest and emotions, it is extremely distressing for families and it is linked with more severe dementia and worse clinical symptoms.

Now, research led by the University of Exeter and presented at the Alzheimer’s Association International Conference in LA has analysed 4,320 people with Alzheimer’s disease from 20 cohort studies, to look at the prevalence of apathy over time.

At the start of the study, 45% presented with apathy, and 20% had persistent apathy over time. Researchers found that a proportion had apathy without depression, which suggests that the symptom might have its own unique clinical and biological profile when compared to apathy with depression and depression only.

Miguel de Silva Vasconcelos, PhD student at the University of Exeter and King’s College London, said : “Apathy is an under-researched and often ignored symptom of dementia. It can be overlooked because people with apathy seem less disruptive and less engaging, but it has a huge impact on the quality of life of people living with dementia, and their families. Where people withdraw from activities, it can accelerate cognitive decline and we know that there are higher mortality rates in people with apathy. It’s now time this symptom was recognised and prioritised in research and understanding.”

Professor Clive Ballard, of the University of Exeter Medical School, said: “Apathy is the forgotten symptom of dementia, yet it can have devastating consequences. Our research shows just how common apathy is in people with dementia, and we now need to understand it better so we can find effective new treatments. Our WHELD study to improve care home staff training through personalised care and social interaction included an exercise programme that improved apathy, so we know we can make a difference. This is a real opportunity for interventions that could significantly benefit thousands of people with dementia.”

The presentation was entitled ‘The Course of Apathy in People with Dementia’.

Our ailing aged care system shows you can’t skimp on nursing care

The royal commission has scrutinised aged care staffing.
From shutterstock.com

Apil Gurung, University of the Sunshine Coast and Samantha Edwards, University of the Sunshine Coast

Staff shortages and a lack of training have once again emerged as key issues underpinning the nation’s aged care crisis, as the aged care royal commission hears testimony in Perth.

Registered nurse Noleen Hausler shared the experience of her 98-year-old father, Clarence, who was force-fed, assaulted and had a serviette held over his nose by a carer who was later convicted of aggravated assault.

Aside from this criminal behaviour, Ms Hausler said the standards at her father’s aged care facility declined after a new operator reduced staffing levels and employed carers with little training. Call bells went unanswered, she said, and incontinence pads were rationed.

Ms Hausler has called for increased ratios of registered nurses in aged care facilities, and better training and registration for carers.

Under-staffing and inadequate training have long been problems in Australia’s aged care facilities, with aged care facilities employing fewer registered and enrolled nurses and more carers who have lower levels of training.




Read more:
Nearly 2 out of 3 nursing homes are understaffed. These 10 charts explain why aged care is in crisis


Who does what in aged care?

A registered nurse (RN) provides nursing leadership and clinical supervision in aged care facilities. They are skilled clinicians who can respond to medical emergencies and are qualified to carry out assessments.

Registered nurses undergo three years of undergraduate study at university and are registered with the Australian Health Practitioner Regulation Agency (AHPRA) in order to practise in health care setting across Australia.

An enrolled nurse (EN) conducts observations and assessments, and collaborates with and seeks assistance from the registered nurse in charge. Enrolled nurses are registered with AHPRA and undergo an 18-month diploma of nursing at TAFE.

Finally, care workers form the bulk of the aged care workforce and perform tasks such as showering, dressing and feeding residents. Titles for carers vary and include assistant in nursing, personal care worker, personal care attendant, and aged care worker, to name a few.

Care workers are required to complete a certificate III-level course, which can take up to six or seven months, but don’t require registration.

Carers cost less than nurses

There is no clear legislation requiring a certain number of registered nurses, enrolled nurses and carers to be on duty at certain point in time. The Aged Care Act 1997 is open to interpretation, so aged care providers are largely free to set their own staffing levels.

As a result, in recent years aged care operators have recruited proportionally fewer registered and enrolled nurses and increasing numbers of unregulated carers.

Residents in aged care have complex needs, and those looking after them need to be equipped.
From shutterstock.com

The changing make up of the aged care workforce is mainly influenced by economic advantage: hiring carers is cheaper than hiring registered or enrolled nurses.

It can also be difficult to find enough nurses. Nurse retention in aged care has been a major challenge for the industry because aged care providers often pay lower wages than hospitals.

But nursing care is worth the investment

Research shows having a greater number of registered nurses increases patients’ well-being and safety. Better staffing levels allow nurses to spend more time caring for residents and reduces the likelihood that vital information is overlooked.

Adequately staffing aged care facilities has economic benefits by reducing staff turnover related to burnout and job dissatisfaction.

Employing skilled registered nurses in aged care facilities can also save the health system money by reducing the number of costly hospital admissions that arise because residents can’t be adequately cared for in their aged care facility.




Read more:
Want to improve care in nursing homes? Mandate minimum staffing levels


Aged care residents often have mental health issues, face cognitive decline or dementia, take multiple medications each day, are physically frail, and often have multiple chronic conditions such as heart disease, diabetes, cancer, arthritis or asthma.

But it’s difficult to meet the needs of these patients with the current aged care staffing and skill levels.

More than 50% of the residents in a residential aged care facilities have some form of dementia, for example, yet more than 50% of aged care workers have no dementia training.

Substituting registered nurses with lesser skilled carers has meant tasks such as medication management have been assigned to carers in some aged care facilities, despite this being a high-risk task that requires a high level of skill and experience.

What are the solutions?

Carers currently make up around 70% of the aged care workforce. We need to reset aged care staffing levels and ensure we have the right skill sets, which industry bodies suggest is: 30% registered nurses, 20% enrolled nurses and 50% care workers.

It’s also time to professionalise caring roles with better regulation and the introduction of carer registration.

Registration would clarify carers’ roles and allow only the delegation of tasks which are deemed safe for carers to carry out within their scope of practice. It would also ensure minimum training standards are met and that quality and safety is maintained.

The aim is not to vilify carers, who are the backbone of our aged care system, but rather to highlight the need for the right level of training, education and support to strengthen the aged care workforce and complement the care provided by registered and enrolled nurses.

Finally, we also need to increase the number of registered and enrolled nurses in the aged care workforce with guided pathways to attract and retain nurses. Well-structured graduate nurse programs, for instance, can provide support and guidance to the graduates who are considering a career in aged care.




Read more:
Don’t wait for a crisis – start planning your aged care now


The Conversation


Apil Gurung, Lecturer, University of the Sunshine Coast and Samantha Edwards, Lecturer in Nursing, University of the Sunshine Coast

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Dementia more preventable in Asia and Latin America

News Release
April 2019 | University College London, Gower Street, London – Dementia more preventable in Asia and Latin America

Close to one in two cases of dementia could be preventable in low- to middle-income countries, finds a new UCL study.

Dancing in Peru
The findings, published in The Lancet Global Health, found how improving childhood education and other health outcomes throughout life could reduce the risk of dementia.

“After our previous research finding that one in three cases of dementia could be preventable, we realised that the evidence was skewed towards higher-income countries,” said the study’s lead author, Dr Naaheed Mukadam (UCL Psychiatry).

“We have now found that in low- to middle-income countries in Asia and Latin America, dementia may be even more preventable than it is in more wealthy countries. If life-course risk factors such as low levels of education in early life and hearing loss, obesity and low physical activity in mid-life to old age are addressed, these countries could see large improvements in their dementia rates.”

While the number of people with dementia is increasing globally, particularly in low- to middle-income countries, there have been modest reductions in age-specific dementia rates in many high-income countries over the last two decades.* The researchers say this could be due to improvements in health outcomes throughout life that affect dementia risk.

The research team built on their previous work for the Lancet Commission on dementia prevention, intervention, and care, published in 2017, which found that 35% of dementia is attributable to nine risk factors: low levels of childhood education, hearing loss, smoking, hypertension, obesity, physical inactivity, social isolation, depression, and diabetes.*

To understand whether the commission’s findings would apply equally to global regions that were underrepresented in the report, a team of UCL researchers sought out data from China, India and Latin America. They drew from the research collective 10/66 Dementia Research Group’s data, which used similar methodology to gauge prevalence of the nine risk factors in those countries, with sample sizes of 1,000 to 3,000 in each country.

The researchers found even more potential for preventing dementia across the globe, as the proportion of dementia linked to the nine modifiable risk factors was 40% in China, 41% in India and 56% in Latin America.

A major factor in that difference is the lower levels of educational attainment in low- to middle-income countries, which the researchers say signals hope for the future, as education levels rise.

“People growing up in Asia and Latin America today are more likely to have completed schooling than their parents and grandparents were, meaning they should be less at risk of dementia later in life than people who are already over 65. Continuing to improve access to education could reap great benefits for dementia rates in years to come,” Dr Mukadam said.

On the other hand, social isolation is a major risk factor of dementia in higher income countries, but much less so in China and Latin America. The researchers say that public health officials in countries such as the UK could learn from China and Latin America in efforts to build more connected communities to buffer against the dementia risk tied to social isolation.

Obesity and hearing loss in mid-life, and physical activity in later life, were also strongly linked to dementia risk in the study area, as well as mid-life hypertension in China and Latin America and smoking in later-life in India.

“Reducing the prevalence of all of these risk factors clearly has numerous health benefits, so here we’ve identified an added incentive to support public health interventions that could also reduce dementia rates. The growing global health burden of dementia is an urgent priority, so anything that could reduce dementia risk could have immense social and economic benefit,” Dr Mukadam said.

Senior author Professor Gill Livingston (UCL Psychiatry) added: “A lot of the findings of health and medical research derive primarily from higher income countries such as in Western Europe and North America, so ensuring that research is inclusive is vital to the development of global public health strategies.”

“While we don’t expect these risk factors to be eliminated entirely, even modest improvements could have immense impact on dementia rates. Delaying the onset of dementia by just five years would halve its prevalence*,” she said.

The researchers are supported by the National Institute for Health Research UCLH Biomedical Research Centre, Wellcome, NIHR, Economic and Social Research Council, and NIHR Collaboration for Leadership in Applied Health Research and Care North Thames.

Links
Research paper in The Lancet Global Health
Dr Naaheed Mukadam’s academic profile
UCL Psychiatry
* The Lancet Commission on dementia, prevention, intervention and care
Image
People dancing in Peru. Credit: Alex Proimos, Source: Flickr
Media contact
Chris Lane
tel: +44 20 7679 9222

E: chris.lane [at] ucl.ac.uk

Australia’s residential aged care facilities are getting bigger and less home-like

File 20180921 129847 1di589.jpg?ixlib=rb 1.1

Residential aged care facilities should be more like a home and less like a hospital.
from shutterstock.com

Ralph Hampson, University of Melbourne

Most older people want to stay at home as long as they can. When this is no longer possible, they move into residential aged care facilities, which become their home. But Australia’s care facilities for the aged are growing in size and becoming less home-like.

In 2010–11, 54% of residential aged care facilities in major Australian cities had more than 60 places, and the size of the average facility is growing.

Today, more than 200,000 Australians live or stay in residential aged care on any given day. There are around 2,672 such facilities in Australia. This equates to an average of around 75 beds per facility.

Large institutions for people with disability and mental illness, as well as orphaned children, were once commonplace. But now – influenced by the 1960s deinstitutionalisation movement – these have been closed down and replaced with smaller community-based services. In the case of aged care, Australia has gone the opposite way.




Read more:
How our residential aged-care system doesn’t care about older people’s emotional needs


Why is smaller better?

Evidence shows that aged care residents have better well-being when given opportunities for self-determination and independence. Internationally, there has been a move towards smaller living units where the design encourages this. These facilities feel more like a home than a hospital.

The World Health Organisation has indicated that such models of care, where residents are also involved in running the facility, have advantages for older people, families, volunteers and care workers, and improve the quality of care.

In the US, the Green House Project has built more than 185 homes with around 10-12 residents in each. Studies show Green House residents’ enhanced quality of life doesn’t compromise clinical care or running costs.

Older people have a better quality of life if they can be involved in outdoor activities.
from shutterstock.com

Around 50% of residents living in aged care facilities have dementia. And research has shown that a higher quality of life for those with dementia is associated with buildings that help them engage with a variety of activities both inside and outside, are familiar, provide a variety of private and community spaces and the amenities and opportunities to take part in domestic activities.

In June 2018, an Australian study found residents with dementia in aged-care facilities that provided a home-like model of care had far better quality of life and fewer hospitalisations than those in more standard facilities. The home-like facilities had up to 15 residents.

The study also found the cost of caring for older people in the smaller facilities was no higher, and in some cases lower, than in institutionalised facilities.




Read more:
Caring for elderly Australians in a home-like setting can reduce hospital visits


There are some moves in Australia towards smaller aged care services. For example, aged care provider Wintringham has developed services with smaller facilities for older people who are homeless. Wintringham received the Building and Social Housing Foundation World Habitat Award 1997 for Wintringham Port Melbourne Hostel. Its innovative design actively worked against the institutional model.

Bigger and less home-like

Historically, nursing homes in Australia were small facilities, with around 30 beds each, often run as family businesses or provided by not-for-profit organisations. Between 2002 and 2013 the proportion of facilities with more than 60 beds doubled to 48.6%. Financial viability rather than quality of care drove the increase in size.

Today, around 45% of facilities are operated by the private for-profit sector, 40% by religious and charitable organisations, 13% by community-based organisations, 3% by state and territory governments, and less than 1% by local governments.




Read more:
It’s hard to make money in aged care, and that’s part of the problem


In 2016, the Australian Institute of Health and Welfare (AIHW) reported that residential care services run by government organisations were more likely to be in small facilities. One-fifth (22%) of places in these facilities are in services with 20 or fewer places. Almost half (49%) of privately-run residential places are found in services with more than 100 places.

All of this means that more older Australians are living out their last days in an institutional environment.

Once larger facilities become the norm, it will be difficult to undo. Capital infrastructure is built to have an average 40-year life, which will lock in the institutional model of aged care.

The built environment matters. The royal commission provides an opportunity to fundamentally critique the institutional model.

Ralph Hampson, Senior Lecturer, Health and Ageing, University of Melbourne

This article is republished from The Conversation under a Creative Commons license. Read the original article.

FACTCHECK: Does eating two teaspoons of nuts really boost your brain function by 60%?

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New Africa/Shutterstock

Sandra-Ilona Sunram-Lea, Lancaster University

Dementia is a cruel disease that robs people of their memory, their judgement and their identity. Unfortunately, there is no cure, and in the past few years a number of clinical trials for new dementia drugs have failed – the latest being Biogen’s drug aducanumab. Without any effective treatments on the horizon, most people’s best hope is to avoid getting dementia in the first place.

One of the hallmarks of dementia is cognitive decline. There are several lifestyle changes that may slow cognitive decline, such as doing mentally stimulating activities (crossword puzzles, learning a new language), getting plenty of exercise and maintaining a healthy diet – especially one low in saturated fats, refined carbohydrates and sugar.

Of these, diet is a favourite among health reporters, perhaps because the message can be delivered clearly and succinctly. The latest such story comes from the Daily Mirror which claims that eating just two teaspoons of nuts a day “boosts brain function by 60%”. If the claim is true, we should all be rushing out to buy a bag of nuts, but is this what the study actually says?

The article is based on an observational study published in the Journal of Nutrition Health and Aging. After assessing the diets of nearly 5,000 adults in China (aged 55 and older) over a period of nine years, the researchers found an inverse relationship between the amount of nuts people ate and the degree of cognitive decline they experienced. Those who consumed more than 10g of nuts and seeds a day were less likely to show a fall in their cognitive function compared with those who consumed less than 10g a day.

Out of the 4,822 participants in the study, 67% had their cognitive ability tested twice (only 16% were tested more than twice over the course of the study). Where more than one cognitive measurement was made, cognitive performance decreased over time, but people who ate more than 10g of nuts per day decreased the likelihood of this decline. Consequently, the results suggest that consuming two teaspoons of nuts per day may preserve cognitive performance and may lead to better cognitive ageing over a lifetime. The results do not show that eating nuts improves cognitive function, as the Mirror headline claimed.

A certain amount of cognitive decline is inevitable with age.
Andrea Danti/Shutterstock

Limitations

Participants in the study inevitably varied on a number of factors, including education, general health, nutritional intake and lifestyle factors, such as exercise. Although the way the data was analysed took those factors into account and still found an association, cognitive decline and dementia are strongly influenced by many environmental and genetic factors, and it is unlikely that consumption of one particular food is sufficient to ward off dementia.

Another weakness of this study is the fact that participants reported their nut consumption via a questionnaire. Evidence shows that self-reported food consumption should always be interpreted with caution.

Although randomised controlled trials indicate that eating nuts has an effect on blood flow (including to the brain), there isn’t enough evidence to draw conclusions about their impact on cognitive function.

What we can say at this point is that the evidence on nuts and cognitive decline is promising, but it isn’t strong enough to make nutritional recommendations. Simply consuming two teaspoons of nuts per day is unlikely to reduce your risk of dementia.


More on evidence-based articles about diets:

Sandra-Ilona Sunram-Lea, Senior Lecturer in Psychology, Lancaster University

This article is republished from The Conversation under a Creative Commons license. Read the original article.

Empathy, a key ingredient in culture change

News Release
April 2019 | University of Pennsylvania – Empathy and cooperation go hand in hand

Taking a game theory approach to study cooperation, School of Arts and Sciences evolutionary biologists find that empathy can help cooperative behavior ‘win out’ over selfishness.

It’s a big part of what makes us human: we cooperate. But humans aren’t saints. Most of us are more likely to help someone we consider good than someone we consider a jerk.

Two figures have heated discussion as a third in the middle observes
Taking the perspective of another can help foster cooperation in a group, according to a new study by Penn evolutionary biologists.

How we form these moral assessments of others has a lot to do with cultural and social norms, as well as our capacity for empathy, the extent to which we can take on the perspective of another person.

In a new analysis, researchers from the University of Pennsylvania investigate cooperation with an evolutionary approach. Using game-theory-driven models, they show that a capacity for empathy fosters cooperation, according to senior author Joshua Plotkin, an evolutionary biologist. The models also show that the extent to which empathy promotes cooperation depends on a given society’s system for moral evaluation.

“Having not just the capacity but the willingness to take into account someone else’s perspective when forming moral judgments tends to promote cooperation,” says Plotkin.

What’s more, the group’s analysis points to a heartening conclusion. All else being equal, empathy tends to spread throughout a population under most scenarios.

“We asked, ‘can empathy evolve?’” explains Arunas Radzvilavicius, the study’s lead author and a postdoctoral researcher who works with Plotkin. “What if individuals start copying the empathetic way of observing each other’s interactions? And we saw that empathy soared through the population.”

Plotkin and Radzvilavicius coauthored the study, published today in eLife, with Alexander Stewart, an assistant professor at the University of Houston.

Plenty of scientists have probed the question of why individuals cooperate through indirect reciprocity, a scenario in which one person helps another not because of a direct quid pro quo but because they know that person to be “good.” But the Penn group gave the study a nuance that others had not explored. Whereas other studies have assumed that reputations are universally known, Plotkin, Radzvilavicius, and Stewart realized this did not realistically describe human society, where individuals may differ in their opinion of others’ reputations.

“In large, modern societies, people disagree a lot about each other’s moral reputations,” Plotkin says.

The researchers incorporated this variation in opinions into their models, which imagine someone choosing either to donate or not to donate to a second person based on that individual’s reputation. The researchers found that cooperation was less likely to be sustained when people disagree about each other’s reputations.

That’s when they decided to incorporate empathy, or theory of mind, which, in the context of the study, entails the ability to understand the perspective of another person.

Doing so allowed cooperation to win out over more selfish strategies.

“It makes a lot of sense,” Plotkin says. “If I don’t account for your point of view, there will be many occasions when I judge you harshly when I really shouldn’t because, from your perspective, you were doing the right thing.”

To further explore the impact of empathy on cooperation, the researchers looked at a variety of frameworks, or social norms, that people might use to assign a reputation to another person based on their behavior. For example, most frameworks label someone “good” if they reward a fellow “good” individual, but social norms differ in how they judge interactions with a person deemed bad. While the “stern judging” norm labels “good” anyone who punishes a bad actor, the “simple standing” norm does not require this punitive approach: A “good” person can reward a bad one.

Plotkin, Radzvilavicius, and Stewart discovered again that capacity for empathy mattered. When populations were empathetic, stern judging was the best at promoting cooperation. But when a group was less willing to take on the perspective of another, other norms maximized rates of cooperation.

This result prompted the team to ask another evolutionary question—whether empathy itself can evolve and become stable in a population. And under most scenarios, the answer was yes.

“Starting with a population where no one is empathetic, with people judging each other based on their own perspective, we saw that eventually individuals will copy the behavior of those who judge empathetically,” says Plotkin. “Empathy will spread, and cooperation can emerge.”

This was the case even when the researchers accounted for a degree of errors, noise, and misperception in their models.

The findings open up a new area of research for both evolutionary theory and empirical studies into how societies behave.

“Empathy is completely foreign to game theory,” Radzvilavicius say. “In a way this is finding a new niche for research to progress to in the future, accounting for theory of mind.”

Looking ahead, the Penn team hopes to pursue such questions, perhaps by pitting different social norms against one another and eventually by testing their ideas against observations from real people, either through experiments they design or through data collected from social media.

“It’s obvious that in social media people are acutely aware of their public persona and reputation and curate it carefully,” Plotkin says. “It would be fascinating to analyze these evolutionary dynamics as they play out in online interactions.”

The study was supported by the David and Lucile Packard Foundationand the U.S. Army Research Office (Grant W911NF-12-R-0012-04).

Joshua B. Plotkin is a professor in the Department of Biology in the University of Pennsylvania School of Arts and Sciences. He has secondary appointments in the Department of Mathematics and the School of Engineering and Applied Science’s Department of Computer and Information Science.

Arunas L. Radzvilavicius is a postdoctoral researcher in Penn’s Department of Biology.

Alexander J. Stewart is an assistant professor at the University of Houston and a former postdoctoral researcher at Penn.