Threat of group extinction proves a powerful motivator

Charles Darwin was right: Groups enjoy an advantage whose members are "ready to aid one another and to sacrifice themselves for the common good," according to a new study by researchers at Rice University, Texas A&M University and the University of East Anglia.

Using variations of the public goods game, the researchers showed that when no other mechanism is present to reinforce group cooperation, the threat of group extinction is sufficiently powerful to motivate and increase cooperation within a group.

"The finding is stunning for what it says about group extinction," said Rice Professor Rick Wilson, one of the authors of the paper appeared this week in the journal PLOS ONE. "People respond to threats to their group. They're willing to forego opportunities to free ride on the efforts of their group members."

The article, "Group-Level Selection Increases Cooperation in the Public Goods Game," provides insight into the origins of group conflict and "supports the notion that competition between groups is part of what has cultivated human cooperation," the authors said.

"History seems to support the idea that a group working together can overcome another group and drive them to extinction," said Wilson, the Herbert S. Autrey Professor of Political Science, professor of statistics and of psychology at Rice. "But it had not been clear whether this was due to groups cooperating when in competition or to pressure of extinction through selection."

The researchers conducted a controlled laboratory experiment to determine whether competition or extinction drives increased cooperation within groups. The experiment was based on the public goods game in which participants in groups are each given a set amount of money. Each group member secretly chooses how much to put into the group account and how much to retain for their own account. The amount in the group account is multiplied by a set factor, and the payoff is equally divided among the members of the group; participants also keep the money they did not contribute to the group account.

In the researchers' experiment, 168 undergraduate students were randomly assigned to groups of four. No participant knew who their fellow group members were, and all interactions were conducted anonymously over a computer network.

The game consisted of two blocks of 10 periods. Each period every subject was given 50 monetary units and decided how much to keep in their private account and how much to put in the group account. The private account paid one to one. The contributions to the group account were doubled by the experimenters, and the total of the group account was divided equally among each member of the group.

"This basic experimental design has been used hundreds of times, and free riding is common," he said. "We wanted to know whether competition or extinction works to eliminate free riding in the way that Darwin suggests."

The researchers used four treatments in their experiment:

The first treatment replicated the standard public goods game. At the end of each period, subjects found out how much was contributed by others in their group to the group account. They were told nothing about the contributions of participants in the other groups.

Group competition was introduced in the second treatment. Subjects saw the same information as in the first treatment; however, they were told that at the end of the first 10 periods their group would be ranked in terms of total earnings against the other groups in the experiment.

In the third treatment, extinction was introduced. Subjects were told that at the end of 10 periods their earnings would be compared with all other subjects' earnings. One-third of the lowest earners would be removed from the experiment and not allowed to participate in the second block of 10 periods.

In the fourth treatment, extinction was applied to groups rather than individuals. Subjects were told that at the end of the first 10 periods their group's earnings would be compared with the other groups' earnings. Groups that fell in the bottom one-third of earners would be removed from the experiment and would not participate in the second block of 10 periods.

The researchers found that in treatments one through three, average contributions declined steadily over the first 10 periods. "Over time, people contribute less to the public good and favor their private investments," Wilson said.

"But when we introduce group extinction, we see a remarkably different result," he said. "At the outset, individuals contribute almost everything to the group account. The pressure of group extinction results in individuals cooperating within the group."

Researchers found that group extinction, the fourth treatment, led to greater contributions to the group account (92 percent of the endowment, on average) than any other treatment (35 percent in first treatment, 36 percent in third treatment, or individual extinction, and 42 percent in the second treatment, group comparison).

The authors noted that "group extinction leads to enhanced cooperation as long as the selection mechanism is present. Once it is removed, contributions remain higher for a time, but fall quickly toward ... zero contributions. The culture of cooperation engendered by the group extinction mechanism has only a brief longer-term carryover after the mechanism is removed."

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Language of women versus men: 'Wonderful' and 'thankful' versus 'battle' and 'enemy' Do women and men communicate differently?

In a computational analysis of the words used by more than 65,000 consenting Facebook users in some 10 million messages, it was discovered that women use language that is warmer and more agreeable than men. Additionally, algorithms of language use predicted one's gender on Facebook 90 percent of the time. The findings are published in PLOS ONE.

In the paper, titled "Women are Warmer but No Less Assertive Than Men: Gender and Language on Facebook," some of the most commonly cited topics, or automatically derived clusters of related words, used by women included words such as wonderful, happy, birthday, daughter, baby, excited, and thankful. Some of the words most commonly cited by men included freedom, liberty, win, lose, battle and enemy.

These language differences by gender on Facebook are being investigated by a team of researchers comprised of psychologists and computer scientists from Stony Brook University, the University of Pennsylvania and the University of Melbourne in Australia. Gender is a complex, multi-faceted and fluid concept. Their paper helps to illuminate some of that complexity through big data and computational analysis, and the findings suggest gender influences the way people express themselves on Facebook.

"Looking at language in social media offers a fresh perspective on understanding gender differences," said H. Andrew Schwartz, PhD, Assistant Professor of Computer Science in the College of Engineering and Applied Sciences at Stony Brook University and a co-author of the paper.

The analysis automatically identified differences in the types of words used by women and men. Women mentioned friends, family and social life more often, whereas men swore more, used angrier and argumentative language, and discussed objects more than people. On average, women used language that was characteristic of compassion and politeness while men were more hostile and impersonal.

Some findings, added Schwartz, illustrated nuances and differences in language by gender not previously revealed.

"We were able to explore the dimensions of warmness and assertiveness with a novel data-driven technique," explained Schwartz, citing one example. "While some previous work suggests men are generally more assertive, the language in Facebook did not reflect this, showing woman use slightly more assertive language than men."

In the analysis, the topics expressed via the Facebook language were rated for how affiliative (socially connected) and assertive they were. The authors built gender-linked language around an interpersonal circumplex. While most language appeared with both genders, other language use was clearly gender-linked.

Psychologist Dr. Margaret Kern, of the University of Melbourne and one of the study authors, noted that "in many ways, the topics most used by women versus men are not surprising -- they fit common gender stereotypes. The computational methods let us make visible what the human mind does to automatically categorize people and thanks that we encounter in our everyday life."

The study also demonstrates a method to test psychological theories at a large scale, with a way to visualize the results.

With such large-scale computational studies, generating thousands of statistical results, visualization is key.

"This is a good example of visualization helping us to see the bigger picture with complex data," said lead author Dr. Gregory Park, a psychologist from the University of Pennsylvania. "If we only look at individual topics in isolation, it's difficult to see patterns in the kind of topics that are used more by women or men. However, when we visualize them together, it's clear that many of the language differences break down along these interpersonal dimensions."

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Common painkillers are more dangerous than we think

Many patients are prescribed NSAIDs for the treatment of painful conditions, fever and inflammation. But the treatment also comes with side effects, including the risk of ulcers and increased blood pressure. A major new study now gathers all research in the area. This shows that arthritis medicine is particularly dangerous for heart patients, and also that older types of arthritis medicine, which have not previously been in focus, also appear to be dangerous for the heart.

"It's been well-known for a number of years that newer types of NSAIDs -- what are known as COX-2 inhibitors, increase the risk of heart attacks. For this reason, a number of these newer types of NSAIDs have been taken off the market again. We can now see that some of the older NSAID types, particularly Diclofenac, are also associated with an increased risk of heart attack and apparently to the same extent as several of the types that were taken off the market," says Morten Schmidt, MD and PhD from Aarhus University, who is in charge of the research project. He adds:

"This is worrying, because these older types of medicine are frequently used throughout the western world and in many countries available without prescription."

Each year, more than 15 per cent of the population in western countries are given a prescription for NSAIDs. This figure increases with age. Sixty per cent of the adult population in Denmark collects at least one prescription for an NSAID within a ten-year period. Heart patients are no exception and previous studies have shown that up to forty per cent of Danish patients with heart failure or previous heart attacks are prescribed NSAIDs.

The study, which was carried out in collaboration between 14 European universities and hospitals, including a number of leading European heart specialists, is today being published in the most prestigious European journal of heart medicine, European Heart Journal.

New guidelines

In the study, the researchers have gathered all research on the use of NSAIDs in patients with heart disease. The survey means that the European Society of Cardiology has now for the first time formulated a number of recommendations about what doctors should consider before prescribing painkillers to their patients.

"When doctors issue prescriptions for NSAIDs, they must in each individual case carry out a thorough assessment of the risk of heart complications and bleeding. NSAIDs should only be sold over the counter when it comes with an adequate warning about the associated cardiovascular risks. In general, NSAIDs are not be used in patients who have or are at high-risk of cardiovascular diseases," says another of the authors, Professor in cardiology Christian Torp-Pedersen, Aalborg University, Denmark.

Consumption should be reduced even more

For a number of years, Danish researchers have made significant contributions in the field. One result of this work has been a reduction in the use of Diclofenac in Denmark. However, according to Morten Schmidt, there is still room for improvement:

"Many European countries consume more of these drugs than Denmark. But we can still do better and it's often the case that paracetamol, physiotherapy, mild opioids or other types of NSAIDs with less risk for the heart would be better for the patients. Of course, the recommendations that have been introduced following our study and its review of the heart-related risks are a big step in the right direction in relation to patient safety," says Morten Schmidt.

FACTS about arthritis medicine (NSAID):

• NSAIDs is an abbreviation for Nonsteroidal Anti-Inflammatory Drugs and is used to treat a wide range of diseases, in particular disorders in the muscular and bone system, where the drug counteracts swelling, pain and limitations in movement associated with inflammation.
• NSAIDs are not antibiotics and therefore do not help to fight infections caused by bacteria.
• NSAIDs are in Denmark sold both in low doses (Ibuprofen 200 mg/tablet) without a prescription and in higher doses and other types with a prescription.
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Eating polyunsaturated fats linked to slowing diabetes progress for some

Research led by a dietitian at King’s College London has found that replacing saturated fat in the diet with polyunsaturated fat, found in foods such as vegetable oils or nuts, is linked to slower progress of type 2 diabetes in people with prediabetes whose muscles do not take up glucose properly.

Prediabetes is a condition in which blood glucose levels are higher than normal but not high enough to be classified as type 2 diabetes. Previous evidence has shown that prediabetes can be split into two distinct conditions, one in which the liver produces too much glucose and one in which glucose is not taken up properly by the muscles.

The study, published in PLOS ONE, is the first to consider the differing effects of dietary fats on prediabetes as two separate conditions, although previous studies have shown that dietary fats have an effect on insulin sensitivity.

This study also considers the distinct paths of diabetes development compared with previous studies which have predominantly used ‘full blown’ diabetes as the measure of progression for the condition.

Currently, weight loss is regarded as the most effective way to prevent the progression of diabetes in patients with prediabetes but researchers examined whether a targeted dietary intervention could have additional impact for patients alongside a weight loss programme.

Scientists tested small groups of people across a wide spectrum of glucose levels including healthy (15) athletic (14), and obese (23) people, and people with prediabetes (10) or type 2 diabetes (11) using robust analysis of glucose levels and fatty acids in their blood. Participants’ diets were evaluated using a dietary questionnaire.

They found that, in the condition where glucose uptake into muscles is impaired, replacing saturated fats in the diet with polyunsaturated fats had a beneficial effect in slowing the development of diabetes. It is thought that this is because polyunsaturated fats promote uptake of glucose by the insulin receptors in the muscles.

In people whose livers were producing too much glucose, reducing saturated fat was found to be linked to slower progress of diabetes but replacing it with polyunsaturated fat was found to have no effect.

Lead author, Dr Nicola Guess, Division of Diabetes and Nutritional Sciences at King’s College London said: ‘This study is the first to explore whether we can target dietary advice taking into account the underlying differences in the two prediabetes states.

‘The findings suggest that increasing dietary intake of polyunsaturated fats may have a beneficial effect for patients with a certain type of prediabetes but also illuminates why certain dietary changes may have no effect on progression of type 2 diabetes in the other subtype.  We intend to build on this work with larger studies, and ultimately test this idea in a randomised trial’.

Limitations of the study included the small number of participants in each group and the overall small sample size of the study. The cross-sectional design of the study also means the authors cannot confirm causality, i.e. a cause-and-effect.
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