Category: Science News

{New model shows how the brain combines information from multiple senses.}

Seeing is not always believing — visual speech (mouth movements) mismatched with auditory speech (sounds) can result in the perception of an entirely different message. This mysterious illusion is known as the McGurk effect. In new research, published in PLOS Computational Biology, neuroscience researchers have created an algorithm to reveal key insight into why the brain can sometimes muddle up one of the most fundamental aspects of the human experience.

The findings will be useful in understanding patients with speech perception deficits and in building computers able to understand auditory and visual speech.

“All humans grow up listening to tens of thousands of speech examples, with the result that our brains contain a comprehensive mapping of the likelihood that any given pair of mouth movements and speech sounds go together,” said Dr. Michael Beauchamp, professor of neurosurgery at Baylor College of Medicine and senior author on the paper with John Magnotti, postdoctoral research fellow at Baylor. “In everyday situations we are frequently confronted with multiple talkers emitting auditory and visual speech cues, and the brain must decide whether or not to integrate a particular combination of voice and face.”

“Even though our senses are constantly bombarded with information, our brain effortlessly selects the verbal and nonverbal speech of our conversation partners from this cacophony,” Magnotti said.

The McGurk effect is an example of when this goes wrong. It happens when mouth movements that are seen can override what is heard, causing a person to perceive a different sound than what is actually being said. Only when the eyes are closed, and when the sound is being heard, can the correct message be perceived. For example, the visual “ga” combined with the auditory “ba” results in the perception of “da.”

Magnotti and Beauchamp were able to create an algorithm model of multisensory speech perception based on the principle of causal inference, which means given a particular pair of auditory and visual syllables, the brain calculates the likelihood they are from single versus multiple talkers and uses this likelihood to determine the final speech perception.

“We compared our model with an alternative model that is identical, except that it always integrates the available cues, meaning there is no casual inference of speech perception,” said Beauchamp, who also is director of the Core for Advanced MRI at Baylor. “Using data from a large number of subjects, the model with causal inference better predicted how humans would or would not integrate audiovisual speech syllables.”

“The results suggest a fundamental role for a causal inference type calculation going on in the brain during multisensory speech perception,” Magnotti said.

Researchers already have an idea of how and where the brain separately encodes auditory speech and visual speech, but this algorithm shines light on the process of how they are integrated. It will serve as a guide, highlighting specific brain regions that will be essential for multisensory speech perception.

“Understanding how the brain combines information from multiple senses will provide insight into ways to improve declines in speech perception due to typical aging and even to develop devices that could enhance hearing across the life span,” Beauchamp said.

Source:Science Daily

{New research involving Monash University biologists has debunked the view that males just pass on genetic material and not much else to their offspring. Instead, it found a father’s diet can affect their son’s ability to out-compete a rival’s sperm after mating.}

The study sought to understand if the nutritional history of fathers had an effect on their sons. Experiments were carried out in the fruit fly, which shares many similar pathways and characteristics with human genes.

One of the lead authors of the study, Dr Susanne Zajitschek from the School of Biological Sciences, said the study highlighted the importance of the paternal environment on future generations, even a long time before offspring were produced.

“Our study found that males that were raised on either high or low protein diets, but spent their adulthood on an intermediate diet, produced sons that had large differences in gene expression, which most likely contributed to the resulting differences in sperm competitiveness,” Dr Zajitschek said.

“They differed in their ability to sire offspring, with the high-protein dads producing sons who were doing much better in sperm competition, which means their sperm was more likely to win against a competitor’s sperm within the female tract.

“We also found that the immune response genes were less active in sons of low-protein fathers, while metabolic and reproductive processes were increased in sons of fathers on a high protein diet,” she said.

The research, published in Biology Letters, is one of only a few studies to have so far reported trans-generational effects in relation to diet quality, and one of the first to report on the post-copulatory advantages conferred by parental diet.

Researchers from Monash University, George Washington University, and the Spanish-based Donana Biological Station took part in the study which examined how high- and low-protein paternal larval diet influenced post-copulatory sexual selection and gene expression in the sons of fruit flies (Drosophila melanogaster).

Source:Science Daily

{Studies have suggested that married people are healthier than those who are single, divorced or widowed. A new Carnegie Mellon University study provides the first biological evidence to explain how marriage impacts health.}

Published in Psychoneuroendocrinology, the researchers found that married individuals had lower levels of the stress hormone cortisol than those who never married or were previously married. These findings support the belief that unmarried people face more psychological stress than married individuals. Prolonged stress is associated with increased levels of cortisol which can interfere with the body’s ability to regulate inflammation, which in turn promotes the development and progression of many diseases.

“It’s is exciting to discover a physiological pathway that may explain how relationships influence health and disease,” said Brian Chin, a Ph.D. student in the Dietrich College of Humanities and Social Sciences’ Department of Psychology.

Over three non-consecutive days, the researchers collected saliva samples from 572 healthy adults aged 21-55. Multiple samples were taken during each 24-hour period and tested for cortisol.

The results showed that the married participants had lower cortisol levels than the never married or previously married people across the three day period. The researchers also compared each person’s daily cortisol rhythm — typically, cortisol levels peak when a person wakes up and decline during the day. Those who were married showed a faster decline, a pattern that has been associated with less heart disease, and longer survival among cancer patients.

“These data provide important insight into the way in which our intimate social relationships can get under the skin to influence our health,” said laboratory director and co-author Sheldon Cohen, the Robert E. Doherty University Professor of Psychology.

Source:Science Daily

{Study takes aim at the psychological effects of population density and finds a ‘slow life strategy’ prevails.}

Big cities with lots of people usually garner images of a fast paced life, where the hustle and bustle of the city is met, and at least tolerated, by those who live there. They live for the “rush” of city life, and all of the competition that lies therein.

But a new study by Arizona State University shows the opposite may be true — that one psychological effect of population density is for those people to adopt a “slow life strategy.” This strategy focuses more on planning for the long-term future and includes tactics like preferring long-term romantic relationships, having fewer children and investing more in education.

The study, “The crowded life is a slow life: Population density and life history strategy,” was published in the Journal of Personality and Social Psychology. Its findings provide novel insights into how population density affects human psychology, and has implications for thinking about population growth, environmental influences on social behavior, and human cultural diversity.

“Our findings are contrary to the notion that crowded places are chaotic and socially problematic,” said Oliver Sng, who led the research while a doctoral student at ASU and who now is a postdoctoral fellow at the University of Michigan. “People who live in dense places seem to plan for the future more, prefer long-term romantic relationships, get married later in life, have fewer children and invest a lot in each child. They generally adopt an approach to life that values quality over quantity.”

Sng, with ASU Foundation Professor Steven Neuberg and ASU psychology professors Douglas Kenrick and Michael Varnum, used data from nations around the world and the 50 U.S. states to show that population density naturally correlates with these slow life strategies. Then, in a series of experiments (e.g., in which people read about increasing crowdedness or heard sounds of a crowded environment), they found that perceptions of crowdedness cause people to delay gratification and prefer slower, more long-term, mating and parenting behaviors.

Why? Using evolutionary life history theory, Neuberg notes that different strategies are useful in different kinds of environments.

“In environments where population density is low, and there is thus relatively little competition for available resources, there are few costs but lots of advantages to adopting a ‘fast’ strategy,” he suggested. “On the other hand, when the environment gets crowded, individuals have to compete vigorously with others for the available resources and territory.”

“To be successful in this competition, they need to invest more in building up their own abilities, which tends to delay having children,” he added. “Because this greater social competition also affects their kids, they tend to focus more of their time and energy on enhancing their abilities and competitiveness. So a slow strategy — in which one focuses more on the future and invests in quality over quantity — tends to enhance the reproductive success of individuals in high density environments.”

Will higher densities always lead to this slow strategy? “Not at all,” said Sng. “In fact, when high densities are paired with unpredictable death or disease, the theory predicts that people will become more present-focused and opportunistic.”

Sng added that the “slow life strategy, when brought to its extremes, also has its own pitfalls. Consider, for example, the pre-school craze in dense places like New York City, where parents are obsessed with getting their children into the best pre-schools. There are similar phenomenon emerging in dense countries like Japan and Singapore.”

“With the world’s population growing,” Neuberg added, “it seems more important than ever to understand the psychological effects of overcrowding and how living in crowded environments might influence people’s behaviors. Applying a new perspective to an old question is allowing us to reexamine the effects of living in crowded environments.”

Source:Science Daily

{Multitaper spectral analysis provides clinicians with a powerful tool for quickly visualizing brain activity during sleep.}

Massachusetts General Hospital (MGH) investigators have developed a novel approach to analyze brainwaves during sleep, which promises to give a more detailed and accurate depiction of neurophysiological changes than provided by a traditional sleep study. In a report published in the January issue of Physiology, the research team describes how applying a technique called multitaper spectral analysis to electroencephalogram (EEG) data provides objective, high-resolution depictions of brainwave activity during sleep that are more informative and easier to characterize than previous approaches. The researchers also present a visual atlas of brain activity during sleep in healthy individuals, highlighting new features of the sleep EEG — including a predictor of REM sleep — that could be of important use to clinicians and researchers.

Clinical sleep analysis has historically centered on identifying and tracking common patterns of brain and physiological activity, called sleep stages. Identifying sleep stages has long been a time-consuming and subjective process. Starting in the late 1930s, sleep staging was performed using EEG machines that would cut a paper tape into sheets with 30-second traces of the patient’s brainwave activity. A skilled technician would painstakingly take each paper sheet — almost 1,000 in an 8-hour sleep recording — and decide which sleep stage the patient was in by visual inspection of the EEG traces.

Almost 80 years later, other than slight refinement of the stages and the fact that the 30-second EEG traces now appear on a computer screen, the process of sleep staging remains virtually unchanged, remaining a time-consuming and fundamentally qualitative process. Consequently, even experienced scoring technicians still agree only 75 to 80 percent of the time. The progression of sleep stages over a night, called a hypnogram, is still used as the primary descriptor of sleep architecture. While the hypnogram has been an important tool for describing sleep architecture, since the numerous bumps and squiggles of brainwave traces become undiscernible by eye over large time scales, there are important drawbacks to relying on subjective summaries of sleep instead of objective data.

“During sleep, the brain is engaged in a symphony of activity involving the dynamic interplay of different cortical and sub-cortical networks,” says Michael Prerau, PhD, of the MGH Department of Anesthesia, Critical Care and Pain Management, lead author of the Physiology report. “Due to practical constraints and established practices, current clinical techniques greatly simplify the way the sleep is described, causing massive amounts of information to be lost. We therefore wanted to identify a more comprehensive way of characterizing brain activity during sleep that was easy to understand and quick to learn, yet mathematically principled and robust.”

The approach used by the MGH investigators provides a paradigm shift allowing clinicians to move away from subjective sleep staging and harness the wealth of objective information contained within EEG data. In their report, the team describes how sleep oscillations are far more easily characterized using spectral estimation than by looking at EEG traces. Spectral analysis is a class of approaches that break a waveform signal into its component oscillations — repeating patterns over time- just as a prism breaks white light into its component colors. In the EEG, these oscillations represent the activity of specific brain networks during sleep and wakefulness.

“At a fundamental level, brain activity is truly organized in terms of oscillations and waves,” says senior author Patrick Purdon, PhD, MGH Anesthesia. “Spectral analysis is just analyzing the signals in terms of these waves, making it the right tool — and in some ways the perfect tool — for the job.” Purdon also points out that traditional sleep scoring is essentially a crude form of spectral analysis, based on recognizing the wave properties by eye.

Spectral analysis may not have been adopted for sleep scoring previously because the prevailing techniques for EEG spectral estimation produced noisy and inaccurate estimates of the power spectrum, making interpretation of the resulting spectrogram difficult. Consequently, the MGH team employed multitaper spectral analysis, a form with greatly reduced noise and increased accuracy compared to more basic methods. Computing a multitaper spectrogram of the sleep EEG, which tracks how the power and frequency of these oscillations change over time, provides more information about which networks are active at different points during sleep.

In their report the researchers use these new vivid images of brain activity to illustrate how the sleep EEG multitaper spectrogram objectively reveals the detailed architecture of an entire night of sleep in a single visualization, rather than 1,000 30-second windows. Repeating patterns of activity — which use color to reflect signal power — become apparent even to the untrained eye, allowing technicians with only a few hours of training to stage with an accuracy comparable to that of traditional sleep scoring.

The investigators comprehensively detailed an atlas of common patterns and transitions seen within healthy individuals during sleep and highlighted the ability of the sleep EEG multitaper spectrogram to show features on time scales ranging from many hours to microevents lasting a few seconds. They were also able to identify novel features of the sleep EEG, including a trend in which bursting in the low-frequency alpha range, which is not currently used in clinical sleep scoring, predicts the onset of REM sleep by several minutes. Purdon says, “We try to remind people that the sleep EEG isn’t just a pile of ‘big data.’ In fact, it’s highly structured, and that structure is deeply connected to the fundamental brain mechanisms of sleep.”

Future research by the team will focus on developing robust quantitative metrics based on the spectrogram. “Moving forward, this enhanced approach will allow scientists to better characterize the complex heterogeneity observed in normal sleep and ultimately to assist in diagnosing sleep and related disorders,” says Prerau, who has received a grant from the National Institute of Neurological Disease and Stroke to identify new disease biomarkers within sleep. “It is also fun and easy to learn!” Prerau has created the website http://sleepEEG.org, which hosts free, interactive tutorials designed to teach clinicians and investigators how to read the sleep multitaper spectrogram.

The researchers also are optimistic about the clinical applications of this method. Co-author Matt Bianchi, MD, PhD, of the MGH Department of Neurology and director of the MGH Sleep Lab, says, “The traditional hypnogram has not had the clinical application one might expect for such a fundamental aspect of sleep. This technique is poised to bring EEG patterns, a classic aspect of sleep medicine, back to the forefront. Overall, by improving physician review of patient data, these techniques hold promise to bring modern analytics to routine care — making the patterns of brain activity during sleep accessible and enabling physicians to see the EEG through this dynamic lens.”

Source:Science Daily

{New research from a team of cognitive neuroscientists at McMaster University suggests that simply putting on a uniform, similar to one the police might wear, automatically affects how we perceive others, creating a bias towards those considered to be of a low social status.}

The study, recently published in the journal Frontiers in Psychology, raises important questions about stereotypes and profiling, and about how the symbolic power and authority associated with police uniforms might affect these tendencies.

“We all know that the police generally do an excellent job, but there has also been a great deal of public discourse about biased policing in North America over recent years,” says Sukhvinder Obhi, an associate professor of Psychology, Neuroscience & Behaviour and senior author of the study, which was conducted with postdoctoral researcher Ciro Civile.

“We set out to explore whether the uniform itself might have an impact, independent of all other aspects of the police subculture, training or work experiences,” he says.

Across a series of experiments, researchers examined how study participants -all of them university students — shifted their attention during specific tasks. In some cases, participants wore police-style attire.

During one experiment, participants were asked to identify a simple shape on a computer screen and were distracted by images of white male faces, black male faces, individuals dressed in business suits and others dressed in hoodies. Researchers tracked and analyzed their reaction times to compare how long they were distracted by the various images.

Researchers were surprised to find no difference in reaction times and no evidence of racial profiling when the distractors were white or black faces. This is surprising, they say, because previous research, much of it conducted in the United States, has revealed that many people associate African Americans with crime.

While more work is needed to explore this further, Obhi suggests the apparent lack of racial bias in the current study might highlight a potentially important difference between Canadian and American society.

The differences, however, were revealed when participants were distracted by photos of individuals wearing hoodies. Reaction times slowed, indicating that the images of hoodies were attention-grabbing. Critically, this bias towards hoodies only occurred when participants were wearing the police-style garb.

“We know that clothing conveys meaning and that the hoodie has to some extent become a symbol of lower social standing and inner-city youth,” says Obhi. “There is a stereotype out there that links hoodies with crime and violence, and this stereotype might be activated to a greater degree when donning the police style uniform. This may have contributed to the changes in attention that we observed. Given that attention shapes how we experience the world, attentional biases toward certain groups of people can be problematic.”

This is especially important for police officers, he explains, who might unconsciously perceive a threat where one doesn’t exist or vice versa.

Researchers hope to study the uniform and its effect on police officers and are conducting follow-up studies with collaborators in the United States.

Source:Science Daily

{Previous studies of flocks, swarms, and schools suggest that animal societies may verge on a “critical” point — in other words, they are extremely sensitive and can be easily tipped into a new social regime. But exactly how far animal societies sit from the critical point and what controls that distance remain unknown.}

Now an analysis of conflicts within a captive community of pigtail macaque monkeys has helped to answer these questions by showing how agitated monkeys can precipitate critical, large-scale brawls. In the study, fights were often small, involving just two or three monkeys, but sometimes grew to be very large, with as many as 30 of the 48 adults in the society. Bryan Daniels at the ASU-SFI Center for Biosocial Complex Systems, together with David Krakauer and Jessica Flack of the Santa Fe Institute, used ideas and models from statistical mechanics to ask whether the monkeys’ conflict behavior was near a critical point. They report what they found in this week’s Nature Communications.

Daniels, Krakauer, and Flack discovered that the distance from the critical point can be measured in terms of the “number of monkeys” that have to become agitated to push the system over the edge. Daniels says that in this system “agitating four or five individuals at a time can cause the system to destabilize and huge fights to break out.” However, Daniels says, each monkey makes a distinct contribution to group sensitivity — and these individual differences may allow distance from the critical point to be more easily controlled. Group members that break up fights can move the system away from the critical point by quelling the monkeys that contribute most to group sensitivity. Other group members, by targeting and agitating these individuals, can move the system towards the critical point and ready it for reconfiguration.

Animal societies may benefit from the group sensitivity that lets them cross critical social thresholds. Being sensitive allows for rapid adaptation — think fish switching from foraging mode to escape mode — but it can also make a society less robust to individuals’ mistakes. This tradeoff between robustness and adaptability is related to distance from the critical point.

An open question is whether animal societies collectively adjust their distance from criticality, becoming less sensitive when the environment is known and more sensitive when the environment becomes less predictable. Daniels says, “I think we’ve just scratched the surface.”

Source:Science Daily

{Cellphones and other devices could soon be controlled with touchless gestures and charge themselves using ambient light, thanks to new LED arrays that can both emit and detect light.}

Made of tiny nanorods arrayed in a thin film, the LEDs could enable new interactive functions and multitasking devices. Researchers at the University of Illinois at Urbana-Champaign and Dow Electronic Materials in Marlborough, Massachusetts, report the advance in the Feb. 10 issue of the journal Science.

“These LEDs are the beginning of enabling displays to do something completely different, moving well beyond just displaying information to be much more interactive devices,” said Moonsub Shim, a professor of materials science and engineering at the U. of I. and the leader of the study. “That can become the basis for new and interesting designs for a lot of electronics.”

The tiny nanorods, each measuring less than 5 nanometers in diameter, are made of three types of semiconductor material. One type emits and absorbs visible light. The other two semiconductors control how charge flows through the first material. The combination is what allows the LEDs to emit, sense and respond to light.

The nanorod LEDs are able to perform both functions by quickly switching back and forth from emitting to detecting. They switch so fast that, to the human eye, the display appears to stay on continuously — in fact, it’s three orders of magnitude faster than standard display refresh rates. Yet the LEDs are also near-continuously detecting and absorbing light, and a display made of the LEDs can be programmed to respond to light signals in a number of ways.

For example, a display could automatically adjust brightness in response to ambient light conditions — on a pixel-by-pixel basis.

“You can imagine sitting outside with your tablet, reading. Your tablet will detect the brightness and adjust it for individual pixels,” Shim said. “Where there’s a shadow falling across the screen it will be dimmer, and where it’s in the sun it will be brighter, so you can maintain steady contrast.”

The researchers demonstrated pixels that automatically adjust brightness, as well as pixels that respond to an approaching finger, which could be integrated into interactive displays that respond to touchless gestures or recognize objects.

They also demonstrated arrays that respond to a laser stylus, which could be the basis of smart whiteboards, tablets or other surfaces for writing or drawing with light. And the researchers found that the LEDs not only respond to light, but can convert it to electricity as well.

“The way it responds to light is like a solar cell. So not only can we enhance interaction between users and devices or displays, now we can actually use the displays to harvest light,” Shim said. “So imagine your cellphone just sitting there collecting the ambient light and charging. That’s a possibility without having to integrate separate solar cells. We still have a lot of development to do before a display can be completely self-powered, but we think that we can boost the power-harvesting properties without compromising LED performance, so that a significant amount of the display’s power is coming from the array itself.”

In addition to interacting with users and their environment, nanorod LED displays can interact with each other as large parallel communication arrays. It would be slower than device-to-device technologies like Bluetooth, Shim said, but those technologies are serial — they can only send one bit at a time. Two LED arrays facing each other could communicate with as many bits as there are pixels in the screen.

“We primarily interface with our electronic devices through their displays, and a display’s appeal resides in the user’s experience of viewing and manipulating information,” said study coauthor Peter Trefonas, a corporate fellow in Electronic Materials at the Dow Chemical Company. “The bidirectional capability of these new LED materials could enable devices to respond intelligently to external stimuli in new ways. The potential for touchless gesture control alone is intriguing, and we’re only scratching the surface of what could be possible.”

The researchers did all their demonstrations with arrays of red LEDs. They are now working on methods to pattern three-color displays with red, blue and green pixels, as well as working on ways to boost the light-harvesting capabilities by adjusting the composition of the nanorods.

Source:Science Daily

{A team of University of Colorado Boulder engineers has developed a scalable manufactured metamaterial — an engineered material with extraordinary properties not found in nature — to act as a kind of air conditioning system for structures. It has the ability to cool objects even under direct sunlight with zero energy and water consumption.}

When applied to a surface, the metamaterial film cools the object underneath by efficiently reflecting incoming solar energy back into space while simultaneously allowing the surface to shed its own heat in the form of infrared thermal radiation.

The new material, which is described today in the journal Science, could provide an eco-friendly means of supplementary cooling for thermoelectric power plants, which currently require large amounts of water and electricity to maintain the operating temperatures of their machinery.

The researchers’ glass-polymer hybrid material measures just 50 micrometers thick — slightly thicker than the aluminum foil found in a kitchen — and can be manufactured economically on rolls, making it a potentially viable large-scale technology for both residential and commercial applications.

“We feel that this low-cost manufacturing process will be transformative for real-world applications of this radiative cooling technology,” said Xiaobo Yin, co-director of the research and an assistant professor who holds dual appointments in CU Boulder’s Department of Mechanical Engineering and the Materials Science and Engineering Program. Yin received DARPA’s Young Faculty Award in 2015.

The material takes advantage of passive radiative cooling, the process by which objects naturally shed heat in the form of infrared radiation, without consuming energy. Thermal radiation provides some natural nighttime cooling and is used for residential cooling in some areas, but daytime cooling has historically been more of a challenge. For a structure exposed to sunlight, even a small amount of directly-absorbed solar energy is enough to negate passive radiation.

The challenge for the CU Boulder researchers, then, was to create a material that could provide a one-two punch: reflect any incoming solar rays back into the atmosphere while still providing a means of escape for infrared radiation. To solve this, the researchers embedded visibly-scattering but infrared-radiant glass microspheres into a polymer film. They then added a thin silver coating underneath in order to achieve maximum spectral reflectance.

“Both the glass-polymer metamaterial formation and the silver coating are manufactured at scale on roll-to-roll processes,” added Ronggui Yang, also a professor of mechanical engineering and a Fellow of the American Society of Mechanical Engineers.

During field tests in Boulder, Colorado and Cave Creek, Arizona, the metamaterial successfully demonstrated its average radiative cooling power larger than 110W/m2 for continuous 72 hours and larger than 90W/m2 in direct, noon-time sunlight. That cooling power is roughly equivalent to the electricity generated using solar cells for similar area, but the radiative cooling has the advantage of continuous running both day and night.

“Just 10 to 20 square meters of this material on the rooftop could nicely cool down a single-family house in summer,” said Gang Tan, an associate professor in the University of Wyoming’s Department of Civil and Architectural Engineering and a co-author of the paper.

In addition to being useful for cooling of buildings and power plants, the material could also help improve the efficiency and lifetime of solar panels. In direct sunlight, panels can overheat to temperatures that hamper their ability to convert solar rays into electricity.

“Just by applying this material to the surface of a solar panel, we can cool the panel and recover an additional one to two percent of solar efficiency,” said Yin. “That makes a big difference at scale.”

The engineers have applied for a patent for the technology and are working with CU Boulder’s Technology Transfer Office to explore potential commercial applications. They plan to create a 200-square-meter “cooling farm” prototype in Boulder in 2017.

The invention is the result of a $3 million grant awarded in 2015 to Yang, Yin and Tang by the Energy Department’s Advanced Research Projects Agency-Energy (ARPA-E).

“The key advantage of this technology is that it works 24/7 with no electricity or water usage,” said Yang “We’re excited about the opportunity to explore potential uses in the power industry, aerospace, agriculture and more.”

Source:Science Daily

{Close friendships facilitate the exchange of information and culture, making social networks more effective for cultural transmission, according to new UCL research that used wireless tracking technology to map social interactions in remote hunter-gatherer populations.}

The research demonstrates how increased network efficiency is achieved through investment in a few strong links between non-kin friends connecting unrelated families, as well as showing that strong friendships are more important than family ties in predicting levels of shared knowledge among individuals.

The study, published in Nature Human Behaviour, was funded by the Leverhulme Trust.

Hunter-gatherers offer the closest existing examples of human lifestyles and social organisation in the past, offering vital insights into human evolutionary history. To map the social networks of populations of Agta and BaYaka hunter-gatherers in Congo and the Philippines, researchers from the Hunter-Gatherer Resilience Project in UCL Anthropology used devices called mote — a wireless sensing technology worn as an armband that can record the interactions a person has in one day.

The motes recorded all one-to-one interactions at two minute intervals for 15 hours a day over a week in six Agta camps in the Philippines (200 individuals, 7, 210 interactions) and three BaYaka camps in the Congo (132 individuals, 3,397 interactions).

With this data, they were able to construct and examine social networks for both groups in unprecedented detail.

Many unique human traits such as high cognition, cumulative culture and hyper-cooperation have evolved due to the social organisation patterns unique to humans.

First author of the study, Dr Andrea Migliano (UCL Anthropology), commented: “Making friends and having a friendship network is an important human adaptation, one that has helped us develop cumulative culture.

“What we see in these hunter-gatherer camps is that people have very strong relationships with their friends — and those relationships are as strong as those with family. These friends connect the different households, facilitating the exchange of information and culture. And it is those connections that make a network efficient.”

The analyses show that randomization of interactions among either close kin or extended family did not affect the efficiency of hunter-gatherer networks. In contrast, randomization of friends (non-kin relationships) greatly reduced efficiency.

The researchers also found evidence that friendships began very early in childhood in both populations.

Dr Migliano added: “In contemporary society, we have the technology to expand these social networks, increasing flow of information over much larger numbers of people. This allows humans to co-operate and work together to build wonderful things. Our work illustrates how friendship is one of the secrets to humans’ success as a species.”

Source:Science Daily