Posts tagged intelligence
Articles and news from the latest research reports.
In a battle of brains, bigger isn’t always better
It’s one of those ideas that seems to make perfect sense: the bigger the brain, the more intelligent the creature. While it is generally true, exceptions are becoming increasingly common. Yet the belief persists even among scientists. Most biologists, for example, assume that rats, with larger brains, are smarter than mice. Cold Spring Harbor Laboratory (CSHL) scientists now challenge this belief. They compared mice and rats and found very similar levels of intelligence, a result that could have powerful implications for researchers studying complex behaviors and learning.
Are rats really smarter than mice? The question is more important than it sounds. For more than a decade, rats have been the rodent of choice for scientists studying how the brain arrives at decisions. They are relatively inexpensive to keep and are the subject of extensive protocols for studying cognitive function. Yet the last few years have seen an explosion in the number of genetic tools available to study their smaller cousins, mice. These tools enable scientists to turn genes on and off within specific populations of neurons – specificity that is critical to understanding how complex behaviors arise. Many investigators have shied away from using these new tools, however, believing that mice simply are not as intelligent as rats.
CSHL Professor Anthony Zador and Santiago Jaramillo, Ph.D., were skeptical. “Mice have the potential to greatly accelerate our research. We didn’t want to discount a very powerful option based on anecdotal evidence of their inferiority,” explains Zador.
The team systematically compared how rats and mice learn to perform a moderately challenging auditory task and found that their performance was similar. “This was a task that tested perceptual ability as well as adaptability, and we were very surprised to see that mice and rats performed about the same,” says Jaramillo, a former postdoctoral researcher in the Zador lab who now heads his own lab at the University of Oregon.
The researchers were able to find only one difference: rats learned somewhat faster than mice. According to Zador and Jaramillo, the training protocol, which was developed and optimized specifically for rats, might account for the slight advantage.
The finding of roughly equal intelligence has broad implications for cognition research. “We’ve found that mice, and all the genetic tools available in them, can be used to study the neural mechanisms underlying decision-making, and they might be suitable for other cognitive tasks as well,” says Zador.
(Source: ekaweb02.eurekalert.org)
Why is educational achievement heritable?
New research, led by King’s College London finds that the high heritability of exam grades reflects many genetically influenced traits such as personality, behaviour problems, and self-efficacy and not just intelligence.
The study, published today in the Proceedings of the National Academy of Sciences (PNAS), looked at 13,306 twins at age 16 who were part of the Medical Research Council (MRC) funded UK Twins Early Development Study (TEDS). The twins were assessed on a range of cognitive and non-cognitive measures, and the researchers had access to their GCSE (General Certificate of Secondary Education) scores.
In total, 83 scales were condensed into nine domains: intelligence, self-efficacy (confidence in one’s own academic ability), personality, well-being, home environment, school environment, health, parent-reported behaviour problems and child reported behaviour problems.
Identical twins share 100% of their genes, and non-identical twins (just as any other siblings) share 50% of the genes that vary between people. Twin pairs share the same environment (family, schools, teachers etc). By comparing identical and non-identical twins, the researchers were able to estimate the relative contributions of genetic and environmental factors. So, if overall, identical twins are more similar on a particular trait than non-identical twins, the differences between the two groups are due to genetics, rather than environment.
Eva Krapohl, joint first author of the study, from the MRC Social, Genetic and Developmental Psychiatry (SGDP) Centre at the Institute of Psychiatry, Psychology & Neuroscience (IoPPN) at King’s, says: “Previous work has already established that educational achievement is heritable. In this study, we wanted to find out why that is. What our study shows is that the heritability of educational achievement is much more than just intelligence – it is the combination of many traits which are all heritable to different extents.
“It is important to point out that heritability does not mean that anything is set in stone. It simply means that children differ in how easy and enjoyable they find learning and that much of these differences are influenced by genetics.”
The researchers found that the heritability of GCSE scores was 62%. Individual traits were between 35% and 58% heritable, with intelligence being the most highly heritable. Together, the nine domains accounted for 75% of the heritability of GCSE scores.
Heritability is a population statistic which does not provide any information at an individual level. It describes the extent to which differences between children can be ascribed to DNA differences, on average, in a particular population at a particular time.
(Source: kcl.ac.uk)
Nature or nurture? It’s all about the message
Were Albert Einstein and Leonardo da Vinci born brilliant or did they acquire their intelligence through effort?
No one knows for sure, but telling people the latter – that hard work trumps genes – causes instant changes in the brain and may make them more willing to strive for success, indicates a new study from Michigan State University.
The findings suggest the human brain is more receptive to the message that intelligence comes from the environment, regardless of whether it’s true. And this simple message, said lead investigator Hans Schroder, may ultimately prompt us to work harder.
“Giving people messages that encourage learning and motivation may promote more efficient performance,” said Schroder, a doctoral student in clinical psychology whose work is funded by the National Science Foundation. “In contrast, telling people that intelligence is genetically fixed may inadvertently hamper learning.”
In past research by Stanford University psychologist Carol Dweck, elementary students performing a task were either praised for their intelligence (“You’re so smart!”) or for their effort (“You worked really hard!”) after correct responses. As the task became harder, children in the first group performed worse after their mistakes compared to the group that had heard effort was important.
The MSU study, which appears online in the journal Biological Psychology, offers what could be the first physiological evidence to support those findings, in the form of a positive brain response. “These subtle messages seem to have a big impact, and now we can see they have an immediate impact on how the brain handles information about performance,” Schroder said.
For the study, two groups of participants read different articles. One article reported that intelligence is largely genetic, while the other said the brilliance of da Vinci and Einstein was “probably due to a challenging environment. Their genius had little to do with genetic structure.”
Participants were instructed to remember the main points of the article and completed a simple computer task while their brain activity was recorded. The findings, in a nutshell:
- The group that read intelligence was primarily genetic paid more attention to their responses, as if they were more concerned with their performance. This extra attention, however, did not relate to performance on trials after errors, suggesting a disconnect between brain and behavior.
- In contrast, those who had read that intelligence was due to a challenging environment showed a more efficient brain response after they made a mistake, possibly because they believed they could do better on the next trial. The more attention these participants paid to mistakes, the faster their responses were on the next trial.
The study does not weigh in on the age-old “nature vs. nurture” debate, Schroder noted. Rather, it investigates the messages about the nature of abilities people are exposed to on a regular basis, from a teacher comforting a student (“It’s OK, not everyone can be a math person.”) to the sports announcer commenting on a player’s skill (“Wow, what a natural!”). These messages are thought to contribute to the attitudes or “mindsets” people hold about their intelligence and abilities.
The research started as part of Schroder’s honors thesis as an undergraduate at MSU working in the Clinical Psychophysiology Lab directed by Jason Moser, MSU assistant professor. Moser co-authored the study along with Tim Moran, an MSU graduate student in cognitive psychology, and Brent Donnellan, a former MSU professor who now works at Texas A&M University.
As an undergraduate and graduate student, Schroder has already co-written nine papers that have appeared in academic journals, including five as lead author. His work is supported by a three-year grant from the NSF’s Graduate Research Fellowship Program.
Children’s drawings indicate later intelligence
How 4-year old children draw pictures of a child is an indicator of intelligence at age 14, according to a study by the Institute of Psychiatry at King’s College London, published today in Psychological Science.
The researchers studied 7,752 pairs of identical and non-identical twins (a total of 15,504 children) from the Medical Research Council (MRC) funded Twins Early Development Study (TEDS), and found that the link between drawing and later intelligence was influenced by genes.
At the age of 4, children were asked by their parents to complete a ‘Draw-a-Child’ test, i.e. draw a picture of a child. Each figure was scored between 0 and 12 depending on the presence and correct quantity of features such as head, eyes, nose, mouth, ears, hair, body, arms etc. For example, a drawing with two legs, two arms, a body and head, but no facial features, would score 4. The children were also given verbal and non-verbal intelligence tests at ages 4 and 14.
The researchers found that higher scores on the Draw-a-Child test were moderately associated with higher scores of intelligence at ages 4 and 14. The correlation between drawing and intelligence was moderate at ages 4 (0.33) and 14 (0.20).
Dr Rosalind Arden, lead author of the paper from the MRC Social, Genetic and Developmental Psychiatry (SGDP) Centre at the Institute of Psychiatry at King’s College London, says: “The Draw-a-Child test was devised in the 1920’s to assess children’s intelligence, so the fact that the test correlated with intelligence at age 4 was expected.What surprised us was that it correlated with intelligence a decade later.”
“The correlation is moderate, so our findings are interesting, but it does not mean that parents should worry if their child draws badly. Drawing ability does not determine intelligence, there are countless factors, both genetic and environmental, which affect intelligence in later life.”
The researchers also measured the heritability of figure drawing. Identical twins share all their genes, whereas non-identical twins only share about 50 percent, but each pair will have a similar upbringing, family environment and access to the same materials.
Overall, at age 4, drawings from identical twins pairs were more similar to one another than drawings from non-identical twin pairs. Therefore, the researchers concluded that differences in children’s drawings have an important genetic link. They also found that drawing at age 4 and intelligence at age 14 had a strong genetic link.
Dr Arden explains: “This does not mean that there is a drawing gene – a child’s ability to draw stems from many other abilities, such as observing, holding a pencil etc. We are a long way off understanding how genes influence all these different types of behaviour.”
Dr Arden adds: “Drawing is an ancient behaviour, dating back beyond 15,000 years ago. Through drawing, we are attempting to show someone else what’s in our mind. This capacity to reproduce figures is a uniquely human ability and a sign of cognitive ability, in a similar way to writing, which transformed the human species’ ability to store information, and build a civilisation.”
Common chemical in mothers may negatively affect the IQ of their unborn children
In some women abnormally high levels of a common and pervasive chemical may lead to adverse effects in their offspring. The study, published recently in the Journal of Clinical Endocrinology & Metabolism, is the first of its kind to shed light on the possible harmful side effects of perchlorate in mothers and their children.
Using data from the Controlled Antenatal Thyroid Study (CATS) cohort, researchers at Boston University School of Medicine (BUSM) and Cardiff University studied the effect of perchlorate, an environmental contaminant found in many foods and in some drinking water supplies, and its effects on children born to mothers with above average levels of this substance in their system. They studied 487 mother-child pairs from women with underactive thyroid glands and in the 50 women with the highest levels of perchlorate in their body, their offspring had below average IQ levels when compared to other children.
"The reason people really care about perchlorate is because it is ubiquitous. It’s everywhere," said Elizabeth Pearce, MD, MSc, associate professor of medicine at BUSM. "Prior studies have already shown perchlorate, at low levels, can be found in each and every one of us."
Perchlorate is a compound known to affect the thyroid gland, an organ needed to help regulate hormone levels in humans. According to Pearce previous studies have attempted to implicate this anti-thyroid activity in pregnant mothers as a possible cause of hypothyroidism, or an underactive thyroid gland. Hypothyroidism in newborns and children can lead to an array of unwelcome side effects, including below average intelligence.
(Source: eurekalert.org)
Declining intelligence in old age linked to visual processing
Researchers have uncovered one of the basic processes that may help to explain why some people’s thinking skills decline in old age. Age-related declines in intelligence are strongly related to declines on a very simple task of visual perception speed, the researchers report in the Cell Press journal Current Biology on August 4.
The evidence comes from experiments in which researchers showed 600 healthy older people very brief flashes of one of two shapes on a screen and measured the time it took each of them to reliably tell one from the other. Participants repeated the test at ages 70, 73, and 76. The longitudinal study is among the first to test the hypothesis that the changes they observed in the measure known as “inspection time” might be related to changes in intelligence in old age.
"The results suggest that the brain’s ability to make correct decisions based on brief visual impressions limits the efficiency of more complex mental functions," says Stuart Ritchie of the University of Edinburgh. "As this basic ability declines with age, so too does intelligence. The typical person who has better-preserved complex thinking skills in older age tends to be someone who can accumulate information quickly from a fleeting glance."
Previous studies had shown that smarter people, as measured by standard IQ tests, tend to be better at discerning the difference between two briefly presented shapes, the researchers explain. But before now no one had looked to see how those two measures might change over time as people grow older. The findings were rather unexpected.
"What surprised us was the strength of the relation between the declines," Ritchie says. "Because inspection time and the intelligence tests are so very different from one another, we wouldn’t have expected their declines to be so strongly connected."
The results provide evidence that the slowing of simple, visual decision-making processes might be part of what underlies declines in the complex decision making that we recognize as general intelligence. The results might also find practical use given the simplicity of the inspection time measure, Ritchie says, noting that the test can be taken very simply on a computer and has been used with children, adults, and even patients with dementia or other medical disorders.
"Since the declines are so strongly related, it might be easier under some circumstances to use inspection time to chart a participant’s cognitive decline than it would be to sit them down and give them a full, complicated battery of IQ tests," he says.
(Source: eurekalert.org)
Social origins of intelligence in the brain
By studying the injuries and aptitudes of Vietnam War veterans who suffered penetrating head wounds during the war, scientists are tackling — and beginning to answer — longstanding questions about how the brain works.
The researchers found that brain regions that contribute to optimal social functioning also are vital to general intelligence and to emotional intelligence. This finding bolsters the view that general intelligence emerges from the emotional and social context of one’s life.
The findings are reported in the journal Brain.
“We are trying to understand the nature of general intelligence and to what extent our intellectual abilities are grounded in social cognitive abilities,” said Aron Barbey, a University of Illinois professor of neuroscience, of psychology, and of speech and hearing science. Barbey (bar-BAY), an affiliate of the Beckman Institute and of the Institute for Genomic Biology at the U. of I., led the new study with an international team of collaborators.
Studies in social psychology indicate that human intellectual functions originate from the social context of everyday life, Barbey said.
“We depend at an early stage of our development on social relationships — those who love us care for us when we would otherwise be helpless,” he said.
Social interdependence continues into adulthood and remains important throughout the lifespan, Barbey said.
“Our friends and family tell us when we could make bad mistakes and sometimes rescue us when we do,” he said. “And so the idea is that the ability to establish social relationships and to navigate the social world is not secondary to a more general cognitive capacity for intellectual function, but that it may be the other way around. Intelligence may originate from the central role of relationships in human life and therefore may be tied to social and emotional capacities.”
The study involved 144 Vietnam veterans injured by shrapnel or bullets that penetrated the skull, damaging distinct brain tissues while leaving neighboring tissues intact. Using CT scans, the scientists painstakingly mapped the affected brain regions of each participant, then pooled the data to build a collective map of the brain.
The researchers used a battery of carefully designed tests to assess participants’ intellectual, emotional and social capabilities. They then looked for patterns that tied damage to specific brain regions to deficits in the participants’ ability to navigate the intellectual, emotional or social realms. Social problem solving in this analysis primarily involved conflict resolution with friends, family and peers at work.
As in their earlier studies of general intelligence and emotional intelligence, the researchers found that regions of the frontal cortex (at the front of the brain), the parietal cortex (further back near the top of the head) and the temporal lobes (on the sides of the head behind the ears) are all implicated in social problem solving. The regions that contributed to social functioning in the parietal and temporal lobes were located only in the brain’s left hemisphere, while both left and right frontal lobes were involved.
The brain networks found to be important to social adeptness were not identical to those that contribute to general intelligence or emotional intelligence, but there was significant overlap, Barbey said.
“The evidence suggests that there’s an integrated information-processing architecture in the brain, that social problem solving depends upon mechanisms that are engaged for general intelligence and emotional intelligence,” he said. “This is consistent with the idea that intelligence depends to a large extent on social and emotional abilities, and we should think about intelligence in an integrated fashion rather than making a clear distinction between cognition and emotion and social processing. This makes sense because our lives are fundamentally social — we direct most of our efforts to understanding others and resolving social conflict. And our study suggests that the architecture of intelligence in the brain may be fundamentally social, too.”
(Source: news.illinois.edu)
Chimp Intelligence “Runs In Families,” Environment Less Important
A chimpanzee’s intelligence is largely determined by its genes, while environmental factors may be less important than scientists previously thought, according to a Georgia State University research study.
The study found that some, but not all, cognitive, or mental, abilities, in chimpanzees depend significantly on the genes they inherit. The findings are reported in the latest issue of Current Biology.
“Intelligence runs in families,” said Dr. William Hopkins, professor in the Center for Behavioral Neuroscience at Georgia State and research scientist in the Yerkes National Primate Research Center at Emory University. “The suggestion here is that genes play a really important role in their performance on tasks while non-genetic factors didn’t seem to explain a lot. So that’s new.”
The role of genes in human intelligence or IQ has been studied for years, but Hopkins’ study is among the first to address heritability in cognitive abilities in nonhuman primates. Studies have shown that human intelligence is inherited through genes, but social and environmental factors, such as formal education and socioeconomic status, also play a role and are somewhat confounded with genetic factors. Chimpanzees, which are highly intelligent and genetically similar to humans, do not have these additional socio-cultural influences.
“Chimps offer a really simple way of thinking about how genes might influence intelligence without, in essence, the baggage of these other mechanisms that are confounded with genes in research on human intelligence,” Hopkins said.
The study involved 99 chimpanzees, ranging in age from 9 to 54, who completed 13 cognitive tasks designed to test a variety of abilities. Hopkins used quantitative genetics analysis to link the degree of relatedness between the chimpanzees to their similarities or differences in performance on the various cognitive measures to determine whether cognitive performance is inherited in chimpanzees.
Genes were found to play a role in overall cognitive abilities, as well as the performance on tasks in several categories.
Traditionally, researchers studying animal intelligence or animal learning have shared the view that environment and how previous behavior is reinforced affect how animals perform on a particular task.
“In our case, at least, it suggests that purely environmental explanations don’t really seem to tell the whole story,” Hopkins said. “Genes matter as well.”
Hopkins also studied the structure of chimpanzee intelligence to determine whether there were any similarities to the structure of human intelligence.
“We wanted to see if we gave a sample of chimpanzees a large array of tasks,” he said, “would we find essentially some organization in their abilities that made sense. The bottom line is that chimp intelligence looks somewhat like the structure of human intelligence.”
In the future, Hopkins wants to continue the study with an expanded sample size. He would also like to pursue studies to determine which genes are involved in intelligence and various cognitive abilities as well as how genes are linked to variation in the organization of the brain.
Hopkins also would like to determine which genes changed in human evolution that allowed humans to have such advanced intelligence.
(Image: Anup Shah / Nature Picture Library)
Researchers at the University of Granada have shown that a universal test of intelligence quotient (IQ) does not exist. Results in this type of test are determined by cultural differences.
Their objective was to study and explain cultural differences in IQ test performance. To do this, scientists from CIMCYC—the University of Granada’s Brain Mind and Behavior Research Center—conducted a study of 54 individuals aged between 18 and 54 years: 27 were Spanish and the other 27 were Moroccans residing in Spain.
The groups were selected to ensure that clear cultural differences existed between them: they spoke different languages (Spanish versus Arabic), professed different religions (Christians versus Muslims), had different traditions, and came from very different geographical contexts (Europe versus Africa).
Both groups underwent different tests of intellectual capacity: for example, a test of non-verbal intelligence, and various neuropsychological tests that measure functions such as visual memory and executive functions.
The same test measures different cognitive functions
Although the two groups were similar in terms of sex, educational level and socio-economic status, the results showed that in the test of non-verbal intelligence, the Spanish group obtained a higher IQ score than the Moroccan group. Moreover, the neuropsychological skills used in each subtest were clearly dependent on the country of origin of each participant. In other words, the same test can measure different cognitive functions in individuals from different cultures.
In the light of the results of this study, the authors suggest that the non-verbal tests cannot be considered culture-free and confirm the importance of validating the tests in their cultural context.
In 2014, this study has been ranked in the top 10 of articles downloaded from Archives of Clinical Neuropsychology.
Neanderthals were not inferior to modern humans
If you think Neanderthals were stupid and primitive, it’s time to think again.
The widely held notion that Neanderthals were dimwitted and that their inferior intelligence allowed them to be driven to extinction by the much brighter ancestors of modern humans is not supported by scientific evidence, according to a researcher at the University of Colorado Boulder.
Neanderthals thrived in a large swath of Europe and Asia between about 350,000 and 40,000 years ago. They disappeared after our ancestors, a group referred to as “anatomically modern humans,” crossed into Europe from Africa.
In the past, some researchers have tried to explain the demise of the Neanderthals by suggesting that the newcomers were superior to Neanderthals in key ways, including their ability to hunt, communicate, innovate and adapt to different environments.
But in an extensive review of recent Neanderthal research, CU-Boulder researcher Paola Villa and co-author Wil Roebroeks, an archaeologist at Leiden University in the Netherlands, make the case that the available evidence does not support the opinion that Neanderthals were less advanced than anatomically modern humans. Their paper was published in the journal PLOS ONE.
"The evidence for cognitive inferiority is simply not there,” said Villa, a curator at the University of Colorado Museum of Natural History. “What we are saying is that the conventional view of Neanderthals is not true."
Villa and Roebroeks scrutinized nearly a dozen common explanations for Neanderthal extinction that rely largely on the notion that the Neanderthals were inferior to anatomically modern humans. These include the hypotheses that Neanderthals did not use complex, symbolic communication; that they were less efficient hunters who had inferior weapons; and that they had a narrow diet that put them at a competitive disadvantage to anatomically modern humans, who ate a broad range of things.
The researchers found that none of the hypotheses were supported by the available research. For example, evidence from multiple archaeological sites in Europe suggests that Neanderthals hunted as a group, using the landscape to aid them.
Researchers have shown that Neanderthals likely herded hundreds of bison to their death by steering them into a sinkhole in southwestern France. At another site used by Neanderthals, this one in the Channel Islands, fossilized remains of 18 mammoths and five woolly rhinoceroses were discovered at the base of a deep ravine. These findings imply that Neanderthals could plan ahead, communicate as a group and make efficient use of their surroundings, the authors said.
Other archaeological evidence unearthed at Neanderthal sites provides reason to believe that Neanderthals did in fact have a diverse diet. Microfossils found in Neanderthal teeth and food remains left behind at cooking sites indicate that they may have eaten wild peas, acorns, pistachios, grass seeds, wild olives, pine nuts and date palms depending on what was locally available.
Additionally, researchers have found ochre, a kind of earth pigment, at sites inhabited by Neanderthals, which may have been used for body painting. Ornaments have also been collected at Neanderthal sites. Taken together, these findings suggest that Neanderthals had cultural rituals and symbolic communication.
Villa and Roebroeks say that the past misrepresentation of Neanderthals’ cognitive ability may be linked to the tendency of researchers to compare Neanderthals, who lived in the Middle Paleolithic, to modern humans living during the more recent Upper Paleolithic period, when leaps in technology were being made.
“Researchers were comparing Neanderthals not to their contemporaries on other continents but to their successors,” Villa said. “It would be like comparing the performance of Model T Fords, widely used in America and Europe in the early part of the last century, to the performance of a modern-day Ferrari and conclude that Henry Ford was cognitively inferior to Enzo Ferrari.”
Although many still search for a simple explanation and like to attribute the Neanderthal demise to a single factor, such as cognitive or technological inferiority, archaeology shows that there is no support for such interpretations, the authors said.
But if Neanderthals were not technologically and cognitively disadvantaged, why didn’t they survive?
The researchers argue that the real reason for Neanderthal extinction is likely complex, but they say some clues may be found in recent analyses of the Neanderthal genome over the last several years. These genomic studies suggest that anatomically modern humans and Neanderthals likely interbred and that the resulting male children may have had reduced fertility. Recent genomic studies also suggest that Neanderthals lived in small groups. All of these factors could have contributed to the decline of the Neanderthals, who were eventually swamped and assimilated by the increasing numbers of modern immigrants.
(Image: Reconstruction by Kennis & Kennis / Photograph by Joe McNally)