1. Study suggests visual intelligence is not the same as IQ

    November 17, 2017 by Ashley

    From the Vanderbilt University press release:

    Just because someone is smart and well-motivated doesn’t mean he or she can learn the visual skills needed to excel at tasks like matching fingerprints, interpreting medical X-rays, keeping track of aircraft on radar displays or forensic face matching.

    That is the implication of a new study which shows for the first time that there is a broad range of differences in people’s visual ability and that these variations are not associated with individuals’ general intelligence, or IQ. The research is reported in a paper titled “Domain-specific and domain-general individual differences in visual object recognition” published in the September issue of the journal Cognition and the implications are discussed in a review article in press at Current Directions in Psychological Science.

    “People may think they can tell how good they are at identifying objects visually,” said Isabel Gauthier, David K. Wilson Professor of Psychology at Vanderbilt University, who headed the study. “But it turns out that they are not very good at evaluating their own skills relative to others.”

    In the past, research in visual object recognition has focused largely on what people have in common, but Gauthier became interested in the question of how much visual ability varies among individuals. To answer this question, she and her colleagues had to develop a new test, which they call the Novel Object Memory Test (NOMT), to measure people’s ability to identify unfamiliar objects.

    Gauthier first wanted to gauge public opinions about visual skills. She did so by surveying 100 laypeople using the Amazon Mechanical Turk crowdsourcing service. She found that respondents generally consider visual tasks as fairly different from other tasks related to general intelligence. She also discovered that they feel there is less variation in people’s visual skills than there is in non-visual skills such as verbal and math ability.

    The main problem that Gauthier and colleagues had to address in assessing individuals’ innate visual recognition ability was familiarity. The more time a person spends learning about specific types of objects, such as faces, cars or birds, the better they get at identifying them. As a result, performance on visual recognition tests that use images of common objects are a complex mixture of people’s visual ability and their experience with these objects. Importantly, they have proven to be a poor predictor of how well someone can learn to identify objects in a new domain.

    Gauthier addressed this problem by using novel computer-generated creatures called greebles, sheinbugs and ziggerins to study visual recognition. The basic test consists of studying six target creatures, followed by a number of test trials displaying creatures in sets of three. Each set contains a creature from the target group along with two unfamiliar creatures, and the participant is asked to pick out the creature that is familiar.

    Analyzing the results from more than 2000 subjects, Gauthier and colleagues discovered that the ability to recognize one kind of creature was well predicted by how well subjects could recognize the other kind, although these objects were visually quite different. This confirmed the new test can predict the ability to learn new categories.

    The psychologists also used performance on several IQ-related tests and determined that the visual ability measured on the NOMT is distinct from and independent of general intelligence.

    “This is quite exciting because performance on cognitive skills is almost always associated with general intelligence,” Gauthier said. “It suggests that we really can learn something new about people using these tests, over and beyond all the abilities we already know how to measure.” Although the study confirms the popular intuition that visual skill is different from general intelligence, it found that individual variations in visual ability are much larger than most people think. For instance, on one metric, called the coefficient of variation, the spread of people was wider on the NOMT than on a nonverbal IQ test.

    “A lot of jobs and hobbies depend on visual skills,” Gauthier said. “Because they are independent of general intelligence, the next step is to explore how we can use these tests in real-world applications where performance could not be well predicted before.”


  2. So-called ‘bright girl effect’ does not last into adulthood, study finds

    September 7, 2017 by Ashley

    From the Case Western Reserve University press release:

    The notion that young females limit their own progress based on what they believe about their intelligence — called the “bright girl effect” — does not persist into adulthood, according to new research from Case Western Reserve University.

    The study also found almost no relationship between gender and intelligence “mindset,” which refers to a person’s beliefs about his or her own intellectual potential.

    According to mindset theory — developed by Carol Dweck, a psychology professor at Stanford University — some people have “growth” mindsets while others have “fixed” mindsets.

    A growth mindset, considered a positive trait, is more likely to lead a person to try to overcome challenges, believing intelligence can improve with effort.

    Fixed mindsets, often seen as a negative, are more likely to lead people to avoid difficult tasks and assume failure is due to intelligence levels that cannot be changed.

    Because girls are thought to mature earlier than boys, according to mindset theory, they are often praised for their attributes — how they “are.” More of this type of praise is given to “bright” girls, which leads them to believe their cognitive abilities are more or less set in stone.

    Published in the journal Intelligence, the new research found little indication such a phenomenon exists in adult women.

    “Overall, we saw no reliable evidence for a relationship between women’s intelligence and their mindsets,” said Brooke Macnamara, an assistant professor of psychological sciences at Case Western Reserve and co-author of the study. “Our results do not support the idea that men and women differ in their beliefs about intelligence.”

    The findings run contrary to some cornerstones of the mindset field: that females, especially smarter females, tend to believe their intelligence levels are static, and that differences in childhood praise given to boys and girls can heavily influence a person’s later beliefs about their own intelligence.

    The study

    In three studies, nearly 400 total participants were given an intelligence test and a measure developed by Dweck that discerns a person’s attitudes toward the plasticity of their own intelligence and talent.

    They were asked, for example, how much they agreed with such statements as, You can always substantially change how intelligent you are, and No matter who you are, you can significantly change your level of intelligence.

    The studies are among the first to investigate three factors among adults: measured intelligence, intelligence mindset, and gender.

    Evidence for the bright girl effect is mostly based on three academic studies conducted with children and adolescents from the 1980’s.

    “These studies help fill in gaps in the mindset research,” said Macnamara. “Some past research has suggested a ‘bright girl effect’ — gender differences among children. However, a ‘bright woman effect’ — gender differences among adults — seemed to be an untested assumption. Across our studies, there were no consistent relationships among intelligence, mindset and gender. Our research did not support the idea of a ‘bright woman effect.'”


  3. Higher IQ in childhood is linked to a longer life

    July 20, 2017 by Ashley

    From the BMJ press release:

    Higher intelligence (IQ) in childhood is associated with a lower lifetime risk of major causes of death, including heart disease, stroke, smoking related cancers, respiratory disease and dementia, finds a study published by The BMJ today.

    It is the largest study to date reporting causes of death in men and women across the life course, and the findings suggest that lifestyle, especially tobacco smoking, is an important component in the effect of intelligence on differences in mortality.

    Previous studies have shown that, on average, individuals with higher IQs tend to live a little longer than those with lower IQs, but these are largely based on data from male conscripts followed up only to middle adulthood.

    So a team of researchers from the University of Edinburgh set out to examine the association between intelligence test scores measured at age 11 and leading causes of death in men and women up to age 79.

    Their findings are based on data from 33,536 men and 32,229 women born in Scotland in 1936, who took a validated childhood intelligence test at age 11, and who could be linked to cause of death data up to December 2015.

    Cause of death included coronary heart disease, stroke, specific cancers, respiratory disease, digestive disease, external causes (including suicide and death from injury), and dementia.

    After taking account of several factors (confounders) that could have influenced the results, such as age, sex and socioeconomic status, the researchers found that higher childhood intelligence was associated with a lower risk of death until age 79.

    For example, a higher test score was associated with a 28% reduced risk of death from respiratory disease, a 25% reduced risk of death from coronary heart disease, and a 24% reduced risk of death from stroke.

    Other notable associations were seen for deaths from injury, smoking related cancers (particularly lung and stomach), digestive disease, and dementia. There was no evident association between childhood intelligence and death from cancers not related to smoking.

    The authors outline some study limitations which could have introduced bias. However, key strengths include the whole population sample, 68-year follow up, and ability to adjust for important confounders.

    They also point out that significant associations remained after further adjustment for smoking and socioeconomic status, suggesting that these factors did not fully account for mortality differences. And they say future studies “would benefit from measures of the cumulative load of such risk factors over the life course.”

    This study is the largest to date reporting causes of death across the life course, and it provides us with interesting results, say researchers based in Sweden, in a linked editorial.

    “Importantly, it shows that childhood IQ is strongly associated with causes of death that are, to a great extent, dependent on already known risk factors,” they write. And they suggest that “tobacco smoking and its distribution along the socioeconomic spectrum could be of particular importance here.”

    In conclusion, they say: “It remains to be seen if this is the full story or if IQ signals something deeper, and possibly genetic, in its relation to longevity.”


  4. Consequences of lead exposure in childhood

    April 4, 2017 by Sue

    From the Duke University press release:

    A long-term study of more than 500 children who grew up in the era of leaded gasoline has shown that their exposure to the powerful neurotoxin may have led to a loss of intelligence and occupational standing by the time they reached age 38.

    The effects are slight, but significant, showing that the higher the blood lead level in childhood, the greater the loss of IQ points and occupational status in adulthood. The study appears Wednesday in the Journal of the American Medical Association.

    Study participants are part of a life-long examination of more than 1,000 people born in Dunedin, New Zealand in 1972 and 1973. During their childhood, New Zealand had some of the highest gasoline lead levels in the world.

    From birth to adulthood, these people have regularly been assessed for cognitive skills such as perceptual reasoning and working memory. At age 11, blood samples were collected from 565 of them which were then tested for lead.

    Participants who were found to carry more than 10 micrograms of lead per deciliter of blood at age 11 had IQs at age 38 that were, on average, 4.25 points lower than their less lead-exposed peers. They were also found to have lost IQ points relative to their own childhood scores.

    The study found that for each 5-microgram increase in blood lead, a person lost about 1.5 IQ points.

    The mean blood lead level of the children at age 11 was 10.99 micrograms per deciliter of blood, slightly higher than the historical “level of concern” for lead exposure. Today’s reference value at which the CDC recommends public health intervention is half that, 5 micrograms per deciliter, a level which 94 percent of children in the study exceeded. No safe blood lead level in children has been identified.

    “This is historical data from an era when lead levels like these were viewed as normal in children and not dangerous, so most of our study participants were never given any special treatment,” said Terrie Moffitt, the senior author of the study and Duke’s Nannerl O. Keohane University Professor of psychology & neuroscience and psychiatry & behavioral sciences.

    “This case is different from the one in Flint, Michigan and other cities where lead in the drinking water has led public health officials to begin special interventions for those children,” Moffitt said. Flint’s children are receiving regular blood monitoring and expanded early childhood education, behavioral health services and special nutrition with the federal government’s support. “Interventions of this sort are intended to forestall the sorts of effects we’ve measured in this study,” she said.

    What makes the New Zealand case an important natural experiment is that automobile traffic goes through all neighborhoods. Unlike exposures to leaded paint or lead pipes in older structures, which pose more of a threat to poorer families, the exposure to leaded gasoline fumes was distributed relatively evenly across all social strata.

    Beginning in the 1920s, a compound called tetra-ethyl-lead was added to gasoline for its ability to boost octane ratings and raise engine power. The lead itself didn’t burn however, and emerged from tailpipes as elemental lead and lead oxides which settled as a particulate in soils around areas where cars were common.

    Soil hangs on tightly to lead particles and soils next to busy roads have been found to have the highest lead concentrations from the leaded gasoline era. Children playing outside were prone to either breathe in lead-laden dust, or swallow small amounts of leaded soil.

    In either case, lead can accumulate in the child’s bloodstream. It then settles into the bones, teeth and soft tissues and accumulates in the body over time.

    Leaded gasoline was phased out in the U.S. and New Zealand between the mid-1970s and the mid-1990s, but is still used in some Asian and middle eastern countries.

    “Regardless of where you start in life, lead is going to exert a downward pull,” said Avshalom Caspi, Edward M. Arnett Professor of psychology & neuroscience and psychiatry & behavioral sciences at Duke, who is a co-author on the paper. A neurotoxin exposure that affects all parts of society relatively equally would move the entire curve of IQ and social status downward. “If everyone takes a hit from environmental pollutants, society as a whole suffers.”

    The study also compared changes in social standing using a measure from the New Zealand government that plots families on a 6-point scale. The childhood social status of each child’s family was compared to their adult standing at age 38. Children who were over 10 micrograms of lead attained occupations with socioeconomic status levels four-tenths lower than their less-exposed peers.

    “The downward social mobility we see mirrors the trend in IQ,” said Aaron Reuben, a Duke psychology graduate student who is first author on the study. After various statistical controls were applied to the data, “the decline in occupational status is partially but significantly explained by the loss of IQ,” he said. “If you’re above the historic level of concern (for lead exposure), you’re doing worse on both.”

    The effects of lead exposure are probably long-lasting as well, Reuben added. “The cognitive deficits associated with lead persisted for decades, and showed in the kinds of occupations people got.”


  5. Emotional intelligence helps make better doctors

    March 24, 2017 by Ashley

    From the Loyola University Health System press release:

    Among the qualities that go into making an excellent physician is emotional intelligence.

    Emotional intelligence is the ability to recognize and understand emotions in yourself and others and to use this awareness to manage your behavior and relationships.

    Emotional intelligence plays a big role in determining a physician’s bedside manner. It helps make patients more trusting, which in turn leads to better doctor-patient relationships, increased patient satisfaction and better patient compliance. Emotional intelligence also can help make physicians more resilient to the stresses of the profession and less likely to experience burnout.

    Loyola University Medical Center is among the centers that are studying emotional intelligence in physicians as a way to improve patient care and physicians’ well-being. In a new study for example, Loyola researchers report that physicians-in-training scored in the high range of emotional intelligence.

    The young physicians as a group had a median score of 110 on an emotional intelligence survey, which is considered in the high range. (The average score for the general population is 100.) The physicians scored the highest in the subcategories of impulse control (114), empathy (113) and social responsibility (112) and lowest in assertiveness (102), flexibility (102) and independence (101).

    The study by Ramzan Shahid, MD, Jerold Stirling, MD, and William Adams, MA, is published in the Journal of Contemporary Medical Education. Dr. Shahid is an associate professor and director of the pediatric residency program. Dr. Stirling is professor and chair of Loyola’s department of pediatrics. Mr. Adams is a biostatistician in the health sciences division of Loyola University Chicago.

    There have been previous studies of emotional intelligence among physicians, but most studies have not included pediatric residents. To address this need, the Loyola study enrolled 31 pediatric and 16 med-peds residents at Loyola. (A resident is a physician who, following medical school, practices in a hospital under the supervision of an attending physician. A pediatric residency lasts three years. A med-peds residency, which combines pediatrics and internal medicine, lasts four years.)

    The residents completed the Bar-On Emotional Quotient Inventory 2.0, a validated 133-item online survey that assesses emotional intelligence skills.

    Residents in their third and fourth years of training scored higher in assertiveness (109) than residents in their first and second years (100). This could be related to the acquisition of new knowledge and skills and increased self-confidence as residents progress in their training.

    But first- and second-year residents scored higher in empathy (115.5) than third- and fourth-year senior residents (110). “One could hypothesize: Does a resident’s level of assertiveness increase at the cost of losing empathy?” the authors wrote.

    There were no differences in emotional intelligence composite scores between males and females or between pediatric and med-peds residents.

    The study is titled, “Assessment of emotional intelligence in pediatric and med-peds residents.”

    Unlike IQ, emotional intelligence can be taught. “Educational interventions to improve resident emotional intelligence scores should focus on the areas of independence, assertiveness and empathy,” the authors wrote. “These interventions should help them become assertive but should ensure they do not lose empathy.”

    The Loyola pediatrics and med-peds residents recently went through an emotional intelligence educational program that consisted of four hours of workshops. Initial data show the intervention has increased residents’ emotional intelligence scores, including the subcomponents related to stress management and wellness.


  6. Dogs, toddlers show similarities in social intelligence

    March 16, 2017 by Ashley

    From the University of Arizona press release:

    Most dog owners will tell you they consider their beloved pets to be members of their families. Now new research suggests that dogs may be even more like us than previously thought.

    Evan MacLean, director of the Arizona Canine Cognition Center at the University of Arizona, found that dogs and 2-year-old children show similar patterns in social intelligence, much more so than human children and one of their closest relatives: chimpanzees. The findings, published in the journal Animal Behaviour, could help scientists better understand how humans evolved socially.

    MacLean and his colleagues looked at how 2-year-olds, dogs and chimpanzees performed on comparable batteries of tests designed to measure various types of cognition. While chimps performed well on tests involving their physical environment and spatial reasoning, they did not do as well when it came to tests of cooperative communication skills, such as the ability to follow a pointing finger or human gaze.

    Dogs and children similarly outperformed chimps on cooperative communication tasks, and researchers observed similar patterns of variation in performance between individual dogs and between individual children.

    A growing body of research in the last decade has looked at what makes human psychology special, and scientists have said that the basic social communication skills that begin to develop around 9 months are what first seem to set humans apart from other species, said MacLean, assistant professor in the School of Anthropology in the UA College of Social and Behavioral Sciences.

    “There’s been a lot of research showing that you don’t really find those same social skills in chimpanzees, but you do find them in dogs, so that suggested something superficially similar between dogs and kids,” MacLean said. “The bigger, deeper question we wanted to explore is if that really is a superficial similarity or if there is a distinct kind of social intelligence that we see in both species.

    “What we found is that there’s this pattern, where dogs who are good at one of these social things tend to be good at lots of the related social things, and that’s the same thing you find in kids, but you don’t find it in chimpanzees,” he said.

    One explanation for the similarities between dogs and humans is that the two species may have evolved under similar pressures that favored “survival of the friendliest,” with benefits and rewards for more cooperative social behavior.

    “Our working hypothesis is that dogs and humans probably evolved some of these skills as a result of similar evolutionary processes, so probably some things that happened in human evolution were very similar to processes that happened in dog domestication,” MacLean said. “So, potentially, by studying dogs and domestication we can learn something about human evolution.”

    The research could even have the potential to help researchers better understand human disabilities, such as autism, that may involve deficits in social skills, MacLean said.

    Looking to dogs for help in understanding human evolution is a relatively new idea, since scientists most often turn to close human relatives such as chimpanzees, bonobos and gorillas for answers to evolutionary questions. Yet, it seems man’s best friend may offer an important, if limited, piece of the puzzle.

    “There are different kinds of intelligence, and the kind of intelligence that we think is very important to humans is social in nature, and that’s the kind of intelligence that dogs have to an incredible extent,” MacLean said. “But there are other aspects of cognition, like the way we reason about physical problems, where dogs are totally dissimilar to us. So we would never make the argument that dogs in general are a better model for the human mind — it’s really just this special set of social skills.”

    MacLean and his collaborators studied 552 dogs, including pet dogs, assistance-dogs-in-training and military explosive detection dogs, representing a variety of different breeds. The researchers assessed social cognition through game-based tests, in which they hid treats and toys and then communicated the hiding places through nonverbal cues such as pointing or looking in a certain direction. They compared the dogs’ results to data on 105 2-year-old children who previously completed a similar cognitive test battery and 106 chimpanzees assessed at wildlife sanctuaries in Africa.


  7. Conformity is not a universal indicator of intelligence in children

    March 15, 2017 by Ashley

    From the UT Austin press release:

    Because innovation is part of the American culture, adults in the United States may be less likely to associate children’s conformity with intelligence than adults from other populations, according to research from developmental psychologists at The University of Texas at Austin.

    U.S. children are often encouraged to engage in non-conformist and creative behavior. But researchers say this stands in contrast to populations in which child socialization is based on fostering collective and cooperative values that emphasize social conformity.

    In a study appearing in the Journal of Experimental Psychology: General, UT Austin researchers examined how adults view children’s behavioral conformity as an indication of their intelligence and good behavior, comparing the U.S. and Vanuatu, a Melanesian archipelago in the South Pacific.

    “Cross-cultural comparisons provide critical insight into variation in reasoning about intelligence. Examining variation in adults’ beliefs about children’s intelligence provides insight into the kinds of behavior adults value and encourage children to engage in,” said Cristine Legare, an associate professor of psychology at UT Austin.

    The study combined methodologies from experimental psychology and comparative anthropology to examine the kinds of behaviors adults associated with intelligence in each population. Rather than describing what makes a child intelligent, participants watched videos of an adult demonstrating a task, followed by two videos: one of a child imitating the actions exactly as they had been demonstrated; and another of a child deviating from the modeled task. Participants then indicated which child was smartest and which child was most well-behaved.

    Ni-Vanuatu adults were more likely to identify the high-conforming child as both smart and well-behaved, particularly when the child was from the same population as them; whereas U.S. adults were less likely to endorse the high-conforming child as intelligent.

    “Conformity is interpreted in different ways in each population — adults from Vanuatu interpret conformity as evidence of children’s competency and adults from the U.S. interpret non-conformity as evidence of children’s creativity,” Legare said.

    Additionally, the researchers examined potential differences in adults’ judgments across socioeconomic status groups within the U.S. to determine the extent to which education level influenced U.S. adult’s judgments of children’s conformity. Results indicated that adults with no college experience were more likely to endorse the high-conforming child on both measures than adults with higher levels of education, but still less likely than Ni-Vanuatu adults to select the high-conforming child as intelligent.

    Children’s learning environments can differ significantly between high and low socioeconomic families, including parents’ beliefs about how children should behave and the extent to which children should be self-directed and independent,” said Jennifer Clegg, the study’s lead author and UT Austin psychology alumna who is now a post-doctoral researcher at Boston University. “Examining variation in adults’ beliefs about children’s intelligence provides insight into the kinds of behavior children are encouraged to engage in diverse populations with distinct childrearing goals and values.”


  8. Study suggests blood vessels in eye linked with IQ, cognitive function

    June 9, 2013 by Ashley

    From the Association for Psychological Science press release:

    senior man visionThe width of blood vessels in the retina, located at the back of the eye, may indicate brain health years before the onset of dementia and other deficits, according to a new study published in Psychological Science, a journal of the Association for Psychological Science.

    Research shows that younger people who score low on intelligence tests, such as IQ, tend to be at higher risk for poorer health and shorter lifespan, but factors like socioeconomic status and health behaviors don’t fully account for the relationship. Psychological scientist Idan Shalev of Duke University and colleagues wondered whether intelligence might serve as a marker indicating the health of the brain, and specifically the health of the system of blood vessels that provides oxygen and nutrients to the brain.

    To investigate the potential link between intelligence and brain health, the researchers borrowed a technology from a somewhat unexpected domain: ophthalmology.

    Shalev and colleagues used digital retinal imaging, a relatively new and noninvasive method, to gain a window onto vascular conditions in the brain by looking at the small blood vessels of the retina, located at the back of the eye. Retinal blood vessels share similar size, structure, and function with blood vessels in the brain and can provide a way of examining brain health in living humans.

    The researchers examined data from participants taking part in the Dunedin Multidisciplinary Health and Development Study, a longitudinal investigation of health and behavior in over 1000 people born between April 1972 and March 1973 in Dunedin, New Zealand.

    The results were intriguing.

    Having wider retinal venules was linked with lower IQ scores at age 38, even after the researchers accounted for various health, lifestyle, and environmental risk factors that might have played a role.

    Individuals who had wider retinal venules showed evidence of general cognitive deficits, with lower scores on numerous measures of neurospsychological functioning, including verbal comprehension, perceptual reasoning, working memory, and executive function.

    Surprisingly, the data revealed that people who had wider venules at age 38 also had lower IQ in childhood, a full 25 years earlier.

    It’s “remarkable that venular caliber in the eye is related, however modestly, to mental test scores of individuals in their 30s, and even to IQ scores in childhood,” the researchers observe.

    The findings suggest that the processes linking vascular health and cognitive functioning begin much earlier than previously assumed, years before the onset of dementia and other age-related declines in brain functioning.

    “Digital retinal imaging is a tool that is being used today mainly by eye doctors to study diseases of the eye,” Shalev notes. “But our initial findings indicate that it may be a useful investigative tool for psychological scientists who want to study the link between intelligence and health across the lifespan.”

    The current study doesn’t address the specific mechanisms that drive the relationship between retinal vessels and cognitive functioning, but the researchers surmise that it may have to do with oxygen supply to the brain.

    Increasing knowledge about retinal vessels may enable scientists to develop better diagnosis and treatments to increase the levels of oxygen into the brain and by that, to prevent age-related worsening of cognitive abilities,” they conclude.

     

     


  9. Study suggests IQ predicted by ability to filter motion

    May 27, 2013 by Ashley

    From the University of Rochester press release via EurekAlert!:

    mind mazeA brief visual task can predict IQ, according to a new study.

    This surprisingly simple exercise measures the brain’s unconscious ability to filter out visual movement. The study shows that individuals whose brains are better at automatically suppressing background motion perform better on standard measures of intelligence.

    The test is the first purely sensory assessment to be strongly correlated with IQ and may provide a non-verbal and culturally unbiased tool for scientists seeking to understand neural processes associated with general intelligence.

    “Because intelligence is such a broad construct, you can’t really track it back to one part of the brain,” says Duje Tadin, a senior author on the study and an assistant professor of brain and cognitive sciences at the University of Rochester. “But since this task is so simple and so closely linked to IQ, it may give us clues about what makes a brain more efficient, and, consequently, more intelligent.”

    The unexpected link between IQ and motion filtering was reported online in the Cell Press journal Current Biology on May 23 by a research team lead by Tadin and Michael Melnick, a doctoral candidate in brain and cognitive sciences at the University of Rochester.

    In the study, individuals watched brief video clips of black and white bars moving across a computer screen. Their sole task was to identify which direction the bars drifted: to the right or to the left. The bars were presented in three sizes, with the smallest version restricted to the central circle where human motion perception is known to be optimal, an area roughly the width of the thumb when the hand is extended. Participants also took a standardized intelligence test.

    As expected, people with higher IQ scores were faster at catching the movement of the bars when observing the smallest image. The results support prior research showing that individuals with higher IQs make simple perceptual judgments swifter and have faster reflexes. “Being ‘quick witted’ and ‘quick on the draw’ generally go hand in hand,” says Melnick.

    But the tables turned when presented with the larger images. The higher a person’s IQ, the slower they were at detecting movement. “From previous research, we expected that all participants would be worse at detecting the movement of large images, but high IQ individuals were much, much worse,” says Melnick. That counter-intuitive inability to perceive large moving images is a perceptual marker for the brain’s ability to suppress background motion, the authors explain. In most scenarios, background movement is less important than small moving objects in the foreground. Think about driving in a car, walking down a hall, or even just moving your eyes across the room. The background is constantly in motion.

    The key discovery in this study is how closely this natural filtering ability is linked to IQ. The first experiment found a 64 percent correlation between motion suppression and IQ scores, a much stronger relationship than other sensory measures to date. For example, research on the relationship between intelligence and color discrimination, sensitivity to pitch, and reaction times have found only a 20 to 40 percent correlation. “In our first experiment, the effect for motion was so strong,” recalls Tadin, “that I really thought this was a fluke.”

    So the group tried to disprove the findings from the initial 12-participant study conducted while Tadin was at Vanderbilt University working with co-author Sohee Park, a professor of psychology. They reran the experiment at the University of Rochester on a new cohort of 53 subjects, administering the full IQ test instead of an abbreviated version and the results were even stronger; correlation rose to 71 percent. The authors also tested for other possible explanations for their findings.

    For example, did the surprising link to IQ simply reflect a person’s willful decision to focus on small moving images? To rule out the effect of attention, the second round of experiments randomly ordered the different image sizes and tested other types of large images that have been shown not to elicit suppression. High IQ individuals continued to be quicker on all tasks, except the ones that isolated motion suppression. The authors concluded that high IQ is associated with automatic filtering of background motion.

    “We know from prior research which parts of the brain are involved in visual suppression of background motion. This new link to intelligence provides a good target for looking at what is different about the neural processing, what’s different about the neurochemistry, what’s different about the neurotransmitters of people with different IQs,” says Tadin.

    The relationship between IQ and motion suppression points to the fundamental cognitive processes that underlie intelligence, the authors write. The brain is bombarded by an overwhelming amount of sensory information, and its efficiency is built not only on how quickly our neural networks process these signals, but also on how good they are at suppressing less meaningful information. “Rapid processing is of little utility unless it is restricted to the most relevant information,” the authors conclude.

    The researchers point out that this vision test could remove some of the limitations associated with standard IQ tests, which have been criticized for cultural bias. “Because the test is simple and non-verbal, it will also help researchers better understand neural processing in individuals with intellectual and developmental disabilities,” says co-author Loisa Bennetto, an associate professor of psychology at the University of Rochester.


  10. Study links flame retardants to hyperactivity, lower intelligence

    May 6, 2013 by Ashley

    From the University of Cincinnati press release via HealthCanal:

    lab_researchA new study led by researchers at the University of Cincinnati (UC) College of Medicine shows that prenatal exposure to chemical flame retardants used in everyday products such as baby strollers, carpeting and electronics is associated with hyperactivity and lower intelligence in early childhood.

    The research on the chemicals, known as polybrominated diphenyl ethers (PBDEs), is being presented Monday, May 6, at the Pediatric Academic Societies (PAS) annual meeting in Washington, D.C. The study’s lead author is Aimin Chen, MD, PhD, an assistant professor of environmental health at UC.

    “In animal studies, PBDEs can disrupt thyroid hormone and cause hyperactivity and learning problems,” says Chen. “Our study adds to several other human studies to highlight the need to reduce exposure to PBDEs in pregnant women.”

    Chen and his colleagues at UC collected blood samples from 309 pregnant women enrolled in a study at Cincinnati Children’s Hospital Medical Center to measure PBDE levels. They also performed intelligence and behavior tests on the women’s children annually until they were 5 years old.

    We found that maternal exposure to PBDEs, a group of brominated flame retardants mostly withdrawn from the U.S. market in 2004, was associated with deficits in child cognition at age 5 years and hyperactivity at ages 2 to 5 years,” Chen says. A 10-fold increase in maternal PBDEs was associated with about a four-point IQ deficit in 5-year-old children.

    Even though PBDEs, except Deca-BDEs, are not used as a flame retardant in the United States anymore, they are found on many consumer products bought several years ago. In addition, the chemicals are not easily biodegradable, so they remain in human tissues and are transferred to the developing fetus.

    Because PBDEs exist in the home and office environment as they are contained in old furniture, carpet pads, foams and electronics, the study raises further concern about their toxicity in developing children,” Chen says.