Author Interviews, Dental Research, JAMA, Mental Health Research, Mineral Metabolism, Pediatrics / 19.08.2019 Interview with: Rivka Green, MA Doctoral Candidate Clinical Developmental Neuropsychology York University What is the background for this study? What are the main findings? Response: We conducted a study on 512 mother-child pairs from 6 major cities across Canada, about half of whom lived in a region that receives fluoridated water. We found that prenatal fluoride exposure was associated with lower IQ scores in 3-4 year old children. (more…)
Author Interviews, NYU, PLoS / 15.02.2018 Interview with: Glenn N. Saxe, MD Professor of Child & Adolescent Psychiatry Hassenfeld Children’s Hospital at NYU Langone Department of Child and Adolescent Psychiatry Child Study Center, One Park Avenue New York, NY 10016 What is the background for this study? Would you briefly explain what is meant by brain entropy and how it relates to intelligence? Response: Think of human intelligence as the capacity for a human being to understand their complex and ever-changing world. The world of a person is really complex and constantly in flux so the human brain must be ready to understand whatever may come – when there is no way beforehand to predict what might come. How does the brain understand its world? It creates specific models of the information it receives through specific patterns of neuronal connection. These are called brain states. The way the brain understands its world is largely through using such models, or brain states, to accurately predict what comes next. So you can see that for an intelligent brain to properly understand and predict events in the world, it will need to have access to a very, very large number of brain states. And this is how entropy is defined. Entropy is a very old and very powerful concept in the history of science. Not only is it fundamental for thermodynamics – what we learned in high school physics – but it is also fundamental for the nature of information and it’s processing. Entropy is defined as the number of states – or distinct configurations – any system has access to at any point in time. High entropy means access to a very large number of states. Low entropy means access to a very small number of states. A solid is a phenomenon with very low entropy. A gas is a phenomenon with very high entropy. Life, and the brain, are somewhere in between. Although it is impossible to precisely measure the number of states a brain has access to at any one moment, there is a highly related concept that can be measured. A system with access to a very high number of possible states (like a gas) has components with behavior that is highly unpredictable. A system with access to very few possible states (like a solid) has components whose behavior is highly predictable. We measured brain entropy through the predictability of the brains components at the smallest scale we had access to: what are called voxels in an fMRI scan. These are 3mm cubes of neurons in a functional MRI scan, and there are many thousands of these voxels in our measurement and each of these voxels contains information on the activity of hundreds of thousands of neurons. We measured the predictability of each of these voxels and then found clusters of voxels where their predictability - or entropy - was related to intelligence. (more…)
Author Interviews, Education, Genetic Research / 26.01.2018

“Reading is fun!” by Isaac Wedin is licensed under CC BY Interview with: Bruno Sauce, PhD and Louis D. Matzel, PhD Department of Psychology, Program in Behavioral and Systems Neuroscience Rutgers University New Jersey, USA What is the background for this study? Response: Scientists have known for decades that intelligence has a high heritability, which means that much of the individual differences in IQ we see in people are due to genetic differences. Heritability is a value that ranges from 0.0 (meaning no genetic component) to 1.0 (meaning that the trait is completely heritable). For example, the heritability of breast cancer is estimated at 0.27; the heritability of body mass index is 0.59; and the heritability of major depression is 0.40. In comparison, the heritability of IQ is estimated to be as high as 0.8 – quite a high value! More recently, however, there have been studies showing that intelligence has a high malleability: the studies cover cognitive gains consequent to adoption/immigration, changes in IQ’s heritability across life span and socioeconomic status, gains in IQ over time from societal and scientific progress, the slowdown of age-related cognitive decline, the gains in intelligence from early education, differences in average IQ between countries due to wealth and development, and gains in intelligence that seem to happen from working memory training. Intelligence being both highly heritable and highly malleable is seemingly paradoxical, and this paradox has been the source of continuous controversy among scientists. Why does it matter? Because IQ predicts many important outcomes in life, such as academic grades, income, social mobility, happiness, marital stability and satisfaction, general health, longevity, reduced risk of accidents, and reduced risk of drug addiction (among many other outcomes). A clear understanding of the genetic and environmental causes of variation in intelligence is critical for future research, and its potential implications (and applications) for society are immense. (more…)
Author Interviews, Brigham & Women's - Harvard, Pediatrics, Psychological Science, Science / 26.11.2017 Interview with: Shari Liu Dept Psychology Harvard University Cambridge, MA 02138 What is the background for this study? What are the main findings? Response: Every day, we look out into the social world and see more than pixels changing across our retinas, or bodies moving in space. We see people brimming with desires, governed by their beliefs about the world and concerned about the costs of their actions and the potential rewards those actions may bring. Reasoning about these mental variables, while observing only people’s overt behaviors, is at the heart of commonsense psychology. (more…)
Author Interviews, Cognitive Issues, Mental Health Research / 20.09.2017 Interview with: Amitai Abramovitch, PhD Assistant Professor Department of Psychology Texas State University What is the background for this study? What are the main findings? Response: Obsessive-Compulsive Disorder (OCD) is associated with moderate degree of underperformance on several cognitive tests such as processing speed, and some higher order functions such as planning and inhibition. While this does not constitute a clinically meaningful impairment on these functions, we set out to explore the prevailing myth that OCD is associated with above-average intelligence. This myth, that was propagated by Sigmund Freud 115 years ago and is still surprisingly all too prevalent -  was never tested empirically. The notion of above average intelligence in OCD didn’t make sense to us given that IQ tests are comprised of subtests that assess cognitive function. To test this, we collected all the available data ever published in the scientific literature regarding IQ in OCD versus control samples, and conducted a meta-analysis. Our results show that OCD is not associated with higher IQ than average. In fact we found a slightly lowered IQ in OCD compared to controls, although IQ scores for OCD samples were in the average range. The total IQ score (Full Scale IQ) is comprised of two subscales, namely Verbal IQ, and Performance IQ. Our results show that reduced Full Scale IQ stems primarily from lowered Performance IQ, a scale that is comprised of a number of timed tests. In other words, as opposed to Verbal IQ tests, test scores on Performance IQ subtests rely heavily on performance within a specific time frame, and not only on performance accuracy. Thus, our findings suggest that reduced processing speed found in OCD could lead to reduced Performance IQ, and subsequently lead to lowered Full Scale IQ, and may not be indicative of specific cognitive deficits. This finding suggests that IQ tests administered to individuals diagnosed with OCD may result in a biased Full Scale IQ scores that does not accurately reflect their full intellectual potential. (more…)
Aging, Author Interviews, Cognitive Issues, Exercise - Fitness / 22.08.2015

Rikke Hodal Meincke PhD student Center for Healthy Aging and the Department of Public Health University of Interview with: Rikke Hodal Meincke PhD student Center for Healthy Aging and the Department of Public Health University of Copenhagen Medical Research: What is the background for this study? Response: A sufficient level of physical capability is a precondition for maintaining independence and quality of life. Physical capability can be assessed objectively by tests of physical performance, for instance handgrip strength, chair-rising and postural balance. Physical performance is associated with mortality and disability in late life, so gaining insights into the variance in physical performance is important to promote sustained physical capability and prevent disability. Research has previously found physical activity, health status and socioeconomic position to be associated with physical performance. In addition, early life factors, such as childhood SEP, have been found to be associated with measures of physical performance later in life. The objective of our study was to examine the association between intelligence in early adulthood and midlife physical performance in Danish men. If an association between intelligence in early life and midlife physical performance exists it may indicate that cognitive abilities and physical performance share some of the same neurodevelopmental processes, but may also indicate that intelligence has an independent effect on later physical performance through various pathways. Medical Research: What are the main findings? Response: In our study of more than 2800 Danish men, we found positive associations between intelligence in early adulthood and five objective measures of physical performance in midlife independent of other early life factors. A one standard deviation increase in intelligence score resulted in 1.1 more chair-rises in 30 seconds, a 1 cm higher jump, a 3.7% smaller balance area, a 0.7 kg increase in handgrip-strength, and a 0.5 kg increase in lower back force. (more…)
Author Interviews, Genetic Research / 01.08.2015

Dr. Rosalind Arden Centre for Philosophy of Natural & Social Science London School of Economics Interview with: Dr. Rosalind Arden Centre for Philosophy of Natural & Social Science London School of Economics London MedicalResearch: What is the background for this study? What are the main findings? Dr. Arden: We've known for a while that people who score higher on IQ-type tests tend to live longer. A study published in the British Medical Journal (Whalley & Deary, 2001) examined intelligence in childhood and later survival. People born in Scotland in 1921 took an IQ-type test at age 11 in 1932. Those with higher test scores were more likely to survive to age 76. What we haven't known is 'why?' One possibility is that advantages from being raised in a wealthier family may enhance intelligence and health - leading to brighter people living longer. Another possibility is that many genes that influence brains also influence bodies. If well-built brains co-occur with well-built bodies, that could also explain the link. These are only two of several possible explanations. We aimed to test whether genes caused the link between intelligence and life-expectancy. We found 1) the link between intelligence and life expectancy is positive but small. 2) The cause of the link is almost all genetic. We found this by examining differences within twin pairs. Twins offer a quasi-natural experiment because they share many features of the environment that are often thought (mistakenly) to cause differences between people. And marvelously, for science there are two kinds of twins, with known genetic relatedness (100 % or 50%). This give us a means to test questions about the cause of differences in a population, as well as the causes of correlations among traits within a population. (more…)
Author Interviews, Mental Health Research, Nature / 18.10.2013 Interview with Dr. Kees-Jan Kan PhD Department of Biological Psychology, VU University Department of Psychological Methods, University of Amsterdam What are the main findings of the study? Answer: We asked ourselves how well theories of intelligence actually predict empirical results. To this end, we reviewed and scrutinized the predictions from intelligence theories and collected relevant results that have been published in the scientific literature over the last decades. The results pertained to intelligence test scores from thousands of subjects across the world. We found that on essential aspects the empirical results were opposite of the predictions from the mainstream theories of intelligence, in which intelligence is interpreted as a biological trait. (more…)