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Intelligence - Genetics or Environmental?

By Dr. Magnus Williams

Conventional wisdom tells us that we are at our peak of mental sharpness when we are young and that our acuity gradually declines over time, but that we offset this natural disadvantage by the experience and wisdom we have built up in our adult years. We have long accepted the view that getting older means we will automatically see a dulling of our intelligence and loss of ability. However, studies has thrown an interesting light on our changing capabilities and we may need to revisit our previously held assumptions about what affects mental sharpness and the inevitability of its decline.

Recent research
According to research by a joint team from the niversity of !ueensland and niversity of "dinburgh our genes may counter the effects of ageing and enable some of us to actually grow smarter as we get older. #he study, published in $ature maga%ine found that genetic factors were responsible for &' percent of the change in a person s mental sharpness between adolescence and old age. #his meant that environmental influences were more important. #he researchers analysed the records of (,)'* unrelated individuals whose intelligence had been measured at the age of (( and then subse+uently at ,-, .* or .). Additionally, participants in the study also provided /$A samples. #he results suggested that the same genetic factors played a part in explaining differences in intelligence in childhood and old age. #he researchers examined more than half a million genetic markers. 0rofessor 1an /eary from the niversity of "dinburgh, said2 Until now, we have not had an estimate of how much genetic differences affect how intelligence changes The results partly explain why some people's brains age better than others. We are careful to suggest that our estimates do not have conventional statistical significance, but they are useful because such estimates have been unavailable to date." #he study could not pinpoint which individual genes or combination of genes were responsible and it is believed that environmental factors, such as lifestyle were also a factor. 1n a commentary accompanying the study, 3obert 0lomin, a psychologist at 4ing5s College in 6ondon said2 The nature-nurture controversy is never more contentious than when it concerns the genetics of intelligence.. This new research! may mar" the beginning of the end of this controversy. #he research is in its early stages and the next goal is to next try and identify which environmental factors were most important in maintaining mental acuity. #he study from the Australian78cottish team ties in with previous work indicating that genes become increasingly important as we grow older. 1n our formative years the family environment is dominant and approximately 9* percent of 1! is a product of family, with family members often scoring within a reasonably close range on 1! testing. However from adulthood onwards, when children create their own family environments the influence of their original family declines to practically %ero and much greater differences between the original family members become apparent. 8cientists in /enmark have conducted studies into mental sharpness among older people and have found evidence that suggests we are better able to maintain our acuity in comparison to the previous generation. 3esearchers tested a group of )-:year olds and compared their tests with another group who had been born ten years earlier and who had been assessed at the same age. 1n tests comprising a combination of +uestions and tasks &9 percent of the more recently:born group scored in the highest category of mental ability compared to (9 percent of the earlier:born group. ;f 9* +uestions asked the later:born group averaged two more correct

responses than the other group. #his research builds on work done by 0rofessor <ames =lynn, an authority in the field, who discovered the trend of humans improving their performance in testing by a rate of three points every decade : the so:called =lynn "ffect. #he reason for the better performance is not yet clear although some factors may include better education and improving diets in the general population. 1ndeed, education has been identified as a factor in increasing mental sharpness by other studies, which found that a college degree may help to delay age related decline by up to a decade. 1n testing by /r. >argie ". 6achman, a psychologist at ?randeis niversity, >asachusetts, and a specialist in ageing, found a positive association between the number of years in education people and their performance in tests of mental sharpness. p to the age of .- the studies showed that those with college degrees performed e+ually well as less:educated participants who were (* years younger. #his was the case even taking into account differences in income, gender, physical activity and age. 0art of the answer seems to be that those with a higher education continued to exercise their brains throughout their lives, by reading, writing, attending lectures and doing pu%%les. #ducation seems to be an elixir that can bring us a healthy body and mind throughout adulthood and even a longer life. - $r. %argie #. &achman We are often told that to eat foods that contain omega:9 fatty acids either naturally or in food supplements. #he belief is that they can help to improve mental sharpness. However, there are disagreements among scientists as to the value of omega:9 and some have argued that the evidence for its benefits is inconclusive. /r. =rank 8acks, 0rofessor of Cardiovascular /isease 0revention, /epartment of $utrition at Harvard 8chool of 0ublic Health has recommended having at least one portion of omega:9 every day. However, /r. <ennifer @. 3obinson from the niversity of 1owa, who conducted a study into the effects of omega:9 on women s brains said that studies trying to prove that omega:9 can protect the brain have not been definitive. 1n an interview with 3euters Health, she said that studies have been all over the place #heres nothing really convincing, AinB one direction or the other. /r. 3obinson analysed data from &,(-. women aged ,- to C* who completed seven different kinds of thinking and memory tests and found that taking omega:9 supplements made no difference to test performance. However, 3obinson did add that that the participants in her study tended to be healthy and well:educated and supplements would have had minimal additional benefit, while others who were less healthy may derive a benefit.

How to im rove mental shar ness

3egardless of our age there are steps we can take to boost our mental abilities. #he brain is a muscle and like any other muscle in our body, is affected by how we use it and how we nourish it. Wor! that "rain "ngaging in mental exercises makes our brains work harder and this can help us to perform better now and slow its decline. According to 0rofessor =lynn, Cognitively complex activities give some protection even against dementia and Al%heimer s. As the brain is like a muscle it becomes stronger the more we use it. #he brain, =lynn has explained, continues to develop once we have entered adulthood and both neurons and their connections do not reach their peak until we are in our early fifties. @ames like poker, chess, crossword pu%%les and sudoku can help to improve mental sharpness by training the brain in areas like spatial awareness, memory and logical reasoning. When we play these games we become better at them, like the way any muscle is strengthened by exercise. 8ome people who wish to improve their memory try testing themselves in everyday situations. #his could take the form of trying to remember where they bought each item of clothing that they put on that day, remembering the details of the last time they went to a restaurant Athe face of the waiter, what courses they had, the decor of the restaurant etc.B. All of these exercises help us to form connections in our brain, which exercises the muscle.

A well known example of the power of mental exercise is the 6ondon black cab driver. #hose doing this job in Central 6ondon have to memorise &-,*** streets, &*,*** landmarks and 9&* routes in 6ondon. 4nown as the knowledge, calling upon this vast store of information on a regular basis exercises a specific part of drivers brains : the hippocampus, which is responsible for memory and spatial navigation. 1n >31 tests the hippocampus of black cab drivers has been found to be enlarged, undoubtedly as a result of the daily exercising. However, it is worth noting that when we strengthen our brains in this way we will only improve the performance of that part of the brain that is actually being used, rather than our minds as a whole. As 0rofessor =lynn explained2 'ertain neurons spray dopamine in the area immediately surrounding them rather li"e a sprin"ler. (ny synapses in the vicinity that have recently been active, that is, have had information passed across them, will react to the dopamine and be strengthened. nfortunately, cognitive exercises can only do so much to improve mental sharpness. 1t cannot turn us into geniuses or hold off the effects of age indefinitely. As =lynn has said2 The active mind will always perform better than the inactive but both will decline in tandem particularly from age )* onwards. +old to the image of the brain as a muscle. (t any age, an athlete is better off for training, but however hard you train, your times will get slower with age. #hysical e$ercise "xercise and particularly aerobic exercise that gets oxygen flowing into the brain, can promote the production of chemicals by the body that cause the brain to increase and develop neurons in the frontal part of the brain, possibly by increasing the networks of blood vessels. "ngaging in regular, moderately intense exercise can keep the brain healthy because when doing so it produces a chemical called brain:derived neurotrophic factor A?/$=B. ?/$= strengthens the wiring of memory circuit. /r. <ohn 3atey, associate clinical professor of psychiatry at Harvard >edical 8chool, explained2 When you exercise and move around, you are using more brain cells Using more brain cells turns on genes to ma"e more -$./. As ?/$= can only be produced by the brain when we engage in regular exercise and cannot be taken as a supplement it is up to us to help our bodies by engaging in moderate:intensive exercise. A suggested level is 9* minutes of exercise that raises the heart rate to .* percent of maximum Aapproximately &&* minus ageB. #his exercise must be regular and must be ongoing. 0ccasional exercise is! probably good for your body but it won't get you there in terms of the cognitive benefits. 1ou also have to continue to do it to continue accruing the benefits. - $r. 2ohn 3atey 3esearch conducted at ;hio 8tate niversity echoed these results and found that while routine exercise among subjects aged over ,- helped to protect against memory decline and strengthen brain function these positive effects only lasted as long as exercise continued. According to /r. 3atey, exercise can make a real difference in maintaining mental sharpness2 D#here5s a lot you can do to prevent cognitive decline, or slow it down, or recover memory function that you might feel you have lost. 1n an interview with the Washington 0ost 3atey said that the benefits of regular exercise are clear2

"#ven if you're in middle age, and you begin to exercise three to four times a wee", at fairly moderate rates . . . adding some weights in there . . . you're going to push bac" cognitive decline by anywhere from 4* to 45 years. According to 3ateys research, >31 scans of the brains of sedentary subjects who had started to exercise showed noticeable enlargement of the hippocampus and frontal and temporary lobes2 "The ma6or implication is that exercise not only "eeps the brain from rotting, but it also reverses the cell deterioration associated with aging 7sic8. Im roving slee 8ituations from the here and now can also impact our mental sharpness. =ailing to get enough sleep it can make us feel tired and foggy. How much sleep we need is not set in stone and varies from person to person. #he standard range is between six and eight hours but each person will probably have a fair knowledge of what is enough for them personally. "ven minor issues with sleeping can damage cognition over time. #he different stages of nightly sleep, from 3"> to deep sleep are important for memory formation and disposing of amyloid beta proteins, which can cause pla+ues to build up on the brain, degrading our cognitive ability. 0oker players often report difficulties caused by tiredness such as recalling cards or the ability to make correct decisions. ?eginner players even make errors in remembering hand rankings. A great deal has been written about improving nightly sleep, from avoiding electronic stimuli before bed Asmartphones, tablets or #EB, limiting caffeine and alcohol in the evening and getting more exercise during the daytime. 1n addition, meditation can also help us to relax when we are trying to sleep. 1nterestingly, as well as helping us to relax meditation can help to strengthen the hippocampal cortex, where memories form. Diet #his is a key factor in improving our mental sharpness as it determines whether we are fuelling or draining our brains of the nourishment it needs in order to perform. >uch of the influence of diet is down to providing the brain with oxygen and improving blood flow, so what we consume plays a big part in keeping us sharp. ;ne positive action we can take is to avoid saturated fat because it helps to ensure that blood flow to the brain and its neurons is free and unobstructed. ;ther studies have suggested that foods that contain antioxidant phytonutrients, often found in fruits and vegetables, can help to maintain brain functionality. A prime example of these types of food are blueberries, which have been found to help protect the brain structure from oxidative damage and so preserve cognitive function. ;xidation is a bit like the rust that appears on iron and in the body, acts as a coating on organs that can disrupt their smooth functioning. When oxidation occurs it can actually change molecular bonds, causing molecular damage and loss of brain function. ;ther foods with antioxidants red kidney beans, cooked artichokes and pecans can have a similar positive effect. Consuming foods that are rich in antioxidants will benefit your health. A somewhat more radical approach is to donate blood. #his will remove the oxidant filled blood, allowing you to replace it healthily. $ote, this can only be tried once every so oftenF A final method of boosting mental sharpness is to raise our levels of vitamin /. #here are receptors specifically for Eitamin / built into the central nervous system and in the hippocampus, which as previously mentioned, is an important area for cognition. #his vitamin protects neurons and regulates en%ymes and cerebrospinal fluid in the brain that affect neurotransmitter synthesis and nerve growth. As we absorb vitamin / from sunlight we can raise our levels just by being outside in the open air on a regular basis. 1n areas of the world that experience lower levels, such as $orthern "urope a way of supplementing our vitamin / intake from sunlight is by taking cod liver oil, beef and butter.