While it had been common for astronauts to spend six months at the ISS, NASA wanted to know what happens when humans spend even longer in space. Depending on the orbit trajectory chosen – which depends on how much fuel you want to take with you – a trip to Mars could take 7 to 9 months (Carter, n.d.). And then once you get there, you probably want to spend some time there. Heck, I spend more than a few days in Australia when I travel there, and that’s just 7,744 miles/12,462 km. And then you have to travel home from Australia – I mean, Mars. If you’re NASA and you have identical twin astronauts, there’s only one reasonable thing to do. You put together a team of researchers who are experts in human physiology, behavioral health, microbiology, and epigenetics to find out everything you can about the twins today. Next, you send one of them into space for twelve months. When the astronaut comes back to earth, repeat the measurements for both astronauts. This is NASA’s Twin Study. Mark Kelly* was the twin who stayed on earth; Scott Kelly was the twin who spent a year aboard the International Space Station (ISS)**. In January, 2018, NASA shared some preliminary research findings from their twin study.   Another interesting finding concerned what some call the “space gene”, which was alluded to in 2017. Researchers now know that 93% of Scott’s genes returned to normal after landing. However, the remaining 7% point to possible longer term changes in genes related to his immune system, DNA repair, bone formation networks, hypoxia, and hypercapnia. This makes it sound like Scott’s genes underwent some kind of change. Journalists grabbed hold of this and declared that Scott and Mark were no longer twins since their DNA was not the same. This was not what the researchers meant. NASA clarified: Mark and Scott Kelly are still identical twins; Scott’s DNA did not fundamentally change. What researchers did observe are changes in gene expression, which is how your body reacts to your environment. This likely is within the range for humans under stress, such as mountain climbing or SCUBA diving. What changed were not Scott’s genes, but rather his gene expression – in other words, his epigenetic code. A Brief History of Everyone Who Ever Lived by scientist and science writer Adam Rutherford is a nice summary of what we know, what we don’t know, and what we would like to know about genetics and, to a lesser extent, epigenetics.  Our epigenome is what turns genes on and off. Women who have two X chromosomes (that’s most of us) have all the genes on one X chromosome in each of our cells turned off. “In mammals, epigenetic modifications tend to get reset each generation, but some, very limited, rare epigenetic tags appear to be passed down from parent to child, at least for a couple of generations.”  Pregnant women who starved in the Netherlands during the winter of 1944 gave birth to low-birthweight babies (no surprise) who then grew up to give birth to babies who were high-birthweight (surprise). Other research in a rural Swedish community with variable harvests found that boys who experienced a lean year just before entering puberty were more likely to have grandsons – yes, grandsons – who lived longer. But most epigenetic changes are temporary (Rutherford, 2017). In the case of reporting that astronauts Mark and Scott Kelly were no longer identical twins, the journalists were merely reporting what they understood the NASA press release to be saying, so I’m not going to fault them. Earlier this month we read headlines declaring that despite years of research showing that the adult human hippocampus produces stem cells that grow into new neurons, that a new study declares that’s not the case at all. I was poised to pounce on journalists for getting this wrong. But I can’t. Once again, it’s the Public Relations department, this time at the University of California at San Francisco. Now UC San Francisco scientists have shown that in the human hippocampus – a region essential for learning and memory and one of the key places where researchers have been seeking evidence that new neurons continue to be born throughout the lifespan – neurogenesis declines throughout childhood and is undetectable in adults (Weiler, 2018). Rutherford (2017) reminds us that “[j]ournals are not all equal, and publication in a journal is not a mark of truth, merely that the research has passed the standard that warrants entering formal literature and further discussion with other scientists.” This is worth hammering into the heads of our students, our students who are the future writers of press releases, the future writers of news articles, and the future readers of those new articles. Our science journals are just one huge chat room. "Hey! This is what I found!" "Huh. How did find that?" "What if we looked at it this way instead?" "Anna used this other method and found something different. Anyone know why that would produce different results?" With additional research, we may discover that, indeed, the human hippocampus does not produce new neurons. And we may discover that living in space where a person is subject to the radiation equivalent of 10 chest x-rays a day (Kelly, 2017) does indeed change one’s genes, and not just the epigenetic code. Those who turn to science for definitive answers may find the responses couched in probabilities less than satisfying. But that’s how science works. Here’s a cautionary tale: Everyone knows that tongue-rolling is genetic. If you can roll your tongue, you have the dominant allele for tongue-rolling. As it turns out, everyone is wrong. The research was easy to do. Find a bunch of identical twins and see who could roll their tongues and who couldn’t. If tongue-rolling were completely genetic, each twin pair should be, well, identical in their tongue-rolling ability. Philip Matlock (1952) looked in the mouths of 33 pairs of twins. In 7 pairs, one twin could tongue-roll while the other one could not. And, yes, that date is right; he did this research in 1952. Similar studies in the 1970s found similar results (Martin, 1975; Reedy, Szczes, & Downs, 1971). If you had asked me last week, “Hey, Sue, is tongue-rolling simply controlled by our genes?” I would have said yes. But now my response is more nuanced. “There’s likely a gene or set of genes that controls it, but there is also probably an epigenetic code that turns that gene or genes on or off for different people. Let me tell you about this interesting research done with identical twins…” The more I learn, the less confidence I have in what I have always known to be true. “Half of what I’m going to tell you is wrong, but I don’t know which half.” I love this quote (or paraphrase?) as it nicely captures the moving nature of science, but I can’t find the origin – and I find that very fitting. My memory says it was something Paul Meehl said to his students, but I can’t find any such reference. A Psychology Today blogger credits an uncited and unnamed surgeon. If you know the origin, please contact me. References Carter, L. (n.d.). If Mars is only about 35-60 million miles away at close approach, why does it take 6-8 months to get there? (Intermediate). Retrieved from http://curious.astro.cornell.edu/physics/64-our-solar-system/planets-and-dwarf-planets/mars/267-if-mars-is-only-about-35-60-million-miles-away-at-close-approach-why-does-it-take-6-8-months-to-get-there-intermediate Kelly, S. (2017). Endurance: A year in space, a lifetime of discovery. New York City: Knopf. Martin, N. G. (1975). No evidence for a genetic basis of tongue rolling or hand clasping. Journal of Heredity, 66(3), 179–180. https://doi.org/doi.org/10.1093/oxfordjournals.jhered.a108608 Matlock, P. (1952). Identical twins discordant in tongue-rolling. Journal of Heredity, 43(1), 24. https://doi.org/https://doi.org/10.1093/oxfordjournals.jhered.a106251 Reedy, J. J., Szczes, T., & Downs, T. D. (1971). Tongue rolling among twins. Journal of Heredity, 62(2), 125–127. https://doi.org/doi.org/10.1093/oxfordjournals.jhered.a108139 Rutherford, A. (2017). A brief history of everyone who has ever lived. New York City: The Experiment. Weiler, N. (2018). Birth of new neurons in the human hippocampus ends in childhood. Retrieved March 24, 2018, from https://www.ucsf.edu/news/2018/03/409986/birth-new-neurons-human-hippocampus-ends-childhood **************** *Mark Kelly’s wife is Gabrielle Giffords, the US Representative from Arizona who survived an assassination attempt in 2011.   **”at the International Space Station” – I had a hard time deciding on the right preposition to use. Can one be on a space station if one is really floating inside it, except when Velcro-ed to a wall? In seemed to be a better choice, but felt clunky when I read it. I was ready to settle for at. NASA dodges the entire question and uses “aboard the ISS.” If aboard is good enough for NASA, it’s good enough for me. I’m confident we’ll get this figured out before we head to Mars. ... View more

Long ago, I read a jest that most people believe in the shaping power of environmental nurture—until they have their second child.   That pretty well sums up the results of a not-yet-published survey of 1000 Americans by an Emily Willoughby-led University of Minnesota team. The researchers report that “educated mothers with multiple children” were particularly cognizant of the heritability of traits, adding: “Parents, after all, have the ability to observe firsthand the results of an empirical experiment on the heritability of human traits in their own home. They can see that their children resemble them along multiple dimensions; furthermore, a parent of multiple children can see how the shared environment does not necessarily make them alike.”   That has been my wife’s and my experience as parents of three children who share some of our traits, but who were distinct individuals right out of the womb. And perhaps your experience, too, as you compare your children, or observe your own or other siblings?   These researchers noted another interesting finding, related to political leanings: When asked about the relative gene and environment contributions to various traits, liberals more than conservatives saw genetics having a strong influence on psychiatric disorders and sexual orientation. As a result, liberals tended not to view sexual orientation as a choice, and they tended to have more compassionate views of those with psychiatric disorders. Conservatives more often saw a strong genetic influence on intelligence and musical ability, thus suggesting that those with these strengths had been largely “born that way” rather than advantaged by opportunity. ... View more

In my psychology texts, and in other writings (such as here for the faith community), I have explained the growing evidence that sexual orientation is a natural, enduring disposition (most clearly so for males). The evidence has included twin and family studies indicating that sexual orientation is influenced by genes—many genes having small effects. One recent genomic study, led by psychiatrist and behavior geneticist Alan Sanders, analyzed the genes of 409 pairs of gay brothers, and identified sexual orientation links with parts of two chromosomes.   Today, Nature will be releasing (through its Scientific Reports) a follow-up genome-wide association study by the Sanders team that compares 1,077 homosexual and 1,231 heterosexual men. They report genetic variants associated with sexual orientation on chromosomes 13 and 14, with the former implicating a “neurodevelopmental gene” mostly expressed in a brain region that has previously been associated with sexual orientation. On chromosome 14 they identified a gene variant known to influence thyroid functioning, which also has been associated with sexual orientation.   Although other factors, including prenatal hormonal influences, also help shape sexual orientation, Sanders et al. conclude that “The continued genetic study of male sexual orientation should help open a gateway to other studies focusing on genetic and environmental mechanisms of sexual orientation and development.” The science of sexual orientation (for females as well) marches on. ... View more

As I draft this on Mother’s Day I think of my mother, who blessed me with nurturing and many other gifts, including, alas, the gift of her hearing loss . . . which she, in turn, had received from her mother. I began my memoir, A Quiet World: Living with Hearing Loss, with this recollection: On one of those treasured visits to my parents' home on Bainbridge Island, Washington, I use a magic pad to communicate with my eighty-year-old mother, who four years previously took the final step from hearing-impaired to deaf as she gave up wearing her by then useless hearing aids. “Do you hear anything?” I write. “No,” she answers, her voice still strong although she cannot hear it. “Last night your Dad came in and found the T.V. blasting. Someone had left the volume way up; I didn't hear a thing.” (Indeed, my father later explained that he recently tested her hearing by sneaking up while she was reading and giving a loud clap just behind her ear. Her eye never wavered from the page.) What is it like, I wonder. “A silent world?” “Yes,” she replies, “it's a silent world.” As with Mother, so, I expect, with me. I have known for many years that I am on a trajectory toward the same deafness. When tested as a teenager, my hearing pattern mimicked Mother's—an unusual “reverse slope” pattern of good hearing for high-pitched sounds and poorer hearing for low-pitched sounds (making soft male voices harder to discern than higher female voices). From upstairs, I can hear the high-pitched microwave oven timer, though my wife, Carol, snuggled beside me in bed, cannot. But I cannot recall ever hearing an owl hoot. Carol touches my leg at each hoot: “There, can you hear it?” I hear nothing.   A quarter century and more later, I continue on that trajectory, unable now (with my hearing aids out) even to hear my wife’s voice from the adjacent pillow, unless she speaks directly into my ear. In daily life I mostly cope well enough, thanks to powerful digital hearing technologies that my mother never knew. Even so, I struggle to hear amid noise—at a party, in a restaurant—or when a questioner is across a room. Like all who suffer this invisible disability, I strain to hear. I move closer. Or, with a smile and a nod, I fake hearing.   On the brighter side, the hearing loss plague has also given me an added life purpose—supporting people with hearing loss by advocating for a “hearing loop” transformation in how America provides listening assistance in public places (through this website, through three dozen articles such as this one, and via nearly 20,000 e-mails). And this advocacy led me to four years representing people with hearing loss on the advisory council of NIH’s National Institute on Deafness and Other Communication Disorders.   There I was privileged to meet and hear from some world class hearing researchers, including the University of Iowa physician-geneticist Richard Smith, who is amassing data on the genes of many thousands of people with hearing loss. When I showed him my audiogram—my profile of hearing loss at various frequencies—he guessed that I carry a mutation on the WSF1 gene, and offered to confirm that.   So I sent in my spit tubes, and last week Smith confirmed: “You have DFNA6/14 hearing loss caused by a mutation in WFS1.”   In psychological science, we teach our students that complex traits, such as intelligence or personality, are the product of “many genes having small effects.” So this is my reminder that some important traits and medical conditions are predisposed by single genes (which my siblings and I each had a 50% chance of inheriting—with my older brother and I, among the four of us, drawing the unlucky cards).   If so, I asked: Is there not some hope that gene editing, such as with the new CRISPR technique, could prevent future hearing loss in children or young adults who carry the gene?  Yes, Smith tells me—this is, indeed, his lab’s exciting aim. Moreover, they plan to conduct the experiment by attempting the gene therapy on but one ear of each volunteer, thus enabling the other ear to serve as what we psychologists call a “within subjects control condition.”   In the meantime, I’m content to be the person Dr. Seuss described in You're Only Old Once!            You'll be told that your hearing's so murky and muddy,            your case calls for special intensified study. They'll test you with noises from far and from near and you'll get a black mark for the ones you can't hear. Then they'll say, "My dear fellow, you're deafer than most. But there's hope, since you're not quite as deaf as a post." ... View more

Did you ever wish you had access to a searchable database of twin correlations and trait heritability statistics? If not, once you see this, you will wonder why you hadn’t been looking for this kind of resource. Shout out to David Myers (Hope College) for pointing me toward MaTCH. Let’s take height as an example. From the first drop-down menu, select “ICF/ICD10 Subch” and then from the second drop-down menu, select “Height (297). The number in parentheses refers to the number of studies included in the displayed data. This is the first chart that is generated. If one identical (mz = monozygotic) twin is tall, there is a very good chance the other will be as well. If one is short, there is a very good chance the other will be as well. The correlation between being a twin and height is .91. The chart also gives correlations for just male identical twins (mzm = monozygotic male) and female identical twins (mzf = monozygotic female). If one fraternal (dz = dizygotic) twin is tall, there is a smaller chance the other will be as well – correlation of .54. Correlations are also given for all same-sex fraternal twins (dzss), just male fraternal twins (dzm), just female fraternal twins (dzf), and all other-sex fraternal twins (dos). Below the chart is this table. “Est.” is the estimated correlation based on the data from all of the studies included in the dataset. These are the correlations reported in the bar chart. “SE” is the standard error – the smaller the number, the more confident we are that the data reflect what’s true in the population. “Ntraits” are the number of studies in the dataset. “Npairs” are how many pairs of twins were included. While the correlations are interesting – and can certainly provide you with some interesting correlations when covering research methods – the real interesting stuff in this website comes from the last chart. This is where we get the “Reported ACE” – the heritability data. ACE is a model used among heritability researchers. A is additive genetics (the contribution of genes), C is common environment (the contribution of experiencing a shared environment), and E is [unique] environment (the contribution of our own, individual experiences). Before we get into the data, let’s a do a quick refresher of what heritability – and the ACE model – is. Within a population, people vary, say, in height. In the United States, the average height for adult females is about 5’ 4” (Onion, 2016). Some women are taller than that average, while others are shorter. It’s that difference between the shortest and the tallest – the variance – that ACE addresses. Let’s look at the “Reported ACE” chart for height. Picture this. Let’s say that we got all of the women in the United States together in one space. We measured each of their heights. A few would be less than 3 feet tall and a few would be more than 8 feet tall. Most would probably fall between 4’ 6” and 6’ 3 inches. The ACE model addresses where those differences in height come from. We are all going to be of some height just by virtue of being born. But what explains the differences in height among us? This article provides a nice explanation of heritability (Adam, 2012). “h2_all” is the heritability estimate for everybody based on the twin data. This means that 63% of the difference (the variability) in the height among all of us is due to genetics. “c2_all” is the estimate of the role played by a shared, common environment. This means that 30% of the difference in the height among all of us is due to a shared environment. Those two variables, genetics and common environment, together account for 93% (63% plus 30%) of the differences in our heights. The remaining 7%? That’s due to our unique environmental experiences. Please note that this says nothing about our own individual height. As a 5’ 4” female from the United States, this does NOT mean that 63% of my height is due to genetics. These numbers are only meaningful in explaining the differences in our heights across a population. To emphasize how population-driven heritability estimates are, on MaTCH’s left navigation menu, click on “Country.” Here you will see the data for height (if you were looking at the height variable) broken down by country. The ‘r’s are the correlations. Scroll to the right to see the heritability and common environment numbers. Canada, for example, shows 34% heritability for height and 60% for common environment, leaving 6% for unique environment. These numbers are very different from, say, the data for the United States. The U.S. shows 85% for heritability and 8% for common environment, leaving 7% for unique environment. Why might this be? Maybe Canadians are more genetically alike than are people in the U.S., thus differences amongst Canadians in their height must be more due to environment. Or maybe there just isn’t enough Canadian data. In the second column of that table, we see that three studies were used to calculate the Canadian estimates whereas 29 studies were used to calculate the U.S. data. There is much data here to explore. Before you dive too deeply into this website, watch this 15-minute tutorial video. Video Link : 1731 If you want to tackle this with your Intro Psych students, perhaps wherever you cover genetics, send your students to the MaTCH website to choose a psychologically relevant trait. Give your students a template like this to complete. The correlation for identical twins (mzall) on ______________ (enter trait name) is ________ (first line in the blue chart). The correlation for fraternal twins (dzall) on ______________ (enter trait name) is ________ (fourth line in the blue chart). The differences in  ______________ (enter trait name) within a population are _____% (h2_all) due to genetics, _____% (c2_all) due to a shared environment, and _____% (100 minus h2_all minus c2_all) due to a unique environment.   If students can’t find the trait they are interested in from the drop-down menu, they can click on “Find my Trait” in the top navigation bar. Searching on “intelligence” for example, tells us that that trait is lumped under “Higher-Level Cognitive Functions”. References Adam, G. (2012, September 6). What is heritability? Retrieved from Science 2.0: Join the Revolution: http://www.science20.com/gerhard_adam/what_heritability-93424   Onion, A. (2016, July 3). Why have Americans stopped growing taller? Retrieved from ABC News: http://abcnews.go.com/Technology/story?id=98438&page=1  ... View more

Originally posted on July 3, 2014. Have you ever wondered why some people struggle to avoid certain foods, whereas others have little trouble passing on a delectable dish? Childhood eating habits, genetics, and willpower offer possible answers. But researchers at Carnegie-Mellon University identified another explanation: Thinking about eating makes food seem less exciting. If you imagine eating 10 pieces of pizza, your mind has already simulated what it’s like to eat pizza. When you see a real pizza, your brain’s pleasure centers no longer perk up. You’ve been there, done that. As a result, you consume less pizza.   In a series of experiments, people who repeatedly imagined eating a food many times ate less of that food compared with those who imagined taking a few bites. Instead of pizza, the researchers used M&M candies. People who imagined eating 30 M&M’s, compared with those who imagined eating only three, ate fewer M&M’s. By simulating eating lots of M&M’s, the thrill from eating the bite-sized candies was gone. The next time you struggle to avoid a tempting food, remember that you can train your brain not to want it. Just imagine eating large quantities of the food. Your brain will think it’s already had more than enough to eat and you will desire the food less.  ... View more

Originally posted on September 30, 2014. Behavior geneticists have gifted us with two stunning findings—discoveries that overturned what I used to believe about the environment’s power to shape personality.  One, dramatically illustrated by the studies of identical twins separated near birth, is the heritability of personality and intelligence.  The other, dramatically illustrated by the dissimilar personalities and talents of adoptive children raised in the same home and neighborhood, is the modest influence of “shared environment.” I know, I know . . . studies of impoverishment during the preschool years, of epigenetic constraints on genetic expression, and of family influences on attitudes, values, and beliefs, remind us that genetic dispositions are always expressed in particular environments.  Nature and nurture interact. And might identical twins have similar personalities not just because of their shared genes, but also their environments responding to their similar looks?  If only there were people who similarly look alike but don’t share the same genes. Happily there are unrelated look-alikes—nontwin “doppelgängers” identified by Montreal photographer François Brunelle (do visit some examples here).  California State University, Fullerton, twin researcher Nancy Segal seized this opportunity to give personality and self-esteem inventories to these human look-alikes. Unlike identical twins, the look-alikes did not have notably similar traits and self-esteem (see here). And in a new follow-up study with Jamie Graham and Ulrich Ettinger (here), she replicates that finding and also reports that the look-alikes (unlike biological twin look-alikes) did not develop special bonds after meeting their doppelgänger.  The take-home message.  Genes matter more than looks. As the evolutionary psychologists remind us, kinship biology matters. ... View more

Originally posted on March 6, 2015. My nominee for psychology’s most misunderstood concept is negative reinforcement (which is not punishment, but actually a rewarding event—withdrawing or reducing something aversive, as when taking aspirin is followed by the alleviation of a headache). In second place on my list of oft-misunderstood concepts is heritability. My publishers’ twitter feed today offered this: Sure enough, the news source says it’s so.  But it isn’t.  Tracking back to the actual study, and its own press release, we see that, as we might have expected, the conclusion was drawn from a twin study that estimated the genetic contribution to variation among individuals in autism spectrum disorder (ASD) scores. Heritability refers to the extent to which differences among people are due to genes. If the heritability of ASD is 80 percent, this does not mean that 80 percent of autism cases are attributable to genes and 20 percent of cases to environment. And it does not mean that any particular case is 80 percent attributable to genes and 20 percent to environment.  Rather it means that, in the context studied, 80 percent of the differences among people was attributable to genetic influence. ... View more

Originally posted on March 17, 2015. One of the pleasures of writing psychological science is learning something new nearly every day, from the continual stream of information that flows across my desk or up my screen.  Some quick examples from the last few days: Nudging nutrition. Joseph Redden, Traci Mann, and their University of Minnesota colleagues report a simple intervention that increases schoolchildren’s veggie eating.  In a paper to appear in PLOS One, they report—from observations of 755 children in a school cafeteria—that, for example, offering carrots first in the serving line (in isolation from other foods to come) quadrupled their consumption. For more on healthy eating nudges, see Mann’s forthcoming book, Secrets from the Eating Lab​. Hugging prevents colds.  In new research by Sheldon Cohen and his team, social support, indexed partly by the frequency of experienced hugs, predicted fewer and milder infections among 404 healthy people exposed to a cold virus.  A hug a day keeps sickness away? Finger digit ratio predicts national differences in gender inequality?  It’s not news that nations vary in female political representation, workforce participation, and education.  It was news to me that they reportedly also vary in 2D:4D—that’s the ratio of the index (2D) and ring finger (4D) lengths.  Nations that purportedly show relatively high female fetal testosterone exposure (supposedly manifest as low 2D:4D) and relatively low male fetal testosterone exposure (high 2D:4D) have higher rates of female parliamentary and workforce participation. Hmmm. How effective is repetitive transcranial magnetic stimulation (rTMS) for treating depression?  A few well-publicized studies suggested it was effective. But a new meta-analysis of all the available studies indicates this treatment actually provides only “minimal clinical improvement.” And this is why teachers and authors need to consider all of the available research, and not just isolated studies. It’s not all in our genes: Exercise really is healthy. Finnish researchers studied 10 identical male twins—one of whom regularly exercised, the other not. Despite having similar diets, the sedentary twins had more body fat, more insulin resistance, less stamina, and less brain gray matter. The moral to us all:  join the movement movement. ... View more

Originally posted on November 14, 2015. Thursday night’s Buffalo Bills versus New York Jets football game was lampooned for its red and green uniforms. “Christmas pjs” in the NFL? But for “colorblind” people there was a bigger problem. As Nathan DeWall and I explain in Psychology, 11th Edition, “Most people with color-deficient vision are not actually ‘colorblind.’ They simply lack functioning red- or green-sensitive cones, or sometimes both.” The classic textbook illustration at left—which the NFL apparently forgot—reminds us that for some folks (most of whom, like most NFL fans, are male) those red and green uniforms likely looked more like this. Twitter messages flowed: Note to the NFL, from psychology teachers and text authors: Thanks for the great example! ... View more

Originally posted on March 1, 2016. Amid concerns about the replicability of psychological science findings comes “a cause for celebration,” argue behavior geneticist Robert Plomin and colleagues (here). They identify ten “big” take-home findings that have been “robustly” replicated. Some of these are who-would-have-guessed surprises. 1. “All psychological traits show significant and substantial genetic influence.” From abilities to personality to health, twin and adoption studies consistently reveal hereditary influence. 2. “No traits are 100% heritable.” We are knitted of both nature and nurture. 3. “Heritability [differences among individuals attributable to genes] is caused by many genes of small effect.” There is no single “smart gene,” “gay (or straight) gene,” or “schizophrenia gene.” 4. "Correlations between psychological traits show significant and substantial genetic mediation.” For example, genetic factors largely explain the correlation found among 12-year-olds’ reading, math, and language scores. 5. “The heritability of intelligence increases throughout development.” I would have guessed—you, too?—that as people mature, their diverging life experiences would reduce the heritability of intelligence. Actually, heritability increases, from about 41% among 9-year-olds to 66% among 17-year-olds, and to even more in later adulthood, studies suggest. 6. “Age-to-age stability is mainly due to genetics.” This—perhaps the least surprising finding—indicates that our trait stability over time is genetically disposed. 7. “Most measures of ‘environment’ show significant genetic influence.” Another surprise: many measures of environmental factors—such as parenting behaviors—are genetically influenced. Thus if physically punitive parents have physically aggressive children both may share genes that predispose aggressive responding. 8. “Most associations between environmental measures and psychological traits are significantly mediated genetically.” For example, parenting behaviors and children’s behaviors correlate partly due to genetic influences on both. 9. “Most environmental effects are not shared by children growing up in the same family.” As Nathan DeWall and I report in Psychology, 11th Edition, this is one of psychology’s most stunning findings: “The environment shared by a family’s children has virtually no discernible impact on their personalities.” 10. “Abnormal is normal.” Psychological disorders are not caused by qualitatively distinct genes. Rather, they reflect variations of genetic and environmental influences that affect us all.                     HOMETOWNCD/Getty Images From this “firm foundation of replicable findings,” Plomin and colleagues conclude, science can now build deeper understandings of how nature and nurture together weave the human fabric. ... View more

As a psychology instructor it is clear to you the myriad ways in which psychology can be used to both understand social issues and speak to solutions. In fact, the APA Guidelines for the Major (2013; see below) encourages us to help our students see the same. Debra Mashek (2016) suggests a few assignments that provide our students opportunities to connect psychology with today’s social issues. Integrative essay The instructor chooses three articles (interesting, nifty methodology, and not too difficult for students to understand – but on the surface may not have anything obviously to do with each other), and assigns one of those articles to each student, i.e. 1/3 of the class gets article A, 1/3 gets article B, and 1/3 gets article C. Each student writes a one-page summary of their assigned article and brings that with them to class. The class breaks up into groups of three, where the groups are composed of students who have all read different articles. In a jigsaw classroom format, the students tell the others in their three-person group about their article. Students then “articulate an applied question that invites application of ideas from all the articles.” Each 3-person group then co-authors a short paper (two to three pages) that identifies their applied question and how each of the three articles speak to that question. Persuasion research activity Right after Hurricane Katrina, Mashek decided she wanted her Intro Psych students to experience psychological research firsthand while also contributing to the relief effort. Mashek gave a brief lecture on foot-in-the-door, door-in-the-face, and reciprocity. She randomly assigned ¼ of students to foot-in-the-door, ¼ to door-in-the-face, ¼ reciprocity (she gave these students lollipops to hand to people before asking for a donation), and ¼ to a command condition (“give money”). During that same class period students were sent out in pairs to different areas of campus to return an hour later. Thirty-five students collected $600. Students reported a greater connection to the victims of Katrina after they returned than they reported before they left. Mashek used this experience as a leaping off point for discussing research methodology in the next class session. Current headline classroom discussion Pick a current headline. Break students into small groups, perhaps as an end of class activity, and give them one or two discussion questions based on the current chapter you are covering that are relevant to the headline. For example, if you are covering the social psychology chapter in Intro Psych, give students this headline from the January 9, 2016 New York Times: “Gov. Paul LePage of Maine Says Racial Comment Was a ‘Slip-Up’.” This is a short article, so you could ask students to read the article itself. Sample discussion questions: (1) What evidence is there of ingroup bias? (2) Do Gov. LePage’s comments illustrate stereotyping, prejudice, and/or discrimination? Explain. If time allows, student groups can report out in class. Alternatively, this could be a group writing assignment or a scribe for the group could post a summary of the group’s responses to a class discussion board. Students will gain an appreciation of the scope of psychology and how it is relevant to today’s social issues. This activity throughout the course should help students, after the course, to continue to see psychology at play. The APA Guidelines for the Major (2013) include these indicators related to social issues: 1.3A Articulate how psychological principles can be used to explain social issues, address pressing societal needs, and inform public policy 3.3c Explain how psychology can promote civic, social, and global outcomes that benefit others 3.3C Pursue personal opportunities to promote civic, social, and global outcomes that benefit the community. 3.3d Describe psychology-related issues of global concern (e.g., poverty, health, migration, human rights, rights of children, international conflict, sustainability) 3.3D Consider the potential effects of psychology-based interventions on issues of global concern American Psychological Association. (2013). APA guidelines for the undergraduate psychology major: Version 2.0. Retrieved from http://www.apa.org/ed/precollege/undergrad/index.aspx Mashek, D. (2016, January 4). Bringing the psychology of social issues to life. Lecture presented at National Institute on the Teaching of Psychology in Tradewinds Island Grand Resort, St. Petersburg Beach. Seelye, K. Q. (2016, January 9). Gov. Paul LePage of Maine Says Racial Comment Was a 'Slip-up'. The New York Times. Retrieved January 9, 2016, from http://www.nytimes.com/politics/first-draft/2016/01/08/gov-paul-lepage-of-maine-denies-making-racist-remarks ... View more