In Brief

Twins in the classroom

TwinsMany schools encourage or require that twins be placed in separate classrooms. But a study in Developmental Psychology finds that separating twins has no significant effect on their academic performance. Researchers analyzed data from two longitudinal studies—one from the United Kingdom that followed 8,705 twin pairs from ages 7 to 16 and one from Quebec that followed 426 twin pairs from ages 7 to 12. Overall, they found almost no effect of classroom separation on school achievement, cognitive ability or academic motivation. The researchers did find that twin pairs placed in the same classroom had slightly more similar achievement scores, but the effect sizes were weak. DOI: 10.1037/dev0000519

Childhood trauma, adult pain

Traumatic childhoodPeople who recall facing more childhood adversity also report more pain as adults, finds a study in the Journal of Behavioral Medicine. Researchers asked 265 U.S. adults to describe the adversity they faced as children and adolescents, as well as their current mood, sleep patterns, optimism, how in control of their lives they felt and whether they had recently felt pain. Greater childhood and teen adversity was associated with greater pain in adulthood, and that association was mostly mediated by sleep disturbances and negative moods. DOI: 10.1007/s10865-018-9917-8

Maternal deprivation

Rats briefly taken from their mothers in infancy later showed signs of memory impairment and other brain abnormalities as adults.Being deprived of one's mother as an infant—even relatively briefly—could cause brain changes that increase the risk of mental illness later in life, suggests a study with rats in Translational Psychiatry. Researchers removed young rat pups from their mothers for 24 hours when they were nine days old, during a crucial period for brain development in these animals. When they were tested 10 weeks later, the now-adult rats who had been briefly removed from their mothers showed signs of memory impairment as well as less connectivity between brain regions compared with rats that hadn't been taken from their mothers. These abnormalities in memory and brain function due to early deprivation may shed light on the development of human neuropsychiatric disorders such as schizophrenia, the researchers say. DOI: 10.1038/s41398-018-0119-5

Autism genetics

Previous research has suggested that the genetic risk for autism is largely passed through the maternal line. However, those studies examined "coding DNA," the genetic material that directly codes for proteins and makes up only about 2 percent of the genome. Now, a new study in Science has looked at noncoding DNA (which regulates the expression of coding DNA) and found evidence that some autism risk is inherited from fathers. Researchers examined variants from noncoding regions of the genome they suspected might be associated with autism in 9,274 participants from 2,600 families. They looked at the pattern in which parents passed on these variants to their autistic and nonautistic children and found that they were passed on from fathers to their autistic children at a higher rate than to their nonautistic children. No evidence was found that mothers' noncoding DNA influences their children's risk for autism. DOI: 10.1126/science.aan2261

Chafing at authority

Some people hate being told what to do; others are more compliant. Now, a study in the Journal of Neuroscience suggests that differences in brain connectivity may reflect this temperamental difference. Researchers asked 61 university students to play 16 rounds of a game in which they divided money between themselves and another sham player. They played this game while undergoing fMRI scanning of their brain activity. In half the rounds, the sham player could decide to restrict the participant's choice by asking for a minimum amount of money; in the other half, participants had free choice of how to divide the cash. Overall, most participants tended to be less generous when their freedom was restricted. This tendency was especially strong, however, in participants who showed less connectivity between their parietal lobule and dorsolateral prefrontal cortex. Those participants who were least generous also reported feeling angrier in the restricted-choice rounds or feeling like the other player distrusted them. DOI: 10.1523/JNEUROSCI.0047-18.2018

Counterbalancing work stress

Taking a yoga break after work could help buffer people from the consequences of work stress.People who detach from their jobs and relax after they clock out of the office can buffer themselves from sleep problems, suggests research in the Journal of Occupational Health Psychology. Researchers surveyed 699 U.S. Forest Service employees about the level of rude behavior they experienced at work, how often they had negative thoughts about work, whether they had insomnia symptoms and how much they were able to detach from work and relax. Those who encountered more rude or negative behavior at work also experienced more insomnia. However, people who detached and did something relaxing after work—such as yoga or going for a walk—slept better than those who didn't. DOI: 10.1037/ocp0000116

Sick days

Workers in the United States who do not get any paid sick leave are more likely to receive government welfare services, finds a study in the American Journal of Orthopsychiatry. Researchers analyzed data from nearly 20,000 respondents to the National Health Interview Survey. Among working adults ages 18 to 64, people without paid sick leave were 1.41 times more likely to receive income from a state or county welfare program, 1.33 times more likely to receive rental assistance and 1.34 times more likely to receive Supplemental Nutrition Assistance Program benefits (food stamps). This analysis controlled for income, education, marital status, health status and other factors. DOI: 10.1037/ort0000318

Our big brains

The human brain evolved its disproportionately large size more in response to ecological challenges—like finding food and shelter—than to the need to adapt to complex social situations, suggests a study in Nature. The proportion of brain size to body size is larger in humans than in other mammals. Due to its size and physiological activity, the human brain uses about 20 percent of the body's energy. Researchers developed a mathematical model that used data about the metabolic costs of brain activity to simulate brain evolution. They found that the human brain attained its current size when the pressures our ancestors faced were 60 percent ecological, 30 percent cooperative/social and 10 percent competitive with other groups. DOI: 10.1038/s41586-018-0127-x

Lite beer, more beer

People imbibe more beer and wine when the drinks are labeled low-alcohol.When alcoholic drinks are labeled as low in alcohol, people drink more of them, suggests a study in Health Psychology. Researchers brought 264 British adults into a lab designed to look like a bar and asked them to participate in a sham taste test in which they would rate the qualities of three different beers or wines. The researchers gave participants 250 mL (about 8 oz) of each beer or 125 mL (about 4 oz) of each wine and told them that they could drink as much or as little as they wished. On average, participants consumed significantly more (214 mL total) of the drinks labeled "super low" in alcohol compared with the drinks labeled "regular" (177 mL). They also showed a tendency (though it was not statistically significant) to drink a greater amount of the drinks labeled "low" in alcohol (194 mL). DOI: 10.1037/hea0000622

Parents' roles in children's friendships

Children with controlling parents, or those whose parents are depressed, are less likely to maintain close friendships in elementary school, a study suggests.Parents' mental health and parenting style can influence the course of their children's friendships in elementary school, finds a study in the Journal of Family Psychology. Researchers analyzed data from 1,523 Finnish schoolchildren, followed from first to sixth grade, and the children's parents. The researchers followed pairs of friends over those years to see whether children remained close to their best pals from first grade. They also used peer reports to assess whether the children were generally popular with their classmates and asked the parents questions about their parenting behavior (including behavioral control, psychological control and affection) and their own depressive symptoms. Overall, children whose parents exhibited a great deal of psychological control, or whose parents were depressed, were more likely to see close friendships end before sixth grade. The effects of these parental variables were above and beyond the effects of the children's status among their peers. DOI: 10.1037/fam0000388

What are they selling?

U.S. television commercials for prescription drugs are longer than they used to be and tout more lifestyle benefits yet offer less actual information about the conditions and the drugs, finds an analysis in the Annals of Family Medicine. Researchers analyzed prime-time prescription drug commercials that ran on major cable TV networks for 13 weeks in 2016. On average, the commercials were 30 percent longer than those from a similar study done in 2004, but they offered fewer facts—just 25 percent discussed the biological nature or mechanism of the conditions, compared with 54 percent in 2004. Only 16 percent of the ads gave information about risk factors for the conditions, compared with 25 percent in 2004. Meanwhile, 57 percent of the 2016 ads showed actors gaining lifestyle benefits from using the drugs, such as social approval and physical endurance, compared with about 40 percent of the 2004 ads. DOI: 10.1370/afm.2220

A disgusted look

Women are better than men at reading disgust from a person’s facial expression, but no better at decoding other emotions, finds a study.There's a widespread popular belief that women are better than men at reading other people's emotions, but a study in Emotion finds that holds true only for detecting disgust. In three experiments with more than 2,000 total online participants, researchers asked participants to view photos of static faces and bodies or to watch videos that showed faces and bodies in motion and to identify which of five emotions were being expressed (anger, disgust, fear, happiness or sadness). Across all experiments, women performed better than men only at recognizing facial disgust; no other sex differences occurred across all three experiments. DOI: 10.1037/emo0000446

No hormone effect on mate preference

Some previous research has suggested that, during the more fertile periods of the menstrual cycle, heterosexual women show a stronger preference for potential mates with more masculine facial features. However, the largest-ever longitudinal study of this claim, published in Psychological Science, finds no evidence for it. Researchers tested 584 women with a mean age of 21.5. Once per week for up to 15 weeks, they tested the women's hormone levels (via a saliva sample) and assessed their preference for masculinized and feminized versions of a male face. They also asked whether the women were on hormonal contraceptives. Overall, they found no indication that the women's mate preferences shifted as their hormone levels fluctuated or that hormonal contraception affected women's preference for masculine faces. DOI: 10.1177/0956797618760197

Contagious yawning

“Catching” yawns easily is a sign of empathy, one study suggests.People who are more likely to "catch" a yawn may also be more empathetic, on average, finds a study in the Journal of Experimental Psychology: General. In two experiments with about 500 total participants, researchers recorded participants' facial expressions as they watched short, silent videos of people yawning. Overall, 22 to 24 percent of participants "caught" the yawn and yawned themselves. Those people scored almost half a standard deviation higher than people who didn't catch the yawns on the Interpersonal Reactivity Index, a scale of empathy that includes items such as "I often have tender, concerned feelings for people less fortunate than me." However, the study also found that those who caught yawns were no more likely than the others to donate some of their payment for participating in the study to charity. DOI: 10.1037/xge0000422

Sneak peek

Social scientists and mathematicians often share details of their research with colleagues before the work is published; computer scientists, engineers and medical researchers keep their work closer to the vest.More researchers than not share details of their work with colleagues before it is published, but the practice varies by field, finds a survey of 7,103 university faculty researchers in nine fields, published in Science Advances. Social scientists and mathematicians are more likely to share ahead of time, while computer scientists, engineers and medical researchers guard their research more closely. About 77 percent of social scientists and 78 percent of mathematicians share some details of their research ahead of publication, compared with just 43 percent of computer scientists and 56 percent of engineers. Among the reasons researchers gave for sharing was to get feedback from colleagues, take credit for a finding ahead of a competitor or gain collaborators on the project. DOI: 10.1126/sciadv.aar2133

Second languages

The window for acquiring a new language stretches almost until adulthood—longer than previously believed, finds a study in Cognition. Nearly 670,000 participants took a grammar quiz through a Facebook app. About 246,000 were native English speakers and 424,000 had learned English as a second language. Participants also answered questions about their ages, the age at which they began learning English and where they learned it. The researchers found that on average, only those who began learning English before age 10 achieved native proficiency. However, the ability to learn grammar remained strong until about age 17, at which point it began to decline steadily. DOI: 10.1016/j.cognition.2018.04.007

Depression and cognitive decline

Older adults with depression are also more likely to experience cognitive decline over time, a meta-analysis finds.Older adults with depression have an increased risk for cognitive decline as well, finds a meta-analysis in Psychological Medicine. Researchers reviewed evidence from 34 longitudinal studies that included measures of depression or anxiety, involving a total of 71,244 older adult participants, none of whom had dementia at the beginning of the studies. Each study followed the participants for at least one year. The researchers found that people with depression experienced a greater decline in cognitive abilities—including memory loss, executive function and processing speed—compared with those without depression. No meta-analysis on the association of anxiety and cognitive decline was conducted because there were an insufficient number of studies assessing anxiety. DOI: 10.1017/S0033291718001137

Curiosity helped the kids

Curious childrenKids who are more curious have better math and reading skills in kindergarten, finds a study in Pediatric Research. Researchers examined data on about 6,200 kindergartners from a U.S. nationally representative longitudinal study that included measures of math and reading achievement, as well as parents' assessments of the children's curiosity and effortful control.

Overall, children who were more curious showed greater math and reading achievement. The effect was not moderated by level of effortful control or by gender, but it was stronger for children from families of lower socioeconomic status. The researchers suggest that fostering curiosity may be an effective approach to reducing the achievement gap between children of lower and higher socioeconomic status. DOI: 10.1038/s41390-018-0039-3

Opioid deaths

OpioidsSynthetic opioids (such as fentanyl) are now linked to more deaths in the United States than prescription opioids, according to an analysis in the Journal of the American Medical Association. Researchers examined data from the National Vital Statistics System on opioid deaths between 2010 and 2016. In 2016, they found, synthetic opioids were involved in 46 percent of all opioid deaths, up from 14 percent in 2010. Prescription opioids, meanwhile, were involved in 40 percent of all opioid deaths and heroin in 37 percent (many deaths involved multiple drugs). DOI: 10.1001/jama.2018.2844

Roommate distress

College students aren’t always aware of their roommates’ mental distress.College roommates tend to underestimate each other's distress, finds a study in Personality and Social Psychology Bulletin. Researchers surveyed 187 roommate pairs at one U.S. university at two times during an academic year, in February and in April, asking each student about his or her distress levels and his or her roommate's distress levels. On average, students underestimated their roommates' distress and tended to believe their roommates' distress levels were similar to their own levels. However, the researchers found that roommates were accurate judges in one way: Students who were judged most distressed by their roommates were more likely to self-report extreme distress. The researchers suggest that college students receive training so they can more accurately identify peers in need of help. DOI: 10.1177/0146167217754192

Early autism diagnosis

EEG scans could help diagnose autism in young infants, long before clinical evaluations are possible, suggests a study in Scientific Reports. The infants (89 who were in a high-risk group because they had a sibling with autism, along with 99 low-risk controls) had EEG measurements taken at least twice between ages 3 months and 36 months. The babies sat still in their mothers' laps wearing electrode caps while experimenters blew bubbles to distract them. By analyzing patterns of six frequencies of the EEG waves, the researchers were able to predict with high accuracy by age 9 months which babies would eventually receive a clinical diagnosis of autism. DOI:10.1038/s41598-018-24318-x

For direct links to the research cited in this section, visit our digital edition at www.apa.org/monitor/digital.