Think your dog likes food? Try praising her. Then try praising her for not liking food as much as she likes praise. Researchers at Emory University recently set out to determine which dogs like more: food or praise. An Emory news release reports that the researchers first trained the dogs to associate three different objects with different outcomes. A pink toy truck signaled a food reward; a blue toy knight signaled verbal praise from the owner; and a hairbrush signaled no reward, to serve as a control. The dogs were then tested on the three objects while in an fMRI machine that revealed activity in their brains’ reward center. Ready? The envelope please….All of the dogs showed a stronger response for the reward stimuli compared to the stimulus that signaled no reward. No, not surprising. Four of the dogs showed a particularly strong activation for the stimulus that signaled praise from their owners. Nine of the dogs showed similar neural activation for both the praise stimulus and the food stimulus. And two of the dogs consistently showed more activation when shown the stimulus for food. Wait, there’s more. In the next experiment, each dog was familiarized with a room that contained a simple Y-shaped maze constructed from baby gates: One path of the maze led to a bowl of food and the other path to the dog’s owner. The owners sat with their backs toward their dogs. The dog was then repeatedly released into the room and allowed to choose one of the paths. If they came to the owner, the owner praised them. Most of the dogs alternated between food and owner, but the dogs with the strongest neural response to praise chose to go to their owners 80 to 90 percent of the time.
Taking this job and shoving it may be good for your health–if you really hate the job to begin with. Researchers at Ohio State University are convinced that job satisfaction in your late 20s and 30s has a real influence on overall health in your early 40s. How do they know? An Ohio State U news release reports that the researchers examined job satisfaction trajectories for people from age 25 to 39, then asked the participants about a variety of health measures after they turned 40. The researchers put participants in four groups: consistently low and consistently high job satisfaction, those whose satisfaction started high but was trending down and those who started low but were trending higher. Here’s what they found: 45 percent of participants had consistently low job satisfaction; 23 percent had levels that were trending downward through their early career; 15 percent were consistently happy at their jobs; and about 17 percent were trending upward. Unsurprisingly, the researchers found that mental health, rather than physical health, was most affected by people’s feelings about their jobs. Those in the low job satisfaction group throughout their early careers scored worse on all five of the mental health measures, with higher levels of depression, sleep problems and excessive worry. Those whose job satisfaction started out higher but declined through their early career were more likely than those with consistently high satisfaction to have frequent trouble sleeping and excessive worry, and had lower scores for overall mental health. And those whose scores went up through the early career years did not see any comparative health problems. Wait, there’s more: those who were in the low satisfaction group and those who were trending downwards reported poorer overall health and more problems like back pain and frequent colds compared to the high satisfaction group.
In most American cities, commuting by bike is faster and cheaper than driving to work. Now comes another reason to think about pedaling instead of stepping on the gas pedal: people who ride bikes weigh less than people who drive. The Imperial College of London reports that researchers at the school monitored 11,000 volunteers in seven European cities, asking them how they move around the city, which mode of transport they use and how much time they spend traveling. They also asked the volunteers to record their height and weight, and to provide information about their attitudes towards walking and bicycling. The take away: people who drive cars as their main form of transport are on average four kilograms (8.8 lbs) heavier than those who ride bikes.
Which is more likely to lead to regrettable sex, alcohol or pot? That’s what researchers at New York University wanted to know, so they interviewed 24 adults (12 males and 12 females) who recently used marijuana before sex. An NYU news release reports that the researchers found that, compared to marijuana, alcohol was more commonly associated with social outgoingness and use often facilitated connections with potential sexual partners; however, alcohol was more likely than marijuana to lead to atypical partner choice or post-sex regret. They also found that while some people reported that marijuana made them more selective in choosing a partner, many participants— both male and female—felt that their “standards” for choosing a partner were lowered while under the influence of alcohol. Wait, there’s more: While people often described favorable sexual effects of each drug, both alcohol and marijuana were associated with a variety of negative sexual effects including the very negative effect of sexual dysfunction. For example, marijuana use was linked to vaginal dryness and alcohol was commonly described as increasing the likelihood of impotence among males. Both drugs appear to be potentially associated with increased feelings of self-attractiveness, but possibly more so for alcohol, and participants reported feelings of increased sociability and boldness while consuming alcohol.
Contrary to some opinions, and to the findings of a well-known 2014 study published in the journal Science suggesting that running made mice forget things, a new study has found that there is no connection between running and the loss of memories. A news release from researchers at Texas A&M reports that researchers at the school did basically the same experiment as the 2014 study, but they used rats instead of mice, because rats are more like humans physiologically. This time, the researchers found that rats who ran further had much greater neurogenesis in their hippocampus (growth of new neurons in the part of the brain that holds memories), and all rats who had access to a wheel (and therefore ran at least some), had greater neurogenesis than the sedentary group. On an average, they ran about 48 miles in four weeks, and neuron formation doubled in the hippocampus of these animals. They also found that despite differing levels of increased neurogenesis, both moderate runners and brisk runners (those who ran further than average) showed the same ability as the sedentary runners to recall the task they learned before they began to exercise. This means even a large amount of running (akin to people who perform significant amount of exercise on a daily basis) doesn’t interfere with the recall of memory.
You know that wonderful high that often follows a good workout? Many post-menopausal women don’t know it, and researchers at the University of Missouri now think they know why. A U of Missouri news release reports that the researchers believe they found a connection between lack of ovarian hormones and changes in the brain’s pleasure center, a hotspot in the brain that processes and reinforces messages related to reward, pleasure, activity and motivation for physical exercise. The researchers compared the physical activity of rats that were highly fit to rats that were less fit, studying rats’ use of running wheels set up in the cages before and after the rats had their ovaries removed. They also examined gene expression changes of dopamine receptors within the brain’s pleasure center. Here’s what they found: The high-fit rat group had more activity in the brain’s pleasure center, which correlated with greater wheel running before and after the loss of ovarian hormones. But…. the high-fit rats still saw a significant reduction in wheel running after their ovaries were removed, and that reduction in running correlated with a reduction in their dopamine signaling levels, indicating that the brain’s pleasure center could be involved.
It may take a while, like 24 months, but eating more fruits and vegetables has been shown to increase life satisfaction as much as moving from unemployment to employment. And you don’t even have to go to work. Researchers at the University of Warwick examined the food diaries of 12,385 randomly sampled Australian adults over 2007, 2009, and 2013 in the Household, Income, and Labour Dynamics in Australia Survey. The authors adjusted the effects on incident changes in happiness and life satisfaction for people’s changing incomes and personal circumstances. A University of Warwick news release reports that the findings suggest that happiness increased incrementally for each extra daily portion of fruit and vegetables up to eight portions per day. The researchers also found that alterations in fruit and vegetable intake were predictive of later alterations in happiness and satisfaction with life.
FitDesks, workstations that allow people to pedal a bike or walk, don’t just help us keep fit. They make us happy. That’s the conclusion of researchers at Clemson University, who focused on the effects the FitDesk Bike, an ergonomic, stationary bike and laptop workstation. A Clemson news release reports that the researchers first looked at the cognitive performance of workers who used the bikes and those who didn’t, and found no difference in the work they did. The researchers did, however, find that those workers using the bike were more motivated and had better morale. How long does the increased motivation last? More research is needed.
It sounds crazy, but, as Gretchen Reynolds reports in the New York Times, research suggests that a common chemical found in many cosmetics and personal care products may influence our will to exercise. The Times reports that scientists at Texas A&M University set out to determine if the chemicals, called phthalates, influenced the behavior of mice. They did that by feeding benzyl butyl phthalate (B.B.P.), a common phthalate, to pregnant mice, while another (control) group of pregnant mice was fed a harmless oil. When the baby mice were born, the researchers tracked their activity levels, observing which mice chose to run on wheels and which did not. Reynolds reports that the male mice that had been exposed to the chemicals in utero ran about 20 percent less during adulthood than the other animals, while the exposed females exercised about 15 percent less. Wait, there’s more. The researchers also found that “the researchers found that the male mice exposed to B.B.P. in utero had notably lower levels of testosterone than the other animals in young adulthood, which is also when their running mileage cratered. Those differences lingered into middle age. The exposed females similarly developed during young adulthood low estrogen levels and other reproductive system abnormalities that then produced a profound desire, it seems, to sit for most of the day.”
Is retirement good for your health? Researchers at the University of Sydney think it may be. The New York Times reports that after following more than 27,000 men and women who retired during a three year period, the researchers found that when compared to people who were still working, the retirees walked for 17 minutes more a week, did moderate-intensity exercise 45 minutes more a week, and slept 15 minutes longer.