Progress Daily

A 10-year Australian study (”Effect of social networks on 10 year survival in very old Australians“) found that older people with a large circle of friends were 22% less likely to die during the study period than those with fewer friends.

A large 2007 study (”The Spread of Obesity in a Large Social Network over 32 Years“) showed an increase of nearly 60% in the risk for obesity among people whose friends gained weight.

In 2008, Harvard researchers reported that strong social ties could promote brain health as we age (”Effects of Social Integration on Preserving Memory Function in a Nationally Representative US Elderly Population“). Over a 6-year period, memory among the least integrated declined at twice the rate as among the most integrated.

In 2006, a study (”Social Networks, Social Support, and Survival After Breast Cancer Diagnosis“) of nearly 3,000 nurses with breast cancer found that women without close friends were four times as likely to die from the disease as women with 10 or more friends. Proximity and the amount of contact with a friend wasn’t associated with survival, nor was having a spouse.

In 2008, researchers studied 34 college students (”Social support and the perception of geographical slant“), taking them to the base of a steep hill and fitting them with a weighted backpack. They were then asked to estimate the steepness of the hill. Some participants stood next to friends during the exercise, while others were alone. The students who stood with friends gave lower estimates of the steepness of the hill. And the longer the friends had known each other, the less steep the hill appeared.

“What Are Friends For? A Longer Life,” by Tara Parker-Pope

According to research by Hasse Walum (”Genetic variation in the vasopressin receptor 1a gene associates with pair-bonding behavior in humans“), men with a particular variant of a gene that influences brain activity (specifically, an allele that regulates the activity of the hormone vasopressin) are less likely to be devoted and loyal husbands.

About 40% of men have one or two copies of the allele. Men with two copies of the allele had a greater risk of marital discord than men with one copy, and men with one copy of the allele were at more risk of such discord than men with no copies.

In a sample of more than 1,000 heterosexual couples, about 15% of the men without the allele reported serious marital discord in the past year, compared with 34% of men with two copies of the allele.

17% of the men without the allele were living with women without being married to them, compared with 32% of men with two alleles.

“Study Links Gene Variant in Men to Marital Discord” by Shankar Vedantam