Dogs in the classroom lower stress of primary school students, new research has found. The study by UK researchers found spending some time with a dog twice a week was better for reducing stress on students than many other classroom relaxation activities. And the benefits of these “dog dates" were similar for children in both normal and special schools.

Stress is known to negatively affect a child’s learning, behaviour, health and mood. This has led schools to try a number of ways to reduce stress, including yoga, mindfulness, physical activities and even having animals in classrooms.

The researchers from the University of Lincoln measured students' stress levels by tracking the level of the stress in their saliva (唾液). They studied 105 students aged 8 to 9 in four normal schools as well as 44 children of a similar age in seven special schools in the UK. The children were randomly (任意) divided into three groups: a group that spent time with a dog; a group that spent time doing relaxation activities; and a “control” group that did neither of these things. Students in the dog group spent 20 minutes with a trained dog twice a week for four weeks. The relaxation group spent the same amount of time doing exercises.

The researchers found that the children in the dog group had “significantly lower” stress levels, while those in the relaxation and control groups recorded an increase over the school term. The study, which was published in the journal PLOS ONE, also found stress was lowest in the children in the dog group immediately after their contact with the puppies. “Dog-assisted activities can lead to lower stress levels in schoolchildren with and without special educational needs,” University of Lincoln researcher Kerstin Meints said, “but more research is needed to discover what was the ideal amount of time and contact with dogs for the best effect.”

For people, many other animals, family matters. Consider how many jobs go to relatives. Or how an ant will cruelly attack intruder(入侵的) ants but rescue injured, closely related nest-mates. There are good evolutionary reasons to aid relatives, after all. Now, it seems, family feelings may stir in plants as well.

A Canadian biologist planted the seed of the idea more than a decade ago, but many plant biologists regarded it as heretical—plants lack the nervous systems that enable animals to recognize kin(家族), so how can they know their relatives? But with a series of recent findings, the belief that plants really do care for their most genetically close peers—in a quiet, planty way—is taking root. Some species control how far their roots spread, others change how many flowers they produce, and a few tilt(倾斜) or shift their leaves to minimize shading of neighboring plants, favoring related individuals.

“We need to recognize that plants not only sense whether it’s light or dark or if they’ve been touched, but also whom they are interacting with,” says Susan Dudley, a plant evolutionary ecologist, whose early plant kin recognition studies sparked the interest of many scientists.

Beyond broadening views of plant behavior, the new work may have a practical side. In September 2018, a team in China reported that rice planted with kin grows better, a finding that suggested family ties can be used to improve crop yields. “It seems anytime anyone looks for it, they find a kin effect,” says Andre Kessler, a chemical ecologist at Cornell University.

Spider monkeys know that the best way to find food is in a group. But when they divide to hunt for fruit, there’s no random (随意的) pairing off. Researchers have found that they use collective computation (群体计算) when they break up into teams.

Typically, the older females lead the rest of the younger monkeys, having the final say in group activities. But that’s not the case for wild spider monkeys living in a protected area near Punta Laguna, Mexico.

When they’re ready to search for food, the monkeys form teams without a single leader picking who goes into which group. Instead, each monkey decides which group to join and when to move to another group.

“The spider monkeys seem to be collecting information about resources by forming these small teams, so that as a group they know their environment better than anyone does on its own,” lead study author, Gabriel Ramos-Femandez of the National Autonomous University of Mexico, said.

To study the animals’ behavior, researchers spent two years recording 47 different spider monkeys for five hours each day. For hunting for food, they usually formed groups of 2 to 17 monkeys. Researchers worked together with the scientists to find out how a spider monkey decided to stay with or leave a group. Their study found that the monkeys’ decisions were influenced by the decisions of the other monkeys on the team. They would feel out their teammates about the best size and then make their own decisions accordingly.

The results produced teams of many different sizes, which were helpful in finding fruit in the forest. The researchers said that the collectively computed sizes were sometimes not a perfect match based on the food that was available. They suggest a similar study should be used to examine how other groups or systems work, such as flocks of birds or schools of fish.