Seniors tend to live longer and enjoy better health if their homes are close to a park or nature, regardless of social or economic status.

College students do better on cognitive tests when their dorm windows view natural settings. Children with Attention-deficit/hyperactivity disorder (ADHD) have fewer symptoms after outdoor activities in lush environments.

These are only a few of the findings from recent studies that support the idea that nature is essential to the physical, psychological and social well-being of the human animal, said Frances Kuo, professor of natural resources and psychology at University of Illinois.

Humans living in landscapes that lack trees or other natural features undergo patterns of social, psychological and physical breakdown that are strikingly similar to those observed in other animals that have been deprived of their natural habitat, Kuo said.

"Now, as human societies become more urban, we as scientists are in a position to look at humans in much the same way that those who study animal behaviour have looked at animals in the wild to see the effect of a changing habitat on this species," said Kuo.

"In animals what you see is increases in aggression, you see disrupted parenting patterns, their social hierarchies are disrupted," she said.

Considerable research has found that violence and aggression are highest in urban settings devoid of trees and grass, for example, said an U-I release.

In a 2001 study of the Robert Taylor Homes (recently demolished), Kuo and her colleague, U-I landscape architecture professor William Sullivan, found that those who lived in housing units with no immediate view of or access to nature reported a greater number of aggressive - including violent - conflicts with partners or children than their peers who lived near trees and grass.

Kuo will present her own and other findings at the annual meeting of the American Association for the Advancement of Science in Chicago.