Aggression could bring about the downfall of the human race and our ultimate survival depends on kindness and co-operation, says scientist Stephen Hawking.

Hawking made his comments during a tour of London's Science Museum with 24-year-old Adaeze Uyanwah, 24, from Palmdale, Calif., who won a "Guest of Honor" competition held by VisitLondon.com.

Uyanwah won over 10,000 other international contestants.

The young California teacher asked Professor Hawking about what human shortcoming he would most like to see changed, and which human virtue he would like to see emphasized.

"The human failing I would most like to correct is aggression," he replied. "It may have had survival advantage in caveman days, to get more food, territory or partner with whom to reproduce, but now it threatens to destroy us all."

"The quality I would most like to magnify is empathy," he said. "It brings us together in a peaceful, loving state."

One possible "safety valve" or "life insurance" for the human race would be space travel, he said, and that should continue.

Putting humans on the moon changed the direction of the future of the human race in ways that we don't quite yet understand, he said.

While he acknowledged space travel hasn't solved any immediate problems humans face here on planet Earth, it has and will provide new perspectives on them, letting us look both inward and outward, he said.

"I believe that the long term future of the human race must be space and that it represents an important life insurance for our future survival," which could "prevent the disappearance of humanity by colonizing other planets," Hawking said.

Hawking has for some time been promoting the advantages space travel could confer on the human race; last year, he stressed the importance of investment in space travel because it has driven and continues to drive major advancements in science and technology.

His cautions on human aggression were not the first dire warnings he has issued about the possible future on humanity.

In December of last year, he warned of the possible peril of pursuing artificial intelligence without regard to possible consequence, telling the BBC that fully developed AI could spell the end of the human race.