In the lab, it's octopus see, octopus do.

A fleshy, rippling octopus lumped in the corner of its tank doesn't seem capable of the dolphin's intelligent feats. Yet two Italian researchers report in the April 24 Science that this eight-armed invertebrate can learn a task simply by watching other octopuses do it -- an ability previously seen only in more sophisticated, social vertebrates like dolphins or humans.

Octopuses are typically asocial animals, so scientists have generally assumed they lacked such imitative learning ability. Working at the Zoological Station of Naples, Graziano Fiorito and Pietro Scotto finally tested the idea.

The researchers placed two balls -- one red, one white -- inside a tank and trained one group of octopuses to attack the red ball and another group to attack the white one. Once trained, the two groups then performed the trick for untrained octopuses watching from an adjacent tank. After four demonstrations, each spectator was tested to see whether it would attack the same color ball as the group it had watched. The observers not only chose the right ball, Fiorito and Scotto found, but they learned more quickly and made fewer mistakes than their teachers did.

Cephalopods, such as octopuses and squid, have less complex neural circuitry than most vertebrates, which makes them good models for investigating the fundamental processes underlying human learning and behavior, says Roger T. Hanlon, an ethologist specializing in cephalopod behavior at the Marine Biomedical Institute in Galveston, Texas.

"If you can find out something about how learning systems operate in a wide range of animals, including very ancient ones like these, then you can learn something about the principles of learning as they pertain to all organisms," he says.

The new findings suggest that scientists may have underestimated the octopus' mental abilities. "Many people have considered observational learning to be a social skill that you would not expect in solitary animals," says Jean Boal, a graduate student in ecology at the University of North Carolina at Chapel Hill. "Yet octopuses can do it."

Boal specualtes that the animals developed the skill to ensure their survival in the wind. An octopus' parents die when it's hatched, Boal says, so the young animal must learn to forage and avoid predators by watching other octopuses.

Hanlon and Boal say more research with octopuses may uncover more unmined scientific gems like the Italian findings. "Octopuses have the largest brain of any invertebrate," says Boal. "We've been much slower to figure out what they're doing with that brain."