To see how long the dogs retained the memory, the owners were then asked to add another step to the test. After saying "Do it!", they walked their pets behind a screen 14 meters away that hid the cone or other experimental objects, so that the animals wouldn't continue to look at them. Then they waited for up to 30 seconds before returning to the starting position. "We just kept slowly increasing the time between the demonstration and the 'Do it!' command," Fugazza explains.
Once the dogs could imitate the behavior twice in a row after waiting for 30 seconds, they were ready for the testing phase. Each dog was given 19 tests in eight different conditions-including copying a familiar action, a novel action, and a distracting action. All the dogs were shown the same novel action to imitate: Each one watched her owner enter a wooden box. This time, they were expected to wait behind the screen for one full minute, before returning to the starting position and being told "Do it!" For the distracting action tests, the dogs watched the owner do something they had seen before. Again, they were led behind the screen, but this time commanded to lie down, or fetch a ball. The waiting periods during these sessions lasted from 30 seconds to 4 minutes.
The dogs endured their longest breaks after watching a familiar action-with times varying from 24 seconds to 10 minutes. "They can wait even longer," Fugazza says, "but we really don't expect the owners to stay behind the screen for an hour!" The dogs also showed their smarts by repeating the action that they'd witnessed, even when a person other than the demonstrator and who did not know which action the dog was expected to copy gave the "Do it!" command. All the dogs completed 18 trials, scoring almost perfect marks; six dogs made one error each, one dog made two, and another made six mistakes, the team reports this month in Animal Cognition. "The statistical results are very robust," Fugazza says, "and they show the dogs can do deferred imitation." This suggests, she adds, that dogs have declarative memory-long-term memory about facts and events that can be consciously recalled. Until now, only humans have been shown to have this type of memory.