It's well known that our human memory can fail us. People can be forgetful, and they can sometimes also "remember" things incorrectly, with damaging consequences in the classroom, courtroom, and other areas of life. Now, researchers show for the first time that bumblebees  can be unreliable witnesses too. Bumblebees are rather clever animals, which explains why Chittka has been studying learning and memory in the insects for the last 20 years. Most times when people have studied memory in animals, errors in performance have been taken to mean that the animals failed to learn the task or perhaps learned it and then forgot. But what if animals can experience a more interesting type of memory failure? To find out, Chittka first trained bumblebees to expect a reward when visiting a yellow artificial flower followed by one with black-and-white rings. During subsequent tests, bees were given a choice between three types of flowers. Two were the types they'd seen in the training before. The third had yellow-and-white rings, representing a mixed-up version of the other two. Minutes after the training, the bees showed a clear preference for the flower that recently rewarded them. One or three days later, however, something very different happened when the bumblebees' memory was put to the test. At first, the bees showed the same preference displayed in the earlier tests, but as the time went on, they began selecting the flower with yellow rings, even though they'd never actually seen that one in training before. Chittka says that insects make similar errors in the conjunction   of long-term memories as humans do. The ability to extract   common features between different events in the environment might come at the expense of remembering every detail correctly. In bees, with their limited brain capacity  , the pressure to store main features of several objects rather than each individual object might be much greater, compared with humans. We can infer from the passage that   _  .
Chittka thinks that bumblebees failed to remember the color of the flowers Researchers have learned that bumblebees are unreliable animals There exist no similarities between the memory errors in humans and bees. It is less challenging for humans than bees to store main features of several objects.