Dog intelligence is the dog's ability to perceive information and retain it as knowledge for applying to solve problems. Studies of two dogs suggest that dogs can learn by inference and have advanced memory skills. A study with Rico, a border collie, showed that he knew the labels of over 200 different items. He inferred the names of novel things by exclusion learning and correctly retrieved those new items immediately and four weeks after the initial exposure. A study of another border collie, "Chaser," documented his learning and memory capabilities. He had learned the names and could associate by verbal command over 1,000 words.Dogs can read and react appropriately to human body language such as gesturing and pointing and human voice commands.A 2018 study on canine cognitive abilities found that dogs' capabilities are no more exceptional than those of other animals, such as horses, chimpanzees, or cats.Various animals, including pigs, pigeons, and chimpanzees, can remember the "what, where, and when" of an event, which dogs cannot do.Dogs demonstrate a theory of mind by engaging in deception.An experimental study showed compelling evidence that Australian dingos can outperform domestic dogs in non-social problem-solving, indicating that domestic dogs may have lost much of their original problem-solving abilities once they joined humans.Another study revealed that after undergoing training to solve a simple manipulation task, dogs faced with an insoluble version of the same problem look at the human, while socialized wolves do not.