According to Dr. Stanley Coren, an expert on animal intelligence, the Yorkshire Terrier is an above average working dog, ranking 27th (32nd including ties) out of the 132 breeds tested.[20] His research found that an average Yorkshire Terrier could understand a new command after approximately 15 repetitions and would obey a command the first time it was given 70% of the time or better.[21] This capacity as working dogs enables Yorkies to excel in sports like obedience and agility, which require the dog to understand communication from the handler and carry out a complex series of commands.[7] Additionally, Yorkies learn to recognize numerous words and can be taught to distinguish and fetch separate toys in a box by their names.[7]