Why can't people resist puppy dog eyes? Throughout history dogs were considered as man's best friend. We never knew why, but this research may clear up our doubts. It's all down those innocent, irrestistible and lovely puppy dog eyes. A hormone ignites feelings of love when an owner looks at his dog eyes. Gazing can lead to an increase of oxytocin, the love hormone, which appears as well between a parent and his child. Everytime a mother breastfeeds or looks at her baby, a strong bond is created. It's thought that the friendship between a dog and its owner developed after humans began domesticating dogs. This happened in Europe 19000 years ago, when agriculture started to grow. The research involved two experiments. The first one had to do with collecting urine from both a group of dogs and their owners before and after thirty minutes interaction. This task was used to show that the bigger surge of oxytocin was in those samples where the owner and the dog gazed at each the most. In the second experiment, researchers sprayed oxytocin only into the group of dogs noses. This time, female dogs were those who stared longer at their owners. One of this hormone's job is to made owners bond with their pets while playing and petting. Scientists who worked on this study said that gazing highlights the power of owners orders, than just telling the dog what to do. Afterwards, this research was also carried out with hand-raised wolves, but in this case, they just held a gaze with humans for a few seconds. Interacting with wolves is a bit different than doing with dogs afterwards.