Oxytocin is a hormone secreted by the posterior lobe of the pituitary gland, a pea-sized structure at the base of the brain. It is secreted into the bloodstream by the posterior pituitary gland. Secretion depends on electrical activity of neurons in the hypothalamus – it is released into the blood when these cells are excited. It’s sometimes known as the “cuddle hormone” or the “love hormone,” because it is released when people snuggle up or bond socially. Even playing with your dog can cause an oxytocin surge, according to a 2009 study published in the journal Hormones and Behavior. But these monikers may be misleading. Oxytocin can also intensify memories of bonding gone bad, such as in cases where men have poor relationships with their mothers. It can also make people less accepting of people they see as outsiders. In other words, whether oxytocin makes you feel cuddly or suspicious of others depends on the environment.