Titi monkeys are one of the few nonhuman primate models that develop social attachment. Therefore, they are involved in the study of neurotransmitters and what they contribute to the biology of social attachment. Recently, the monkeys were involved in research to develop a new technique to visualize oxytocin receptors in human brain tissue. This has led to the ability to study oxytocin receptor distribution in the brain tissue of people with autism spectrum disorder. Tiki monkeys are good models because of their biological similarities to humans.