Final answer:
Oxytocin is the neuropeptide known as the social neuropeptide; it plays a key role in social bonding, labor induction, and milk production, differing from vasopressin, which regulates blood pressure.
Step-by-step explanation:
The neuropeptide that is known as the social neuropeptide because of its ability to regulate social recognition, affiliation, and modulation of anxiety, mood, and aggression is oxytocin. This chemical is part of a group of neurotransmitters that are made up of chains of amino acids called neuropeptides. Oxytocin and vasopressin are two closely related hormones produced by the pituitary gland. While vasopressin mainly acts as an antidiuretic hormone that regulates blood pressure, oxytocin is specifically influential in social bonding, inducing labor in pregnant women, and initiating milk production in nursing mothers. It has been noted for its critical role in facilitating not just physiological processes but also behavioral patterns associated with social interactions.