Visits 2A&B and 3A&B: Intranasal Oxytocin vs. Placebo Administration In this double-blind cross-over placebo-controlled trial of intranasal oxytocin, maternal brain and behavioral responses to infant cues will be assessed within & between subjects. Each participant will be administered both the active (oxytocin) and inactive (placebo) nasal spray just prior to separate behavioral or fMRI scanning sessions, with order of administration balanced across subjects and between attachment groups. All involved will be blinded to the identity of the oxytocin or placebo sprays. Before each visit, parent(s) will be asked to abstain from tobacco, food and drink (except water) for at least 2 hours prior to the visit. The investigators will attempt to schedule visits during the latter half of the mother's menstrual cycle, to minimize potential confounding from fluctuations in estrogen levels. Mothers without regular menstrual cycles will be scheduled one month apart. Mothers who are still breastfeeding will be asked to feed their infant at least one hour prior to the visit. For the four visits involving intranasal drug administration (two behavioral testing visits and two fMRI scanning visits), the following protocol will apply: participants will be given a urinary pregnancy test prior to the start of each visit. If a mother tests positive, she will be excluded from the study due to theoretical concern about possible effects of oxytocin on uterine contraction. Due to the fact that the pregnancy test may still not detect an early pregnancy, the mothers will also be asked to abstain from unprotected sexual intercourse during the 2 weeks prior to the visit, and will confirm, in signing the consent form, that there is no substantial chance of a current pregnancy. Just prior to drug administration, the parent(s) will complete the Positive and Negative Affect Scale, to rate her current emotions, for comparison to post-spray. The parent(s) will then self-administer a dose of either oxytocin (3 puffs per nostril [4 IU per puff] = 24 IU total) or a placebo spray that contains only the inactive ingredients of the oxytocin solution. Both experimenters and subjects will be blind to the treatment they are receiving. A stopwatch will be started at the moment the subjects begins intranasal administration, so that the behavior assessment or fMRI scanning can begin exactly 50 minutes later. Most other studies of intranasal oxytocin have used a 50 minutes delay time, based on CSF studies of other intranasally administered neuropeptides, such as the analogous hormone vasopressin. Forty minutes after drug administration, the PANAS will be repeated.