The aim of the study is to explore how the rewarding effect of men's verbal compliment is modulated by oxytocin and gonadal hormone in a romantic context.

To investigate whether oxytocin (24IU) might interact with female sex hormone in modulating the rewarding effect of compliment to women in a romantic context.

The study employs a double-blind, within-subject, placebo-control design. Women will be administered with the same drug twice (oxytocin or placebo) respectively the fertile and luteal phase followed by a MRI scanning. During fMRI participants will rate men's attraction based on their facial pictures of average attractiveness associated with compliments of different combination of form and topic. Each male face will be paired with two sentences of the same kind. After the fMRI participants will recall the judgment followed by a memory test during which they have to indicate whether the they have seen the face during scanning (old) or whether it is an unknown face (new).

Inclusion Criteria:

• Single in the past 3 months
• Healthy subjects with regular menstrual cycle

Exclusion Criteria:

• Pregnant, menstruating, taking oral contraceptives
• metal implanted, with tatoo, or hair dyed within 6 months
• participated in another intranasal experiment within 6 months
• with a history of past or current psychiatric or neurological disorder