Matching of female participant characteristics related to their ovarian cycle.

Number or female subjects that assumed hormonal contraceptives and that were in their pre-ovulatory or post-ovulatory phase of their menstrual cycle at the time of EEG recording. As visible, women were matched across classes so that it can be excluded that higher levels of either estrogen or progesteron (whose concentration changes in the 2 phases) might modulate neural responses to social stimuli similarly in all female participants.