May not be strong enough to be obvious, but researchers say, the oral contraceptive pills could be blurring the social judgement in women who use it on a regular basis.

In the study, the women using contraceptive pills were asked to identify complex emotional expressions like pride or contempt, rather than basic ones like happiness or fear. The results were as expected. These women were less accurate in the recognition of the most subtle complex expressions than no-users. And the difference was nearly 10% between the two.

The effect held for both positive and negative emotions, and regardless of the type of oral contraceptive pills or the menstrual cycle phase of non-users. Since these impairments are subtle in nature, they are difficult to recognise and get noticed. The scientists therefore used very challenging emotion recognition task that required the recognition of complex emotional expressions from the eye region of the faces.