Coping with difference

Both Liu and Tao said they are especially poor at recognizing foreigners.

"The only thing I can tell is the color of their skins," said Liu. The first time Liu heard about face blindness was after reading a news report that said Brad Pitt, the famous US actor she adores, suffers from face blindness.

She said she realized that even though she had long been an enthusiastic fan of David Beckham and Brad Pitt, it took her years before she could tell which was which. Cheng said this was not unusual, even among those who did not have face blindness. Known as the "other-race effect," it describes a phenomenon whereby people find it more difficult to recognize people of another ethnicity.

Cheng said the effect was social and cultural, citing the fact that Asian people who are born and raised in Europe or America were comparatively stronger in identifying Caucasian faces but comparatively weaker in identifying Asian faces.

Cheng said he has spent one year helping people with face blindness identify their disorder and to build coping strategies, through interviews, case studies and seminars. He has also devoted his efforts to raising greater awareness about face blindness.

In most cases, prosopagnosia is congenital. In a smaller number of cases, acquired education might have some influence, with studies showing not being exposed to a large number of people might affect people's abilities to recognize faces after they grow up, he said.

How to cope with face blindness

1. Find and stay in a work and living environment that you are familiar with.

2. Learn to manage the feelings that arise from the failure to recognize faces, and stay positive.

3. Try smiling at everybody you meet and don't be afraid of enlarging your social circle.

4. Look into the eyes of the person you are talking to.

5. Use association methods, such as matching the sound of someone's name to their body shape, to identify people.

6. Embrace your face blindness. It can help in scenarios such as bumping into someone who you would dislike if you recognized them.

Source: Cheng Lehua, professor of psychology at Sun Yat-sen University