We don't look like we think we do!

Will you believe that we do not know exactly how we look? In comparison, others are a better judge of our appearance, says a study.

In the study, an initial group of over 130 undergraduate students downloaded 10 suitable photos of themselves from Facebook and ranked them in order of the best to worst likeness.

These participants took part in a minute long web cam video of their face and two still photos were also taken (one smiling, one neutral).

Sixteen participants who did not know the students, watched the webcam videos and afterwards ranked the Facebook photos in order of resemblance to the person they had seen in the video.

A further 73 participants were then recruited to complete an online face matching test.

Results of the study showed that the unfamiliar participants chose a different set of 'good likeness' images compared to those that people had selected of themselves.

Surprisingly, the images selected by strangers also led to better performance on the online face-matching test.

The size of the advantage in other-selection over self-selection was quite large - self-selected images were matched seven percent less accurately compared to other-selected images.

"It seems counter-intuitive that strangers who saw the photo of someone's face for less than a minute were more reliable at judging likeness," said lead researcher David White from the University of New South Wales (UNSW), Australia.

"Although we live with our own face day-to-day, it appears that knowledge of one's own appearance comes at a cost. Existing memory representations interfere with our ability to choose images that are good representations or faithfully depict our current appearance."

The researchers also said, there were better results when people were smiling in the photos.

Current passport guidelines in most countries prohibit smiling in photographs as this may distort the normal facial features.

"Given that faces are generally pictured smiling and these images are rated as being more like familiar faces, it may be beneficial to permit expression in passport photographs," white said.

The study was published in the British Journal of Psychology.