It happens to all but the most confident of characters  -  you fall for someone but daren't say anything in case you make a fool of yourself.

But the message from scientists is: Take the risk.

Telling a prospective partner 'I really like you' could make him or her immediately find you more attractive, research suggests.

Making eye contact and smiling has a similar effect.

Telling people you fancy them can make you more attractive , new research shows

Previous research has concentrated on the type of features and voice which tend to lead to the most romantic success.

The latest study, however, reveals the science of attraction to be far more complex.

It found that 'social cues'  -  someone's efforts to show how much they like a person  -  are of great importance in the blossoming of mutual attraction.

Psychologist Dr Ben Jones, of Aberdeen University, one of the authors of the study, said: 'Our latest research highlights how social cues, which signal the extent to which others are attracted to you, also play a crucial role in attraction.'

The study, Integrating Facial Attractiveness And Cues Of Social Attractiveness, was published in the journal Psychological Science.

Scientists showed volunteers four flash cards, picturing a face with different expressions.

The face is shown making eye contact and not smiling; not making eye contact and not smiling; making eye contact and not smiling: and making eye contact and smiling.

A total of 230 men and women took part in the study at the university's Face Research Laboratory. Dr Jones said: 'What we found was that the preference for the attractive face was much stronger when people were judging those faces that were looking at them and smiling.'

Attractiveness, according to the study, was how someone combined natural beauty and these 'social cues'.

Dr Jones carried out his research with Dr Lisa DeBruine, also of the University of Aberdeen.

The pair will present their research today at the British Association Festival of Science in Liverpool.

Dr Jones said singletons could use his findings to help prevent wasting time chatting up people who were clearly not interested.

'Combining information about others' physical beauty with information about how attracted they appear to be to you allows you to allocate your social effort efficiently,' he said.

'In other words, avoid wasting effort on attractive individuals who appear unlikely to reciprocate.

'This research shows that attractiveness is not as straightforward as simply preferring flawless skin or symmetrical features.'

Text-message 'fingerprinting' could soon be used to secure convictions in court, say scientists.

They have devised a technique which allows them to work out the likely sender of a message and believe it could be used to convince juries within as little as four years.

Commonplace texts are loaded with clues about a person's identity, the Festival of Science heard.

Dialects and abbreviations such as 'cu l8r' and '2moro' differ from person to person, and forensic linguist Tim Grant has devised a computer program to analyse messages in detail.