Women are twice as likely as men to use emoticons in text messages, according to a study by a US university.
The emoticons, which began as happy and sad faces, have developed into dozens of other expressions, and have become hugely popular in text messages and email.
The study by Rice University used smartphone data from men and women over six months and analysed 124,000 text messages, the Daily Mail reported.
Texting has become one of the most popular forms of communication. In 2012 alone, it is estimated that eight trillion text messages will be sent out across the world.
In the Rice University study, all of the participants used emoticons, but they did not use them very often. Only four percent sent all of their text messages containing one or more emoticons.
The study confirmed previous research that women are more emotionally expressive in non-verbal communication.
The authors also found that while women may use emoticons more than men, the men used a larger variety of emoticons to express themselves.
Participants in the Rice study texted a wide variety of emoticons, the Daily Mail said.
A total of 74 different emoticons were used, but the top three emoticons - happy, sad and very happy - made up 70 percent of the total emoticons sent by the participants.