Teen girls' inability to control their impulses is one of the main factors behind their tendency to bully using text messages, psychology researcher Jim Sanderson says.

The former teacher interviewed 210 girls aged 13 and 14 in New Zealand and Canada to determine which personality traits were related to text bullying.

He found a lack of impulse control was one of the main factors, as was lack of maturity.

"Text bullying is different and potentially more damaging to victims than other forms of cyber-bullying, such as threatening or hurtful emails, because cellphones can be used anywhere, anytime," Mr Sanderson said.

"The anonymity of the technology can embolden the bully because they do not see the immediate results of their actions and they can express more extreme forms of indirect aggression without immediate consequences."

His study also showed girls were just as likely to bully friends as people they did not know well, and that girls were more likely to bully using texts than boys.

"Girls are less likely to use physical violence and much more likely to use indirect violence," Mr Sanderson said. "Girls hold grudges longer than boys do and they often involve others to 'gang up' on the victim."

Mr Sanderson recommended schools offer impulse and conflict training to students.

- NZPA