Babies are known to cry to alert their parents to their distress to help ensure their survival.

Yet, confirming what many parents already suspect, scientists have found that infants also fake cry simply to get extra attention - particularly if they have brothers and sisters.

Japanese researchers studied two babies crying over a period of six months and believe the infants are capable of the clever deception.

Hiroko Nakayama, a researcher at the University of the Sacred Heart, Tokyo, said one of the babies faked crying, after filming the children for an hour twice a month, for half a year.

The scientists coded the video footage in five second segments to document 68 episodes of crying for seven month old ‘Baby R’ and 34 episodes for ‘Baby M’ who was nine months old at the beginning of the study, The British Psychological Society reported.

They looked for the presence of emotion in the minutes before and after the babies cried and found that all of Baby M’s crying episodes were preceded by evidence of upset, shown by the child grimacing, making noises or looking sad.

However, the researchers also found that there was an instance when Baby R cried shortly after smiling and laughing.

While they said that 98 per cent of Baby R’s crying episodes did follow a negative effect, the incident at 11 months was recognised by her mother as fake crying and analysis confirmed this.

‘Infant R appeared to cry deliberately to get her mother's attention,’ said Nakayama, who added that ‘she showed smile immediately after her mother came closer.’Dr Nakayama said fake crying successfully attracts the attention of a parent and contributes 'greatly' to an infant's social development as well as their emotional development.

‘Infants who are capable of fake crying might communicate successfully with their caregivers in this way on a daily basis. Fake crying could add much to their relationships,’ she added.The study also revealed that typically after a crying episode, the babies continued to be distressed or sad and they only slowly became happier with physical contact from a parent.

While the researchers only observed two children, they think that Baby R might used fake crying as she had two siblings, whereas Baby M was an only child and did not have to compete for her parents’ attention.

Dr Nakayama said that siblings can enrich social interactions at home and increase their variety.

‘Such environmental factors are known to stimulate the development of communication skills of infants,’ she added.