An economic professor has advised parents to leave their babies to ‘cry it out’ at night.
Emily Oster, 39, wrote in her new book Cribsheet that babies sleep better if they are trained from a young age.
The mum-of-two has claimed the controversial practice does not cause developmental damage and will not make children less attached to their parents.
Her research was done by looking through ‘thousands of papers of academic literature’, she said.
She said: ‘There doesn’t seem like there’s any downside long-term.
‘That doesn’t mean it’s going to be the right choice for everybody but for those who do want to do that, there’s a reassuring picture from the data.’
Professor Oster claimed that negative connotations of letting a baby cry it out stem from Romanian orphanages in the 1980s, where children suffered abuse and had limited adult contact.
Visitors to the orphanages then remarked on how quiet the children were, as they no longer cried because ‘they knew no one would come’.
Professor Oster said in reality, a few nights of sleep training is unlikely to have such a negative impact – and can actually make babies sleep better.
She told MailOnline: ”In studies where parents were encouraged to use this technique and others were not, they found – on average – after the sleep training, babies sleep better.
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‘Many studies found parents reported their babies are happier after the sleep training than before. In addition, there seems to be some benefits to parents, including less maternal depression and better marital satisfaction.’
She added that it was every parent’s ‘personal choice’ as to how to look after their baby – but she does not support telling families they will damage their child by leaving it to cry out.
‘Having parents who are exhausted and depressed may also have consequences for children even if we do not want to put value on the parents at all,’ she said.
Professor Oster’s work has already drawn considerable debate online, with some parents strongly disagreeing with her argument.
One person tweeted: ‘She’s an *Economic* Professor who’s read a lot of studies, not a psychologist, paediatrician or sleep expert; which makes her about as much an expert on this as many mothers of two.’
Another added: ‘Never ever allow babies to cry. It creates a lot of psychological issues… so said psychology professor AND the textbooks. That trumps an economics professor.’
While a third called Professor Oster ‘crazy’, adding: ‘Babies cry because they want to survive, that’s their only way of communication! They fall asleep because nobody comes, they give up.
‘This way of thinking is dangerous and live psychological scars on the little human.’
But some users did agree with Professor Oster’s writing, with one stating: ‘We did this with both of ours. Both were settled sleepers well inside 6 months.’
Another continued: ‘When they are crying for attention, just ignore them. This claim is spot on.’