A new study has shown us why we favour the left side when carrying a child.

The phenomenon is known as left-hand bias.

Carrying a baby on the left is an ancient evolutionary feature that helps us keep babies safe, by allowing information to be processed by the right side of our brain.

Previous research has shown a bias of 70 to 85 per cent of women and girls cradle babies to the left.

Scientists from Saint Petersburg State University in Russia looked into the extent of left-cradling bias and not only found it is present in a variety of animals, but that it benefits the interactions between mother and baby, reports Daily Mail.

‘Left-cradling bias is a distinctive feature of maternal behaviour in humans and great apes, but its evolutionary origin remains unknown,’ the authors wrote in a paper, published today in Nature Ecology and Evolution.

The authors say left-cradling is the best way or a mother to notice and respond to a baby’s behaviour, like tears, laughter or yawns.

This is because holding a baby in this position helps important infant responses to be sent to the right side of the mother’s brain, which is used to process emotion. This in turn helps to encourage mother and child bonding, the authors said.

‘Our findings suggest that sensory lateralisation facilitates mother–infant bonding.’

The researchers studied ten species of animals, and found each had a preference for keeping their babies on their left side.

They looked at a range of animals from walruses and orcas to kangaroos, and said the sheer variety of animals that tend to keep their babies on the left is .

‘In this study we provide the first direct demonstration of lateralization in an infant’s active choice of spatial position near the mother in a diverse range of mammal species.’

The muscles on our left side are controlled by the right side of our brains, and vice versa. But on top of this, either side of our brains are responsible for different things.

The left side of the brain is generally used for language. It processes what we hear and handles most of the speaking and also carries out calculations.

But the right hand side is responsible for face recognition, spatial awareness and listening to music. The right hemisphere also helps us make sense of what we see.

This is why it is the more important in looking after a baby, recognising its expressions and interpreting what the child needs.

Now that makes sense!

Have you ever pondered this question?

Share your comments below.


  • I have always carried a baby or small child on my right side. I am a definitely “left handed” person according to a paediatrician. It keeps mi left hand free if needed to do anything while carrying, handing something to a baby or older person, feeding with a spoon or drink container. I myself eat right handed with a fork and knife (the fork has to be guided into my mouth), use a soup or dessert spoon with my left hand; write left handed, hand sew left handed. I know a lady who was Forced to do things as a right handled person and had more than one nervous breakdown as a child because of it. The Paediatrician told my Mum I was never to be changed as it would be detrimental to my health.


  • I have carried both on my left side. I always though tI did to leave my right, dominant, hand free…


  • i have always carried my two on my left, but the i am right handed.


  • I can’t believe this is not being called bullshit. The largest portion of persons who are right handed is what I say is the answer. If you are holding your child in your dominate hand you leave yourself unable to assist with anything necessary to care for the child. Right handed people carry their infants on their left and left handed on their right.
    Plain and simple! Stop looking for some dumb excuse to do a study.


  • Never pondered this question and always carried on my right side.

    • I am always amazed by the grants that are given for studies and the outcomes of these studies. Three always need to be comparisons provided.


  • I guess its something I never gave great thought to but if I had been asked i would have so it was so our right arm and hand was free. (most people being right handed)


  • Very interesting reading and I always wanted to know why it felt more comfortable holding my babies on the left side rather than the right side.


  • I thought it would be so they can hear our heartbeat better.
    Or from an evolutionary point of view so that our dominant hands were free to defend our children


  • I tried and tried in vain to swap the side I carry my youngest son as I had a sore back & neck, but he would insist on the left side, even now at 3 1/2 if I pick him up and put him on my right hip, he either says no and taps my left side or shuffles round himself, but I did wonder why I always put both my kids to the left


  • Rubbish. I’m left handed and held my son on the right as it left me open to do things with my left without the hassle of changing over. And what percentage of women are right handed? Wouldn’t the percentages support this option!


  • As the mother of twins I regularly carried one on each side when I was carrying both together……. they were tiny as small children but I could not have juggled both of them together on the one side – and for a few months after they turned two years old when I went out, I would be carrying them while at the same time their baby sister was often in a front pack I was wearing…..


  • ohhhhhhhhhhhhhh.. now I get it… this is why I didn’t bond so well with my kids eh? I always carried on the right side, I have a natural dip there


  • I thought it was because i was right handed as well hahah


  • I’ve just returned from visiting my 9 month old grandson and was thinking about this. Why was I always carrying him on my left hip when I’m right handed. I tried him on my right hip but it didn’t feel right


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