Baby Vision

What can a baby see? 

Since birth, Science Baby has been staring at lights, and tracking a light around the room, and by 6 weeks she was tracking our faces and smiling back at us. Naturally, I've been conducting a few simple experiments at home.

Over the past few months, by grinning at her from different distances, and moving different objects in front of her, it was easy to figure out her visual depth and colour / pattern preferences (see also babycentre and AOA, who report similar findings).

Playing around with my D-SLR camera (changing focal length, colour depth and depth of field) I made these "baby-vision" photos, to get a better idea of what the world looks like to Science Baby...

Birth 

Baby can only focus to about 30cm (about the distance to the face of the person holding her). She prefers high contrasts - mainly orienting to bright light sources.

1 month

Baby's vision is still blurry, but responds to high contrast edges up-close, especially black and white stripes. Her eyes still wander independently and struggle to focus as the muscles aren't yet fully developed, but she is very interested in faces.

2 months

Baby still can't distinguish colour shades, but bright (primary) colours become more interesting, and she enjoys tracking colourful objects that move slowly in front of her.

3 months

Baby can now see up to 1m (She reliably smiles back to a grinning face 1m away). Her colour vision is much more developed too, and her ability to focus is much better as the eye muscles have now strengthened. She is now beginnning to develop her hand-eye coordination.

4-6 months

Baby is beginning to develop her depth perception, and her eyes will visibly move in tandem to focus at different depths. She will now smile back at people 3 metres away. If it isn't already, her vision will be close to the level of an adult soon.

Who's the Daddy?

Can anyone recommend a good lawyer? Science Baby has brown eyes, even though Science Mum and I have blue eyes. There is only one conclusion - Science Mum must have been sleeping around!

We all learned in school that two blue eyed parents necessarily produce a blue eyed child. A novel I read recently, The Rosie Project, challenged this notion.

From this eye colour calculator, it's difficult to see how it might happen, but it's all because we were lied to at school.

We were taught in school the eye colour gene comes in two alleles: (b)lue and (B)rown. The capital B means that brown is dominant. Genes come in pairs, one from mum and one from dad, so we have the following possibilities:

genes	result
BB	brown
Bb	brown
bb	blue

This obviously ignores green eyes, plus it also assumes only one gene coding eye colour. There are actually two known genes (OCA2 and HERC2), and both are needed to produce the brown pigmentation. Without worrying which gene is which, we get 3 new possibilities:

genes	result
BB BB	brown
Bb Bb	brown
bb bb	blue
BB Bb	brown
BB bb	blue
Bb bb	blue

Not all of these outcomes are equally likely - the two genes are close together on the same chromosome so they tend not to differ. Hence the latter 3 scenarios in the above table are rare, but nonetheless possible.

We can see how two blue eyed parents could produce a brown eyed child - if Science Dad is BB bb and Science Mum is bb BB then they are both blue-eyed. However, Science Baby, taking a gene from each, would be Bb Bb, i.e. brown-eyed.

Obviously the chances of Science Mum and Science Dad both having these rare genes is very unlikely. We might still need those lawyers after all...

Lookalikes

Can we really see the features of parents in little babies?

Genetically it makes sense that babies look a bit like their parents - they do, after all, share 50% of their genome wity each parent. Eye colour, nose shape, etc, are going to be obvious indicators. It makes evolutionary sense, too: in the days before paternity testing, it may have been necessary to convince a father that the child was indeed his and therfore worthy of his time, effort and resources.

A quick survey of the panel of old wives reminds us of these common phrases:
"He looks just like his dad."
"She's got your eyes."

Science Dad is sceptical. Whenever I hear these phrases applied to a child in front of me,  I often don't agree, and wonder if it's just something people say to makeconversation, alleviate potential concerns of dubious paternity, or at least to strengthen the parent/child bond. I'm more inclined to believe the null hypothesis:
"All babies look more or less the same"

Science Mum is adamant she can identify these features. An experiment is needed!

I scanned through my facebook friends (only the ones that my wife hasn't met) looking for pictures of mums, dads and babies. I found 4 good candidates (4 mothers, 3 fathers, 4 babies), with a handful of pictures for each person to avoid too much repetition. I then coded up a little survey and tested her.

It looked a bit like this (I've blurred it to protect identities):

The answer was the left option 25% of the time, the right option 25% of the time, and the middle option ("neither") 50% of the time.

Science Mum picked the correct option 68% of the time - much better than as if by chance. That said, she hadn't twigged that there were only 4 children - she thought there were a lot more! Her comparison was therefore on features alone, she hadn't recognised the children.

I tweaked the survey to see if she could match each parent to one of the four children. It looked more like this:

This time she got the right answer 75% of the time.

She was quickly identifying the children using subjective criteria: "plain one", "better looking one" etc. She had failed to do this in the previous version of the experiment, but now seeing the children side by side she was able to build quite a reliable face recognition index. Soon it didn't matter which of the photos of the child were used, she could tell them all apart easily (much better than I was able to do). Matching to the parents was then a matter of comparing obvious features such as nose shape, hair colour etc. Two of the children were easily matched to their parents, but the other two were harder because the dads looked similar.

The conclusion: Science Mum did better than Science Dad had expected. She's clearly superior at face recognition, which perhaps gives her a more extensive feature set for making comparisons between faces. Nevertheless she wasn't getting 100% accuracy, so Science Dad reckons he's still won the argument.

The Afterbirth

Placenta. Is it delicious? Is it cannibalism? Is it good for you?

Science Mum and I decided we'd eat it. We'd taken a big tupperware into the hospital deliberately, and a few days after the birth we decided we were ready to try it.

A placenta. Looks pretty horrible, but tastes great!

Firstly, let's be clear that there is probably no good scientific reason to eat it. Science Mum has a very healthy diet, rich in iron and protein as well as all other essential food groups, vitamins and minerals. Although packed with goodness, the placenta would not offer any significant nutritional benefits.

All this nonsense about drying it out and supplementing your diet with placenta in capsule form is surely pointless. And definitely not nearly as fun.

However, it seems like a waste not to eat it. It's free, it's got a very low carbon footprint and it's free range (not organic though). All other mammals eat theirs, so why not humans?

It was actually delicious, even our vegetarian friends ate some. A lot of people asked us:

• "Was it like liver?",
• "Was it chewy and gristly?",
• "Did it have a strong taste?"

The answer to all of these questions was no. Due to the high blood content, it had a consistency more like black-pudding than liver. It didn't have a strong smell or taste, and was actually remarkably succulent and tender.

Here are some of the recipes we tried...

Pan-fried Placenta

Ingredients Placenta Flour Butter Soy sauce Onion Garlic Bacon Mushrooms Parsley

Method Soften the onions by cooking oh so slowly in a heavy-based frying pan. Cut the placenta into little chunks and coat with flour (it keeps the juices in and avoids it going dry). Cut the bacon into little pieces. Turn up the heat, add a little more oil and fry the placenta with the softened onions and bacon, adding a splash of soy sauce for extra flavour if desired. Add the butter and garlic when the meat has gone crispy, wait until the garlic has softened, then add the mushrooms. Sprinkle with parsley to serve.

Placenta Pate

Ingredients Placenta Butter Onion Garlic

Method Sterilise the blender and ramekins that you are going to store the pate in - hygiene is essential. Soften the onions by cooking oh so slowly in a heavy-based frying pan. Cut the placenta into little chunks, season and and fry gently with the onions. In a separate pan, melt some butter. When the meat has cooked through, blend it all to a smooth paste, adding the melted butter to achieve your preferred consistency. Pour into the ramekins and top with more melted butter to keep any germs out. Refrigerate until set.

The Birth

A warning to all dads out there - no matter how prepared you think you are, you'll never be ready for your first experience of childbirth.

Maybe this youtube video will help:

The mother's experience of childbirth gets a lot more coverage, naturally. She needs to prepare for the most painful experience of her life, so understandably gets all the attention! But the role of the birth partner should not be understated - it's an emotional journey for everyone involved...

For context, a bit about me: I consider myself a typical man - I'm not particularly squeamish (for example, I enjoy the gratuitous gore in Game of Thrones), and I'm rationally sensitive but not overly empathetic (I don't cry often, and actually quite enjoy sad films). Yet these character traits were to be challenged dramatically.

The Labour certainly was a difficult experience for us both - Science Mum was (of course) absolutely amazing. It must have taken tremendous amounts of focus and inner strength to overcome the pain over a gruelling 60 hour Labour.

For Science Dad, the challenges weren't physical (I actually think I cope with those better) - they were emotional and psychological. There were probably about 1200 contractions from start to finish, and I quickly ran out of creative ways to keep relaxed and positive through each one. The motivational cliches soon become irritating, especially when no progress is apparent. Add to that the vomiting, the screaming, 3 days without sleep. I honestly can't remember how we got through it.

More than that, it was simply unbearable to see Science Mum in pain. I never realised how much it would affect me. It was certainly far easier to watch the business end being stretched beyond recognition than look her in the eye during the contractions. In my front-row seat, I could see the progress, but it was incredibly slow and gradual with each contraction (maybe a millimetre every 5 minutes, and sometimes the progress seemed to be reversing). After 3 days the end still seemed far away. When I looked at Science Mum, I could see the hope in her eyes: hope that it would soon be over, that she was going to make it after all, that soon she would be holding Science Baby. Seeing her like this brought to my eyes. She was utterly exhausted, and she had no idea what how it was progressing - but she kept on pushing with all her might. All I could do was wipe my tears and smile back at her. I was so proud!

Eventually, Science Baby was born. Healthy, happy, and absolutely beautiful.

To all dads out there - there's really nothing that can prepare you for the experience. An emotional rollercoaster with highs and lows greater than any you've ever felt, and moments that you'll never forget like seeing your baby's face for the first the, except it's dangling out of a teeny tiny hole and taking it's first ever breaths and with a furrowed brow that's saying "wtf was that?! put me back in!"

A few days after the birth I was up at 3am watching Chitty Chitty Bang Bang with my nocturnal daughter. And I cried.

Boy or Girl?

We're keeping the sex of Science Baby a surprise. But what's the most likely outcome?

First, Science Dad asked the panel of "old wives".

• Dangling a pendant over the bump didn't seem to be a very robust indicator, and probably more likely a measure of Coriolis than conception. 
• Carrying low is presumably just a matter of orientation, not ovulation. 
• Cravings for salty versus sweet food certainly just dietary, and definitely not a factor in due-datery.

Old wives, you are full of lies! See a full list here.

I don't think the 'Mayan gender predictor' (here) is any more credible.

Ok, then what does Science say?

Science Mum (like all women) has two X chromosomes. Her eggs contains half of her genes, and so her eggs all contain an X chromosome. Science Dad (like all men) has both an X and a Y chromosome. Half of his sperm are X and the other half Y.

(from here)

Therefore, whether Science Baby is a boy or a girl comes down to which of Science Dad's sperm meets Science Mum's egg. Half of his sperm are "female" (X) and the other half "male" (Y) and when combined with the egg will produce a cell with two X chromosomes, or an X and Y respectively.

What conditions might increase the likelihood of the male sperm fertilising the egg rather than the female sperm?

• Male sperm move faster but don't survive as long as female sperm. A boy is more likely if you conceive close to when you ovulate.
• Therefore regular attempts to conceive will increase the chance of it being a boy.
• For couples who live together, 51.5 per cent of births are male.
• The longer you are married, the more likely it will be a girl (no prizes for guessing why).

• Male sperm and embryos are more 'fragile', and so are statistically less likely to survive.
• More boys are conceived in early summer, and more girls in winter. perhaps due to increased level of illness in winter.
• More girls are born in the tropics than anywhere else in the world. perhaps due to high temperatures burning dad's balls, or maybe due to the effects of melatonin on reproduction.
• The average calorie intake for women who had boys was 2,413. The average calorie intake for women who had girls was 2,283. Does this mean women need to be more nourished in order for a boy to survive?

• Mother's high stress levels lead to increases in both testosterone and cortisol, which leads to changes in the egg that makes it easier for male sperm to penetrate.
• More boys are born at times of stress (such as after a war).

• Severe pregnancy sickness is linked to female babies, due to high levels of oestrogen.

Check out this predictor on the babycentre. In reality, these factors probably tip the bias in favour of a boy or a girl by only a few percent. Unless you are planning to have hundreds of children, it probably won't be of much use when deciding what colour to paint the nursery*.

*although Science Dad doesn't believe nursery colour should reflect what sex organs the baby has. This is just a turn of phrase. 

Due Date Bingo

Has Science Dad got time for a quick holiday before Science Baby arrives?

The clock is ticking, Science Mum is approaching 35 weeks pregnant and (of course) glowing! Meanwhile, it's ski season, and the lads are packing for a week of alpine fun and apres-ski. It will probably be my last chance to ski for a long long time, should I join them?

First, let's ask the panel of "old-wives". The result: a resounding: "The first child is usually late". According to this article, first children are indeed less likely to be on time, but are in fact more likely to be early. Sorry, old wives, you got it wrong.

It's not a new question. A cursory google-image search reveals the weekly probabilities from Minnesota:

And a daily view from whattoexpect.com

The UK Office for National Statistics (ONS) suggests that about 5-7% of babies are born between 32-36 weeks (depending on ethnicity).

So, what's the probability of Science Baby arriving in the 35th week? Reading directly from the Minnesota graph, it's 2%. From the daily graph, adding the probabilities from 42 to 35 days early gives a number less than 1.5%. I also calculate 1.5% when dividing the ONS data into 4 equal weeks.

OK, a 1.5% chance is pretty slim. Probably worth the gamble, right?