The Cat in the Hat in the Amniotic Sac: What Can Sucking Tell Us About Hearing?

 What's with the feline in the millinery?  As with yesterday's post, try not to shoot the blogger if you've already heard this one. It's an old study (early 80's - never mind that I can remember the time...just barely I'll have you know), but the media has gone wild with it ever since it first came out. I just could NOT think of a week of posting on methods in infant research without mentioning it. What about that title? Gotta love it!

This study used sucking to shed light on prenatal hearing.In earlier work, the researches had determined that very young infants would adjust their sucking rate to be rewarded with hearing their mothers voice (I bet this doesn't happen in the teenage years...but I digress...). Mothers read The Cat in the Hat Story or another one of two other stories to their unborn fetuses, 2x per day for the last 6 weeks or so of pregnancy. Soon after birth, the researchers measured infant sucking when they heard the story they heard prenatally vs. one of the other stories. What happened? The newborns worked hard (sucked faster or slower) to hear the story they heard in the womb - moreso than to hear the other story. By playing with this method a bit more, later work showed that it was the rhythm of the story and not the words that the babies were responding to. BTW, the babies also worked harder to hear mom do the reading over some other female voice reading the same story. This study was a real landmark in establishing at least a couple of things: 1). the state of development of hearing in the womb and 2). how the prenatal environment helps tweek perception. 

If you're now thinking "Wow, amazing how far these researchers will go", consider this: in another (now old) study a pregnant woman was asked to swallow a tiny microphone so that researchers could gain a better sense of just exactly what the baby can hear in there. Can you imagine it? "It's in the name of science ma'am. Please just please swallow the technology." 

So I'm on a roll now. Here's another interesting way that researchers have used sucking. The main question was whether information taken in through one sense (e.g. sight) is stored in such a way that it can be accessed through other senses (e.g. touch). The technical term is cross-modal or inter-modal perception. In one study, 1-month old babies were allowed to suck on either a smooth or a bumpy pacifier - but they were NOT allowed to see it. The babies were then shown two simultaneous pics, one of the smooth pacifier and one of the bumpy one. And guess what? They looked longer at the one they had sucked on but NEVER SAW, as though they recognized it. So what they had taken in through sucking or touch was stored in a more general way, a way that was accessible through another sense, sight.  

Finally, I wanted to briefly mention the use of "geodesic nets" - think "hairnets with sensors" that provide real-time information on the patterns of brain activity as the brain processes something e.g. a picture, a sound, an event etc. The baby wears a get-up like the one shown here. 
It's not painful at all and many babies are surprisingly co-operative about the whole experience. For more on geodesic nets and language studies, put in user friendly terms, try here.

Phew. It's been a whirlwind tour through infant research this week. Now seems like a good time to ask how this stuff is all working out for you. Too technical? Nerdy? Boring? Less on studies, more on parenting connections?  It would be great to hear some feedback. I hope that even if the details were too much or we covered too much ground that you might have gained a new respect for that bundle of sweet-smelling, soft, cuddly goodness. That's one amazing brain growing in there!

--Tracy

Comments

[Sheila]

I for one think this is all very interesting but then I'm the nerd who tried (and failed) to replicate the perseverating experiment with my own baby. :) By the way, I eventually tried it again with more familiar toys and it worked.

[Judy B]

I'm loving the nerdy science stuff! I loved the sleep stuff to, so keep including that.

I guess I'd ask you to add how we can include/benefit from the science in our everyday lives.

[Tracy]

@Sheila
Hooray for nerds. Darn it, we can make good parents too! Great that you persevered with the perseverating task (I take it you mean the A not B thing). Really brings it home when you see your own child do these things doesn't it? Thanks for comment.

@Judy B
Some studies yield findings that are somewhat removed from everyday child-rearing. The benefit to parenting may then be more indirect, just something to have at the back of your mind when you are trying to find ways to handle a new behaviour, think about your child's reactions etc. But point taken that where the results are more readily applicable to parenting, we'll try to draw them out more.
Thanks for the input. Really helps.

[Miranda]

Keep it coming, the more I learn the more I'm lovin this baby of mine. (and I'm a die-hard, terrified of infants gal from WAY back) Knowing how they thing, and perceive situations helps so much during the day to day stuff. Thanks. Now, if only I could get my darling 6 month old to sleep more than 2 hours at a time. ;)

[fahmi]

I've been loving the studies, both as understanding what's going on with my kids, as well as coming up with more ideas on things to try. I tried the 15-minutes delayed gratification on my husband. *He* failed. Next step, my son!

I'd heard about the sucking studies before, but the hearing one was interesting and new.

Also, in case I haven't said, I love the new site design.

[Tracy]

@Miranda
Great, thanks for the feedback. You probably already know that there is a ton of great stuff on sleep on this site. Hopefully, you're finding it useful. As a mom who spent the first 6 months walking her child 4 hours a day (2 hours in the morning, 2 in the afternoon - the only way he would sleep), I FEEL FOR YOU SISTER! But oh, it REALLY, TRULY does get better and just wait until you're having real, live, sensible conversations with your child. WAY, WAY worth any loss of sleep.

@Fahmi
Thanks for comment on the new site. We're very happy with it too. Probably tweak a bit more, but we're generally happy with the new look. Great to hear from you!

[Chaosgirl]

Nerd-a-licious. LOVE the detail and want more! The in-utero research might explain why my son was more easily soothed by being bounced to one particular Rufus Wainwright song over and over and over again. I became obsessed with this one tune toward the end of my pregnancy and sang it all the time in the car. Who knew that would be the dress rehearsal for the never-ending performance to come.

[Cloud]

I like the science. But I'm a geeky scientist (in a very different field).

I would find a post about how to best encourage early development helpful. I'm home with my second baby now (she's 6.5 weeks old) and I find myself wondering what I'm supposed to DO with her.

I read a bunch of books before her sister was born and feel like I had a better idea of appropriate activities then. I've forgotten most of what I read, and have less time for research this time around. I know I'm supposed to talk lots and hold her lots. Anything else?

[Isabela]

@Cloud: The thing you probably forgot MOST from the first time around is how BORING babies can be sometimes. Seriously. You all know I love the little critters to death, but there really isn't a whole lot you CAN do with under 3 month olds. Which is TOTALLY fine: coo, goo, talk about what you're doing, take him outside lots, hold him, play music you like, dance with him in a sling, walk to places you enjoy, cook simple things you like and let the smells waft to him, whatever. Take care of yourself as much as possible in this early phase and take baby along for the ride. Babies just soak it all in. Yeah, there are mobiles you can put them under and mats to put them over but really... there's nothing special you NEED to do to encourage normal early development other than to be there with him close by. So my advice would be to try to do things you enjoy to which you can also bring baby along or meet up with other moms with similar-aged kids, at your place at someone else's. Personally, I found that whole period a tad mind-numbing and I was always perplexed by what to actually DO with them. Maybe some other parents could chime in with what they do with their newborns all day...

[Isabela]

OOPS, Sorry Cloud. I kept referring to the baby as "he"... I realize you have a little baby girl.

[Tracy]

@Cloud: I'm with Isabel on this one. Six and half weeks is teeny weeny. So much to see and learn by just being around you, others, going about in the world. As you mentioned, talking to your baby is very important. Since we're going down that road anyway, there's talking and then there's talking. Have a pretend conversation, let you voice go up and down just like it does in real conversation (if you just talk aloud about something in particular, this will happen naturally). Stop as you normally would to let someone else take a turn, wait a bit, then respond and so on. This gets baby familiar with the rhythm and also the rituals of communication. "What's that?" (stop...), "I know honey. But you know you can't choose your family." (hah, hah) and so on. I started reading to my son at 3 months of age - for a number of reasons but especially because I got a kick out of how transfixed he was (seriously, saucers for eyes!). Research has shown that reading to your child early on yields benefits later on. You may have to wait a few weeks in part because baby needs to be able to attend to what you are doing and they are such rolls of jelly at this age. I used the bouncy seat and sometimes lots of pillows, then just sat across from him and held up the book to face him. I also used a lot of animated speech. Try "Olivia's opposites", our first and favourite book for a long time. Who knew what worked, but something seemed to. He remains a highly interested, avid reader (That doesn't necessarily have to be the outcome, I'm just saying that it's generally good). And finally, know that reaching (for objects) and looking take some time to get co-ordinated. Seriously, pay attention to this now. See how baby swipes at stuff (when it starts) while looking elsewhere? It's like the arm has no idea what the eyes are up to. Very soon, these things come together and baby can reach for something specific in front of them. So hang a toy in front of baby- on those arches or supports that are found on some bouncy seats, the stroller and so on. And change the toy from time to time to keep it interesting. I guarantee you he or she will eventually start swiping and then one miraculous day just reach out and touch. Sweet victory. And remember, just lookin' around and hanging out with you as Isabel says is plenty of stimulation right now. Take advantage of this time to schedule activities for YOU, ones where baby can come along too. Happy mummy = happy baby.

[paola]

Keep it coming. I'm finding it all fascinating.

[Cloud]

Thanks for the reassuring comments! I think part of my problem is that baby #2 will actually let me put her down in her bouncy chair for reasonable stretches (in fact, she sometimes seems to WANT to be put down), whereas baby #1 wouldn't. So I feel guilty, because I don't feel like I'm interacting as much... and I want to try to be "fair" to baby #2. Yes, I know this is silly. I blame the hormones. Basically I blame all my silly hang ups on the hormones until I wean.

[Penny]

Thanks for the posts! This is truly fascinating - how amazing babies are.

I read a lot to #1DS as a baby but not as much since #2DD and #3DS were born. Not feeling that guilty (most days), because I have continued to sing to them constantly, both in utero and after, and intend to until they tell me to shut up :-)

I now see musicality in the older 2 (5.5 and 3), and wonder if there are any studies in this area? I would love to know if there is any science to support my gut feeling that musicality is not just inherited, it is influenced by environment, particularly mom's voice; and whether there are any links between exposure to nursery rhymes etc and literacy in toddlers/preschoolers?

Maybe I should stop commenting now. I think I've probably given you guys at least a year's worth of material.

Thank you so much for this blog!

[caramama]

I'm loving it! You guys are really doing a great job on this site.

Wish I could provide more insight, but apparently my brain development needs more sleep. ;-)

[Irene]

I love this blog, although I wonder if it needs an updated name, since it's about so much more than bed and sleep.

I think the nerdiness and the level of detail are great! How many other knowledge sources out there just say things like "studies show" or "researchers have found" or even more vaguely "it is believed" or better yet "in our expert opinion" (!!!)

[Isabela]

@Irene: Are you getting these posts through a feed or something equally vague and beyond my tech-dumb knowledge? Because we DID update the name of the blog and I sure hope that's clear to people. If you read this, please let me know if you can see the "Child of Mind: Developmental Science and Everyday Parenting" title. Much appreciated!

[Carmen]

I love these posts: not too nerdy, not too technical (in fact, as I'm a scientist I'd say not technical enough, but I do realize that's likely just me). Keep 'em coming!