The book: "What's going on in there? How the brain and mind develop in the first five years of life" by Lise Eliot.
This took a few weeks to get through! It's not something to rush if you really want to absorb everything. The book cites something like 450 medical & child development studies... that's a bit more than your typical parenting bestseller. As academic as it is sometimes though it's totally worth it. The author is a research neuroscience and mother of three, who clearly dove deeply into the topic out of motivation to understand & make her own kids smarter. Turns out there's not a TON of stuff you can do to make your child a super-genius.
The "first five years of life" bit is a little misleading because the book is mostly devoted to earlier development. It goes deep into fetal brain development, how brain tissues and neurons are organized. I got to feeling weird during some of these parts, like I'm just a collection of cells & electrical pulses (well okay, I am). When newborn Josie smiled in her sleep, I used to imagine she was remembering the wonderful things she'd learned that day. But it turns out babies just have a lot of extra synapse connections, and the part of the brain controlling facial gestures is located close to the part that controls REM sleep.
Anyway, all those extra connections need to sort out which path works best for our world, and that's where the development starts. Adaptation is based on the input. So development is all about getting information into the brain. Colorful toys give babies something to look at, hearing people talk is something to listen to. Being bounced around provides input about balance and motion. Everything a baby detects with his senses helps tune his brain to our world. We gain a lot. We also lose some things... for instance newborns can tell the difference between vowel sounds in different European languages, but once we're tuned into English for a few months that ability goes away.
Actual intelligence is really hard to measure. IQ often doesn't predict whether a child will be successful in school (or life), there are different types of IQ. And it's very hard to detect whether an infant or small child is "smart" because their most notable achievements are in the form of motor skills. Motor skills have no relation to intelligence later in life.
The book goes into a lot of details about how the male and female brain are different. They definitely have differences that start very early in life, but what isn't clear is how much we then accentuate and divide boys and girls up by our behavior. Fathers tend to toss their sons around more, is that why boys are more adventurous? Caretakers praise little girls for playing nice with dolls, is that why they prefer dolls?
The last chapter of the book is the best take-home bit if you don't have much time to read, it's all about stuff to do to make your kid smart.
For instance, you can help kids recall events by helping with their narrative skills... tell them stories, and when they tell you stories ask them for the "who what where when how why" so they understand how to "place" and organize memories.
You can help kids with language & pronunciation by talking a lot so they have good examples of how language works. You should not correct them too often or force them to repeat words, it's discouraging. Also, preschools shouldn't be too academic or "pushy", it should be a creative place to get them to love learning.
For a while researchers thought deaf parents' babies would benefit from having a TV left on so they'd hear language. It didn't work. Babies learn through interactivity and how things relate to their world, they need someone to react to them and focus their attention on real-world objects. If anything, learning sign language from your deaf parents is really a better pathway into the language lobes of your brain. There's a critical period for learning language. If babies themselves are deaf, it's incredibly important that it's diagnosed early so they can start experiencing sign language... deaf babies even "babble" with their fingers. I wondered why Josie got a hearing test in the hospital the day after she was born, but I guess it's not all that easy to tell when a baby is deaf.
There's been lots of research done on whether babies suffer when parents go to work and leave them with other caretakers. The conclusion so far is that a really good daycare can be as good or better than a mom at home. A bad daycare is definitely much worse. In fact there's a lot of support for the idea that early childcare needs to be a public matter, the early years are so important for development that society would benefit tremendously if we weren't shipping our babies to whatever cheap babysitter we could afford, resulting in 12:1 adult-child ratios and daycares being run by people who've never actually studied child development.
Variety and new experiences are important. Toys are very important, especially new toys, but for a toy to be "new" to a baby's brain you can just take it away for a few weeks and re-introduce it, or move it to another room so it's in an unfamiliar setting when they see it.
Breastfeeding = 8 bonus IQ points.
Anyway I could go on but the real conclusion I got was as long as you pay lots of attention to your baby, she'll grow up smart. And it supports my "billboard theory" of parenting techniques. What I mean is, there used to be this billboard in town that said pregnant women shouldn't smoke or drink. We KNOW that smoking and drinking during pregnancy leads to unhealthy babies, we're certain of it, and society has taken up that flag and advertised it as much as possible. So if something is really important for me to know, it'll be obvious, I can't miss it, the word will get out. Reading every little magazine article about what you should do or avoid or be afraid of is pointless... it changes too much. Today a pregnant woman might have to listen to classical music and avoid the wrong facial soap, next week it'll say to avoid avocados and listen to relaxation tapes, who know. So just pay attention to the big stuff. The book even says that being stressed out while pregnant is a lot worse than anything the random little articles of the week are cautioning against. Love your kid, set good expectations, they'll all be cool.