What is smart?
First we need to define 'smart'. Most people think that intelligence is doing well at school, but that is only a teeny tiny portion of it. Studies by Howard Gardner have shown that there are actually 8 intelligences:
1. logical-mathematical (numbers, cause and effect)
2. linguistic-verbal (reading, talking)
3. spacial-visual (puzzles, drawing)
4. musical-rhythmic (instruments, clapping)
5. bodily-kinesthetic (moving, athletics, dancing)
6. interpersonal (interacting with others)
7. intrapersonal (analysing yourself)
8. naturalistic (organization, categorization)
So the real question is not "are you smart," but "how are you smart." Building an "intelligent" child should address each of these areas.
Big Brain
We have all heard that you can't grow brain cells and that is true, but studies by Dr. Marion Diamond have shown that smarter people have denser brains. This is because when you learn something a new neural connection is created. Ok, so what does that mean? Basically, your brain cell (or neurons) are connected to each other with extensions called dendrites and axon 
terminals. Learning creates more dendrites and axon terminals that connect one part of the brain to another. This is a huge idea! One can actually change the shape of their own brain by learning. "Neurons that fire together, wire together." So when someone is "smart" really they just have more connections between ideas. In turn, that means the more you learn, the easier it is to learn. You already know that though. Just think of a time you learned something. The way you learned it was to apply it to something you already new. If you didn't have any background knowledge, it was that much more difficult to learn. For example, it is easier to learn the guitar after you have already learned the piano.
terminals. Learning creates more dendrites and axon terminals that connect one part of the brain to another. This is a huge idea! One can actually change the shape of their own brain by learning. "Neurons that fire together, wire together." So when someone is "smart" really they just have more connections between ideas. In turn, that means the more you learn, the easier it is to learn. You already know that though. Just think of a time you learned something. The way you learned it was to apply it to something you already new. If you didn't have any background knowledge, it was that much more difficult to learn. For example, it is easier to learn the guitar after you have already learned the piano.Making Smarter Babies
How do you do it? Simple. Building more connections. Actually babies are born with an estimated 1000 trillion neural connections and by age ten this number will be reduced to approximately 500 trillion. This process is called pruning. Babies are wired to learn quickly, but if those don't use those neural connections, they lose them. That means exposing you little one to new sights, smells, textures, sounds, feelings, toys, locations, etc. is important in maintaining neural connections. Every new experience is a learning experience. This is a critical time in the babies development.
Do Baby Einstein DVDs Work?
Well, define "work"? It does stimulate the baby, but is that stimulation really teaching them anything? For example, it does not teach babies social interactions (interpersonal) because the TV is not (despite what they claim) interacting with your baby. Your baby might smile, but Baby Einstein doesn't care. In reality, when a baby smiles or coos, people will react and your baby learns from this interaction. What about the classical music? Well, music of all sorts will help your baby learn, but the so called "Mozart Effect" has been debunked as stated in this BBC article. More importantly, I personally do not recommend Baby Einstein because the American Academy of Pediatrics recommends that babies don't watch TV until their two. That's not to say that they can't see a little bit, but it should be limitted. There are many reasons for this. First of all, they can learn much more with real toy/parent interactions and secondly studies have shown a link between watching TV and ADHD. The TV screen is constantly changing scenes and sounds which does not develop long term attention span. Read this TIME article for more information on the negative effects of baby einstein and TV in general.
studies have shown that Baby Einstein DVDs aredetrimental to babies' language development
Baby Sign Language
Baby sign language is a powerful tool to teach language. It reinforces words both verbally and visually which makes creating neural connections that much easier. Basically, it makes learning language for the little guys easy because they can distinguish words easier with two different cues. Also, babies are more developmentally ready to make signs with their hands earlier than they have the coordination with their tongues and mouths to speak. This means babies can communicate earlier (translation: less crying). The benefits to baby are amazing. Signing babies develop a larger vocabulary earlier, they use longer sentences, have a larger IQ (by 12 points on average), and read earlier than their counterparts.
Baby signing 'more'the first sign to teach your baby
