So here you have it, infant development in three easy-to-understand stages.
Months 0-3: The Alien Phase
Congratulations! You just welcomed a small, strange creature into your life. This little alien has absolutely no way to communicate with you except to scream and cry whenever it needs something. It's up to you to decipher the screams and not lose your sanity in the process.
The little alien doesn't like to sleep on a schedule, wants to eat at all hours of the night, and frequently will poop, pee, and spit-up on you. Without care to what you are wearing or if you are trying to get out of the door without having to change your outfit for the third time. And you are expected to handle this with grace and class, even though you are thinking to yourself, "If anyone else in my life pooped or peed on me, I would terminate the relationship." You don't get a lot back during this phase, but the good news is that when the little alien is sleeping, he/she looks angelic and snuggly, making you forgive them for the last time they puked on you.
During this phase, your life is going to be ruled by one word: SLEEP. Because you are not getting enough of it. Moms-to-be may dismiss this with a quick hand wave ("I went to college...I know what it's like to pull an all-nighter") when in reality, it's like pulling an all-nighter for TWO MONTHS straight. I think they intentionally make baby bath products smell good so you can at least snuggle up to your baby and breathe in their smell without packing up your car and joining the witness protection program. Your emotional brain loves your baby, but your logical brain is asking, "Um...when does this get better?"
Months 4-6: The Blob Phase
Good news! That small little alien you welcomed into your life several months ago is growing. And growing, and growing, and growing. And with that growth means better sleep, for both you and the little alien. Best of all, the alien finally stopped its futile protest to re-enter the womb and has finally accepted his lot in life: to live in this world as a small blob. Because during this time, your baby doesn't do much.
You don't really care that your baby doesn't do much; you are just so excited to get more than 4 hours of sleep (in a row) at night that you high-five random strangers on the street. You whistle in the morning out of sheer joy that REM sleep has returned and the bags under your eyes are finally starting to go away. During this time, you might also seriously consider rejoining the human race. Because you finally have time to shower, put make-up on, and be pleasant to other people (i.e. when others ask how you are doing, you are able to use an indoor voice, instead of scream, "I AM SO TIRED!!".)
Baby development, however, is kind of stalled at this time. They are not really sitting up, so its hard to play with toys. They don't really acknowledge other babies, so playdates are also tough. They are still eating their very weird diet of breastmilk and/or formula, so its not like they can join you for a meal. Most of the time, they are happy to bounce in a jumperoo and cram their chubby legs into a Bumbo seat. Now is a very good time for you to get your hair highlighted, make a nice meal for your husband (to make up for the last three months of constant whining about how tired you are), and perhaps check your email. Welcome back, Mom.
Months 7-12: The Puppy Stage
And finally, the golden age of infant development. Your baby is not quite human yet and reached that moment I like to call 'the dawn of consciousness,' but they are awfully cute and fun to interact with. You can teach them tricks at this age ("high five!"). You can feed them table scraps and they bounce up and down with excitement. People stop you when you are out walking to comment on how adorable your 'puppy' is and you never, ever leave the house without a poopy bag (aka the Diaper Bag.)
The downside of this stage? The mess. Like any good puppy, they are into everything. Nothing in your home is sacred. Just this past weekend, I skyped with my parents and sister (who is in IN visiting), and in the 10 minutes baby Ben was on camera, he managed to sit still for 2 minutes (only because he was pooping in his diaper), scuttle onto the carpet, avert my mother's arms and head straight for the coffee table, wedge himself into the coffee table and start chewing on the electrical cords. It was like watching a small, very determined tornado in action. I half expected him to put a hole in the drywall or knock down the desk, but my mom and sister were right there to stop him in his path of destruction.
So yes, while you will lavish in the praise of others who think your baby is adorable, your house will also never be the same. They will make a mess on your carpet, eat your houseplants, and lick anything that comes their way. But at this point, they are sleeping so you could really care less.
There you have it. Put down those silly baby books and just use my easy three-phase system. And be sure to get some sleep!