Wednesday, May 16, 2012

The First Two Years: Cognitive Milestones

So we know about baby's growth on the outside, but let's talk more about what goes on in her head during the first two years.

When it comes to cognitive development, the first place to go is to Jean Piaget. He was the first to demonstrate through research that infants really are intelligent and gave us insight into what baby's brain. His stages of cognitive development are the basis for what we know about baby.

The first stage of cognitive development identified by Piaget is called Sensorimotor Intelligence. That means baby will explore her world and use her senses and motor skills to figure it out. This period of development lasts for her first two years and is divided into substages.

Stages one and two of sensorimotor intelligence are know as baby's Primary Circular Reactions. Primary for her first reactions and circular for the way that sensation, perception and cognition work together in a cycle. Her primary reactions mostly involve her own body.

Makes sense, doesn't it? Baby figures out herself first and then turns outward for more information. Stage one is comprised of her reflexes in the first month such as sucking, grasping, staring and listening. Stage two begins when baby is about one month old and begins to adapt; her reflexes change slightly as she learns that a pacifier and a nipple are different things, she can hang on to a bottle to suck it, and she learns that a blanket is more for hanging on than sucking.

At about four months old, she moves into her next stage. Three and four are known as Secondary Circular Reactions. From about 4 to 8 months (stage three) she'll try to make interesting events last longer. She'll shake that rattle until it drives you crazy, but lucky for you, she'll also get excited when you come over to play patty-cake. From about 8 to 12 months (stage four) she'll become more deliberate in her actions and even initiate that game of patty-cake. During these stages, usually by 8 months, baby will gain object permanence; she'll know that rattle you just took away is still around somewhere even though she can't touch, see or hear it.

Around one year of age, baby becomes what Piaget referred to as a "little scientist." Entering stages five and six - the Tertiary Circular Reactions - baby will actively experiment with her world (you may want to put a child lock on that toilet seat). Stage six starts at about 18 months. Baby continues to experiment but she thinks about it first; she'll hesitate before she tries flushing something new because last time the toilet overflowed. She's making mental combinations for the first time.

Fortunately for you (and your plumbing) these stages also mean baby is starting to play pretend. She know that her doll is a doll, but can pretend that doll is a baby and knows the difference. She also starts imitating behaviors she saw days before, so this may be a good time to kick that nasty swearing habit. This ability is called deferred imitation.

One of the shortcomings of Piaget's research lies in technology. He did most of his research in the 1920s, long before computers could helps us identify brain waves. His research was based purely on what he could see the children do. With the help of technology, we now know that before six months of age, baby perceives far more than Piaget thought. Through a study technique called habituation - repeated exposure to see when baby gets bored - and technology we can build on the foundation Piaget left us years ago. Today we can measure baby's brain activity with fMRI - functional magnetic resonance imaging. Much like an MRI, it shows us an image of inside, but the fMRI records electric activity in baby's brain. Researchers find that baby really is an avid learner. These studies are expensive, but they tell us a lot about the brain.

One theory of the brain is called information-processing theory, a model that basically suggests the brain is a biological computer. There is input, output, memory, programs, and even calculations. Using this theory, we can think of perceptions and sensations as information coming in and getting processed in the brain.

A couple of researchers - Eleanor and James Gibson - assert that perception is less than automatic, and that our environment is full of affordances, in other words, a chance to perceive and interact. They insist that each of us (baby included) choose whether to perceive a thing based on four things: sensation, motive, age, and experience. These four factors make baby quicker to recognize an affordance. She's always on the lookout for a new perception.

One experiment called the visual cliff tests the depth perception of babies. It provides the illusion of a sudden drop-off on a horizontal surface. Research shows that babies as young as 3 months old noticed the cliff, at 6 months the baby would cross it with urging from mom, and at 10 months the baby refused to cross it at all. The affordance here depends on baby's experience. A novice walker might tumble over the visual cliff anyway, fearless and reckless while an experienced walker will be much more cautious.

You'll notice right off the bat that baby loves movement. Baby's perception that focuses on movement is called dynamic perception. This is why most babies work so hard to master motor activity - motion changes the world around them. Baby especially loves her caregiver, who moves around with ease through the world. The infant perception here is called people preference - that is that baby is innately attracted to humans everywhere. We all know that baby smiles when you do, but research shows that when Mom smiles they smile twice as fast, seven times as long and much more brightly than they do for a stranger.

Memory for infants is limited because we use language to store memories. Children who have not yet learned to speak have a difficult time with recall. Ever heard a child try to tell you how things were when they were babies? It may as well be a fantasy; however, some experiments show that with reminders, repetition and motivation, baby can remember quite a few things - like how to get that mobile in her crib spinning by kicking it. Memory does improve with age: by 9 months a child can remember how to play with a toy they saw the day before and by 16 months she remembers sequences of instruction.

Language is a key to young development. Even a deaf baby will babble and if given cochlear implants will catch up quickly to her peers. By 18 months, baby knows about 50 words, and goes through what is called the naming explosion, she starts learning about 3 words per day. By 21 months she should be able to speak two-word sentences and by 24 months her sentences become more complex and most utterances are at least two words long. Baby will learn a lot from you and your motherese: the active, high-pitched and simple way you tend to speak to baby. A lot of what baby learns first depends on you and your background, but baby will begin building her grammar as soon as possible. Her grammar is evidenced by the two-word utterances such as "More juice!" Even the simple syntax shows that baby is understanding the rules of your language and working towards articulation.

While there are a number of theories regarding language learning, it is evident that baby is in a critical period for learning her first language. Children raised in the wild or without human interaction tend to end up in a bad way - like Genie, the girl who was locked in her room until she was 13. They found her in 1970 and today she lives in a mental institution for the mentally undeveloped.

Baby will be fine with interaction, play, and lots of experimentation. She will choose her affordances as she goes, so cognitively, the first two years should be a breeze.

No comments:

Post a Comment