Developmental Psychology
Think about a cluster of cells that will eventually become a human baby. Perhaps even you.
Now, think of a cluster of cells that will eventually become a sea sponge.
"I'm pretty sure I'm the one on the left. Probably," you say. Both beings start life as single cell organisms that eventually multiply a bazillion times and grow into more complex ones, capable of feeding, reproducing and paying taxes (or at least one species can do that, albeit begrudgingly).
Why don't human babies look like sea sponge babies? To their mothers, they are equally cute. What makes a person develop? Genes are the force, of course. Slight differences in the code behind how we replicate at a very early age make all the difference.
Genetic differentiation applies to physical things: Why does Michael Phelps look like a ripped dolphin in the water whereas Ben Roethlisberger sinks like a stone?
Genetic differentiation applies to intellectual things as well: Why does Abel "get it" in math whereas Baker takes an hour just to do one page—some people are simply smarter than others. Look at the parents and grandparents—odds are good that you'll find a pattern.
Genetic differentiation applies to a host of other things as well: emotional makeup, desire, focus, and so on. Much of this is deep space in the cranium of exploration. Like you, we're still learning.
Study Break
"I was born with an adult head and a tiny body. Like a 'Peanuts' character." – Jon Stewart
Research Methods
Because developmental psychology is an area of interest and debate which stimulates high emotions, even anger in various corners of study, there is quite a bit of research on the subject. To get a flavor for how emotions can run high, Google (or we guess Bing these days) The Bell Curve and read the hate mail that the author received after writing it.
He mapped the evolution of domesticated pets and noted how much humans by forcing "selective breeding" were able to control the attitudes of the animals. Modern house dogs were bred to be submissive and follow their leaders. There was little controversy over this element of the book. The author then went on to explain how other forces like religious practice, slavery and social mores went on to shape the same "optimal" outcomes in races and ethnicities today. This is not a book we Shmoop—but it's a book that engendered so much debate, its precepts are likely worth your 15 minutes' perusal.
On the less controversial path, consider the key two manners in which we study people of different age groups. There are two main ways to conduct a study: longitudinal or cross-sectional.
Longitudinal Study
These studies follow the same person or the same group of people over many years. (An awesome PBS series called The 7 Ups ran for 42 years and followed a dozen kids, making a video documentary of their lives every 7 years—it's still running and is absolutely worth the gigs of download time on YouTube or wherever you can find it.)
We could study hair color preferences over a woman's life. Enroll her when she is twelve years old and has virginal locks of her natural blond shade. Five years later, check in on her and she reports she has dyed her hair green after a stint as a redhead. Another five years go by, and she has decided that being a brunette is the way to go. She finally returns to blond at the age of thirty before going white at fifty-five. What makes it "longitudinal" is that we are studying her as a single long study—how does she change intrinsically? The process takes a long time.
The same methodology can be used for any study where time matters, such as progression or remission of disease or even an improving sports team: Read Moneyball for details—it's a great book, but you already know that we at Shmoop love our sports.
