The Nature-Nurture Rorscharch Test

Does nature or nurture have more of an impact on who we are?

Always an interesting topic of conversation.  Are we the way we are because of our DNA or because of the experiences we’ve acquired?  Of course, the right answer is “both,” but which one matters more?  Are our personalities more of a result of the genes we inherited or how we were raised?

Despite its ability to be an endless source of conversation, speculation and debate, the question, when phrased generally as it usually is, is meaningless.  The problem is that there’s no single measure of “us” (or “you” or “me”) and thus no linear scale to determine what variable had a larger impact.  We’re made up of many different attributes, and there’s no such thing as a meaningful composite score we can create to “measure” who we are.  Maybe my DNA strongly influences my tendency for salty foods over sweet foods, and maybe my early-stage family environment is more responsible for me being tidy.  But what weights do we attribute these different characteristics?  Does my food preference make up 0.02% of “me,” and my cleanliness make up 0.5%? There is no single data point that measures the entirety of who we are, and so in the absence of more narrow parameters, the question is invalid.

What makes the issue even more complicated is how do you determine what mattered “more” if both nature and nurture are each necessary?  If Albert Einstein was born 10,000 years ago, he’s not coming up with the theory of relativity.  Someone with a severe learning disability and an IQ of 70 isn’t coming up with it either.  In response to the generic nature-vs.-nurture question, psychologist Donald Hebb once retorted, “Which contributes more to the area of a rectangle, its length or its width?”

A nature-nurture question is only valid if both the inputs and the outputs are clearly defined.  For example, an interesting question would be, “How much narrower, if at all, would the differences in IQ be if everyone was raised in the exact same environment?”  Or, “How different would someone be if they were raised in a household in the 80th percentile of IQ/income/happiness/BMI (choose your metric of interest) versus the 20th percentile?”  A well-done Atlantic article covers the revelation that people may have different genetic predispositions to how impressionable they are to their early-stage environments: some are like tenacious dandelions who do fine in most environments and others are like fragile orchids with highly varying outcomes.

Since the simplistic nature-vs.-nurture question is logically invalid, the most interesting part about it is that it reveals someone’s default perspective on human nature — their initial bias.  A “nature” person is more likely to believe our outcomes are predetermined at birth, while a “nurture” person is more likely to believe that everyone would be good, smart people if only they had the right upbringing.  A “nature” person is more likely to being politically conservative; a “nurture” person is more likely to be liberal.

The next time you have a nature-vs.-nurture debate, specify the parameters unless you want to tip your hand.