Heredity/Evolution English
등록일 : 2018-04-11 14:09 | 최종 승인 : 2018-04-11 14:09
Cedric Dent

[리서치페이퍼=Cedric Dent 기자] One of the biggest fears most common to expecting parents is that they will unwittingly ruin their children as people in some way. No one wants to raise a sociopath or stunt a child's ability to mature into a well-adjusted adult, so it's common to spend lots of time during the pregnancy worrying about how to parent the child with respect to any of a variety of issues. Research shows, of course, that genetics determines far more of who a child will grow up to be than we used to think, and as we learn more and more about just how much this is the case, it's beginning to beg the question: does parenting have a meaningful effect?

Daniel Engber, a family writer for Slate, suggests that parenting doesn't matter much as long as you don't deviate from the ways in which you're likely to parent. This can seem like an almost teleological statement, but he backs it up with scientific research. On the other hand, though, there are a lot of personality traits that are influenced by hidden forces other than genetics, which suggests that parenting could still play every bit as large a role as you're inclined to think in the first place. Those same forces can be so random that they may also serve as a reason why parenting, once again, seems to become insignificant.

Everyone can agree that a child can't just simply be left to his or her own devices, but the development of a child's personality is an incredibly complex phenomenon that no one fully understands yet. Recent research suggests that there are other biological aspects in addition to genetics that factor into it as well, further complicating the issue. These factors range anywhere from the microbes in a kid's gut to hormones or a child's immune system, and the research on any one of those as contributors to a personality's maturation is voluminous at this point, believe it or not.

Two traits that parents fear for the children to have or not have to varying extents, for example, are neuroticism and conscientiousness, and think about the ramifications of determining that these things, which factor greatly into physical and mental health, might be the products of biological factors that no one — not parents, not pediatricians, not therapists, not teachers — takes into consideration. Gordon Allport is viewed as one of the founding fathers of personality psychology in the US, and in 1961, he wrote that believed "sometime in the distant future, well-proven facts concerning personality will be found to interlock with well-proven facts of human biology." Those correlations are slowly but surely being made today.

Cortisol is a hormone that we release when we're stressed, and there's a preponderance of old research attempting in vain to correlate it with personality. Those studies largely relied on saliva swabs, though, which is now understood to be the wrong method for testing cortisol's area of effect since a person's cortisol levels fluctuate pretty wildly in any 24-hour period. A study published late last year, in contrast, circumvented that obstacle by analyzing cortisol in people's hair; the study's cohort consisted of a whopping 2,000 subjects who also completed surveys. The three centimeters of hair they took from each volunteer served as documentation for cortisol levels for the past three months like rings in a tree might show all the events endured by said tree as of late.

Participants' conscientiousness scores on the survey correlated with their cortisol observed levels, and inherently, this suggests that conscientiousness tends to go with a relative lack of stress compared to other people. Another study similarly found that neuroticism correlates rather bizarrely with the microbacterial content of one's gut. Once again, it's significant because neuroticism is a trait that encompasses how prone people are to hostility, anger, worry and low moods. This study was also published last year, and the research team reached their findings based on DNA extrapolated from 672 fecal samples matched to survey answers from the participants who volunteered their stool.

Slate's Daniel Engber touts what he calls the "weird-shit rule." Obviously, there's nothing official about it, but it does have an academic basis to its underlying rationale. "When behavioral geneticists study pairs of fraternal and identical twins, including those who grew up together or separately, and measure how they differ as adults, they tend to find very little impact from what they call the siblings' 'shared environment,'" Engber explains, defining that shared environment as "the set of factors that includes whatever aspects of their lives those kids might have in common if they lived together: things like their neighborhood or school, or their parents' personalities, social class, and strategies for raising children."

Engber essentially poses the question on that basis: "what does affect a child's future?" He cites about 3,000 published studies on twins conducted between 1958 and 2012 that ultimately point to the idea that DNA is the strongest determinant of the personality a child will mature into as an adult. He backs them up with The Nurture Assumption, a book written by the well-known psychologist, Judith Rich Harris. In essence, the consensus isn't much of a consensus, but the science suggests that parents change and kids don't; ergo, much of the change in children from the perception of adults isn't what it seems.

More importantly, parenting is not what's causing children to become the people they're gradually becoming, especially considering how close they are to being those people from the earliest of ages. This feeds what Engber says is a thriving philosophy of parenting in academic circles these days that suggests kids will be who they'll be so long as parents don't do anything too weird to throw them off the path to their ideal maturation.

[researchpaper 리서치페이퍼=Cedric Dent 기자]

[리서치페이퍼=Cedric Dent 기자]
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