“Out of the veeery long reading I did today, the bottomline of what I learned is this: Intelligence is highly heritable, and personality is moderately heritable,” I declared as I sat down for dinner with my mother earlier this evening.
I had just finished reading two chapters on genetics and hereditary influences on human development, in preparation for a report I’m set to do for a class in graduate school. While my mother and I ate dinner, I proceeded to expound on my introductory statement (which, by the way, was an unforgivably grave oversimplification of the matter), and shared what I found interesting about the topic.
Regarding the heritability of intelligence, I talked about how numerous research studies found that identical twins (who are 100% genetically alike) show a higher correlation score than fraternal twins (who are only 50% genetically alike) on IQ tests—strong proof that genes play an important role in determining intelligence. On the heritability of personality, I shared that certain personality traits such as introversion/extraversion and empathic concern have also been found by studies to be reasonably heritable attributes.
Research findings in genetics are relevant in the long-standing issue of Nature vs. Nurture, which itself has evolved in its focus over the years. From a question of whether it is genes (nature) or environment (nurture) that is wholly and solely responsible for how an individual turns out to be, the question has changed to how much of each weighs in on how the person turns out. In other words, how do we untangle the influence of genes versus the influence of environment on such complex human attributes as intelligence, temperament, and personality? Still more recent developments in the matter has led some to question not how much of an attribute is genetic or how much of it is environmentally influenced, but to how genes and environment interact to make an individual what or how he is.
As much as I would like to be able to launch a full-length scientific essay on this matter — to be fair with you who might’ve stumbled upon this post in the hope of also finding out answers for your report in Psych class — I should reveal as early as now that the length of this post is not going to be so.
Save for the next few lines and a block quote from a textbook, the rest of this post is going to be an entirely non-scientific and much more personal sharing that stemmed from my mother and I’s conversation earlier during dinner. Now, regarding the Nature vs. Nurture controversy, I’ll leave the scientific discussion of it at saying that I believe Curt Stern’s “rubber band” hypothesis to be true, especially on the matter of the heritability of intelligence. Here’s a summary of Stern’s argument:
“The genetic endowment with respect to any one trait can be compared to a rubber band, and the trait itself to the length which the rubber band assumes when it is stretched by [environmental] forces. Different people may initially have been given different lengths of unstretched [genetic] endowment, but the natural forces of the environment may have stretched their expression to equal lengths, or led to differences in attained length sometimes corresponding in their innate differences, and at other times in reverse of [these innate predispositions] (Stern, 1956, p.56).”
While I did share the rubber band hypothesis with my mother, our ensuing conversation on genetics and developmental psychology took less of an intellectual and more of an emotional turn when she touched on the subject of a woman I know only as “Lola Rosie” (I don’t even know if that’s the proper way to spell her name).
Lola Rosie was my grandmother in the paternal side. She died when I was just 3 years old, and all I know of her were born only out of stories my mother used to tell me about her. My mother had often shared with me how fond Lola Rosie was of me as a baby, how she would teach me a game of cards even when I was just a toddler, and how she’d take me out with her to stroll along at parks and other places. My mother had also often cited how intelligent Lola Rosie was, sharing how Lola Rosie would, due to financial constraints, manage to attend only a day of class per week, and yet still graduate every year level at the top of her class. She remembers Lola Rosie as a good-natured, always-smiling kind of woman who never had a bad thing to say about anyone, even when she lived a life of hardship, poverty, and trials.
My mother said that just this Christmas Eve’s, she was tearing up a little as Lola Rosie’s memory filled her thoughts. She said she recognized how much I grew up to be like Lola Rosie, not only in the way I look, but even in the way I am— always with great self-control, with “maturity and refinement,” calm, and not given to acting impulsively. In linking back to our original topic of conversation, she said I must’ve inherited such attributes from my Lola Rosie, in support (intuitively, if not scientifically) of the notion on the moderate heritability of personality traits.
When I was a child, people would always remark how I looked very much like my father — something which I deeply and overtly detested because I’ve always been a “mama’s girl” and wanted to look more like my mother than my father. I’ve never been close to my father, and frankly, for most of my life I didn’t want to have anything to do with him.
But as I grew older, I recognized that my facial features did resemble more of my father than those of my mother, and I had grown to accept it with a sort of resigned indifference, given the visible evidence. But tonight, for me, came a deeper form of acceptance of the other half of my genetic ancestry. Out of our conversation on genetics detouring to our own family tree and Lola Rosie, I came to recognize how I cannot depart from the paternal side of my being, and how much I still am a representation and continuation of the generations past in my ancestry, whether by virtue of the genes I carry, the way I look, the way I behave, the way I am, and the way I will be.
I’m really not the emotional type, but I couldn’t stop my tears from falling when I heard the final part of my mother’s story on Lola Rosie. My mother said that when Lola Rosie was lying on her deathbed, at the early age of 49 robbed of health by uterine cancer, one of the last things she struggled to whisper was, “Gusto ko makita si Carla” (“I want to see Carla”). I was just 3 years old then, and living in our home province while she was in a hospital in Manila, so we were not granted that opportunity to be together again at the final moments of her short life.
During that time, I could not have been aware of the situation, but now that I know of it, I cry. I cry of mourning for the woman I have grown up to be so similar to yet have no personal memories of, for the woman who must’ve so fondly looked at me so many times yet I couldn’t remember smiling up at even for a single moment.
Seeing my tears, my mother said, “Don’t cry for your Lola Rosie. I’m sure she was welcomed in a good place, in Heaven.”
Indeed. I’m sure of that, too. 🙂
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This is for you, Lola Rosie. May you rest in peace, dear grandma; you are fondly remembered. My mother says that if she could choose a mother-in-law all over again, she’d still choose you. I will strive to be a better person, so that in this lifetime I may embody even just half of the good person that you were, and so I may be worthy of being called your granddaughter. ♥
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