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Nature Loves Nurture
In the spring of 2002, Psychologist Wallace Dixon published the results of a survey of 1,500 randomly selected, doctoral-level members of the Society for Research in Child Development (SRCD). He had asked the society members which studies, published since 1950, they considered "most revolutionary."In this series, psychologist Christopher Thurber - an ACA member as well as a member of SRCD - shares a summary of the top twenty most revolutionary studies. Thurber has grouped these twenty studies into six topics: (1) nature and nurture; (2) attachment and temperament; (3) language; (4) cognitive development; (5) parenting and socialization; and (6) risk and resilience.Each of the six articles, to be published consecutively for the 2003 volume of Camping Magazine, will present a digest of several studies, reflections on what made the research revolutionary, and ideas about how the findings apply to today's campers and camp professionals.
Few questions in science or the humanities have engaged and frustrated scholars more than "Why are people the way they are?" We wonder: Were we born that way? Were we injured by someone or something? Is it cultural? Did our parents raise us that way?
The three studies reviewed in this article were revolutionary in the way they advanced our thinking about hereditary influences and environmental influences on development. Or, as many of us heard the issue labeled in school - Nature Versus Nurture.
In the Nature Versus Nurture debate, there is, of course, no winner. Therefore, framing the question as one factor versus the other is misguided. For any given human trait or behavior, heredity and environment do not compete to see which will win, or which factor will emerge as the singular reason why someone is the way they are. Instead, heredity and environment interact.
For decades now, psychologists and geneticists alike have thought of heredity and environment as interactive - hence, the title of this article. Nature and nurture work together - each influencing the other at different times - to shape the way people are. Prior to the 1950s, however, most people did think in terms of Nature Versus Nurture. Psychologist Anne Anastasi helped change that.
In her 1957 presidential address to the American Psychological Association's Division of General Psychology, Anastasi challenged her colleagues to think in a new way: "Psychologists began by asking which type of factor, hereditary or environmental, is responsible for individual differences in a given trait. Later, they tried to discover how much of the variance was attributable to heredity and how much to the environment . . . a more fruitful approach is to be found in the question 'How?'"
In 1957, this was a revolutionary way of thinking. Subsequent studies, with humans and other animals, sought to answer Anastasi's challenge. Sometimes, the results were surprising.
How Do Heredity and Environment Interact?
Two other studies on the "Top 20" list offer intriguing answers to the manner in which heredity and environment interact. Research suggested that some abilities, such as facial recognition and the perception of movement, were innate. Soon after birth, maturation and learning help these abilities develop.
In 1961, developmental psychologist Robert Fantz published a summary of his research on infant form perception. At the time Fantz published this work, the scientific community agreed that very young human infants could see light, color, and movement. Fantz and his colleagues set out to learn whether newborns had an innate ability to perceive certain forms, such as faces. He and his colleagues had already shown that newborn chicks had a preference for objects shaped like seeds. (Fantz had measured the pecking frequency of newly hatched chicks who were given objects of all different shapes.)
With human newborns, Fantz measured how long they gazed at two-dimensional versus three-dimensional circles, high-contrast versus low-contrast designs, and organized drawings of faces versus scrambled patterns of similar shapes. Interestingly, newborns gazed longer at three-dimensional objects, high-contrast designs, and faces.
Fantz deduced that human babies are hard-wired to recognize visual stimuli that are important for survival and later development. But Fantz also cited studies that showed how visual perception was impaired when animals were deprived of certain visual stimuli for some period after birth.
Thus, his conclusion was: ". . . there appears to be a complex interplay of innate ability, maturation, and learning in the molding of visual behavior, operating in this manner: there is a critical age for the development of a given visual response when the visual, mental, and motor capacities are ready to be used and under normal circumstances would be used together. At that time, the animal will either show the response without experience or will learn it rapidly."
To understand Fantz's conclusion, think about this: there are some human traits that have a well understood hereditary cause. For example, the presence of an extra twenty-third chromosome causes Down's syndrome. Other conditions, such as infant lead poisoning, are purely environmental. Both conditions result in cognitive deficits, but the causes are completely different. Fantz's research was revolutionary in its suggestion that hereditary visual abilities exist at birth, but that babies need exposure to complex visual stimuli in order for these abilities to mature and develop fully. Perhaps the same would turn out to be true for other traits.
In 1965, Harvard neurophysiologists David Hubel and Torsten Wiesel took Fantz's research a step further. They wanted to know exactly which neurons in the visual cortex were responsible for our innate perceptual abilities. Of course, sticking probes in infants' brains and conducting post-mortem exams was ethically impossible. So, Hubel and Wiesel used very young kittens. (This may also seem unethical, but the findings have guided our treatment of numerous visually impaired humans.)
Hubel and Wiesel measured the electrical impulses of individual brain neurons when kittens were exposed to moving patterns on a screen located about five feet from the kittens' faces. Their revolutionary finding was that kittens had specific neurons that were activated by specific patterns. For example, one set of neurons was activated by a line on the screen that moved up and down; another set of neurons was activated by a line that moved left and right. The "hard wiring" that Fantz had hypothesized could be physically located in an animal's brain!
The most extraordinary part of this research was that different kittens' neural responses were the same, regardless of whether the kittens had spent their first open-eyed days in total darkness or in light. Hubel and Wiesel concluded that what Fantz had called "critical periods" may not be - at least for some innate abilities - as sensitive to environmental stimuli as had been believed. In other words, the neural architecture that enables animals to do some of the things they do is there at birth and easily activated without extensive prior exposure or learning.
This research by Fantz, Hubel, and Wiesel matters to anyone who works with children. These studies, and many subsequent studies, have helped answer Anastasi's challenging question about how heredity and environment interact (or do not interact) to shape different human traits. Knowing something about how heredity and environment have interacted over the course of a child's life to shape a certain behavior guides our approach with that child.
Take, for example, a noncompliant behavior. Imagine that you explain to your campers during orientation that they are not allowed in the water without the permission of an adult. On the second day of camp, you see a camper wading into the water and you shout, "Please come out of the water! General swim starts at 11:30. Until then, no campers are allowed in the water." But the camper fails to comply and continues wading into the water. What's going on? In this case, knowing something about the hereditary and environmental causes of the camper's behavior will guide your approach.
Perhaps the child was born deaf, with a congenital defect in her auditory cortex. She didn't hear your explanation at orientation, and she's not hearing your shouting now. In this case, you'll have to write or use sign language. The point is that the camper's noncompliant behavior is not intentional. In other words, she is not behaving defiantly, just ignorantly. She doesn't know better, and your approach would first be to teach her the rules in a way she can understand.
Alternatively, perhaps the child hears perfectly well, but has never experienced reasonable consequences for her misbehavior. Her parents and teachers were permissive, and the camp she went to last year allowed the campers to wade into the water without adult supervision (!). Given her environmental exposure, it's logical that she hasn't heeded the rules you explained. Naturally, your approach would be different than with the deaf child. This defiant child needs a second explanation of the rule, a reasonable consequence for her misbehavior, solid examples of good behavior to follow, and a continuous set of boundaries that are consistently reinforced by the entire staff. She will have to learn what adult authority is.
In this example of a single behavior, one begins to appreciate the importance of understanding causes for behaviors. As fate would have it, though, most explanations for child behavior are not as attractively simple as our noncompliant bather. Why else might she be disobedient?
As Complex as It Gets
Despite decades of quality psychological research, complex human behaviors - including the full range of abnormal behaviors we all see at camp - are still a confusing tangle of hereditary and environmental factors. High-tech brain imaging techniques, such as functional magnetic resonance imagery (fMRI) have helped us see the human brain in action like never before. Imagine how excited Hubel and Wiesel would have been to have this technology in the early 1960s! But just knowing the neurochemistry involved in a behavior doesn't necessarily answer Anastasi's question of how nature and nurture have interacted to cause a particular trait. With each child, we need to become a sort of "behavior detective."
For example, we know that children with true Attention Deficit Hyperactivity Disorder (ADHD) have a biological deficit (itself the result of a complex heredity-environment interaction). In these children, certain neural pathways between their brain stem and frontal lobes don't have enough of the neurotransmitters dopamine and norepinephrine. Without enough of these important chemical messengers, these children have difficulty sustaining attention.
Of course, treating the chemical dysfunction in these children's brains with stimulant medications is tremendously helpful. But, as anyone who works with children with ADHD can tell you, both medical treatment and adjustments to the environment are necessary for maximum symptom relief. This is where the detective work comes in.
Knowing the biological facts does not explain why a particular child does not pay attention in a particular instance. To know this, we must also know the history of how that child has been treated by others, the tasks to which that child has been exposed, and the rewards that child has received for paying attention in other circumstances. Knowing all this, of course, is impossible. At best, camp staff get a tiny snapshot of a camper's history. At worst, parents with-hold pertinent information, and staff must rely on intuition.
Using What You Know
The three landmark studies reviewed in this article provide a scientific basis for a useful approach to managing camper behavior. First, we must "use what we know." We know that every camper was born with some hard-wired traits. We also know that in the years before they attend our camp, their hard-wired neural networks have grown, as a consequence of maturation and learning. We know that each camper was exposed to different environmental stimuli. Some of those stimuli have even promoted new neural connections and literally changed some of the hard wiring. Finally, we know that most of the behaviors, thoughts, and emotions that our campers possess reflect years of complex interactions between heredity and environment.
Knowing What to Use
We stretch our understanding of the nature/nurture question each time we sit up late on the lodge porch lamenting, "I just don't understand what drives this kid." At camp, our campers captivate and concern us, often leaving us asking, "Where did this child learn such a behavior?" Or, "What kind of parents does this child have?" Or even "How can a child be born like this?"
It's at frustrating moments such as these when we must "know what to use." Below is a list of suggestions for applying our knowledge of the heredity and environment interaction.
Each of us arrives in this world with a genetic endowment primed for learning. Perceptual skills, such as vision, take only limited environmental exposure to be activated. More complex skills, such as language, take more time to learn, but are possible only because our brains have the necessary structures to acquire syntax without effort. And the most complicated skills, such as impulse control or understanding our own emotions, take years of practice, loving guidance, and brain tissue maturation.
So, the next time you praise a camper or stop him from fighting or put your hand on his shoulder to comfort him or remind him to take his medication or use humor to keep his attention or smile back when he smiles at you, remember that you've just provided the next important piece of nurturing in his young life. Over time, your nurturing will influence his very nature.
Christopher A. Thurber, Ph.D., is a licensed clinical psychologist, camp consultant, and the co-author of The Summer Camp Handbook. For questions about this article or to inquire about staff training on this or other topics, send e-mail to firstname.lastname@example.org.
Originally published in the 2003 January/February issue of Camping Magazine.