PROFESSOR: In this unit, we will discuss nature and nurture. If you haven't already completed the Nature or Nurture class activity, please pause this presentation and do that now.

Let's begin with a thought exercise. If scientists cloned you, when that clone grew up, how would the clone be similar to you? How would the clone be different from you? Please pause the video to consider your answer before you continue.

When students answer this question, they often focus on biologically driven similarities, such as height, hair color, and eye color. They also focus on experience-driven differences, mentioning things like different friends, different parents, or experience with different technologies.

Many students think that their clones would look like them, but not necessarily act or think like they do. Think back for a moment to the class activity. Which parts of who we are did you and your classmates attribute to biology? Which did you attribute to experience? Which is more important in making us who we are?

The debate about which matters more, biological or experiential factors, is called the nature versus nurture debate. Nurture, or experience, clearly matters quite a bit. Take, for example, the sad case of Genie. Genie—not her real name—was profoundly neglected and abused until she was a young teenager. She was kept alone in a room. Because of this isolation, she had virtually no social interaction and she did not learn to speak during her childhood.

Nature, or biology, also matters quite a bit. Many of you may be familiar with Down syndrome, a disorder caused by the presence of an extra chromosome. The presence of that extra chromosome causes learning disabilities. These are extreme cases that show that both nature and nurture matter. Which one matters more?

Rather than asking which is more important, a better question is to ask how the two interact to make us who we are. Let's take Albert Einstein as a working example. We can probably all agree that he was brilliant. What made him so smart? Was it nature? Was it nurture? He probably started with some biological advantages. But he likely also had a number of opportunities that helped him to make the most of his potential.

This illustrates what is called a reaction range. The reaction range is the idea that biology provides constraints, but the environment will determine where you fall within those constraints. Let's return to intelligence as our example.

Biology may determine that a child's IQ will fall somewhere between, say, 90 and 110. If that child is reared in an environment in which her opportunities for learning are limited, she may end up toward the bottom of that range. If she is given many opportunities, however, she may end up toward the top of that range.

It is important to note that, for some things, opportunities are more valuable when they occur at the right time. Think back to the description of Genie, the abused child who did not learn to speak as a child. Even when she did eventually hear a language, she never developed the language skills that all of us share, because she was not exposed to language early enough.

This is the idea of a critical window, or a critical period, the idea that your brain is ready to make the most of opportunities when they occur during certain times of childhood. For example, we know that there are critical periods for vision, language learning, second language learning, learning a musical instrument, and learning to read.

We know that nature and nurture can work together. They can also influence each other. Our nature can affect our nurture. For example, some people are uncomfortable in warmer weather, and that might motivate them to seek out cooler climates. This will affect their experiences.

Children who are tall may be encouraged to play sports like basketball and volleyball, while shorter children may be encouraged to participate in different sports or activities. As those of you with children know, each child is born with his or her own temperament or personality. Some children are easier to soothe, for example, and their temperaments may elicit different nurturing experiences from their parents and caregivers.

Nurture can also affect nature. For example, growing up in consistently stressful environments can change the way your brain functions. Over a longer time period, the environment will dictate biology through evolution. If one particular trait makes it likely that people will survive to reproduce in a certain environment, that trait is more likely to be passed on, determining the biology of future generations.

In your core assignments and Digging Deeper assignments, you will learn more about nature and nurture. When you finish these assignments, be sure to check out the Penn State Connections presentation. You will learn some information about Penn State nature/nurture researcher Jenae Neiderhiser, as well as information about World Campus psychology courses that build on the material presented in this unit.