How do Children Develop Their Understanding of Biology? Insights from Children with Williams Syndrome
By Adrienne Gelpi Lomangino, Head Teacher
Worms can’t have babies. They’re worms, not animals!” We’ve all heard young children make observations about the natural world that to adult ears sound wrong. But are they wrong, or do they perhaps reflect different theories about how the world works?
Questions like this one are central to the research of Professor Susan Johnson, who recently joined Stanford’s developmental psychology faculty. On September 6, 2000, Dr. Johnson asked the Bing staff to consider whether children merely hold false beliefs about the natural world or, as she proposes, actually have an entirely different world view from that of adults, in the context of which their apparent misconceptions are true and reasonable. If children hold false beliefs, then presumably they would change their views if they were told why their ideas are incorrect. However, if children’s ideas reflect different theories of the world, then changing their conceptions would require changing their theories.
It may be, in short, that adults’ and children’s theories of the world are incommensurable—that is, explaining a phenomenon in one theory involves concepts that cannot be represented in the other theory. However, Dr. Johnson points out a learning paradox: if adults’ and children’s theories are truly incommensurable, so that children cannot represent the adult conception, how can children’s concepts change? Being able to resolve incommensurability is fundamental for the children to change their concepts.
Johnson contrasts two positions about how children gain knowledge. In the accretionist position, knowledge acquisition occurs through a single learning process of enrichment, of accreting more and more details. In the conceptual change position, knowledge acquisition involves not only enrichment but also the creation of new knowledge through analogy, case analysis, and comprehension monitoring.
Prior research by Susan Carey of Harvard University found that children construct adult conceptions of biology between four and ten years of age. Following the accretionist view of learning through a single mechanism, Johnson says, one would then expect eleven-year-olds to possess not only detailed information about folk biology but also accompanying explanatory knowledge.
Separating children’s knowledge of information about animals from their underlying theories about animals might seem impossible. However, Johnson was able to distinguish the two by studying people with Williams Syndrome, a neurodevelopmental disorder in which language and thought seem disconnected. These individuals have mild to moderate mental retardation and difficulty with metacognition, but they also have precocious control over discourse and normal syntax. They are social and can give extensive verbal descriptions, but they cannot provide explanations of causality. There is a disjuncture between the information they possess and their deep understanding of it.
To learn whether people with Williams Syndrome could give causal explanations of folk biology as well as if they could give detailed information about animals, Dr. Johnson compared them with two control groups: children of a matched mental age of eleven years, and children of a younger mental age of six years.
One task involved children in simply naming animals, not explaining causes. On this task, children with Williams Syndrome responded similarly to the older control group. They also performed similarly to the older control group, and better than the younger control group, on a battery of questions about the properties of objects, such as “Do dogs breathe?” “Do dogs have hearts?” “Does the sun breathe?”
However, subsequent tasks showed that having detailed knowledge about living things is not necessarily the same as having causal knowledge about them. When children were asked what kinds of objects are alive, what happens to something that dies, and whether transformations would change animals’ essences, the children with Williams Syndrome answered more like the younger than the older control group. In fact, they showed more animism than either control group, asserting that an inanimate object such as a car is alive “because it moves.” The control groups were less likely to view a car as alive, responding, “It doesn’t feel,” “It doesn’t hear,” “It doesn’t talk,” “It doesn’t have feelings,” “It doesn’t have a heart,” “It doesn’t have a brain.”
The children with Williams Syndrome also held more misconceptions about death, such as that not all people die. And they conveyed a conception of death as a departure or altered state, rather than as a breakdown of the body or cessation of life. For example, their descriptions of death included “It means not to wake up, never to come back.” In contrast, the older control group provided responses such as “They can’t think anymore. They can’t feel anymore,” and “Your heart stops working, they stop breathing.”
In the tasks involving a transformation of appearance, the participants were presented with pictures of animals wearing costumes resembling other animals (e.g., a zebra wearing a horse costume) and with pictures of animals that they were told were surgically altered to give them external characteristics of another animal (e.g., a raccoon with a white stripe resembling a skunk). Individuals with Williams Syndrome expressed uncertainty about whether a costume changed the identity of an animal. They focused on the animal’s outward appearance when asked “What kind of animal is it?” about an animal with altered external characteristics. Their underlying theories about living things did not include the causal understanding found in the older control group. The participants with Williams Syndrome had not bridged the incommensurability between their theories and adults’ theories.
For Dr. Johnson, this work reveals the existence and importance of conceptual change in development: children start with a different set of theories about the world, and if their capacity to reconceive these theories is compromised, so is their depth of understanding.
In her future work, Dr. Johnson would like to shift her focus from biology to sociology, asking, “What does the concept of family mean to young children?” This question connects to the play that occurs daily in Bing classrooms as children engaged in dramatic play enact roles based on their evolving conception of family. Such play may not only reflect but also transform their understanding of family.