In the first weeks and months after birth, infants start to adapt to their social world—that is, the schedule of experiences created largely by their caregivers. How do infants do this? What patterns in parents’ actions are regular enough for babies to “latch on to” and learn? How, indeed, does this capacity for social pattern-finding allow human cultures to pass on complex social routines and sensitivities?
Our research explores the development of social skills, focusing mostly on the first two years of life. During these pivotal months, infants show profound changes in social awareness. They notice, and start to expect, many regularities in their parents’ actions. They also master “attention-sharing”—for example, checking what another person is looking at, or working to get another person’s attention. Attention-sharing skills are of particular interest because they are crucial for social learning, including school-based learning. We have found, for example, that infants younger than 6 months old do not follow another person’s gaze (despite some confusing claims to the contrary), but that by 12 months of age, babies are pretty good at following the angle of an adult’s head.
However, babies are most interested, in some situations at least, in watching their parents manipulate objects with their hands. This discovery might have deep implications for understanding the development of tool-using skills, early learning of specific action patterns, and the propagation of culturally important skills.
The ability to learn languages is often seen as uniquely human, and so it is sometimes described in quasi-mystical terms. But if you view humans as a peculiar sort of ape (as biologists do), then a scientific approach should de-mystify language and look for continuity with other forms of communication in primates. So we ask how primate learning and communication abilities, plus hominid social structures, give rise to the features of human languages. We can further ask what sorts of symbolic or conceptual abilities might additionally be required.
To address these questions, we examine factors that affect the course of language learning in human infants. We also examine the precise processes of word learning—the behaviors and brain-based computations that allow infants, children, and adults to share symbols to communicate about their world. We have found, for example, that contrary to popular claims, young children do not learn words especially fast; they learn facts or visual patterns faster. Also, contrary to the popular claim that children learn languages much more easily than adults, we found that preschool-aged children learn new words slower than adults, and younger children learn words slower and with more misunderstandings than older children. Such results suggest that whatever might be specialized in language acquisition, it does not include learning the meanings of new words.
Cognitive development entails more than just learning and remembering a lot of facts and procedures. Even as children, we face constant decisions about what to attend to; whether, when, and how to act; and how to use our actions strategically, efficiently, and with proper timing. In other words, we must control our thinking. It is this need for control, rather than, say, brute memory capacity or processing speed, that frequently determines how well we do at a complex task.
One aspect of cognitive control is the ability to “change our mind”: that is, cognitive flexibility. Whenever you shift attention from one sort of information to another, change strategies to solve a problem or win a game, switch languages to communicate, take another person’s perspective, or use various cues and tricks to learn new information, you are exercising some sort of cognitive flexibility. We study cognitive flexibility in children because young children sometimes show startling failures of flexibility, even in fairly easy tasks. For example, when asked to switch from following one simple rule to another, 3-year-olds sometimes “barrel through” and keep using the first rule, despite understanding and acknowledging the latter rule. Because young children make such prominent errors, they provide a good “model organism” for studying factors that can affect flexibility. Also, we want to know what sorts of circumstances facilitate children’s flexibility, so teachers can adopt practices that encourage children to think critically and creatively.
How does flexibility change with age? Are young children generally poor at cognitive control? Or is the problem that children are inexperienced, and our cognitive control improves as we become more proficient at the fundamental skills that any complex activity demands? We are attempting to answer these questions. We have found, for example, that sometimes when young children appear to be inflexibly stuck following one rule, the problem is simply that they did not process (or notice, or remember) a cue to switch to a new rule. So some claims that young children are incapable of flexible thinking are not quite accurate.
Since the 1980s, developmental psychologists have gradually demonstrated that young children are capable of many kinds of complex “adult-like” thinking. However, children do not know as much as adults, and haven’t learned “rules” for showing their reasoning. It is these limitations—not, perhaps, fundamental reasoning abilities—that make children’s thinking seem so different from adult thinking.
The best research suggests a complex picture: By 4 to 6 years of age, children can, in some tasks, show reasoning that is similar to adults. However, this only works if the tasks are made scrupulously “fair” in terms of the demands of language comprehension and factual-knowledge. So test materials, questions, test procedures and instructions must be meticulously crafted.
However, it is not that nothing changes during childhood in terms of abstract reasoning. Even between 4 and 6 years of age, children show subtly different ways of reasoning about very abstract things like mental states. Our research has shown unexpected abilities, and subtle difficulties, of preschool children when reasoning about: categories and category membership; whether or not new categories share subtle properties (induction); the functions of objects and possible uses of tools based on their design; and the mental states (beliefs, intentions, preferences) of the self and other people.