In order for children to understand and reason about the world in an adult-like fashion, they need to learn that conceptual categories are organized in a hierarchical fashion (e.g., a dog is also an animal). While children learn from their first-hand observation of the world, social knowledge transmission via language can also play an important…

Being connected to other people at the level of inner and unobservable mental states is one of the most essential aspects of a meaningful life, including psychological well-being and successful cooperation. The foundation for this kind of connectedness is our theory of mind (ToM), that is the ability to understand our own and others' inner…

Rakison and Yermolayeva (this issue) argue that domain specificity is difficult to reconcile with U-, N-, or M-shaped developmental trends. They are justified because: (1) There is no compelling evidence that nonlinear trends require mechanisms beyond general, well-known cognitive processes; and (2) epigenetic neuroscience provides no clear…

A longstanding and fundamental debate in developmental science is whether knowledge is acquired through domain-specific or domain-general mechanisms. To date, there exists no tool to determine whether experimental data support one theoretical approach or the other. In this article, we argue that the U- and N-shaped curves found in a number of…

This article introduces a promising new methodology called optical imaging. Optical imaging is used for measuring changes in cortical blood flow due to functional activation. The article outlines the pros and cons of using optical imaging for studying the brain correlates of perceptual, cognitive, and language development in infants and young…

In the present paper we investigated the development of the ability to reproduce extent in elementary school students. Children were shown a target line in a frame and were asked to reconstruct the line in a frame of a different size. One experimental condition involved reproducing "absolute extent," i.e., drawing a line that would be…

The articles featured in this issue make apparent the variety of perceptual and cognitive competencies that follow curvilinear developmental courses as well as the complexities inherent in accounting for such phenomena. What is revealed is the way in which a fit is achieved between organisms and the environments they occupy. Curvilinear…

A modified elicited imitation task was used to examine the development of the ability to resist and overcome interference in the 2nd and 3rd years of life. In the modified task, distractor props were included in the test array, so that children could imitate the modeled sequence but could also produce actions with the additional props provided,…

When a behavior disappears and then resurfaces, developmental psychologists typically look more closely at the behavior to figure out what is different before and after--that is, they increase the grain with an eye toward discovering how the system that generates that behavior has changed. But what ought to count as a U-shaped phenomenon? How…