Warning others is a paradigm case of communicative helping and prospective action understanding. The current study addressed the ontogeny of warning in infants' gestural communication. We found that 12- and 18-month-olds ("n" = 84) spontaneously warned an adult by pointing out to her an aversive object hidden in her way…

Children growing up in a dual-language environment have to constantly monitor the dynamic communicative context to determine what the speaker is trying to say and how to respond appropriately. Such self-generated efforts to monitor speakers' communicative needs may heighten children's sensitivity to, and allow them to make better use of,…

Susan Goldin-Meadow's "Hearing Gestures: How Our Hands Help Us to Think" synthesizes findings from various domains to demonstrate that gestures convey meaning and comprise a critical and fundamental form of communication. She also argues convincingly for the cognitive utility of gesture for the gesturer. Goldin-Meadow presents an airtight case…

U-shaped developmental functions, and their N-shaped cousins, have intrigued developmental psychologists for decades because they provide a compelling demonstration that development does not always entail a monotonic increase across age in a single underlying ability. Instead, the causes of development are much more complex. Indeed,…

This article reports 2 experiments examining the changing role of iconicity in symbol learning and its implications regarding the mechanisms supporting symbol-to-referent mapping. Experiment 1 compared 18- and 26-month-olds' mapping of iconic gestures (e.g., hopping gesture for a rabbit) vs. arbitrary gestures (e.g., dropping motion for a rabbit).…

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…

The development of the "inversion" effect in face processing was examined in infants 3 to 6 months of age by testing their integration of the internal and external features of upright and inverted faces using a variation of the "switch" visual habituation paradigm. When combined with previous findings showing that 7-month-olds use integrative…

The aim of this article is to introduce readers to an alternative way of applying U-shaped functions to understand development, especially cognitive development. In classical developmental applications, age is the abscissa; that is, in the fundamental equation B = f(A), some behavioral variable (B) plots as a U-shaped or inverted U-shaped function…

The articles in this collection consider one very interesting puzzle of development: U-shaped developmental functions. At some point during development, an organism might exhibit what seems like a regression from its expected developmental trajectory and, according to continuity models of development, this is aberrant. In this special issue,…

Interest in U-shaped development has itself undergone a U-shaped progression. Twenty-five years ago, interest in U-shaped development was high. This interest was evident at a 1978 conference in Tel Aviv on "U-shaped Behavioral Growth" that resulted in the publication of a book of the same title 4 years later (Strauss, 1982). The breadth…

It has been 20 years since Bever's (1982) and Strauss and Stavy's (1982) books on U-shaped functions in human development were published. The three target articles in this issue describe several old and new U-shaped functions and new theoretical explanations for their existence. In this article, the authors will comment on two aspects of U-shaped…