Developmental Cascades

This chapter describes in depth the developmental cascade framework. The authors argue that developmental scientists need to recognize how a documented change reflects or builds on other observed changes, involves mechanisms in the same and other domains, and is influenced by the specific learning infants and young children might have had, as well as their genetic make-up. Thus, it is proposed that developmental cascades underpin every aspect of development change from walking to talking to playing to thinking. In this chapter, the authors suggests that the developmental cascade approach allows scientists to gain insight into the key questions of developmental science that have largely remained unsolved and raises new questions that developmentalists should be asking about change. The focus, the authors argue, should not be about when change occurs but rather on how change is the result of a multitude of factors across a range of levels and systems in the developing child.

The “Humpty-Dumpty” Problem in the Study of Development

This goal of this chapter is to describe how developmentalists have suffered from the humpty-dumpty problem; that is, there has been a focus on individual developmental achievements in isolation. The study of development in pieces provides an incomplete understanding of change because abilities, skills, and knowledge do not develop in isolation. Rather every development reflects interactions between and across different aspects of processing, different mechanisms, and a variety of abilities. Put another way, the development of any ability (e.g., searching for hidden objects, uttering the first word, taking a step) involves the whole child. The chapter proposes that a complete and coherent understanding of development will only emerge from a consideration of how changes in one domain influence or determine cumulative changes in other domains.

Introduction

This chapter introduces the core concept of the book. Specifically, the premise of the book is that a focus on developmental milestones has limited our understanding of change, and that we will gain more insight about change by thinking about developmental cascades. The term development is defined, and the key tenants of the cascade approach are presented. These are: (a) All developmental change reflects the use of multiple mechanisms; (b) the mechanisms of any specific developmental change operate at many levels involving sensation, perception, and cognition, and (c) the emergence of any behavior or milestone represents one point in an ongoing developmental cascade.

Cascades and Object Knowledge

Chapter 7 applies the cascade framework to the development of object knowledge in infancy. Many theories on the development of object knowledge focus either on a single mechanism or on a single level of mechanism. This chapter presents an alternative view of infants’ developing object representation and knowledge by considering the effect of mechanisms of change at multiple levels and as involving multiple skills and abilities, cascades across development, and structural, environmental, and learned constraints. Multiple examples are presented that demonstrate how changes in motor skills affect object representations and, as such, show that there are multiple pathways to object knowledge.

The Development of Looking Behavior in Infancy

Chapter 6 illustrates how the developmental cascade framework can be used to understand the development of looking behavior in infancy. Historically, researchers have focused on one cue, feature, or mechanism to explain infants’ looking behavior in a variety of contexts, including experimental paradigms designed to assess high-level conceptual understanding. In this chapter, the authors argue that a cascade approach can provide a deeper understanding of the development of looking behavior both in the laboratory setting and in the real world. Three examples are presented that illustrate how a single behavior—attending to one’s mother, to an event, or to a novel stimulus—reflects multiple processes, and developmental change in this behavior reflects mechanisms that occur at multiple levels.

Developmental Mechanisms

The focus of this chapter is an understanding of mechanisms of development and how any developmental change reflects multiple mechanisms. The term mechanism is defined from various perspectives (e.g., Piagetian, Gibsonian, information-processing, evolutionary psychology). The chapter discusses how a single model of mechanism is insufficient to explain the broad range of developmental changes that occur in infancy and beyond, and instead the authors argue that theorists should consider how development is best explained by considering mechanisms at multiple levels and across multiple domains. Also discussed is how a cascade approach obviates the dichotomy between domain-general and domain-specific mechanisms. Potential mechanisms of change are also outlined.

The Development of Knowledge of Animates and Inanimates in Infancy

Previous theories have tended to focus on a single mechanism to explain the development of knowledge of animates and inanimates infancy, although for some theorists this mechanism is domain-specific and for others it is domain-general. In contrast to these well-documented positions, in this chapter the authors claim that infants’ understanding of animacy reflects many developmental changes that occur at many levels, reflect many mechanisms—some that are domain-specific and some that are domain-general—and reflect structural, environmental, and learned constraints on that development. Examples of such developmental cascades are provided with a focus on infants’ developing knowledge of goal-directed action.

The Role of Constraints in Development

One potential problem with the development cascades approach is that it appears to be unconstrained. However, as discussed in this chapter, constraints in development can be broadly defined. Constraints have typically been conceived of as either innate and present at birth or acquired through experience. This chapter argues instead that developmental cascades are influenced profoundly by different kinds of constraints that do not have a single foundation. Constraints can be structural (e.g., originating from the structure of the child’s nervous system and body), a function of the physical or social environment, or the result of accumulated knowledge and experience. These constraints, it is argued, occur at multiple levels of processing and change over time, both of which contribute to developmental cascades and are the product of cascades.

Conclusions

This chapter summarizes the developmental cascades perspective and outlines a number of implications of this framework. These implications include the heuristic value of a developmental cascades approach and how developmentalists logistically can adopt a cascade approach. The generalizability of the cascade approach is also outlined by illustrating how this approach can be applied to other domains outside of infant cognitive development, namely, the development of attachment and gender. The chapter concludes with a discussion of potential criticisms of the approach, including reframing those criticisms in terms of potential strengths or limitations that can be overcome. This chapter concludes with a “call to arms” encouraging all developmental scientists to consider change in terms of developmental cascades.