Higher cognition encompasses a broad range of processes that allow us to take the products of more discrete cognitive functions and transform them to generate concepts, reason, and decide how to interact with the world. Given the complexity and diversity of processes that fall under the domain of higher cognition, part IX offers a wide variety of topics and approaches. One change from previous editions of The Cognitive Neurosciences is that the higher cognition section has been expanded to encompass both higher cognition and decision making. In previous editions, decision making was included sporadically under different section headings. With the exception of perceptual and motor decision making, the first edition did not include any contributions on decision making. In the second edition, decision making was included as a single contribution under higher cognition. The third edition was produced around the time neuroeconomics was starting to emerge as a new discipline within cognitive neuroscience. Reflecting this novelty, chapters on decision making were included in a section on perspective and new directions. Now, as interest in neuroeconomics has grown, research on the cognitive neuroscience of decision making has gained recognition as an important and exciting development in our endeavors to understand the neuroscience of human behavior. Reflecting this change, roughly half of the contributions in this section concern the processes driving decisions.

The contributions to section IX reflect three main themes and an interesting new perspective. The first two chapters focus primarily on the role of the prefrontal cortex as it represents higher cognitive functions. Knowlton and Holyoak in chapter 69 examine how the prefrontal cortex supports relational reasoning, that is, the ability to draw inferences based on relations, as opposed to specific features, a principle underlying analogies. By combining cognitive and computational models with neuropsychological and imaging data, they isolate and describe the component processes and neural representations that underlie complex reasoning. Chapter 70 by Summerfield and Koechlin provides a global, hierarchical model of the prefrontal cortex that accounts for the integration of executive functions, including the representation of goals and selection, with motivational and evaluative information across the lateral, medial, and orbital prefrontal cortices. They outline how this model of the prefrontal cortex supports decision processes.

The next two chapters are concerned with the foundations of conceptual and semantic knowledge. How we group and organize the information we encounter to allow us to generalize across instances, avoid redundant representations, and extract general principles is fundamental to navigating a complex world. In chapter 71, Martin explores the foundations of conceptual knowledge by examining the neural systems mediating the formation, representation, and utilization of concepts about objects. In chapter 72, McClelland, Rogers, Patterson, Dilkina, and Lambon Ralph expand on the topic by introducing a computational framework for capturing the nature of semantic cognition. They explore how this model reflects the principles underlying both the development of conceptual knowledge and its disintegration with semantic dementia.

In chapter 73, Raichle provides a new perspective on how to view brain function. He argues that most functional imaging studies have a reflexive view of the brain, in which its primary purpose is to respond to external events. In contrast, he suggests that investigating the intrinsic operations of the brain may be equally important, if not more, in understanding brain function. Although this chapter sits apart from the other chapters in this section, in both the topic and the emphasis on methodological issues in functional imaging, it is hard to imagine what else intrinsic functions might entail, if not, at least in part, some components of higher cognition. In this way, the chapter by Raichle is not only an important perspective in how we approach our understanding of the human brain, but also, potentially, a contribution to understanding the cognitive neuroscience of higher cognitive processes.

Decision making, specifically from a neuroeconomic perspective, is the focus of the last three chapters. In chapter 74, Rangel uses a neuroeconomic approach to explore how we make a simple goal-directed choice between two options. By walking through the stages of a simple choice, he examines how computational approaches and human neuroscience studies can be combined to capture the complex representation of a relatively simple decision. In chapter 75, Glimcher highlights how the neuroeconomic approach has evolved by combining neuroscience research in human and nonhuman primates with economic and psychological models of decision making. He suggests that initial findings suggest a two-step neurobiological process that includes valuation and choice. The final chapter on this topic, chapter 76 by Delgado and myself, highlights the importance of emotion in decision making and reviews issues and progress in integrating affective neuroscience with neuroeconomics.