In this issue…
Genetics, genomics, and the related other –omes (proteomes, metabolomes, interactomes, and the like) are often perceived as the fastest-breaking field in modern science. But if we turn from the small size scale of molecules and cells to look at the other end of the size continuum—the large-scale studies of the functions of the human brain—we also see a pattern of rapid and dynamic change. The study of cognitive systems, the topic of this issue, has grown enormously in scope, size, and sophistication during the past decade. This growth has been facilitated by several factors. One is the maturation of imaging technologies, such as structural and functional magnetic resonance imaging (sMR, fMR). Another is the rather courageous decision to expand the domain of study into complex and difficult fields such as consciousness, creativity, or decision-making. New fields are emerging, such as neuroeconomics or neuroethics. Very importantly, barriers between disciplines are also breaking down or disappearing, as philosophers study the brain and brain scientists study questions posed by philosophy. And as this issue illustrates, these advances often have important clinical implications.
The issue starts with three State of the Art articles. Schacter (p 7) begins the issue by addressing the topic of constructive memory. While simple conceptualizations of memory perceive it as involving the recollection of information that has been previously learned (a reproductive process), Schacter reminds us that it is very much a dynamic process instead. In other words, it is constructive. Using a clinical case of confabulation and a forensic case of false identification, he clearly demonstrates that memories are often inaccurate and distorted. He goes on to consider why the distortions occur, suggesting that they may represent an adaptive process. He uses the example of the ”gist effect” (a tendency to misremember what one has learned by making associations that condense and simplify the memory) to illustrate the possibility that memory “errors” are adaptive in that they facilitate the ability to generalize and abstract. He then discusses another type of constructive memory “error” that occurs when people “imagine the future,” as opposed to recalling the past. Finally, he examines the neural basis for this understanding of the nature of memory by describing multiple neuroimaging studies. Sternberg (p 19) summarizes current thinking about the nature of intelligence, a topic that can be both controversial and extensive. He describes changing definitions and concepts, discusses its stability over time, and summarizes the history of the development of IQ tests. He describes the “Flynn effect,” or the fact that IQs (as measured using raw scores) are increasing by approximately 3 points during each decade of the 20th century. He also describes various theories of intelligence, such as the Cattell-Horn-Carroll theory, Gardner’s multiple intelligences theory, and his own triarchic theory. He reviews what is known about the neural basis of intelligence, its heritability, and the role of gene-environment interactions. In his discussion of whether there are racial differences in intelligence, in the context of discussing genetic influences on intelligence, he points out that race does not fit into the discussion at all, since race is a social construct, not a biological or genetic one. Linking our understanding of cognitive processes to the conceptualization of mental illnesses is a major goal of contemporary psychiatric neuroscience. Morris and Cuthbert (p 29) tackle this issue through their discussion of the National Institute of Mental Health initiative to define Research Domain Criteria (RDoC). This innovative initiative is an effort to encourage rethinking of traditional categorical diagnoses, which are based largely on symptom patterns, because these traditional diagnoses have proved to have limited utility in the search for underlying mechanisms of mental illnesses. The RDoC initiative instead proposes that cognitive domains (broadly defined) and their neural circuits can be used as the basis for conceptualizing mental disorders and searching for their mechanisms. The domains include a broad variety of systems, ranging from working memory and arousal/regulatory systems to positive and negative valence systems and social processes.
Three Basic research articles examine basic questions about the nature of cognitive systems. Executive function is among the most widely used terms and concepts in cognitive neuroscience, and yet, as Bilder (p 39) points out, we are still struggling with multiple different approaches to defining what it means. He provides a good summary of its history and raises some challenging questions. Should the definition be tied to specific cognitive constructs? To specific tests? Or to brain regions such as the various areas of the frontal lobes? He proposes that an evolutionary cytoarchitectonic trends theory may provide the most comprehensive way to integrate the multiple complex cognitive operations that are attributed to the concept of executive function. Andreasen (p 49) discusses the nature of creativity in the arts and sciences and questions the common assumption that they represent “two cultures.” She summarizes preliminary neuroimaging data from an ongoing study of highly creative (“big C”) individuals from the arts and sciences; the fMR 6 scans show nearly identical patterns of activation, involving associative regions involved in higher-order socioaffective processing and Random Episodic Silent Thought (REST)/the default mode network. Finally, Sturm (p 55) approaches the question of consciousness from the perspective of a philosopher. He describes the debate about the mind-body problem that occurs at the interface between philosophy and neuroscience, a debate that must be addressed in order to understand the nature of consciousness. After summarizing the various arguments that have been presented, he suggests that the “reductive physicalism” that is usually supported by the neuroscience perspective may have a stronger case, but also that there is “no knock-down proof.”
Three Clinical research articles examine recent advances in the study of cognitive systems from a more clinical perspective. Paradiso and Rudrauf (p 65) begin the section with a call to action. Not only must cognitive science move beyond the narrow study of cognitive processes to a broader examination of social and affective processes, but it must also integrate the study of the self, self-awareness, and inter-subjectivity. This integration is necessary if insights from these processes can be made useful in clinical psychiatry, since clinicians must work with individuals caught up in a “struggle for life” and a “struggle for love.” Harvey (p 91) provides a comprehensive review of the ways that the tools of neuropsychology can be used in a clinical setting. These include the characterization of the nature and severity of cognitive dysfunctions in a broad range of disorders, assisting in diagnosis for those disorders for which evidence of cognitive impairment is built into the diagnostic criteria (eg, Alzheimer’s disease), and tracking disease progression or improvement over time. In concert with neuroimaging studies neuropsychological testing can be used to examine the functional significance of abnormalities or lesions that are observed. Marewski and Gigerenzer (p 77) conclude the section with an interesting discussion of decision-making in medical settings. They discuss the use of heuristics and ways to identify the “right” amount of information that physicians need to make medical decisions. Although we tend to assume that a maximal amount of information will be helpful, the science of heuristics is suggesting that “less is more” and that “fast and frugal” approaches to making medical decisions may lead to better outcomes.
The issue ends with a Brief Report by Simonton (p 100), which provides an interesting counterpoint to the “big C” study described by Andreasen. Simonton raises several important questions: how should creativity be defined? Can it be measured and quantified? What are its distributional characteristics? For example, is the approach used for measuring IQ a reasonable model, leading to the creation of a Creativity Quotient, or CQ? Or should we separate the highly creative (“Big C”) creative individuals from those with more modest levels of creativity (“little c”)? Can measures “span the spectrum”? One proposed solution is the creation of a Creativity Achievement Questionnaire that could be used as a measurement tool.
Nancy C. Andreasen, MD, PhD