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7 Behavioral Neurophysiology Behavioral neurophysiology is broadly defined here as the study of the interplay between basic behavioral processes (e.g., affective, cogni- tive, motivational) and biological processes, including control (e.g., neural, endocrine) and operational (e.g., autonomic and somatic) ones. The field includes not only the areas and technologies of the behavioral brain sciences (e.g., affective, cognitive, perceptual, and social neuroscience) but psycho- neuroendocrine and peripheral psychophysiological ones, as well. The last 25 years have seen important advances at all levels in the field, including philosophical, theoretical, and technological ones. PHILOSOPHICAL, THEORETICAL, AND TECHNOLOGICAL ADVANCES Philosophically, the breakdown of the ancient concept of mind/body dualism continues (see Damasio, 1994; LeDoux, 1996; Pinker, 1997). The subject matters of the behavioral and biological sciences are now regarded as interdependent rather than as necessarily independent. No longer is the scientific impetus for understanding the interplay between behavior and biology one of reductionism. Pioneering contributions such as Ader and Cohen’s (1975) startling discovery that immunosuppression could be clas- sically conditioned led others (e.g., Kiecolt-Glaser and Glaser, 1995) to begin to study how human behavior and the nervous, endocrine, and im- mune systems influence one another. Technologically, rapid advancements in computerized neurophysiological recording systems—such as peripheral physiological (autonomic and somatic) recording devices, endocrine assay 64

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BEHAVIORAL NEUROPHYSIOLOGY 65 tools, and brain imaging technologies—have allowed for the noninvasive collection, cleaning, storage, and sophisticated analysis of behavioral neu- rophysiological data at both central and peripheral levels. Biopsychosocial approaches and models of affect, motivation, and cognition have become firmly established in scientific theory. These advances have initiated a paradigm shift, integrating behavioral and neurophysiological research approaches to the understanding of human behavior. The advantages of biopsychosocial approaches to classic issues in the behavioral, biological, and biomedical sciences are not only important in terms of advancement in theory and basic understanding of the human condition, but also hold great promise for applications to military, as well as civilian, work in such areas as leadership, assessment of human per- formance, training, and health. This research is taking advantage of new technologies that increase the value and scope of empirical assessments of basic processes. Sophisticated tools are helping behavioral scientists, such as cognitive and social psychologists, to investigate empirically the implicit (fast, automatic) processes that underlie human behavior, such as social perception, evaluation, and decision making. More broadly, these tools are leading to the development of more powerful, comprehensive, and integrated theories that account for the interaction among implicit and explicit (effortful, deliberate) processes in ways that were not possible even as recently as a decade or two ago. Importantly, many neurophysiological technologies make possible on- line, continuous, and covert assessments that provide rich databases for theoretical analyses. These technologies do not necessarily constrain or interfere with the thoughts and, often, even the overt behaviors of research participants. They include technologies that permit advanced noninvasive measurement of autonomic processes (e.g., impedance cardiography, con- tinuous blood pressure monitoring) that are associated with potentially threatening performance situations; somatic assessments (e.g., facial elec- tromyography and facial video tracking) that are associated with the experi- ence and expression of affect and emotion; endocrine analyses (e.g., cortisol and cytokines assays) that are associated with stress-related health problems; and measures of brain electrophysiology (e.g., electroencephalography) and imaging (e.g., functional magnetic resonance imaging [fMRI] and positron emission tomography [PET]) that are associated with the full spectrum of psychological processes (e.g., sensation, perception, memory, affect, and motor behaviors). Among the most practical of these techniques are those that do not interfere with or constrain behaviors, especially those related to individual and group performance, social interactions, and so on, topics particularly relevant to military needs. In combination with each other and with traditional techniques, such as self-report and behavioral observation, advanced neurophysiological and behavioral technologies make possible the

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66 HUMAN BEHAVIOR IN MILITARY CONTEXTS simultaneous collection of affective, motivational, cognitive, and behav- ioral data. These technologies can also be used simultaneously with other advanced technologies (e.g., immersive virtual environment technology) to create human experimental scenarios that are high in both experimental control and mundane realism. Resulting data allow for more comprehensive theories and for more generalizable or externally valid findings. MOTIVATION AND AFFECT Almost all areas of basic behavioral neurophysiological research have potential applied significance for the military, and several have implications for the near term, 5 to 10 years. Research should be targeted toward basic understanding of motivation, cognition, and affect. Such research should be based on extant or newly developed biopsychosocial theoretical rationales that are supported by promising data. It should be focused on high-level constructs—for example, challenge versus threat motivation, peripheral versus central attitudes, positive versus negative affect—and it should in- corporate the role of individual differences. Crucial to this work is the use of validated neurophysiological markers of key theoretical constructs. In the very near term (i.e., the next 5 years) research efforts incorpo- rating peripheral neurophysiological (i.e., autonomic and somatic ones), neuroendocrine, and central electrophysiological (e.g., high density electro- encephalographical) assessments are more likely to produce applications for the military than research on central neurophysiological assessments using brain imaging techniques. For example, peripheral physiological measures can be used to monitor when a soldier moves from being challenged by an activity to being on the verge of being overwhelmed by task demands. Such measures could be useful for the selection of personnel, for the monitor- ing and calibration of training activities, and for real-time assessment of performance in the field. The committee’s attention to inclusion of research on motivation and affect is not based on a judgment that it has more value than cognitive and perceptual research, but on what the committee perceives as a histori- cal imbalance in the military’s research portfolio. Although the military’s research focus understandably mirrors historical trends in psychology, the focus now needs to reflect the dominant view that any understanding of cognitive processes unaccompanied by a simultaneous understanding of motivational and affective processes lacks relevance to behavior in real- world settings, particularly ones that are threatening, stressful, or involve social interaction. Recent research has developed strong biopsychosocial models of moti- vation (e.g., Blascovich and Mendes, 2000; Dickerson and Kemeny, 2004) and affect (e.g., Barrett, 2006b) supported by empirical data that take into

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BEHAVIORAL NEUROPHYSIOLOGY 67 account individual and dispositional differences. Many of these theories have incorporated validated neurophysiological and neuroendocrine mark- ers of superordinate motivational and affective constructs. The committee’s judgment that the military’s basic behavioral and social science agencies should focus on research that incorporates periph- eral neurophysiological, neuroendocrine, and central electrophysiological measures in the relative near term is based on several considerations. None of them reflects negatively on the importance and long-term value of brain imaging techniques. However, if brain imaging techniques are likely to be applicable to military needs, highly specific and sensitive theory-based brain imaging markers of affective and motivational constructs, in addition to cognitive ones, must be developed and validated, as Heatherton, Krendl, and Wagner (in this volume) point out. Such markers are not likely to be developed and validated using brain imaging technology (i.e., fMRI, PET, etc.) for at least 10-20 years, nor are the markers likely to be practical and cost-effective to use in field settings. Second, the military budget for basic behavioral and social science research, even if it is increased as the com- mittee recommends, cannot support the expensive technology necessary for brain imaging without significantly reducing support for other important aspects of its research portfolio. Third, other military research organiza- tions, including the Army Research Laboratory and DARPA (see Begley, 2006), are beginning to undertake brain imaging-based research. PREDICTING PERFORMANCE As an intensively human organization whose decisions are fraught with danger and serious geopolitical consequences, the military has a paramount stake in the quality of human performance, whether it occurs on or near a battlefield, through remote control of armaments (e.g., drones) and other battle relevant technology, or in support of military operations and readi- ness. Hence, it is not surprising that basic and applied military research in the behavioral and social sciences has focused on personnel in general and on personnel selection, training, leadership, and organization more particularly. Prediction of future performance is critical not only for the recruitment of military personnel, but also for the assignment of personnel to specific performance specialties and leadership positions, as well as for the design and evaluation of training programs and organizational structures. Tra- ditionally, research to develop predictors of military-relevant human per- formance has used personal and observational methods in which data are gathered through self-reports or through overt behavioral recordings during training and assessment tasks. The precision and value of the predictions

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68 HUMAN BEHAVIOR IN MILITARY CONTEXTS based on those methods can very likely be increased by using neurophysi- ological methods to complement the traditional methods. In general, neurophysiological methods (e.g., peripheral autonomic, peripheral somatic, and central electrophysiological ones) often permit data collection that is covert, continuous, and on-line. In comparison with subjective self-report and observational behavioral data, neurophysiologi- cal data are generally not affected by the individuals being studied and/or the potential biases of their observers. Neurophysiological data also can be continuously recorded, thereby permitting both increased reliability and the assessments of changes over very short or very long time periods. Finally, human neurophysiological data can be recorded and analyzed on-line (even remotely) simultaneously with performance and environmental data, with minimal or no interference and without interrupting task performance. Several areas of behavioral neurophysiological research can translate in the relative near term to military application and use. These include, for example, somatic indexes of prejudice (e.g., Vanman, Saltz, Nathan, and Warren, 2004), endocrine markers of affect and emotion (e.g., Dickerson and Kemeny, 2004), electrodermal markers of facial memory (e.g., Tranel and Damasio, 1985), cognitive processing load (e.g., Beatty and Lucero- Wagoner, 2000), and cardiovascular markers of motivation. Expanding on the latter as a more detailed illustration, there are theo- retically based, well-validated peripheral physiological markers of motiva- tional states that are predictive of human performance on tasks pertinent to the military. For example, over the last decade or so, research has dis- tinguished between two types of approach-avoidance motivation: challenge and threat. Research has shown that when a person evaluates situational and task demands (consciously or unconsciously), as well as the avail- ability of individual resources (both before and during the performance of goal-relevant tasks), the evaluation is marked by distinctive patterns of multiple cardiovascular responses (markers) over time. People who have the individual resources to meet the performance demands of a potentially threatening situation are termed “challenged.” They exhibit increases in heart rate and ventricular contractility coupled with decreases in total peripheral resistance and increases in cardiac output. Those who do not have the individual resources to meet performance demands are termed “threatened.” They exhibit similar increases in heart rate and ventricular contractility, but these are accompanied by little change or even increases in total peripheral resistance and decreases in cardiac output (for reviews, see Blascovich and Mendes, 2000; Blascovich, in press). Such responses can be recorded using physiological recording equipment that allows for both laboratory and field-based research. Importantly, these markers can and have been used to predict future hu- man performance on both metabolically demanding tasks (Blascovich, Seery,

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BEHAVIORAL NEUROPHYSIOLOGY 69 Mugridge, Norris, and Weisbuch, 2004) and nonmetabolically demanding tasks (Seery, Weisbuch-Remington, Hetenyi, Moore, and Blascovich, 2005). Generally, performance is superior when individuals are challenged rather than threatened, although threat does appear to increase performance on vigilance tasks (Hunter, 2001). Moreover, the threat pattern of cardiovas- cular responses is indicative of pathophysiological mechanisms leading to hypertension or cardiovascular disease or both (see Manuck, Kamarck, Kasprowicz, and Waldstein, 1993). Research directed toward neurophysiologically assessing challenge or threat before and during performance training could use the measure- ment of individual differences to provide an important tool for personnel selection and training, both for leadership and other tasks. Furthermore, research on the plethora of external (i.e., nontask-specific) factors that probably influence challenge or threat motivation can help in the design of training programs themselves. Finally, the monitoring of individuals’ chal- lenge or threat physiological states while in the field can provide important on-line information for commanders, including not only motivational state and performance, but also indicators of acute cardiovascular pathology. The above is but one example of the potential utility of behavioral neu- rophysiological methods. However, the principles embodied in the example (i.e., established theoretical framework; validated neurophysiological mark- ers of theoretical constructs; the covert, continuous, and on-line nature of these markers; and their applicability in terms of prediction of performance) are ones that can be applied to behavioral neurophysiological approaches to many important military tasks and problems.