Steven R. Hursh

BEHAVIORAL ECONOMICS AND EMPIRICAL PUBLIC POLICY

The application of economics principles to the analysis of behavior has yielded novel insights on value and choice across contexts ranging from laboratory animal research to clinical populations to national trends of global impact. Recent innovations in demand curve methods provide a credible means of quantitatively comparing qualitatively different reinforcers as well as quantifying the choice relations between concurrently available reinforcers. The potential of the behavioral economic approach to inform public policy is illustrated with examples from basic research, pre-clinical behavioral pharmacology, and clinical drug abuse research as well as emerging applications to public transportation and social behavior. Behavioral Economics can serve as a broadly applicable conceptual, methodological, and analytical framework for the development and evaluation of empirical public policy.

Developing Mathematical Models of Neurobehavioral Performance for the "Real World"

Work-related operations requiring extended wake durations, night, or rotating shifts negatively affect worker neurobehavioral performance and health. These types of work schedules are required in many industries, including the military, transportation, and health care. These industries are increasingly using or considering the use of mathematical models of neurobehavioral performance as a means to predict the neurobehavioral deficits due to these operational demands, to develop interventions that decrease these deficits, and to provide additional information to augment existing decision-making processes. Recent advances in mathematical modeling have allowed its application to real-world problems. Developing application-specific expertise is necessary to successfully apply mathematical models, in part because development of new algorithms and methods linking the models to the applications may be required. During a symposium, “Modeling Human Neurobehavioral Performance II: Towards Operational Readiness,” at the 2006 SIAM-SMB Conference on the Life Sciences, examples of the process of applying mathematical models, including model construction, model validation, or developing model-based interventions, were presented. The specific applications considered included refining a mathematical model of sleep/wake patterns of airline flight crew, validating a mathematical model using railroad operations data, and adapting a mathematical model to develop appropriate countermeasure recommendations based on known constraints. As mathematical models and their associated analytical methods continue to transition into operational settings, such additional development will be required. However, major progress has been made in using mathematical model outputs to inform those individuals making schedule decisions for their workers.

The Fatigue Avoidance Scheduling Tool: Modeling to Minimize the Effects of Fatigue on Cognitive Performance

Operator fatigue and time-of-day induced variations in cognitive effectiveness can lead to lapses in attention, slowed reactions, and impaired reasoning and decision-making that has been shown to contribute to accidents, incidents and errors in a host of industrial and military settings. During the past three years, the US Air Force has sponsored the development of a model of human fatigue and circadian variation and a scheduling tool based upon the model that will be used to minimize aircrew fatigue. The initial test version of the tool has passed review by the operational wings of the AF and a final operational product is in advanced development and validation. The software was developed by SAIC and NTI and is called the Fatigue Avoidance Scheduling Tool (FAST). This fatigue forecasting system is being developed and tested by NTI under a small business innovative research (SBIR) grant from the US Air Force, now in the third year of a three-year program. Fatigue predictions are derived from the Sleep, Activity, Fatigue, and Task Effectiveness (SAFTE) model invented by Dr. Steven Hursh of SAIC. The patented SAFTE model has received a broad scientific review and the DoD considers it the most complete, accurate, and operationally practical model currently available to aid operator scheduling. The Department of Transportation is in the second phase of a three-phase project to validate and calibrate the model for avoiding excessive fatigue in transportation operations. The FAST scheduling tool uses the model to compare schedules in terms of predicted performance effectiveness. FAST allows easy entry of proposed schedules and generates graphical predictions of performance along with tables of estimated effectiveness scores for objective comparison. Optimal schedules may be selected based on average effectiveness for proposed work periods or mission critical events. The tool may also be used for retrospective analysis of fatigue related factors that may have contributed to an accident, error or safety related incident. In this mode, information on the work and sleep schedules of operators prior to the event may be entered into the tool and a projection of performance effectiveness at the time of the event is determined. In combination with other information, this analysis can project the combined effects of time of day and sleep history as a contributing factor to safety related events.

Modification of ethanol’s reinforcing effectiveness in rhesus monkeys by cocaine, flunitrazepam, or gamma-hydroxybutyrate

BackgroundAlthough ethanol is frequently used in combination with other psychoactive drugs, the behavioral and pharmacological reasons for this form of polydrug abuse have not been well described.Materials and methodsRhesus monkeys with indwelling intravenous catheters produced intravenous injections of ethanol (50, 100, or 200xa0mg/kg/inj), flunitrazepam (0.001–0.03xa0mg/kg/inj), cocaine (0.01 or 0.03xa0mg/kg/inj), or combinations of ethanol and these drugs or gammahydroxybutyrate (GHB) (1.0 or 3.2xa0mg/kg/inj) by lever pressing according to a fixed-ratio schedule. The response requirement for each drug or drug combination was increased across sessions (10, 32, 100, 320, or 1,000). The dependent variables were rates of responding maintained by the drug or drug combination and the elasticity of drug demand when consumption was expressed as a function of price.ResultsElasticity (Pmax) values for each drug varied among the monkeys but retained the same rank order for the monkeys, suggesting a fundamental difference in the animals’ apparent sensitivities to the reinforcing effects of the drugs. Combining ethanol with the other drugs did not increase their reinforcing effectiveness. GHB (ineffective in previous studies) did not modify ethanol’s reinforcing effects; demand functions for the combination of ethanol and flunitrazepam were slightly less elastic than for ethanol alone, but no different from that for flunitrazepam alone; adding ethanol to cocaine detracted from the reinforcing effectiveness of cocaine.ConclusionsThe hypothesis that use of ethanol in combination with sedative and stimulant drugs is due to an ability of ethanol to enhance the reinforcing effects of these drugs is not supported.

Distributed interactive communication in simulated space-dwelling groups

This report describes the development and preliminary application of an experimental test bed for modeling human behavior in the context of a computer generated environment to analyze the effects of variations in communication modalities, incentives and stressful conditions. In addition to detailing the methodological development of a simulated task environment that provides for electronic monitoring and recording of individual and group behavior, the initial substantive findings from an experimental analysis of distributed interactive communication in simulated space dwelling groups are described. Crews of three members each (male and female) participated in simulated planetary missions based upon a synthetic scenario task that required identification, collection, and analysis of geologic specimens with a range of grade values. The results of these preliminary studies showed clearly that cooperative and productive interactions were maintained between individually isolated and distributed individuals communicating and problem-solving effectively in a computer-generated planetary environment over extended time intervals without benefit of one anothers physical presence. Studies on communication channel constraints confirmed the functional interchangeability between available modalities with the highest degree of interchangeability occurring between Audio and Text modes of communication. The effects of task-related incentives were determined by the conditions under which they were available with Positive Incentives effectively attenuating decrements in performance under stressful time pressure.

Toward quantifying the abuse liability of ultraviolet tanning: A behavioral economic approach to tanning addiction

Many adults engage in ultraviolet indoor tanning despite evidence of its association with skin cancer. The constellation of behaviors associated with ultraviolet indoor tanning is analogous to that in other behavioral addictions. Despite a growing literature on ultraviolet indoor tanning as an addiction, there remains no consensus on how to identify ultraviolet indoor tanning addictive tendencies. The purpose of the present study was to translate a behavioral economic task more commonly used in substance abuse to quantify the abuse liability of ultraviolet indoor tanning, establish construct validity, and determine convergent validity with the most commonly used diagnostic tools for ultraviolet indoor tanning addiction (i.e., mCAGE and mDSM-IV-TR). We conducted a between-groups study using a novel hypothetical Tanning Purchase Task to quantify intensity and elasticity of ultraviolet indoor tanning demand and permit statistical comparisons with the mCAGE and mDSM-IV-TR. Results suggest that behavioral economic demand is related to ultraviolet indoor tanning addiction status and adequately discriminates between potential addicted individuals from nonaddicted individuals. Moreover, we provide evidence that the Tanning Purchase Task renders behavioral economic indicators that are relevant to public health research. The present findings are limited to two ultraviolet indoor tanning addiction tools and a relatively small sample of high-risk ultraviolet indoor tanning users; however, these pilot data demonstrate the potential for behavioral economic assessment tools as diagnostic and research aids in ultraviolet indoor tanning addiction studies.

Behavioral economic analysis of demand for fuel in North America

Emerging research clearly indicates that human behavior is contributing to climate change, notably, the use of fossil fuels as a form of energy for everyday behaviors. This dependence on oil in North America has led to assertions that the current level of demand is the social equivalent to an addiction. The purpose of this study was to apply behavioral economic demand curves-a broadly applicable method of evaluating relative reinforcer efficacy in behavioral models of addiction-to North American oil consumption to examine whether such claims of oil addiction are warranted. Toward this end, we examined government data from the United States and Canada on per capita energy consumption for transportation and oil prices between 1995 and 2008. Our findings indicate that consumption either persisted or simultaneously increased despite sharp increases in oil price per barrel over the past decade.

Effects of Autonomous Mission Management on Crew Performance, Behavior, and Physiology: Insights from Ground-Based Experiments

Technical constraints during long-duration space expeditions will limit the ability for Earth-based management of astronaut crews and will thus increase the prevalence of autonomous operations. To provide experimentally-derived insights on the effects of crew autonomy, we utilized a laboratory-based simulation model to assess crew performance effectiveness and biopsychosocial adaptation under rigid schedule-based management of crew activities by Mission Control versus more flexible, autonomous management of activities by the crews themselves. In 2 separate experiments, 33 research volunteers formed 11 long-term 3-person mixed-gender crews that were extensively trained over several months in an interdependent computer-based planetary surface exploration task. Following training, in Experiment 1, three crews each completed two different types of 3–4 h test missions: Scheduled missions, in which they were directed by Mission Control according to a strict topographic and temporal region-searching sequence, and Autonomous missions, in which the crews received minimal baseline support from Mission Control and were free to establish their own protocols for exploring the planetary surface. In Experiment 2, eight 3-person crews were trained in identical fashion as Experiment 1, except these crews were each tested under four different scenarios, with the Scheduled and Autonomous sessions completed either under normal conditions of full communications capabilities or following the unexpected loss of audio and text-messaging functions. Overall, autonomous mission management led to improved task performance (more high-valued geologic samples were retrieved), increased subjective self-reports of positive mood, fewer references to negative emotions, greater use of socially-referent language in unstructured debriefing logs, and attenuated physiological stress reactivity. Consistent with observational field research, these laboratory-based investigations provide powerful experimental evidence supporting a causal relationship between crew autonomy and improved performance, enhanced psychosocial adaptation, and sustained biobehavioral health. Future work should systematically examine interactions with culture and personality in diverse multinational crews, assess the effects of other operationally-relevant stressors such as heavy workload and circadian disruption, and evaluate the effects of bounded autonomy in space analogue environments and on the International Space Station using rigorous experimental methods. The controlled laboratory data presented herein contribute to an emerging empirical knowledge base on crew autonomy which the international astronautics community may build upon for future research and ultimately draw upon when designing and managing long-duration exploratory missions.

Substitutability of nicotine alone and an electronic cigarette liquid using a concurrent choice assay in rats: A behavioral economic analysis

BACKGROUNDnFor the Food and Drug Administration to effectively regulate tobacco products, the contribution of non-nicotine tobacco constituents to the abuse liability of tobacco must be well understood. Our previous work compared the abuse liability of electronic cigarette refill liquids (EC liquids) and nicotine (Nic) alone when each was available in isolation and found no difference in abuse liability (i.e., demand elasticity). Another, and potentially more sensitive measure, would be to examine abuse liability in a choice context, which also provides a better model of the tobacco marketplace.nnnMETHODSnDemand elasticity for Nic alone and an EC liquid were measured when only one formulation was available (alone-price demand) and when both formulations were concurrently available (own-price demand), allowing an assessment of the degree to which each formulation served as a substitute (cross-price demand) when available at a low fixed-price.nnnRESULTSnOwn-price demand for both formulations were more elastic compared to alone-price demand, indicating that availability of a substitute increased demand elasticity. During concurrent access, consumption of the fixed-price formulation increased as the unit-price of the other formulation increased. The rate of increase was similar between formulations, indicating that they served as symmetrical substitutes.nnnCONCLUSIONnThe cross-price model reliably quantified the substitutability of both nicotine formulations and indicated that the direct CNS effects of non-nicotine constituents in EC liquid did not alter its abuse liability compared to Nic. These data highlight the sensitivity of this model and its potential utility for examining the relative abuse liability and substitutability of tobacco products.