Steven R. Lawyer

Percent body fat is related to delay and probability discounting for food in humans

This study describes delay and probability discounting patterns for hypothetical food and money in relation to percent body fat (PBF). Sixty university students completed four computerized discounting tasks in which they were asked to make a series of hypothetical decisions between (a) 10 dollars after one of several different delays (1, 2, 30, 180, and 365 days) or a smaller amount of money available immediately; (b) 10 bites of food after one of several delays (1, 2, 5, 10, and 20h) or a smaller number of bites available immediately; (c)

Forcible, Drug-Facilitated, and Incapacitated Rape and Sexual Assault among Undergraduate Women.

10 at one of several probabilities (0.9, 0.75, 0.5, 0.25, 0.1) or a smaller amount of money to be received for sure; and (d) 10 bites of food at one of several probabilities (0.9, 0.75, 0.5, 0.25, 0.1) or a smaller number of bites to be received for sure. Median indifference points for all participants across each task were well described using the hyperbolic discounting function. Results suggest that percent body fat predicted discounting for hypothetical food, but not money, using regression analyses with the entire sample and when comparing individuals in the high and low quartiles for PBF. None of the other dietary variables (body mass index, subjective hunger, and time since last meal or snack) were related to discounting patterns. This suggests that individuals with high PBF may exhibit heightened sensitivities to delay and probability when making decisions about food.

Probability and delay discounting of hypothetical sexual outcomes

Abstract Objective: To examine the prevalence of drug-related sexual assaults, identify the frequency of assaults that occur following voluntary versus involuntary drug or alcohol consumption, and identify contextual correlates of drug-related assaults. Participants: College-student females (n = 314). Methods: Volunteers reported experiences with forcible and drug-related sexual assaults in the spring semester of 2004. Follow-up queries regarding the most severe drug-related assaults determined whether the assaults followed voluntary or involuntary alcohol or drug consumption. Results: 29.6% (n = 93) of the respondents reported a drug-related sexual assault or rape; 5.4% (n = 17) reported a forcible sexual assault or rape. Voluntary incapacitation preceded 84.6% of drug-related assaults and involuntary incapacitation preceded 15.4% of drug-related assaults. The majority of drug-related assaults (96.1%) involved alcohol consumption prior to assault. Conclusions: Drug-related sexual assaults on college campuses are more frequent than are forcible assaults and are most frequently preceded by voluntary alcohol consumption.

Discounting of hypothetical and potentially real outcomes in nicotine-dependent and nondependent samples.

The present study used the discounting procedure to characterize choice behaviors regarding hypothetical sexual outcomes. Eighty-six adult undergraduate students completed computerized delay and probability discounting tasks concerning hypothetical money and hypothetical sexual activity. Consistent with other discounting findings, hyperbolic and hyperbola-like decay models described individual and group median indifference point data well. These findings contribute to a growing literature on the relevance of the discounting procedure to decision-making processes and suggest that the discounting procedure may be useful for understanding the processes that underlie social problem behaviors associated with impulsive sexual decisions.

Predicting domain-specific outcomes using delay and probability discounting for sexual versus monetary outcomes.

Discounting is a behavioral phenomenon in which the value of an outcome diminishes as a function of its increased delay or decreased probability and is related to substance abuse research because of its theoretical ties with behavioral models of impulsive choice. Research to date suggests that hypothetical outcomes used in discounting research yield data that are indistinguishable from those using potentially real outcomes. However, the extant literature focuses primarily on delay discounting in non-drug-using humans and has not examined whether hypothetical outcomes yield disproportionate numbers of nonsystematic response patterns. In two experiments, we compared hypothetical and potentially real monetary outcomes in delay and probability discounting tasks in terms of rates of discounting and the frequency of nonsystematic response patterns. In Experiment 1, 61 adults reported no smoking, binge drinking, or illicit drug use in the past year. Experiment 2 included a community sample of nicotine-dependent adults (N = 36). In both experiments, discounting for hypothetical and potentially real outcomes yielded similar data, replicating and extending a growing literature pointing to the empirical equivalence of these outcomes. These findings are relevant to research on discounting that is frequently used in the study of substance use and other impulse-control behaviors.

Current Psychopathology in Previously Assaulted Older Adults

Discounting, the tendency to devalue an outcome as a function of its delay or probability, is emerging as a fundamental process that underlies a broad range of impulsivity-related behaviors. Recent research suggests that people discount the value of sexual outcomes and individual differences in rate of discounting of sexual outcomes may represent an important behavioral process that underlies sexual risk behavior. However, it is not clear that discounting the value of domain-specific sexual outcomes (e.g., sexual activity) is a better predictor of sexual behaviors than is discounting for domain non-specific outcomes (e.g., money). Adult undergraduates (n=103) completed delay and probability discounting procedures in relation to money and sexual activity and a series of self-report measures concerning sexual and non-sexual outcomes. Results revealed domain-specific relationships such that (1) discounting for sexual and monetary outcomes were significantly correlated; (2) discounting for sexual activity was significantly associated with sexual excitability, but not with non-sexual outcomes; and (3) discounting for money was not related to the sexual outcomes. A consistent gender effect across measures suggests that gender may moderate the relationships between discounting and sexual and non-sexual outcomes. The relevance of these findings for domain-specific discounting is discussed.

Differential associations between obesity and behavioral measures of impulsivity

Older adult women age 55+ years (N = 549) were interviewed as part of a population-based epidemiological research study of lifetime experiences with physical and sexual assault and current mental health problems. Although overall rates of psychopathology were low, producing very small cells for comparison, women who reported experiencing physical assault an average of 28 years previously were more likely to present with past year substance abuse, depression, and avoidance and reexperiencing symptoms of posttraumatic stress disorder (PTSD) than those with no previous physical or sexual assault. Women who reported experiencing sexual assault an average of 50 years previously were more likely to present with autonomic arousal and avoidance symptoms of PTSD than those with no prior sexual assault. The aforementioned findings should be considered with caution, however, as sample cell sizes were minimal for all but the PTSD symptom subtypes. Mental health service implications for older adults are discussed.

Measurement and validation of measures for impulsive food choice across obese and healthy-weight individuals

A growing literature indicates that impulsivity is a fundamental behavioral process that underlies obesity. However, impulsivity is a multidimensional construct, which comprises independent patterns of decision-making that could be uniquely associated with obesity. No research to date has clarified whether obesity is differentially associated with specific behavioral aspects of impulsivity. This study examined whether obesity was differentially associated with patterns of decision-making associated with impulsivity-delay discounting, probability discounting, and response inhibition. Young adults (n = 296; 44.3% male) age 18-30 were recruited from the community with media advertisements. Participants completed a series of standard self-report measures of health outcomes and behavioral measures of delay discounting, probability discounting, and response inhibition individually in a laboratory. Associations between body mass index (BMI) and behavioral outcomes in the whole sample indicated that BMI was associated with age, delay discounting, and probability discounting, but not response inhibition. A logistic regression that included age, sex, and substance use as covariates found that delay discounting, but neither probability discounting nor response inhibition, was associated with obesity status. Sensitivity to delay, rather than response inhibition and sensitivity to uncertainty, may be the best correlate of obesity status in adults. These findings are relevant to our understanding of the fundamental behavioral processes associated with obesity.

Web-Based versus Paper-and-Pencil Course Evaluations

The present study established a brief measure of delay discounting for food, the Food Choice Questionnaire (FCQ), and compared it to another more established measure of food discounting that uses the adjusting amount (AA) procedure. One hundred forty-four undergraduate participants completed either two measures of hypothetical food discounting (a computerized food AA procedure or the FCQ) or two measures of hypothetical money discounting [a computerized monetary AA procedure or the Monetary Choice questionnaire (MCQ)]. The money condition was used as a replication of previous work. Results indicated that the FCQ yielded consistent data that strongly correlated with the AA food discounting task. Moreover, a magnitude effect was found with the FCQ, such that smaller amounts of food were discounted more steeply than larger amounts. In addition, individuals with higher percent body fat (PBF) discounted food more steeply than individuals with lower PBF. The MCQ, which also produced a magnitude effect, and the monetary adjusting amount procedure yielded data that were orderly, consistent, and correlated strongly with one another, replicating previous literature. This study is the first to show that a novel measure of food discounting (the FCQ) yields consistent data strongly correlated with an established measure of food discounting and is sensitive to PBF. Moreover, the FCQ is easier and quicker to administer than the AA procedure, which may interest researchers who use discounting tasks in food-related research.

Steeper delay and probability discounting of potentially real versus hypothetical cigarettes (but not money) among smokers

Our study compared the quantitative and qualitative outcomes associated with course evaluations collected over the Internet with those collected using a paper-and-pencil method. We randomly assigned students to 1 of the 2 different formats. There was no significant difference in quantitative student responses based on administration method, but students who completed evaluations over the Internet were more likely to give qualitative feedback compared to students who completed their evaluations in the classroom. Moreover, students in the Web-based condition provided longer qualitative comments than students in the paper-and-pencil group. We discuss the implications of these findings.