A two‐part mixed effects model for cigarette purchase task data

The Cigarette Purchase Task is a behavioral economic assessment tool designed to measure the relative reinforcing efficacy of cigarette smoking across different prices. An exponential demand equation has become a standard model for analyzing purchase task data, but its utility is compromised by its inability to accommodate values of zero consumption. We propose a two‐part mixed effects model that keeps the same exponential demand equation for modeling nonzero consumption values, while providing a logistic regression for the binary outcome of zero versus nonzero consumption. Therefore, the proposed model can accommodate zero consumption values and retain the features of the exponential demand equation at the same time. As a byproduct, the logistic regression component of the proposed model provides a new demand index, the “derived breakpoint”, for the price above which a subject is more likely to be abstinent than to be smoking. We apply the proposed model to data collected at baseline from college students (N = 1,217) enrolled in a randomized clinical trial utilizing financial incentives to motivate tobacco cessation. Monte Carlo simulations showed that the proposed model provides better fits than an existing model. We note that the proposed methodology is applicable to other purchase task data, for example, drugs of abuse.     

Sibling Death and Adult Maladjustment Indices: A Brief Report

While symptoms of grief pose the most immediate psychological concern in the aftermath of sibling death, emerging research suggests that distal correlates may include strained interpersonal relations and externalized forms of psychological distress. College students with a history of Sibling Loss (n = 36), Parental Loss (n = 32), or No Loss (n = 367) were compared on the Minnesota Multiphasic Personality Inventory (MMPI-2). Sibling Loss was associated with higher Psychopathic Deviate (Pd; d = .62) and Hypomania (d = .42) scores. The relative risk (RR = 2.96) of a Pd elevation (T > 65) was higher after sibling death.     

Ensemble coding remains accurate under object and spatial visual working memory load

A number of studies have provided evidence that the visual system statistically summarizes large amounts of information that would exceed the limitations of attention and working memory (ensemble coding). However the necessity of working memory resources for ensemble coding has not yet been tested directly. In the current study, we used a dual task design to test the effect of object and spatial visual working memory load on size averaging accuracy. In Experiment 1, we tested participants’ accuracy in comparing the mean size of two sets under various levels of object visual working memory load. Although the accuracy of average size judgments depended on the difference in mean size between the two sets, we found no effect of working memory load. In Experiment 2, we tested the same average size judgment while participants were under spatial visual working memory load, again finding no effect of load on averaging accuracy. Overall our results reveal that ensemble coding can proceed unimpeded and highly accurately under both object and spatial visual working memory load, providing further evidence that ensemble coding reflects a basic perceptual process distinct from that of individual object processing.     

Exploring the Public Understanding of Basic Genetic Concepts

It is predicted that the rapid acquisition of new genetic knowledge and related applications during the next decade will have significant implications for virtually all members of society. Currently, most people get exposed to information about genes and genetics only through stories publicized in the media. We sought to understand how individuals in the general population used and understood the concepts of “genetics” and “genes.” During in-depth one-on-one telephone interviews with adults in the United States, we asked questions exploring their basic understanding of these terms, as well as their belief as to the location of genes in the human body. A wide range of responses was received. Despite conversational familiarity with genetic terminology, many noted frustration or were hesitant when trying to answer these questions. In addition, some responses reflected a lack of understanding about basic genetic science that may have significant implications for broader public education measures in genetic literacy, genetic counseling, public health practices, and even routine health care.     

Exploring Parent-Adolescent Communication About Gender: Results from Adolescent and Emerging Adult Samples

Although parents are assumed to be children's primary models of socialization when it comes to gender, little is known about direct communication of gendered values in the family. Accordingly, this study assessed the amount and content of recalled parental gender socialization messages using data from 291 U.S. college undergraduates attending a large Midwestern university and 259 U.S. adolescents enrolled in public high schools in the Midwest. The study examined the amount and content of parental communications of five gendered discourses and then tested for connections to current gender beliefs. Findings indicate that gender socialization may be quite similar for sons and daughters, with some evidence of gender typing in patterns of communication. No significant age differences emerged in the patterns of socialization, although high school students reported receiving greater amounts of communication than college students on two of the five discourses. In general, receiving messages promoting traditional gender roles was associated with more traditional gender beliefs (and vice versa), although interpretation of some messages appeared to vary by gender.     

Voluntary Consent in Correctional Settings: Do Offenders Feel Coerced to Participate in Research?

A major ethical concern in research with criminal offenders is the potential for abuse due to coercive influences that may adversely affect offenders' capacity to give voluntary consent to participate in research conducted in correctional settings. Despite this concern, to date there have been almost no systematic scientific investigations of the extent to which offenders themselves perceive that coercion occurs in these settings or that it is likely to influence their decisions about research participation. In a sample of over 600 ethnically diverse men and women recruited from various prisons and community corrections facilities in Texas and Florida, we used a vignette-based survey concerning a hypothetical research project to measure and compare offenders' global perceptions of coercive processes, as well as the differential salience and perceived coercive influence of specific factors (e.g., coercion by other inmates, inducements from staff). Somewhat surprisingly, across multiple outcome measures our participants on average reported relatively little in the way of significant coercive influences on their capacity to make voluntary decisions concerning research participation. Implications and directions for future research on coercive influences in offender research are discussed.     

Sensitization and habituation of motivated behavior in overweight and non-overweight children

The rate of habituation to food is inversely related to energy intake, and overweight children may habituate slower to food and consume more energy. This study compared patterns of sensitization, as defined by an initial increase in operant or motivated responding for food, and habituation, defined by gradual reduction in responding, for macaroni and cheese and pizza in overweight and non-overweight 8- to 12-year-old children. Non-overweight children habituated faster to both foods than overweight children (p = .03). All children recovered motivated responding for a new food (chocolate). Overweight children consumed more energy than non-overweight children (p = .0004). Children who showed a sensitization in responding consumed more food (p = .001), and sensitization moderated the effect of overweight on habituation, with slower habituation for overweight children who sensitized (p < .001). This study replicates previous data on overweight/non-overweight differences in habituation of food and energy intake, and provides new information that individual differences in sensitization and habituation of motivated responding to obtain food may be associated with a sustained motivation to eat, resulting in greater energy intake.     

Induced loudness reduction as a function of frequency difference between test tone and inducer

When a high-intensity tone (inducer) is followed by a moderate-intensity tone (test tone), the loudness of the latter is reduced. This phenomenon, called induced loudness reduction (ILR), depends on the frequency separation of the two tones; as the difference in frequency increases, the amount of ILR decreases. However, the precise course of this decrease is not well known. This article presents two experiments that address this question. In the first experiment, the amount of loudness reduction produced by a 2.5-kHz 80-dB-SPL inducer was measured with the frequency of the test tone swept from 800 Hz to 6 kHz. In the second experiment, the amount of ILR was measured with the same inducer and with test tones set at 2, 2.5, 3, and 4 kHz. Both experiments show that some ILR occurs at frequency separations as wide as four critical bands.