Discriminability and sensitivity to reinforcer magnitude in a detection task

Three pigeons discriminated between two sample stimuli (intensities of red light). The difficulty of the discrimination was varied over four levels. At each level, the relative reinforcer magnitude for the two correct responses was varied across conditions, and the reinforcer rates were equal. Within levels, discriminability between the sample stimuli did not change systematically as reinforcer magnitude varied. Across levels, the sensitivity of behavior to changes in the reinforcer-magnitude ratio decreased as the discriminability between the sample stimuli increased. Subsequent analysis showed that this relation was limited to performance following only one of the sample stimuli, the dim red light that remained constant across all conditions. Extant behavioral models of signal detection cannot easily accommodate these results.     

An examination of the effects of 5-Methoxy-n, n-di(ISO)propyltryptamine hydrochloride (Foxy) on cognitive development in rats

The hallucinogenic "designer drug" known as Foxy or Methoxy Foxy and formally know as 5-Methoxy-N,N-di(iso)propyltryptamine hydrochloride (5-MeO-DIPT) is rapidly gaining popularity among recreational users. However, little is known about the consequences of its use on neuropsychological development or behavior. During one of two adolescent periods, the rats were given repeated injections of either saline or 5 mg/kg of 5-MeO-DIPT. Once the animals reached 80 days of age, they were trained and tested on a number of tasks designed to assess the effects of 5-MeO-DIPT, if any, on memory tasks with spatial components that presumably involve declarative memory systems and on a nonspatial task that is considered sensitive to disruptions in nondeclarative memory. With one exception, both the 5-MeO-DIPT- and saline-treated rats were able to master the spatial navigation tests at comparable rates. However, the performance of the drug-treated rats was markedly inferior to that of the control animals on a response-learning task, suggesting a lack of flexibility in adapting their responses to changing task demands. This could indicate reductions in serotonin activity in the forebrain similar to the effects of studied drugs such as methylenedioxymethamphetamine (MDMA), suggesting 5-MeO-DIPT may act as a toxin compromising serotoninergic systems in the brain.     

Bullying and victimization among black and Hispanic adolescents

The prevalence of bullying and victimization by gender, grade level, and race/ethnicity was examined among a sample of low socioeconomic, Black and Hispanic 6th- to 12th-graders in a large urban school district in Texas. Bullying and victimization were measured using specific behaviors. Students were classified as bullies (7%), victims (12%), bully-victims (5%), or neither (76%), depending on the number and frequency of reported experiences. For specific types of bullying (e.g., spreading rumors, excluding others), 4.5%-9.4% of students reported participation. Specific types of victimization (e.g., being hit or pushed, picked on) ranged from 6%-12%. Gender differences were not observed for general bullying and victimization, but physical and some verbal types were more prevalent among males. Blacks were more likely to participate in bullying and victimization, and these experiences seemed to peak in the 9th grade. This study adds to the literature as few U.S. studies on both general and specific types of bullying have been conducted among low socioeconomic, racial/ethnic minority students in middle and high school.     

Cognitive behavioral therapy for compulsive buying disorder

To our knowledge, no psychotherapy treatment studies for compulsive buying have been published. The authors conducted a pilot trial comparing the efficacy of a group cognitive behavioral intervention designed for the treatment of compulsive buying to a waiting list control. Twenty-eight subjects were assigned to receive active treatment and 11 to the waiting list control group. The results at the end of treatment showed significant advantages for cognitive behavioral therapy (CBT) over the waiting list in reductions in the number of compulsive buying episodes and time spent buying, as well as scores on the Yale–Brown Obsessive Compulsive Scale—Shopping Version and the Compulsive Buying Scale. Improvement was well-maintained at 6-month follow-up. The pilot data suggests that a cognitive behavioral intervention can be quite effective in the treatment of compulsive buying disorder. This model requires further testing.     

Recruitment of first-generation Latinos in a rural community: the essential nature of personal contact

The purpose of this article is to report on the success of various recruitment activities for a behavioral observation study with Spanish-speaking Latino families in a rural community in the western United States. Recruitment activities are pivotal to research to research because the enormous impact to the quality of the sample and, thus, the quality of the answers to the questions posed by the research. Recruitment can be especially challenging for researchers working with ethnic minorities due to a historical legacy of mistreatment by researchers that has led to healthy reticence to participate in research investigations. The present research presented unique challenges in that the data collection (1) took place in a rural community, (2) sought participation of a recent immigrant population, and (3) required videotaping. Data were collected from 50 families in a western rural community. After multiple recruitment strategies were used, the research team learned that word of mouth and use of existing community resources were the most powerful recruitment strategies. However, participant reports suggest that the other recruitment strategies helped familiarize participants with the study and potentially strengthened the influence of word of mouth referrals. Important differences were found between the easy-to-recruit and the hard-to-recruit samples within this study that support engagement in multiple recruitment strategies.     

Mathematics learning disability in girls with Turner syndrome or fragile X syndrome

Two studies were carried out to examine the persistence (Study 1) and characteristics (Study 2) of mathematics learning disability (MLD) in girls with Turner syndrome or fragile X during the primary school years (ages 5-9 years). In Study 1, the rate of MLD for each syndrome group exceeded the rate observed in a grade-matched comparison group, although the likelihood of MLD persisting through the primary school years was comparable for all three groups. In Study 2, formal and informal math skills were compared across the syndrome groups, a normative group, and children from the normative group who had MLD. Few differences were observed between the Turner syndrome and normative groups. Despite having rote counting and number representation skills comparable to those in the normative group, girls with fragile X had difficulty with counting rules (e.g., cardinality, number constancy). However, this difficulty did not distingush them from the MLD group. Overall, counting skills appear to distinguish the Turner syndrome and fragile X groups, suggesting that the specificity of math deficits emerges earlier for fragile X than Turner syndrome.     

The role of infant soothability in the relation between infant negativity and maternal sensitivity

Maternal perceptions of infant soothability moderated the relation between negative infant temperament and maternal sensitivity. Infant negative temperament and maternal sensitivity were significantly positively related when maternal perception of infant soothability was high and significantly negatively related when maternal perception of infant soothability was low.     

Delay of gratification: impulsive choices and problem behaviors in early and late adolescence

High school students were offered a monetary incentive for participating in research. They were given a choice between a smaller fee immediately or a larger fee one week later. Compared to students who delayed gratification, those who chose the immediate fee showed more self-regulatory deficits. They showed greater involvement with cigarettes, alcohol, and marijuana, had a poorer self-concept and underperformed academically. A replication study with middle-school students and different reward parameters yielded equivalent results. Younger adolescents who chose the immediate monetary incentive showed a similar pattern of problem behaviors as the high school students. The findings indicate that this simple choice-delay procedure yields an unobtrusive behavioral measure of self-regulation and offers a developmentally appropriate extension of the delay-of-gratification paradigm for use with older children and adolescents.     

Preference and resistance to change with constant- and variable-duration terminal links: independence of reinforcement rate and magnitude

Pigeons responded in a three-component multiple concurrent-chains procedure in which the variable-interval reinforcement schedules were the same across components but magnitudes differed across components. The terminal links were arranged either as a variable delay followed by presentation of a reinforcer ("variable duration") or as a fixed period of access to the schedule during which a variable number of reinforcers could be earned ("constant duration"). Relative reinforcement rate was varied parametrically across both types of conditions. After baseline training in each condition, resistance to change of terminal-link responding was assessed by delivering food during the initial links according to a variable-time schedule. Both preference and resistance to change were more sensitive to reinforcement-rate differences in the constant-duration conditions. Sensitivities of preference and resistance to change to relative reinforcement rate did not change depending on relative reinforcement magnitude. Taken together, these results confirm and extend those of prior studies, and suggest that reinforcement rate and magnitude combine additively to determine preference and resistance to change. A single structural relation linking preference and resistance to change describes all the data from this and several related studies.