Acquisition of cocaine self-administration with unsignaled delayed reinforcement in rhesus monkeys

Six experimentally naive rhesus monkeys produced 0.01 mg/kg/infusion cocaine by lever pressing under a tandem fixed-ratio 1 differential-reinforcement-of-other-behavior schedule. One lever press initiated an unsignaled 15- or 30-s delay culminating in cocaine delivery. Each press made during the delay reset the delay interval. With two exceptions, responding was acquired and maintained at higher rates than responding on a second (inoperative) lever. For the exceptions, a cancellation contingency was arranged in which each formerly inoperative-lever response reset the tandem schedule. This manipulation reduced presses on the inoperative lever. Subsequently, the consequences of responding on the two levers were reversed, and the monkeys again responded at higher rates on the operative lever. As a comparison, 3 additional experimentally naive monkeys received response-independent cocaine deliveries. Although lever pressing was observed, it extinguished and was subsequently reestablished under the tandem schedule. The results suggest that although response-reinforcer contiguity is not required for cocaine to acquire reinforcing functions, a response-reinforcer relation appears necessary.     

Does a causal relation exist between the functional hemispheric asymmetries of visual processing subsystems?

Past research indicates that specific shape recognition and spatial-relations encoding rely on subsystems that exhibit right-hemisphere advantages, whereas abstract shape recognition and spatial-relations encoding rely on subsystems that exhibit left-hemisphere advantages. Given these apparent regularities, we tested whether asymmetries in shape processing are causally related to asymmetries in spatial-relations processing. We examined performance in four tasks using the same stimuli with divided-visual-field presentations. Importantly, the asymmetry observed in any one task did not correlate with the asymmetries observed in the other tasks in ways predicted by extant theories. Asymmetries in shape processing and spatial-relations encoding may not be due to a common causal force influencing multiple subsystems.     

Interactive visual and postvisual processes and their roles in form-specific memory.

Effects of depth of encoding on form-specific memory were examined. After viewing words (e.g., "bear") presented centrally during initial encoding, participants completed word stems (e.g., "BEA") presented laterally and pattern masked during subsequent test. When the encoding task was perceptual, letter-case specific memory was not observed, unlike in previous experiments without pattern masking. However, when the encoding task required both perceptual and conceptual processing, letter-case specific memory was observed in direct right-hemisphere, but not in direct left-hemisphere, test presentations, like in previous studies without pattern masking. Results were not influenced by whether stems were completed to form the first words that came to mind or words explicitly retrieved from encoding. Depth of encoding may influence form-specific memory through interactive processing of visual and postvisual information.     

Randomized controlled trial of a prenatal focused coparenting consultation for unmarried black fathers and mothers: One-year infant and family outcomes

In the infant mental health field, scant conceptual attention has been given to coparenting and family adaptations of non-white family systems, with no evidence-based, community-informed coparenting interventions responsive to unmarried Black mothers’ and fathers’ life circumstances. This study examined 1-year post-partum child and family outcomes of a novel, modest dosage (six sessions) prenatal focused coparenting consultation (FCC) using randomized controlled trial methodology. One-hundred-thirty-eight expectant families (one or both parents identified as Black/African American) were randomized to an intervention (N = 70) or treatment-as-usual (TAU; control) condition (N = 68). TAU families received navigational support in accessing existing community services for pregnant families. Intervention families received TAU plus 6 dyadic FCC sessions led by a Black male-female Community Mentor team. When infants were three and 12 months old, parents reported on coparenting, father engagement, interparental aggression, depressive symptoms, and infant social and emotional adjustment. Intent-to-treat analyses focusing on 12-month post-partum data indicated significant intervention effects on coparenting, interparental psychological aggression, and infants’ emotional adjustment. Improvement was also seen in depression and father engagement, with gains for both groups. Results suggest FCC delivered by same-race Community Mentors to unmarried Black coparents transitioning to parenthood supports infant and family adaptation during the first year of life.     

Form-specific visual priming for new associations in the right cerebral hemisphere

In three experiments, we examined the internal processing mechanisms of relatively independent visual-form subsystems. Participants first viewed centrally presented word pairs and then completed word stems presented beneath context words in the left or right visual field. Letter-case-specific priming in stem completion was found only when the context word was the same word that had previously appeared above the primed completion word and the items were presented directly to the right cerebral hemisphere. This pattern of results was not found when participants deliberately recollected previously presented words when completing the stems. Results suggest that holistic processing, not parts-based processing as assumed in many contemporary theories of visual-form recognition, is performed in a subsystem that distinguishes specific instances in the same abstract category of form and that operates more effectively in the right hemisphere than in the left hemisphere.     

Abstractionist versus exemplar-based theories of visual word priming: A subsystems resolution

Three experiments addressed abstractionist versus exemplar-based theories of the visual representations underlying word priming. Participants first read centrally presented whole words (each displayed in all lowercase or in all uppercase letters), and then they completed laterally presented word stems (each displayed in all lowercase or in all uppercase letters). Word stem completion priming was letter-case specific (greater for same-case primed items than for different-case primed items) when stems were presented directly to the right cerebral hemisphere but not when stems were presented directly to the left cerebral hemisphere. This interaction was not influenced by the typicality of the test stems, but it was observed only for stems composed of letters with visually dissimilar lowercase and uppercase structures (e.g., bea/BEA) and not for stems composed of letters with visually similar lowercase and uppercase structures (e.g., sco/SCO). In contrast, cued recall was letter-case specific when similar-case or dissimilar-case stems were presented directly to the right hemisphere. Results do not support strongly abstractionist or exemplar-based theories. Instead, they suggest a resolution to these differing perspectives: Relatively independent neural subsystems operate in parallel to underlie abstract-category and specific-exemplar priming of word forms.     

Online racial discrimination and the protective function of ethnic identity and self-esteem for African American adolescents

A growing body of literature has shown that being victimized online is associated with poor mental health. Little is known about the factors that protect youth from the negative outcomes that may result from these victimization experiences, particularly those related to race. Using a risk and resilience framework, this study examined the protective function of ethnic identity and self-esteem among African Americans who experience online racial discrimination. For the sample of 125 adolescents, hierarchical regression results revealed that higher levels of ethnic identity and self-esteem significantly moderated the negative impact of online racial discrimination on anxiety levels. These findings show that ethnic identity and self-esteem can buffer the negative mental health outcomes associated with online racial discrimination, at least with respect to adolescents' anxiety. Findings from the current study have significant implications for adolescent adjustment given the increased time youth spend doing online activities.     

The Loneliness Questionnaire-Short Version: an evaluation of reverse-worded and non-reverse-worded items via item response theory

Although reverse-worded items have often been incorporated in scale construction to minimize the effects of acquiescent reporting biases, some researchers have more recently begun questioning this approach and wondering whether the advantages associated with incorporating reverse-worded items is worth the complexities that they bring to measures (e.g., Brown, 2003 ; Marsh, 1996 ). In this study, we used item response theory (IRT) to determine whether there is statistical justification to eliminate the reverse-worded items (e.g., "I have lots of friends") from the Loneliness Questionnaire (LQ; Asher, Hymel, & Renshaw, 1984) and retain only the non-reverse-worded items (e.g., "I'm lonely") to inform the provision of a shortened LQ version. Using a large sample of children (Grades 2-7; n = 6,784) and adolescents (Grades 8-12; n = 4,941), we examined the psychometric properties of the 24-item LQ and found support for retaining the 9 non-reverse-worded LQ items to make up a shortened measure of loneliness in youth. We found that the non-reverse-worded items were associated with superior psychometric properties relative to the reverse-worded items with respect to reliability and IRT parameters (e.g., discrimination and item information). A 3-point Likert-type scale was also found to be more suitable for measuring loneliness across both children and adolescents compared to the original 5-point scale. The relative contributions of reverse-worded and non-reverse-worded items in scale development for youth instruments are also discussed.     

Predicting Treatment Response for Oppositional Defiant and Conduct Disorder Using Pre-Treatment Adrenal and Gonadal Hormones

Variations in adrenal and gonadal hormone profiles have been linked to increased rates of oppositional defiant disorder (ODD) and conduct disorder (CD). These relationships suggest that certain hormone profiles may be related to how well children respond to psychological treatments for ODD and CD. The current study assessed whether pre-treatment profiles of adrenal and gonadal hormones predicted response to psychological treatment of ODD and CD. One hundred five children, 6–11?years old, participating in a randomized, clinical trial provided samples for cortisol, testosterone, dehydroepiandrosterone, and androstenedione. Diagnostic interviews of ODD and CD were administered up to 3?years post-treatment to track treatment response. Group-based trajectory modeling identified two trajectories of treatment response: (1) a High-response trajectory where children demonstrated lower rates of an ODD or CD diagnosis throughout follow-up, and (2) a Low-response trajectory where children demonstrated higher rates of an ODD or CD diagnosis throughout follow-up. Hierarchical logistic regression predicting treatment response demonstrated that children with higher pre-treatment concentrations of testosterone were four times more likely to be in the Low-response trajectory. No other significant relationship existed between pre-treatment hormone profiles and treatment response. These results suggest that higher concentrations of testosterone are related to how well children diagnosed with ODD or CD respond to psychological treatment over the course of 3?years.