Asymptotic reinforced responding as a function of the operant level of the instrumental response

The relationship between operant level (base rate) and asymptotic reinforced instrumental responding was investigated in several contingencies in which licking was contingent upon running, under different FR schedules. For Group I the relationship was examined by selecting rats who naturally differed in their running base rates and for which the licking base rates were equivalent. For Group II the relationship was examined by selecting rats with equivalent running and licking base rates, but whose running rates were eventually made to differ by manipulating wheel-torque requirements. Asymptotic reinforced instrumental responding was found to be linearly related to pre-contingent running base rates, for all FR schedules, and independent of the procedures used to obtain differing running base rates. The results support Premack's contention that asymptotic reinforced instrumental responding is a joint function of the reinforcing response and the operant level of the instrumental response.     

The effects of natural category size on memory for episodic encodings

Previous findings indicate that natural category size affects cued recall but not recognition performance. Words that define or belong to larger categories are not as likely to be recalled in the presence of an extralist cue. However, category size has no effect on recognition in the presence of the target as the cue. Theoretically, this difference could be due to inherent differences between these tasks, to the use of different types of test cues, or to differences in the nature of the required responses (naming compared with “yes/no”decisions). Three experiments indicated that none of these factors is a sole determinant. Natural category size effects were found in cued-recall and recognition tasks, with extralist and target cues and regardless of the required response. The critical factor is whether the testing conditions require or encourage subjects to search the category defined by the cue. With the initiation of such a search, information represented in semantic memory is likely to influence memory for episodic information.     

FOCAL,FORTRAN, and BASIC programs for reformatting and analyzing data collected by the SKED program

Several programs have been written in the FOCAL, FORTRAN, and BASIC languages for reformatting and analyzing SKED data. These programs include selection and explicit labeling of sets of recording counters representing distributions and/or total counts of events, several general manipulations of distributional data, and standard statistical treatment of distributions.     

Do Overgeneral Autobiographical Memories Predict Increased Psychopathological Symptoms in Community Youth? A 3-Year Longitudinal Investigation

Research suggests that an overgeneral autobiographical memory style (i.e., retrieval of general memories when instructed to retrieve a specific episodic memory) represents a vulnerability marker for depression. Although adolescence is a period of high risk for the emergence of depression, little research has investigated the associations among overgeneral memory, psychopathology, and risk factors longitudinally in a community sample in this age group. We, therefore, investigated overgeneral memory, psychopathology (depression and anxiety), and rumination (an established risk factor for psychopathology) longitudinally in 269 typically-developing youth (125 females, 144 males) across 3 annual assessment points. We sought to determine whether 1) overgeneral memory would predict psychopathology across the entire sample, and 2) whether associations would vary as a function of longitudinal rumination growth. Across the entire sample, overgeneral memory did not predict psychopathology. For youth who reported elevated, and increasing, patterns of rumination over time, transient relationships between overgeneral memory and subsequent increases in anxiety were found. We conclude that overgeneral memory may represent a vulnerability marker for adverse psychological outcomes only for youth at risk for psychopathology.     

Gay Identity and HIV Risk for Black and Latino Men Who Have Sex with Men

Strong gay identity among white men who have sex with men (MSM) has been associated with decreased HIV risk, but data for black and Latino MSM (BLMSM) are inconclusive. We examined gay identity and HIV risk among BLMSM to inform social and structural HIV intervention strategies. BLMSM were administered a computerized survey as part of an HIV research study during 2011–2012 conducted in New York City. We used a brief scale of Gay Identity Questionnaire. After data analysis, Stage I (not fully accepting) and Stage II (fully accepting) gay identity were determined based on participant responses. We used logistic regression to calculate adjusted odds ratios (aOR) and 95% confidence intervals (CI) for the association between gay identity with HIV risk and social determinant factors. Among 111 self-identified BLMSM (median age = 32 years, 68.4% with some college or higher education), 34.2% reported receptive anal sex without condoms in the previous three months. Gay Identity Questionnaire Scale assessment indicated that 22 (19.8%) were Stage I, and 85 (76.6%) were Stage II in this BLMSM sample. Stage II gay identity was more likely seen among BLMSM with high involvement in the gay community (aOR 3.2; CI 1.00, 10.26) and less likely among BLMSM who exchanged sex for food or shelter (aOR 0.15; CI 0.02, 0.98). Fully accepting gay identity may be protective for BLMSM as it relates to transactional sex; these factors warrant further research and consideration as part of HIV prevention strategies.     

Poststimulation time interval-dependent effects of motor cortex anodal tDCS on reaction-time task performance

Anodal transcranial direct current stimulation (tDCS) induces long-term potentiation-like plasticity, which is associated with long-lasting effects on different cognitive, emotional, and motor performances. Specifically, tDCS applied over the motor cortex is considered to improve reaction time in simple and complex tasks. The timing of tDCS relative to task performance could determine the efficacy of tDCS to modulate performance. The aim of this study was to compare the effects of a single session of anodal tDCS (1.5 mA, for 15 min) applied over the left primary motor cortex (M1) versus sham stimulation on performance of a go/no-go simple reaction-time task carried out at three different time points after tDCS—namely, 0, 30, or 60 min after stimulation. Performance zero min after anodal tDCS was improved during the whole course of the task. Performance 30 min after anodal tDCS was improved only in the last block of the reaction-time task. Performance 60 min after anodal tDCS was not significantly different throughout the entire task. These findings suggest that the motor cortex excitability changes induced by tDCS can improve motor responses, and these effects critically depend on the time interval between stimulation and task performance.