The effects of nodality on the formation of equivalence classes

A four-member equivalence class (A → B → C → D) can be formed by training AB, BC, and CD. The nodal stimuli, B and C, mediate all of the derivative (transitive and equivalence) relations in the class. The derivative relations AC, CA, BD, and DB are separated by one node, whereas AD and DA are separated by two nodes. How do the number of nodes that separate the stimuli in a derivative relation influence the induction of stimulus control exerted by that relation? Seven college students learned two four-member classes made up of nonsense syllables. After training, all derivative relations were presented repeatedly without informative feedback. Stimulus control exerted by each derivative relation was assessed concurrently. For the 7 subjects, control exerted by the derivative relations increased gradually with repeated presentations. With 6 of the 7 subjects, the one-node relations exerted more control than the two-node relations during the process. However, the disparity between the one- and two-node relations decreased with repeated presentations. Eventually, all derivative relations exerted complete control. The control exerted by derivative relations during induction was inversely related to the number of nodes separating the terms in the derivative relations. These results demonstrate that nodal distance is a determinant of the relatedness of stimuli in equivalence classes. The findings are discussed in terms of remote association, semantic memory networks, and the study of transitive inference.     

Contextualizing Gender and Acculturative Influences on Sexual Initiation of Asian Indian Emerging Adults

Although Asian Indians represent one the fastest growing demographics in the United States, no studies exist on the sexual behavior of Asian Indian youth or its association with acculturation. Previous research has demonstrated a link between earlier sexual initiation and subsequent sexual risk and the role of acculturation and sexual initiation in other Asian groups. The present exploratory study examined gender and acculturation with regard to sexual initiation in Asian Indians (n = 37). Results reveal no significant gender differences in sexual initiation and total acculturation scores. Gender differences did emerge for the association among sexual behaviors and the influence of specific areas of acculturation on sexual initiation. Findings suggest that gender and acculturation may be important variables in understanding sexual behavior but that current acculturation measures may be insufficient to adequately assess acculturation levels of Asian Indian youth. Future research should focus on Asian Indians as an understudied minority group.     

Is it Too Soon to Meet? Examining Differences in Geosocial Networking App Use and Sexual Risk Behavior of Emerging Adults

Location-based geosocial networking smartphone applications (GSN apps) have become a popular way to meet romantic and casual sex partners. Although first used primarily by men who have sex with men (MSM), GSN apps are now commonly used in the population at large, particularly among emerging adults. Although, these apps may potentially contribute to increases in STI/HIV incidence, previous research linking GSN app use to sexual risk behavior has been mixed, with some suggesting app users report greater sexual risk behavior and others suggesting less. The present paper details findings of two studies with independent samples of emerging adults. The first, a pilot study, examined GSN app use among young MSM (n = 64) to identify possible within-group factors relating dating app use to sexual risk behavior. Results indicated that the time app users spent talking to each other through the app before meeting in person (time before meeting) was related to engagement in sexual risk behavior. Those who talked less before meeting in person engaged in more sexual risk behaviors than those who spent more time talking before meeting in person. The second study sought to expand upon this finding in a more representative sample of GSN app users (n = 129) and compared sexual risk behavior and impulsivity to non-users (n = 88). There were no differences in sexual risk behavior between GSN app users and non-users. However, when examining app users by time before meeting, those with a shorter time before meeting were more impulsive and more likely to report sexual risk behavior. These findings highlight the importance of understanding GSN app use in the spread of STIs/HIV among emerging adults.     

Health-related quality of life in Parkinson's disease after pallidotomy and deep brain stimulation

This study explored the multidimensional outcome of three neurosurgical interventions for Parkinson's disease (PD): pallidotomy (N = 23), pallidal deep brain stimulation (DBS) (N = 9), and thalamic DBS (N = 7). All patients completed the Sickness Impact Profile (SIP) and the Beck Depression Inventory. Pallidotomy patients also completed the Profile of Mood States, the Beck Anxiety Inventory, and a disease-specific quality of life (QOL) measure, the Parkinson's Disease Questionnaire (PDQ-39). Three months after surgery, all neurosurgical groups showed significant improvements in mood and function, including physical, psychosocial, and overall functioning. Pallidal DBS and pallidotomy patients who completed additional QOL measures reported decreased anxiety and tension, increased vigor, improved mobility and ability to perform activities of daily living, and decreased perceived stigma. Psychosocial dysfunction scores from the SIP were related to depressed mood both at baseline (r = .42) and at followup (r = .45), but the physical dysfunction subscale was not related to mood at either time point, suggesting that disruption of social relationships due to PD may have more impact on affective distress than physical symptoms alone. Results suggest that neurosurgical interventions for PD improve disabling PD motor symptoms and also improve several domains of quality of life.     

Discrimination and Puerto Rican children's and adolescents' mental health

Two studies of Puerto Rican youths' development on the U.S. mainland examined the consequences of perceived racial/ethnic discrimination on mental health. In Study I, children were found to have a low likelihood of perceiving discrimination, whereas in Study 2, nearly half of the adolescent sample reported perceiving racial/ethnic discrimination. Although both groups scored high on multiple indicators of mental health, perceiving discrimination and worrying about discrimination were negatively associated with some dimensions of self-esteem and positively associated with depression and stress. Adolescents were aware of negative stereotypes about Puerto Ricans, and nearly half of them related discriminatory instances. Results suggest that both perceiving discrimination and anxiety regarding discrimination can serve as risk factors for the mental health of this population.     

An Integrative Brief Treatment Approach for Obsessive-Compulsive Disorder

This article reports on the integrated application of cognitive therapy, transactional analysis techniques, and the behavioral technique of response prevention using self-instructional training and behavioral substitution in a brief therapy approach. These methods were applied in the case of a young man who presented with compulsions to perform repetitive and ordering rituals with the belief that it would prevent his girlfriend from becoming pregnant. A 21-year-old white male who had performed 3 to 5 hours of rituals daily for several years was able to eliminate the majority of his compulsive behaviors and reduce his level of anxiety after eight clinical therapy sessions. Results were maintained at 6-month follow-up. The clear precipitating factors and the unusual maintaining variables for the disorder in the client are described. The author discusses the case in light of current theoretical, therapeutic, and biomedical understandings of the disorder.     

Early and late introduction of probes and stimulus control acquisition in fading

College students learned to name Braille patterns presented visually using a fading procedure in which Braille patterns were superimposed on letter names after which letter names were attenuated. Measurement of acquisition was accomplished by presenting probes—consisting of the Braille stimuli only—throughout fading. Effects of probes upon acquisition were assessed by introducing probes early or late in fading. Fewer fading levels were needed for Braille elements to acquire control when probes were introduced early rather than late. When probes were introduced late, all subjects learned to name the Braille elements as the letters were being faded out. When probes were introduced early, however, most subjects learned to name the Braille elements as they were being faded in. Since virtually no errors occurred during compound-stimulus presentations, the probe procedure did not induce errors during acquisition. Quantitative analysis of probe data suggested that inclusion of probes enhanced the control acquired by the Braille elements during compound-stimulus presentations. The reported effects may have been due to differences in the relative frequency of reinforcement presented during compounds and probes.     

Union Influence on Internal Organizational Decisions: An Empirical Analysis

The development of appropriate models of organizational decision making requires a complete determination of the different groups that affect the decision-making process. The present investigation examines the influence of union officials as a group on internal organizational decisions. The rank and file membership of three local unions ( N = 1324) and their first level supervisors ( N = 205) were surveyed regarding the perceived influence of five different groups within the organizational hierarchy. A methodology developed by Tannenbaum (1968) and his associates was modified to include lower-level union representatives as one of five groups who potentially wield influence over organizational decisions. The results of this investigation determined that union representatives are seen as possessing significant levels of influence regarding microlevel organizational decisions. Additional analyses revealed that first-level supervisors believed that union representatives possessed more influence in organizational decisions than they possessed as a group. The implications of these findings and suggestions for future research are discussed.     

STIMULUS GENERALIZATION AND EQUIVALENCE CLASSES: A MODEL FOR NATURAL CATEGORIES

Two three-member classes were formed by training AB and BC using a conditional discrimination procedure. The A and B stimuli were nonsense syllables, and the C stimuli were sets of “short” or “long” lines. To test for equivalence, C1 or C2 was presented as a sample with A1 and A2 as comparisons. Once the class-related comparison was chosen consistently, different line lengths were substituted for the training lines in the CA tests. In general, the likelihood of choosing a given comparison was an inverse function of the difference in the length of the test line from the training line. Stimuli in an equivalence class became functionally related not only to each other but also to novel stimuli that resembled a member of the equivalence class. The combination of primary generalization and equivalence class formation, then, can serve as a model to account for the development of naturally occurring categories.     

The formation of linked perceptual classes

Multiple-exemplar training with stimuli in four domains induced two new fill-based (A1' and A2') and satellite-image-based (B1' and B2') perceptual classes. Conditional discriminations were established between the endpoints of the A1' and B1' classes as well as the A2' and B2' classes. The emergence of linked perceptual classes was evaluated by the performances occasioned by nine cross-class probes that contained fill variants as samples and satellite variants as comparisons, along with nine other cross-class probes that consisted of satellite variants as samples and fill variants as comparisons. The 18 probes were first presented serially and then concurrently. Class-consistent responding indicated the emergence of linked perceptual classes. Of the linked perceptual classes, 70% emerged during the initial serial test. An additional 20% of the linked perceptual classes emerged during the subsequently presented concurrent test block. Thus, linked perceptual classes emerged on an immediate or delayed basis. Linked perceptual classes, then, share structural and fuctional similarities with equivalence classes, generalized equivalence classes, cross-modal classes, and complex maturally occurring categories, and may clarify processes such as intersensory perception.