Effects of concurrent schedules on human fixed-interval performance

Young adults performed a lever-pressing task for money on two schedules of reinforcement: concurrent fixed-interval 1 min—differential-reinforcement-of-low-rate 20-sec, and concurrent fixed-interval 1-min—fixed ratio 100 responses. All subjects were trained on both schedules. Fixed-interval performance concurrent with the differential reinforcement procedure was characterized by high constant rates with no post-reinforcement pauses. Fixed-interval performance concurrent with fixed ratio was characterized by low rates and lengthy post-reinforcement pauses. These results differ from those obtained in prior studies on the effects of conditioning history upon subsequent fixed-interval performance. The prior work, using non-concurrent procedures, had shown that fixed-interval performance following differential reinforcement of low rates was characterized by post-reinforcement pauses and low rates, while fixed-interval performance following fixed ratio exhibited high constant rates and no post-reinforcement pause. The present results suggest that alternative concurrent contingencies are another major determinant of human fixed-interval performance.     

Gender and patterns of sexual risk taking in college students

The role that gender plays in influencing the prevalence and patterns of sexual risk taking was examined in 245 college students from two samples (about 60% of whom were White, 20% Asian, 10% Black, and 6% Hispanic). The sexual experiences of these students were analyzed for potential risk associated with type of partners or sexual practices. Consistent with previous findings, males engaged in more risk taking behaviors relevant to partner choice (e.g., more partners and more casual knowledge of partners) and sexual practices (e.g., lower levels of contraceptive use) than females. Gender differences in patterns of risk taking were also found: For females, potentially risky behavior in the partner domain was negatively related to risky behavior in the sexual practice domain, whereas for males, the domains were positively related. The results suggested that males engaged in greater risk taking across many domains, while females compensate for risk in one domain by lower risk in another.     

Human performance on conjunctive fixed-interval fixed-ratio schedules

Eighteen young adults performed a lever-pulling task for money. Subjects were initially exposed to a fixed-interval 80-second schedule and subsequently to one of three conjunctive schedules in which the added fixed-ratio requirement was set at either 10, 80, or 120 responses. Three fixed-interval response patterns emerged: high constant rate, intermediate rate, or low rate, with most subjects displaying the last. Conjunctive performance was related to the subjects' prior fixed-interval patterns and the conjunctive ratio requirements. Low-rate subjects tended to optimize reinforcement (maximum reinforcers for minimum responses) on conjunctive schedules. Response rate was directly related to ratio requirements. Subjects' performance closely corresponded to their verbal statements of the contingencies.     

Response allocation to concurrent fixed-ratio reinforcement schedules with work requirements by adults with mental retardation and typical preschool children.

The present experiments examined the effect of work requirements in combination with reinforcement schedule on the choice behavior of adults with mental retardation and preschool children. The work requirements of age-appropriate tasks (i.e., sorting silverware, jumping hurdles, tossing beanbags) were manipulated. Participants were presented with their choice of two response options for each trial that varied simultaneously on both work requirement and reinforcement schedule. Results showed that when responding to both choices occurred on the same reinforcement schedule, participants allocated most of their responses to the option with the easier work requirement. When the response option requiring less work was on a leaner reinforcement schedule, most participants shifted their choice to exert more work. There were individual differences across participants regarding their pattern of responding and when they switched from the lesser to the greater work requirement. Data showed that participants' responding was largely controlled by the reinforcement received for responding to each level of work. Various conceptualizations regarding the effects of work requirements on choice behavior are discussed.     

Stimulus generalization and the response-reinforcement contingency

Generalization gradients along a line-tilt continuum were obtained from groups of pigeons that had been trained to peck a key on different schedules of reinforcement. In Exp. I, gradients following training on a differential-reinforcement-of-low-rate (DRL) schedule proved to be much flatter than gradients following the usual 1-min variable interval (VI) training. In Exp. II, the value of the VI schedule itself was parametrically studied; Ss trained on long VI schedules (e.g., 4-min) produced much flatter gradients than Ss trained on short VI schedules (30-sec; 1-min). The results were interpreted mainly in terms of the relative control exerted by internal, proprioceptive cues on the different reinforcement schedules. Several implications of the results for other problems in the field of stimulus generalization are discussed.     

Predictors of disclosure of human immunovirus-positive serostatus among Latino gay men

To test a theoretical approach to disclosure of human immunovirus (HIV) status, 301 HIV-positive Latino gay men were interviewed using Audio-CASI (Computer Assisted Self-Interview technology with Audio enhancement). Consequence theory and social influence theory were combined to create a model of antecedents of disclosure. Results provided support for both theories. Perceived positive consequences were associated with greater disclosure to casual partners, families, and friends, whereas perceived negative consequences were associated with less disclosure to friends and family members. Social influence of peer behavioral norms was predictive of disclosure to all three target groups. Gay community social influence produced different effects on disclosure of HIV-positive status: a negative association for casual partners, a positive association for close friends, and no relationship for family members. Time since diagnosis was also predictive of disclosure.     

Disclosure of HIV-Positive Status to Latino Gay Men's Social Networks

This study explored disclosure of serostatus in a sample of 155 HIV-positive Latino gay men from New York City and Washington, DC. We examined rates of disclosure to different members of the social network: mothers, fathers, close friends, and primary sexual partners. There were high rates of disclosure of HIV-positive serostatus to main partners and closest friends and lower rates to fathers and mothers. We examined the role of 3 contextual target-dependent factors (emotional closeness to target, anticipated reactions from target, and target's knowledge of sexual orientation), as well as acculturation and time since diagnosis. Three separate logistic regression models were performed to predict disclosure of HIV-positive status to 3 targets: mothers, fathers, and closest friends. We found that disclosure was not a generalized tendency, but rather different factors were influential depending on the target. Whether the target was aware of participant's sexual orientation was associated with disclosure in all 3 models. Greater emotional closeness also predicted disclosure to mother and father; greater U.S. acculturation was associated with disclosure to father and marginally to mother. A longer time since diagnosis was associated with disclosure to the closest friend. These findings highlight the importance of taking into account roles and relationships, and their effect on disclosure.     

Human fixed-interval performance with concurrently programmed schedules: A parametric analysis

Young adults pressed a lever for points, exchangeable for money, programmed on concurrent schedules in which one component was a fixed-interval and the other component either a fixed-ratio (Experiment 1) or a differential-reinforcement-of-low-rate (Experiment 2). Two general patterns of fixed-interval responding, postreinforcement pause or constant rate, occurred in both experiments as a function of the parameter values of each component. Also patterns of interaction between the component schedules developed, in which responding or point delivery on one component appeared to be discriminative for responding on the other component. Once a pattern of responding was established, it tended to persist when the parameter values of the schedule were changed. On many schedules, subjects with an experimental history responded differently than did naive subjects, although certain schedule values were resistant to the history effects. The role of verbal strategies in mediating history effects was discussed.     

College Women and Condom Use: Importance of Partner Relationship

Because women who want to use condoms as protection against STDs must gain compliance from their male partners, women's use of condoms was examined within the context of their relationships with their sexual partners. Sexual history, condom attitudes, and relationship information were gathered from a sample of 272 heterosexual college women. For the 121 women with a current sexual partner, logistic regression analyses revealed that both regular condom use and completely consistent condom use were more likely in shorter relationships and for women who perceived lower barriers to use. Regular condom use was also greater in relationships described as high in trust, whereas consistent condom use was greater for women in their first sexual relationships. In addition, many women reported using condoms early in their relationships, but changing to lower levels of use later. Implications of the current findings for safer-sex interventions are discussed.