A note on Horwich’s notion of grounding

Synthese - Horwich (Deflationism and paradox, Oxford University Press, Oxford, pp 75–84, 2005) proposes a solution to the liar paradox that relies on a particular notion of...     

Effects of compounding drug-related stimuli: escalation of heroin self-administration

Previous experiments have demonstrated that presenting independently established discriminative stimuli in compound can substantially increase operant responding maintained by food reinforcement or shock avoidance. Recently, this phenomenon was also shown to occur with cocaine self-administration. The present study further assessed the generality of these stimulus-compounding effects by systematically replicating them with heroin self-administration. Rats' nose-poke responses produced intravenous heroin (0.025 mg/kg per infusion) on a variable-ratio schedule when either a tone or a light was present. In the absence of these stimuli, responding was not reinforced. Once discriminative control by the tone and light had been established, the stimuli were presented in compound under extinction (with heroin discontinued) or maintenance conditions (with heroin available during test-stimulus presentations). In extinction, the tone-light compound increased responding approximately threefold compared to tone or light alone. Under maintenance conditions, compounding increased heroin intake approximately twofold. These effects closely matched those obtained earlier with cocaine. This consistency across pharmacological classes and across drug and nondrug reinforcers further confirms that (a) self-administered drugs support conditioning and learning in a manner similar to that supported by other reinforcers; and (b) multiple drug-related cues interact in lawful and predictable ways to affect drug seeking and consumption.     

The integration of habits maintained by food and water reinforcement through stimulus compounding.

In Experiment 1, a light and a tone were correlated independently with water reinforcement of bar pressing by rats. With different naive subjects in Experiment 2, one of these stimuli was correlated with food and the other with water reinforcement (counterbalanced). In both experiments the absence of tone and light signaled extinction. Tests of stimulus-reinforcer independence in Experiment 2 indicated that tone and light controlled behavior whose rate was specifically affected by deprivation state. In the stimulus-compounding tests of both experiments, response rates were higher to tone-plus-light than to tone or light presented alone (additive summation). This is the first report of additive summation produced through compounding stimuli paired with different reinforcers. The results are discussed in the context of the effects of incentive motivation on operant performance.     

Contralateral visual search deficits following TMS

Transcranial magnetic stimulation of posterior parietal vs. superior temporal sites cause differential effects on conventional conjunction vs. feature search tasks, respectively. We now report that when a decision has to be made on the target's left/right location, different lateralized deficits emerge in these two cases. With full‐field arrays, we found a specific PPC search deficit for contralateral space. With smaller, structured arrays presented in left or right hemispace, we found a specific STG deficit for contralateral parts of the array.     

Classes,why and how

Philosophical Studies - This paper presents a new approach to the class-theoretic paradoxes. In the first part of the paper, I will distinguish classes from sets, describe the function of class...     

Stimulus control of cocaine self-administration

Environmental stimuli that set the occasion wherein drugs are acquired can "trigger" drug-related behavior. Investigating the stimulus control of drug self-administration in laboratory animals should help us better understand this aspect of human drug abuse. Stimulus control of cocaine self-administration was generated here for the first time using multiple and chained schedules with short, frequently-alternating components--like those typically used to study food-maintained responding. The procedures and results are presented along with case histories to illustrate the strategies used to produce this stimulus control. All these multicomponent schedules contained variable-interval (VI) components as well as differential-reinforcement-of-other-behavior (DRO) or extinction components. Schedule parameters and unit dose were adjusted for each rat to produce stable, moderate rates in VI components, with minimal postreinforcement (infusion) pausing, and response cessation in extinction and DRO components. Whole-body drug levels on terminal baselines calculated retrospectively revealed that all rats maintained fairly stable drug levels (mean, 2.3 to 3.4 mg/kg) and molar rates of intake (approximately 6.0 mg/kg/hr). Within this range, no relation between local VI response rates and drug level was found. The stimulus control revealed in cumulative records was indistinguishable from that achieved with food under these schedules, suggesting that common mechanisms may underlie the control of cocaine- and food-maintained behavior.     

Development and structural dynamics of personal life investment in old age

The development of personal life investment (PLI) during old age was investigated with longitudinal and cross-sectional data from the Berlin Aging Study (N = 516, ages = 70-103 years). PLI measures motivational energy expended in life domains that require (obligatory PLI) or do not require (optional PLI) investment in old age. The authors used structural modeling to determine developmental trajectories and dynamics of the PLI types. On average, obligatory PLI remained unchanged between 70 and 101 years. Optional PLI declined during the transition to the 4th age (between 80 and 90 years). When change on the intraindividual level was considered, reductions in optional PLI were not related to changes in obligatory PLI, but declining obligatory PLI was associated with declining optional PLI.     

Conditioned inhibition of cocaine seeking in rats

Despite its potential relevance to the treatment of drug abuse, conditioned inhibition of drug seeking has not been systematically investigated before. In this study, rats could self-administer cocaine by lever pressing whenever a click or tone was present. Responding was not reinforced when a light was present. The light was presented simultaneously with the click (i.e., in an excitatory context) in 1 group, but the light was always presented alone in another group. When it was later presented in compound with the tone, the light was a highly effective conditioned inhibitor, suppressing cocaine seeking by 92% in the former group and by 74% in the latter. These results suggest ways to improve cue-oriented behavioral treatments for drug abuse.     

Barriers and Bridges to Intimacy and Mutuality: A Critical Review of Sexual Advice Found in Self-Help Bestsellers

Sexuality in a committed relationship is based ideally on both intimacy and mutuality. Gender socialization may limit women's and men's capacities in these two important areas of sexual relationships. This article describes the results of a content analysis of nine best-selling popular press books on the New York Times Bestseller List between 1988 and 1998 according to their advice related to sexual intimacy and mutuality. Books were analyzed to determine the degree to which they built barriers or bridges to the development of intimacy and mutuality. Results indicate that while most authors offered advice that built bridges to intimacy, several built barriers to the development of mutuality. Implications for therapists are discussed.     

Linking admiration and adoration to self-expansion: Different ways to enhance one's potential

How is admiration different from adoration? We provided one answer to this question by examining the pathways through which admiration and adoration linked to self-expansion in a questionnaire and an experimental (autobiographical recall of emotion episodes) study. Both emotions were associated with increased potential efficacy to accomplish goals (i.e., self-expansion), but different action tendencies accounted for these links. While our emotion inductions did not successfully distinguish between admiration and adoration, we could statistically disentangle their effects through mediator models. In both studies, self-reported admiration linked to self-expansion through the tendency to emulate admired others. Adoration related to self-expansion through the tendency to affiliate with adored others. These findings were obtained after controlling for other emotions in response to the target person (awe, love, hope, benign envy) and mutuality of the relationship. Our findings also suggest that considering specific emotions (rather than undifferentiated positive affect) helps uncover different pathways to self-expansion.