Tolerance to and residual effects of cocaine in squirrel monkeys depend on reinforcement-schedule parameter.

Lever pressing by 4 squirrel monkeys was maintained under a three-component multiple fixed-ratio schedule of food presentation; components differed with respect to ratio size. For each monkey, acute administration of cocaine (0.03 to 1.3 mg/kg, i.m.) produced dose-dependent decreases in overall response rate in each component. During repeated daily administration of 1.0 mg/kg of cocaine, tolerance developed to the rate-decreasing effects under each of the ratio contingencies, but developed to a greater extent and was evident in earlier parts of sessions for performance under the smaller ratios. Response rates of 2 monkeys increased above nondrug control levels despite the putative reinforcer not being consumed during the session. When saline or a smaller dose of cocaine was substituted for 1.0 mg/kg, response rates often were suppressed below nondrug control-level responding. This suppressive effect was observed in each monkey and was more likely to be observed and/or to be of greater magnitude in large-ratio components for 3 of the 4 monkeys. When saline was administered chronically at the end of the chronic-drug phase, response rates remained suppressed in the large-ratio component for 2 of the monkeys. There was, therefore, a schedule-dependent dissociation between behavioral tolerance and the residual effects: Tolerance was greater when small ratios were arranged, whereas the residual effects were more pronounced when larger ratios were arranged.     

Behavioral economics of drug self-administration. II. A unit-price analysis of cigarette smoking.

In behavioral economics, the ratio of response requirement to reinforcer magnitude is referred to as unit price. Previous research with nonhuman subjects has demonstrated that (a) comparable amounts of food are consumed at the same unit price even though different response requirements and reinforcer magnitudes comprise that unit price and (b) increases in unit price decrease food consumption in a positively decelerating fashion. The present study assessed the generality of these findings to the cigarette smoking of 5 human volunteers. During approximately 18 3-hr sessions, various combinations of response requirement (fixed-ratio 200, 400, and 1,600) and reinforcer magnitude (1, 2, and 4 puffs per bout) were arranged. Consumption (i.e., the number of puffs) generally was comparable at the same unit price independent of the response requirement and reinforcer magnitude comprising that unit price. In addition, increasing unit price generally decreased consumption in a positively decelerating fashion. These results extend the generality of the unit-price analysis to human cigarette smoking. Moreover, these results further support the position that reinforcer magnitude and response requirement are functionally equivalent and interact to determine consumption. The concept of unit price, by integrating and summarizing the effects of those two operations, provides a more parsimonious explanation of the results than do separate evaluations of the effects of response requirement and reinforcer magnitude.     

Fixation-point offsets reduce the latency of saccades to acoustic targets

If an observer’s fixation point is extinguished just prior to the onset of a peripheral target, the latency to saccade to that target is reduced. We show that this "gap effect" is not specific to visual targets. Observers made saccades to a light flash or to a white-noise burst. A warning tone was presented on every trial to control for the possible warning effect of the fixation-point offset. For both target modalities, saccade latencies were significantly reduced when the fixation point was extinguished 200 msec prior to the target onset. Implications of this outcome for interpretations of the gap effect are considered. It is argued that the presence of a gap effect for tones, in conjunction with previous findings, is consistent with the hypothesis that the gap effect is produced by a facilitation of premotor processes in the superior colliculus.     

Treatment of handwriting problems utilizing EMG biofeedback training.

The effects of EMG biofeedback training on cursive handwriting were investigated for 4 girls and 5 boys in Grade 4. A significant reduction in EMG between the first baseline session and the last training session was obtained. Four of 5 characteristics of handwriting improved significantly. The need for carefully designed research comparing EMG biofeedback training and relaxation training was indicated. A self-control factor in handwriting was hypothesized.     

Defining the Assessment and Treatment Competencies to Deliver Low-Intensity Cognitive Behavior Therapy: A Multi-Center Validation Study

Despite the vastly increased dissemination of the low-intensity (LI) version of cognitive behavior therapy (CBT) for the treatment of anxiety and depression, no valid and reliable indices of the LI-CBT clinical competencies currently exist. This research therefore sought to develop and evaluate two measures: the low-intensity assessment competency scale (LIAC) and the low-intensity treatment competency scale (LITC). Inductive and deductive methods were used to construct the competency scales and detailed rating manuals were prepared. Two studies were then completed. The first study used a quantitative, fully-crossed design and the second a multi-center, quantitative longitudinal design. In study one, novice, qualified, and expert LI-CBT practitioners rated an LI-CBT assessment session (using the LIAC) and an LI-CBT treatment session (using the LITC). Study two used the LIAC and LITC across four training sites to analyze the competencies of LI-CBT practitioners over time, across raters, and in relation to the actor/patients’ feedback concerning helpfulness, the alliance, and willingness to return. Both the LIAC and LITC were found to be single factor scales with good internal, test-retest reliability and reasonable inter-rater reliability. Both measures were sensitive to measuring change in clinical competence. The LIAC had good concurrent, criterion, discriminant, and predictive validity, while the LITC had good concurrent, criterion, and predictive validity, but limited discriminant validity. A score of 18 accurately delineated a minimum level of competence in LI-CBT assessment and treatment practice, with incompetent practice associated with patient disengagement. These observational ratings scales can contribute to the clinical governance of the burgeoning use of LI-CBT interventions for anxiety and depression in routine services and also in the methods of controlled studies.     

Splitting the affective atom: Divergence of valence and approach-avoidance motivation during a dynamic emotional experience

Current Psychology - Valence and approach-avoidance motivation are two distinct but closely related components of affect. However, little is known about how these two processes evolve and covary in...