Oral self-administration of pentobarbital by rhesus monkeys: relative reinforcing effects under concurrent fixed-ratio schedules.

During daily 3-hr sessions, orally delivered pentobarbital solutions and water, or two separate pentobarbital solutions, were concurrently available to rhesus monkeys according to fixed-ratio schedules of mouth contacts with a spout. First water, and then each of four "comparison-concentration" pentobarbital solutions (0.0625, 0.25, 1, and 4 mg/mL), was successively available from one spout for a block of sessions under a fixed-ratio-64 (three monkeys) or fixed-ratio-16 (one monkey) schedule. Under an identically sized fixed-ratio schedule, deliveries of a "standard-concentration" pentobarbital solution were concurrently available from a second spout. The concentration of the standard solution remained unchanged throughout testing of the series of comparison solutions. Each of three pentobarbital concentrations (4, 1, and 0.25 mg/mL) in turn served as the standard concentration. Within each pair of concurrently available solutions, the higher drug concentration maintained more behavior than the lower concentration. Thus when monkeys were provided with concurrent access to different pentobarbital concentrations, relative reinforcing effects were directly related to drug concentration. Further, the amount of behavior maintained by a particular drug concentration was dependent on the concentration of the concurrently available drug solution. Thus, the relative effectiveness of a reinforcer in maintaining behavior is a function of both the reinforcer's magnitude and the availability of alternative reinforcers in the environment.     

A rasch model for continuous ratings

A unidimensional latent trait model for continuous ratings is developed. This model is an extension of Andrich's rating formulation which assumes that the response process at latent thresholds is governed by the dichotomous Rasch model. Item characteristic functions and information functions are used to illustrate that the model takes ceiling and floor effects into account. Both the dichotomous Rasch model and a linear model with normally distributed error can be derived as limiting cases. The separability of the structural and incidental parameters is demonstrated and a procedure for estimating the parameters is outlined.     

Emotional modulation of attention orienting: A classical conditioning study

Emotional modulation of attention shifting was investigated in Posner's (1980) spatial orienting task by conditioning the attention cue to an aversive white noise. Prior to the attention task, the Conditioning group received a 90dB white noise unconditioned stimulus (UCS) contingent upon the frame-lit rectangle attention cue, while the Control group received non-contingent presentations. The Conditioning group evidenced greater skin conductance responses to the frame-lit rectangle in the conditioning phase, reflecting an electrodermal conditioned response. In the attention phase, the frame-lit rectangle served as the attention cue in the spatial orienting task. The Conditioning group showed equally fast reaction times (RTs) to targets presented outside the location of the cue as to targets at the same location as the cue, reflecting elimination of the cognitive cost usually involved in shifting attention. The Control group evidenced the regular cost of shifting attention away from the location of the cue. The Conditioning group also evidenced a larger N1-component with a parietal distribution of the event-related brain potentials to the cue and a larger N1-component at the frontal regions to targets presented outside the cued location. This suggests that both visual orienting to the cue and attention shifting from cue to target on invalid trials were amplified by the emotional salience attached to the cue through the classical conditioning procedure.     

The influence of gender, hypertension risk, and aerobic fitness on cardiovascular responses to laboratory-induced stress

The study sought to evaluate the influence of gender, hypertension risk, and aerobic fitness on cardiovascular responses to laboratory-induced stress. Sixty nonsymptomatic subjects (30 males, 30 females) participated in the experiment. Half of the subjects had at least one biological parent with hypertension, while half had no parental history of hypertension and served as comparison subjects. Subjects completed a laboratory procedure measuring cardiovascular responses (i.e., pulse rate and blood pressure) while performing stressful laboratory tasks (i.e., the Stroop Color Naming Test and a sham IQ test). Aerobic fitness (i.e., VO_2max using the Bruce protocol) was also determined using a submaximal treadmill test in the laboratory. Results suggest that males with a family history of hypertension were more stress responsive based on systolic blood pressure, while females were more stress-responsive according to pulse rate activity. Fitness levels were significantly associated with diastolic blood pressure throughout the stress and recovery periods but were unrelated to pulse rate and systolic blood pressure.     

Three versions of the additive theories of behavioral contrast

The additive theories of behavioral contrast state that contrast will occur only when two types of responses interact during multiple schedules. Three more specific versions of the theories may be defined according to how they distinguish these two types of responses. A strong version physically distinguishes them. A second version distinguishes them according to the theoretical processes which control them. A weak version distinguishes them on the basis of the environmental relations which control them. Only the weak version of the theories is currently testable. The weak theory should be tested by establishing each of the two environmental relations independently and then combining them to assess their effect on behavior. Because this test is not usually performed, many of the results which have been taken to support or contradict the additive theories are actually ambiguous.     

Enhancement of conditioned autonomic responses in monkey when preshock signals occasion operant suppression.

Classical pairings of a sound stilulus with shock elicited larger magnitude and more rapidly conditioned autonomic responses when subjects were responding on variable-interval schedules for food than when they were eating freely available food. The difference was not attributable to changes in control values of heart rate and blood pressure, or to alterations in motor activity, but appeared related to operant suppression.     

Effects of barbiturates and other sedative hypnotics in pigeons trained to discriminate phencyclidine from saline.

Pigeons were trained to peck the center key (lighted white) of three response keys to turn off the center keylight and to light one of the side keys with a red keylight and the other side key with a green keylight. Five responses (fixed-ratio component) on either side key relighted the center key. Food was delivered following 10 fixed-ratio components on the red key if 1.5 mg/kg phencyclidine had been given before the session. The position of the red and green keylights on the side keys varied randomly each time they were lighted by a peck on the center key. Subsequently, increasing doses of phencyclidine, barbital, amobarbital, phenobarbital, methaqualone, methyprylon, diazepam, oxazepam, and d-amphetamine were substituted for the training dose of phencyclidine, using a cumulative dosing procedure. At low doses of the sedative hypnotics, birds pecked the keylight color associated with saline. At higher doses, birds pecked both key colors. At the highest doses of pentobarbital and amobarbital, some birds responded almost exclusively On he color associated with phencyclidine. When responding on keys of both colors occurred following administration of phencyclidine or other sedative hypnotics, this responding was controlled by key position rather than by key color.     

SATIATION THERAPY: A PROCEDURE FOR REDUCING DEVIANT SEXUAL AROUSAL

Two single-case experiments demonstrated the efficacy of satiation therapy with adult males who had long-standing deviant sexual interests. The procedure involves the pairing of prolonged masturbation (1 hour) with the verbalization by the patient of his deviant sexual fantasies and in both cases the designs permitted the attribution of control over aberrant responding to the satiation therapy. The results are discussed in terms of the possible active ingredients of the procedure.     

Periodicities within a fixed-interval session

Within-session periodicities in number of responses per interval and postreinforcement pauses were investigated on fixed-interval schedules of 1, 2, and 3 minutes with rats. Postreinforcement pause values and the number of responses in successive intervals were not systematically related. The direction of change of these variables from one pair of intervals to the next revealed periodicities in that the direction of change varied more than would be expected by chance. A response prevention technique used to manipulate the length of time spent responding in an interval had little effect on the postreinforcement pause value of the next interval except when only a single response was permitted in an interval. This procedure tended to reduce the postreinforcement pause value of the next interval to an abnormally low level.