Differences In Responsiveness Research Articles

Effects of primary reinforcement on pigeons' initial-link responding under a concurrent chains schedule with nondifferntial terminal links.

The effect of primary reinforcement on initial-link responding under concurrent-chains schedules with nondifferential terminal links was assessed in 12 pigeons. The iniitial and terminal links were variable-interval schedules (always the same for both alternatives). The positions (left or right key) of the initial-link stimuli (red or green) were randomized while the correlation between color and food amount remained constant within each condition. The terminal-link stimuli were always presented on the center key. Except in two control groups and conditions, the terminal-link stimuli were the same color (nondifferential, blue or yellow). Over six conditions, the differences in food amont and the durations of the initial- and terminal-link schedules were manipulated. In 57 of 60 cases, birds generated choice proportions above .50 in favor of the initial-link stimlus that was correlated with the larger reinforcer. There was some indication that preference increased with shortened terminal-link durations. Because the terminal-link stimuli were nondifferential, differential responding in the initial links cannot be explained easily by conditioned reinforcement represented by the terminal-link stimuli. Thus, primiary reinforcement has a direct effect on initial-link responding in concurrent-chains schedules.

Sertraline Treatment for Alcohol Dependence: Interactive Effects of Medication and Alcoholic Subtype

Characteristic behaviors of some alcohol-dependent individuals, e.g., binge drinking, comorbid psychopathology, and some types of alcohol-related problems, have been linked to abnormalities in serotonergic neurotransmission. However, studies that have evaluated serotonergic pharmacotherapy for reducing drinking have yielded conflicting results. One explanation for these findings is a general failure to distinguish alcohol subgroups that may be differentiated on the basis of serotonergic abnormalities. However, in 1996, Kranzler and colleagues reported that Type B alcoholics, who are characterized by high levels of premorbid vulnerability, alcohol dependence severity, and comorbid psychopathology, showed less favorable drinking outcomes in response to treatment with fluoxetine, a serotonin reuptake inhibitor, than with placebo. This medication effect was not seen in Type A alcoholics, i.e., those with lower risk/severity of alcoholism and psychopathology. The aim of the present study was to explore the validity of differential responding by alcohol-dependent subtypes using the serotonin reuptake inhibitor, sertraline. A k-means clustering procedure was applied to a sample of alcohol-dependent subjects enrolled in a 14-week, placebo-controlled trial of 200 mg/day of sertraline, classifying them into lower-risk/severity (Type A: n = 55) and higher-risk/severity (Type B: n = 45) subgroups. A significant interaction between alcoholic subtype and medication condition was found, confirming the findings of Kranzler and colleagues that alcoholic subtypes responded differentially to serotonergic medication. Somewhat at variance with their results, however, the present study showed that the lower risk/severity (Type A) subjects had more favorable outcomes when treated with sertraline compared to placebo. Alcoholic subtypes differentially responded to sertraline when used as a treatment to reduce alcohol drinking, with one subtype having more favorable outcomes. Subtyping alcoholics may help to resolve conflicting findings in the literature on serotonergic treatment of alcohol dependence.

Prenatal experience and neonatal responsiveness to vocal expressions of emotion.

Newborn differentiation of emotion and the relevance of prenatal experience in influencing responsiveness to emotion was tested by examining newborn responses to the presentation of a range of vocal expressions. Differential responding was observed, as indicated by an increase in eye opening behavior in response to the presentation of happy speech patterns. More importantly, differential responding was observed only when the infants listened to emotional speech as spoken by speakers of their maternal language. No evidence of discrimination was found in the groups of infants listening to the same vocal expressions in a novel language. The results suggest that as a consequence of prenatal exposure to the distinctive prosodic maternal speech patterns that specify different emotions and to the temporally related stimuli created by distinctive maternal physiological concomitants of emotion, the fetus learns to differentiate those emotional speech patterns typical of the infant's maternal language.

Gender Differences in Marmosets and Tamarins: Responses to Food Tasks

The study of behavioural gender differences among Callitrichid primateshas been generally neglected. We describe evidence from experimental studies inwhich adult female tamarins (Saguinus) and marmosets (Callithrix) demonstrate priorityof access to food that is spatially and temporarily restricted. Differences in behaviouralstrategies between both reproductive and non-reproductive females, and males, areconsistent with differences between the genera in their feeding ecology and socialorganisation. They are also functionally plausible. A recent study gives preliminarydata to show that, although mated females in family groups of common marmosetsdemonstrate priority of access to food sources, overall there are differences inresponsiveness that may be influenced by factors such as the time of feeding, energycontent and preference of food.

Perceptual mechanisms for individual vocal recognition in European starlings,Sturnus vulgaris

The capacity for vocal recognition of individual conspecifics is well documented in many species, but the perceptual mechanisms that underlie this ability in oscines are less well understood. Using operant conditioning, we trained three groups of European starlings on a baseline task to discriminate the songs of one male starling from those of four others. Each subject heard songs from the same five singers, but the to-be-recognized individual varied among birds. We grouped the subjects according to sex and their degree of previous exposure to the songs used as stimuli in this experiment. The first group (N=5 males) identified their own songs from those of four familiar males. The second group (N=5 males) was familiar with the song stimuli, but none of the songs was their own. The third group (N=4 females) was unfamiliar with the songs. After learning the baseline discrimination, the subjects were exposed to new natural and synthetic stimuli. The subjects maintained the ability to identify correctly an individual on the basis of novel song bouts, and showed differential responding on the basis of the sequence of song types in song bouts that were modelled using Markov chains. Based upon patterns of responding to these different stimuli, we conclude that European starlings are capable of individual vocal recognition, and that this process is mediated by mechanisms involving the memorization of individually specific song types, the sequential ordering of song types within different bouts of an individual, and perhaps by individually specific spectral (or voice) characteristics that generalize across song types.

‘‘STRESS CONTROL’’ LARGE GROUP THERAPY FOR GENERALIZED ANXIETY DISORDER: TWO YEAR FOLLOW-UP

While treatments for Generalized Anxiety Disorder have considerably improved recently, they remain less effective than similar treatments for other anxiety disorders. This paper reports on a comparative outcome study of a large group didactic therapy specifically designed to teach patients to “become their own therapists” in an attempt to counter the relapse problems commonly associated with this condition. The data suggest that improvements noted at six month follow-up are maintained at two years. Suggestions are forwarded to explain the lack of differential responding found among different therapy approaches.

Effectiveness of treatments for infantile colic: systematic review

Objective: To evaluate the effectiveness of diets, drug treatment, and behavioural interventions on infantile colic in trials with crying or the presence of colic as the primary outcome measure.Data sources:...

Differential effects of ondansetron and α-flupenthixol on responding for conditioned reward

Previous experiments have suggested that 5-HT3 antagonists such as ondansetron may alter reward-related behaviour that is dependent in part upon raised mesolimbic dopamine activity. However, the evidence for this is far from conclusive. One major behavioural role of dopamine is in the control of behaviour elicited by conditioned rewarding stimuli. To date, the effects of 5-HT3 antagonists on this function of mesolimbic dopamine have not been examined. Two experimental procedures were employed to examine the effects of ondansetron (10 and 100 micrograms/kg) on the acquisition of responding for conditioned reward, and on the response potentiating effect of intra-accumbens d-amphetamine (10 micrograms). These effects were compared to those elicited by the dopamine antagonist alpha-flupenthixol (0.1 mg/kg). In the first procedure, rats were trained to associate food pellet delivery with a conditioned stimulus (CS). Rats subsequently allowed to respond on a lever delivering this CS, and on an inactive lever, showed a greater preference for the lever delivering the CS, indicating that this CS functioned as a conditioned reward (CR). Ondansetron administered during the conditioning phase did not alter subsequent responding for the CR, but alpha-flupenthixol induced a small but significant reduction in responding on the CR lever. These results suggest that blockade of dopamine receptors, but not 5-HT3 receptors interfere with the learning of stimulus reward relationships. In the second procedure, d-amphetamine injected into the nucleus accumbens markedly potentiated responding for CR. Ondansetron at 10 micrograms/kg induced a small attenuation of this effect, without altering responding in its own right. However, at a higher dose (100 micrograms/kg) ondansetron plus amphetamine treatment significantly enhanced responding on the inactive lever. At both doses, the net effect of ondansetron was to produce a subtle impairment in the allocation of responses such that the differential responding on the CR versus NCR lever was diminished. In contrast to these effects alpha-flupenthixol significantly attenuated d-amphetamine's selective enhancement of responding for conditioned reward, as well as impairing the ability of the conditioned reward to elicit and maintain behaviour. These results confirm the role of dopamine in responding for conditioned reward, and suggest a possible modulators role for 5-HT3 receptors in this process. However, the effects of ondansetron on the acquisition of, and responding for, conditioned reward are clearly different from those induced by blockade of dopamine receptors.

Infants' Responses to Facial and Vocal Emotional Signals in a Social Referencing Paradigm

The independent effects of facial and vocal emotional signals and of positive and negative signals on infant behavior were investigated in a novel toy social referencing paradigm. 90 12-month-old infants and their mothers were assigned to an expression condition (neutral, happy, or fear) nested within a modality condition (face-only or voice-only). Each infant participated in 3 trials: a baseline trial, an expression trial, and a final positive trial. We found that fearful vocal emotional signals, when presented without facial signals, were sufficient to elicit appropriate behavior regulation. Infants in the fear-voice condition looked at their mothers longer, showed less toy proximity, and tended to show more negative affect than infants in the neutral-voice condition. Happy vocal signals did not elicit differential responding. The infants' sex was a factor in the few effects that were found for infants' responses to facial emotional signals.

Drug states as modulators of conditioned immobility in a latent discrimination procedure

Midazolam, amphetamine, and flesinoxan were used in four rat experiments to examine the usefulness of a latent Pavlovian discrimination procedure to assess the discriminative-stimulus, or occasion-setting, properties of drugs. Experiment 1 first assessed the unconditioned effect of each of the drugs on the dependent measure used, which was immobility. Relative to saline, midazolam enhanced immobility, whereas flesinoxan, and especially amphetamine decreased it. In each of the Experiments 2–4, subjects received a limited number of training sessions during which they consistently received a footshock in a distinctive box after a drug but not after saline, or vice versa. Subsequently, non-reinforced test sessions were performed in the drug and saline states in both the conditioning box and a novel box. Relative to the saline state, rats previously shocked under midazolam were less mobile in the conditioning box under midazolam, whereas rats previously not shocked under amphetamine or flesinoxan were more mobile under the drug. The remaining animals did not show differential responding. The response profiles were accounted for in terms of the combined operation of an associative, or occasion-setting, effect and a non-associative effect of the drug-induced states.

Differential gazing and vocal response to mother and stranger of full-term and preterm infants across age.

Full-term infants at both 2 and 3 months and preterm ones at 3 months from due date vocalized more to mother than to a stranger and gazed more at a stranger than the mother. Preterm infants at 3 months from birth, but 6 weeks from due date, did not show differential responding by any mode, indicating the importance of maturational rather than environmental factors in these behaviors.

Discriminative stimulus properties of isradipine: Effect of other calcium channel blockers

This study constitutes the first report of a calcium channel blocker used as a drug capable of controlling differential responding in a drug-discrimination paradigm. Male Sprague-Dawley rats were trained to discriminate between intraperitoneally administered 10.0 mg/kg isradipine and its vehicle in a two-lever, food-motivated, operant task. Once trained, rats displayed a dose-related decrease in discriminative responding when tested with lower isradipine doses. An analysis of the dose-response curve indicated an ED 50 = 5.71 mg/kg. As all training and dose-response testing occurred at 60 min postadministration, experiments were conducted with varying injection-to-test intervals ranging from 15–240 min. Results indicate that the optimum time for discriminative performance was at the time used in training, and that discrimination returned to nondrug (vehicle) levels 2 h postinjection. Administration of other L-type calcium channel blockers, viz., nifedipine (5–50 mg/kg), diltiazem (10–60 mg/kg), or nicardipine (0.5–3.0 mg/kg), as well as a novel antipsychotic that inhibits dopamine release (10–30 mg/kg of CGS 10746B), did not produce isradipine-like discriminative effects. Thus, there was no generalization from the training dose of 10 mg/kg isradipine to any of these other agents, and the results are discussed in light of the possible specificity of the isradipine discriminative stimulus cue as it is produced in the central nervous system.

Automatically elicited fear: Conditioned skin conductance responses to masked facial expressions

Abstract This study examined automatic elicitation of conditioned skin conductance responses (SCRs), when a backward masking procedure prevented the subject's conscious awareness of the conditioned stimuli (CSs). The CSs were pictures of emotional facial expressions. A differential conditioning procedure was used. One facial expression (e.g. an angry face) was aversively conditioned by a shock unconditioned stimulus, whereas another facial expression (e.g. a happy face) was never presented with the shock. After conditioning, the CSs were presented backwardly masked by a neutral face. This procedure prevented conscious perception of the CS. Nevertheless, reliable differential SCRs were obtained when the CS had been an angry face. This effect, however, was dependent on the subject's direction of attention. When attention was focused on the mask, no differential responding was observed. Thus it was concluded that, when fear-relevant stimuli (angry faces) served as the CS, elicitation of SCRs was automatic in...

Nonconscious associative learning: Pavlovian conditioning of skin conductance responses to masked fear-relevant facial stimuli.

We examined the possibility of nonconscious associative learning in a context of skin conductance conditioning, using emotional facial expressions as stimuli. In the first experiment, subjects were conditioned to a backwardly masked angry face that was followed by electric shock, with a masked happy face as the nonreinforced stimulus. In spite of the effectively masked conditioned stimuli, differential conditioned skin conductance responses were observed in a subsequent nonmasked extinction phase. This effect could not be attributed to differential sensitization or pseudo-conditioning. In the second experiment, the differential responding during extinction was replicated with angry but not with happy faces as conditioned stimuli. It was concluded that with fear-relevant facial expressions as the conditioned stimulus, associative learning was possible even in conditions where the subjects remained unaware of the conditioned stimulus and its relationship to the unconditioned stimulus.

Insulin, 2-deoxy- D-glucose, and food deprivation as discriminative stimuli in rats

Using a two-lever drug discrimination procedure, two groups of four rats each were trained to discriminate the stimulus effects of 1.0 U/kg insulin or 125 mg/kg 2-deoxy- D-glucose (2-DG) from saline. A third group was trained to discriminate food deprivation produced by feeding 23 h prior to sessions from satiation produced by feeding 2 h prior to sessions. Differential responding was a direct function of dose or deprivation level in each group. Rats trained to discriminate insulin responded as if they had received insulin when they received 2-DG and vice versa. Insulin and 2-DG produced deprivation-appropriate responding in two of four rats trained to discriminate food deprivation. Low insulin and 2-DG doses produced drug-appropriate responding in rats deprived 47 h, but not in rats deprived 23 h. Blood glucose level was altered by the training doses of insulin and 2-DG, but not by 23-h deprivation. These results indicate that operations that induced feeding produce discriminable stimuli, and that these effects overlap or interact. Thus, drug discrimination procedures can be useful in the analysis of ingestive behavior.

Role of differential sample responding in the differential outcomes effect involving delayed matching by pigeons.

The role of differential sample responding in the differential outcomes effect was examined. In Experiment 1, we trained pigeons on a one-to-many matching task with differential sample responding required. Differential outcomes were associated with samples and comparisons, with comparisons only, or with neither samples nor comparisons. Slopes of delay functions for trials with pecked versus nonpecked samples suggested use of a single-code-default strategy in the nondifferential-outcomes group but not in the differential-outcomes groups. In Experiment 2, differential sample responding and differential outcomes were manipulated independently. Again, there were significant differences in the relative slopes of the delay functions. Results suggest that differential outcomes exert their effect independently of differential sample responding.

The differential responding of college students to subtle and obvious MCMI subscales.

This study investigated the differential responding of 49 male and 92 female college students to subtle and obvious MCMI scale items. It had been predicted that item subtlety would be correlated positively with item endorsement. This prediction was supported across all 175 MCMI items (r = .34). In addition, subjects endorsed a greater percentage of subtle than obvious subscale items for eight Basic Personality scales and two of three Pathological Personality scales. However, this pattern was not consistent for the nine Symptom Disorder scales. It also had been predicted that gender would moderate subjects' differential responding to subtle and obvious items, whereby males would show a greater tendency than females to endorse relatively more subtle than obvious items. This prediction was not supported.

Cocaine discrimination is attenuated by isradipine and CGS 10746B

The discriminative stimulus properties of cocaine are thought to be mediated by dopaminergic mechanisms that may be modulated by calcium ion influx and/or interact with 5-hydroxytryptamine 3 (5-HT 3) receptors. To test these possibilities, rats were trained to discriminate between the stimulus properties of 10.0 mg/kg cocaine and its vehicle in a two-lever, food-motivated operant task. Once trained, rats showed a dose-related decrease in discriminative performance when tested with lower cocaine doses. An analysis of the dose-response curve indicated an ED 50 value of 3.04 mg/kg. Pretreatment with the presynaptic dopamine release-inhibiting agent CGS 10746B (20–40 mg/kg) resulted in a dose-related decrease in cocaine discrimination with the highest dose significantly attenuating cocaine discrimination. Pretreatment with 10–30 mg/kg isradipine, a calcium channel blocker, also resulted in a dose-related decrease in cocaine discriminative performance. In contrast to these positive results, pretreatment with the 5-HT 3 receptor antagonist MDL 72222 (3.5–7.0 mg/kg), or the same doses of ibogaine, did not significantly affect cocaine discrimination. The results suggest that cocaine controls differential responding in a discriminative stimulus task by mechanisms that involve presynaptic release of dopamine, which may be regulated by neuronal calcium influx through L-type calcium channels.

Operant responding controlled by milk or milk contaminated with alcohol as positive reinforcers in infant rats

Infant rats during the first, second, or third week of life were tested in operant conditioning with uncontaminated milk or milk supplemented with 6.0% v/v absolute ethanol (EtOH) as the reinforcer. Relative to voked controls, pups of each age group reinforced on a response-contingent basis exhibited a significantly higher rate of responding with either reinforcer. In terms of amount of reinforcement, milk induced a higher rate of lever pressing than did the EtOH-contaminated compound. Age-related differences in the onset of differential responding for plain milk and EtOH-contaminated milk suggested developmental changes in the effects of alocohol. In a second experiment, forced drinking of milk and EtoH-contaminated milk was compared in similar age groups. Patterns of intake resembled the patterns of operant responding controlled by the same substance in the first experiment. These experiments indicate that the presence of alcohol in milk partially inhibits the reinforcing capacity of uncontaminated milk. Nevertheless, the former compound is still effective as a positive reinforcer during the first weeks of life.

The use of Sexually Anatomically Detailed dolls in the assessment of sexual abuse

The use of sexually anatomically detailed (SAD) dolls in the assessment of child sexual abuse is reviewed, and research which provides evidence relevant to the psychometric properties of SAD dolls with this population is examined. There are a number of unanswered questions concerning the reliability, standardization of administration procedures, adequacy of norms, criterion-oriented validity, incremental validity, external validity, and mechanisms by which this assessment method works, as well as underlying theory predicting differential responding of sexually abused children to SAD dolls. Recommendations for future research are given.