The behavioral theory of timing: Reinforcer rate determines pacemaker rate

In the behavioral theory of timing, pulses from a hypothetical Poisson pacemaker produce transitions between states that are correlated with adjunctive behavior. The adjunctive behavior serves as a discriminative stimulus for temporal discriminations. The present experiments tested the assumption that the average interpulse time of the pacemaker is proportional to interreinforcer interval. Responses on a left key were reinforced at variable intervals for the first 25 s since the beginning of a 50-s trial, and right-key responses were reinforced at variable intervals during the second 25 s. Psychometric functions relating proportion of right-key responses to time since trial onset, in 5-s intervals across the 50-s trial, were sigmoidal in form. Average interpulse times derived by fitting quantitative predictions from the behavioral theory of timing to obtained psychometric functions decreased when the interreinforcer interval was decreased and increased when the interreinforcer interval was increased, as predicted by the theory. In a second experiment, average interpulse times estimated from trials without reinforcement followed global changes in interreinforcer interval, as predicted by the theory. Changes in temporal discrimination as a function of interreinforcer interval were therefore not influenced by the discrimination of reinforcer occurrence. The present data support the assumption of the behavioral theory of timing that interpulse time is determined by interreinforcer interval.     

An investigation of the differential-outcomes effect within sessions

The differential-outcomes effect is manifest as more accurate performance of a delayed conditional discrimination when alternative choice responses are followed by different reinforcers than when they are followed by the same reinforcer. In Experiment 1, a differential-outcomes effect was demonstrated within sessions by signaling the duration of food access for correct responses with stimuli appearing in conjunction with the sample stimuli. The delayed matching-to-sample performance of 5 pigeons was more accurate when green choice responses (matching a green sample) were followed by 3.5-s food access and red choice responses (matching a red sample) were followed by 0.5-s food access (different-outcome trials) than when the correct choice responses were both followed by 1.5-s reinforcers (same-outcome trials). In Experiment 2, the acquisition of this differential-outcomes effect was characterized by a progressive decrease in rate of forgetting on different-outcome trials and no change in rate of forgetting on same-outcome trials. In addition, accuracy at the shortest delay intervals for both different-outcome and same-outcome trials increased over acquisition, but to a greater extent for different-outcome trials. These data suggest that both memorial and attentional (time-dependent and time-independent) factors contribute to the differential-outcomes effect.     

A Follow-up Dual-Task Investigation of Lateralized Effects in Right- and Left-Handed Males

A dual-task follow-up investigation examined the influence of sample size and ideational complexity of cognitive tasks on lateralized effects. With a larger sample (n = 128), results showed a "manual dominance effect" for relaxed and paced nonideational vocalized tasks. A hierarchy of ideational verbal tasks yielded the expected lateralized effects which corresponded with increasingly greater interference in concurrent tapping, but not in strength of lateralized effect. Instead of a trend seen in the earlier work (Steiner, Green, & White, 1992), results revealed a significant difference between handedness groups for one complex spatial task. Finally, outcomes for the other spatial task highlight the importance of assessing tradeoffs in attention.     

Affective deficits and pain insensitivity in schizophrenia

Affective deficits have long been considered a prominent feature of schizophrenia and play a central role in recent theory and research on the pathophysiology of this disorder. However, it has recently been argued that current approaches to the conceptualization and assessment of affective flattening in schizophrenia are confounded by the social and neuromotor deficits that are also prevalent in this disorder. Insensitivity to pain in individuals with schizophrenia — a phenomenon that has been reported frequently but never systematically investigated — provides one approach to examining affective flattening unconfounded by social and neuromotor deficits. Two studies are described in which signal detection theory measures of thermal pain sensitivity were examined in patients with schizophrenia, mood disorder, and normal controls; in addition, in the patients with schizophrenia, the relationships between these measures and measures of affective deficits were examined. Patients with schizophrenia had significantly poorer sensory discrimination of painful thermal stimuli than control subjects, but did not differ from controls with respect to their response criterion for reports of pain; patients with mood disorder had a significantly higher (i.e., more stoical) criterion for reports of pain than controls. As predicted, among the patients with schizophrenia, higher response criterion was significantly correlated with greater affective flattening and less intense affective experience (as well as with fewer positive symptoms and poorer premorbid adjustment). The results of these studies suggest that pain insensitivity in schizophrenia may reflect affective as well as sensory abnormalities, and that pain insensitivity in schizophrenia may provide a method for studying affective flattening in this disorder that is relatively independent of the social and neuromotor deficits that confound existing measures of this symptom. Continued examination of the relationship between pain insensitivity and affective deficits in schizophrenia is also important because numerous clinical reports have suggested that pain insensitivity is detrimental to health and can have life-threatening consequences in individuals with this disorder.This research was supported, in part, by research grants from the National Institute of Neurological Disorders and Stroke to Robert H. Dworkin (NS-30714) and W. Crawford Clark (NS-09263, NS-20248).     

Social goals: Relationship to adolescent adjustment and to social problem solving

Examined the relations between adolescent boys' social goals of dominance, revenge, avoidance, and affiliation and (1) self-reported negative adolescent outcomes; (2) subjective sense of self-esteem; and (3) externalizing, internalizing, and prosocial behaviors, as rated by peers and teachers. Results indicated that social goal values were related to diverse aspects of self-, teacher-, and peer-reported social and behavioral functioning, with a consistent association found between a range of delinquent, substance-using, and behavioral difficulties, and endorsement of high goal values for dominance and revenge and low goal values for affiliation. Results also indicated that teacher-identified aggressive boys differed from nonaggressive boys in the value they placed on social goals, with aggressive boys placing a higher value on goals of dominance and revenge, and lower value on goals for affiliation. Finally social goal choice had a clear relation to the social problem-solving differences of aggressive and nonaggressive boys.This study was funded by a research grant for the National Institute of Mental Health (MH 39989). Acknowledgment is made for the administrative support provided by the Durham County Schools and The Durham Community Guidance Clinic of the Duke University Medical Center.     

A Primer on Consultation Theory: Building a Flexible Worldview

The purpose of this article is to provide potential consultants with a broad introduction to the learning, gestalt, systems, organizational, psychoanalytic, and chaos theories of consultation. The goal of this article is to demonstrate how the consultant can map each of these theories onto the consultation environment to produce a unique perspective that each theory alone cannot provide. Each theory is described as to how it views and frames the consultation problem and how interventions are then based on these frames. Additionally, each theory is examined as to its view of process difficulties and when termination is deemed appropriate.     

The impact of training in sexual counselling for drugs workers upon HIV related risk behaviours and attitudes among injecting drug users

Forty-five drug-using clients attending two drug services at a London hospital were interviewed before and after a training programme on sexual counselling delivered to staff working at the two units. Following staff training, clients reported increased interaction during counselling with staff on sexual issues. Results indicated that drug use and injecting behaviours were unaflected by the stag training and that changes in sexual behaviour were modest. Attitudinal changes were more substantial with more positive attitudes emerging to limiting the number of sexual partners and towards the use of condoms. The value of observed attitudinal changes and the importance of decision-making processes of clients for harm minimization are discussed     

Issues of knowledge in the policy of self-determination for aboriginal Australian communities

Since 1972, the direction of policy concerning development of Aboriginal Australian communities has been towards adoption of the notion of self-determination. This paper presents a case study of how one particular Aboriginal community has combined local knowledge with non-Aboriginal knowledge to develop an alternative mathematics curriculum that will promote community development and authentic self-determination.     

Child study at Clark University: 1894-1904

A first cooperative research program in developmental psychology was established in the Clark questionnaire studies. The program was not meant to be free-standing but to elaborate an evolutionary conception of child development synthesized from findings of several scientific fields. The short-lived program had some serious faults, but an examination of its research papers suggests that it produced some worthwhile work. The child-study researchers gathered information about children's social and emotional reactions in everyday settings; one or two of their studies were replicated; they found pattern and order; they elaborated a meaningful social-biological view of child development.