Oral self-administration of pentobarbital by rhesus monkeys: maintenance of behavior by different concurrently available volumes of drug solution.

For 4 rhesus monkeys, mouth-contact responses with either of two brass spouts were reinforced according to fixed-ratio schedules by 0.65-mL liquid deliveries during daily 3-hr sessions. Three experiments were conducted. In each experiment, independent fixed-ratio schedules were concurrently in effect at the two spouts. Following completion of each fixed ratio on a spout, a specified number of liquid deliveries were available from that spout under a continuous-reinforcement schedule. The number of such deliveries available at each spout was manipulated independently. In Experiment 1, a 1-mg/mL pentobarbital solution was simultaneously available with water (the drug vehicle) under concurrent fixed-ratio schedules of 32 responses for 3 subjects and 64 responses for the remaining subject. The number (N) of liquid deliveries that were available after completion of each fixed ratio was varied in the following order: 8, 4, 2, 1, and 8 (retest). For each subject at each condition, drug maintained more responding than water. The number of drug deliveries obtained per session was directly related to the amount of drug available per fixed ratio (i.e., to N), whereas the number of fixed ratios completed per session generally was inversely related to the value of N. In Experiment 2, fixed-ratio size was the same for each subject as in Experiment 1, but deliveries of a 1-mg/mL pentobarbital solution were available at both spouts. The number of drug deliveries available under one fixed-ratio schedule (Ns, the "standard" reinforcer amount) was held at eight, and the number of drug deliveries available under the second schedule (Nc, the "comparison" reinforcer amount) was changed across blocks of six sessions of stable responding in the following order: 1, 2, 4, 8, 4, 2, and 1. The identical series of comparison reinforcer amounts (Nc) was then tested twice more, but with the standard reinforcer (Ns) held first at four and then at two deliveries. Across the three choice series, reinforcing effects were directly related to reinforcer magnitude. In Experiment 3, deliveries of a 1-mg/mL pentobarbital solution again were available at both spouts. However, the two reinforcer amounts were held constant at N = 8 deliveries under one schedule and N = 4 deliveries under the second schedule, and fixed-ratio size was systematically varied. Across the range of fixed-ratio sizes from low to high, the degree to which behavior was better maintained by the larger of the two drug quantities was an inverted U-shaped function of fixed-ratio size.(ABSTRACT TRUNCATED AT 400 WORDS)     

A Thurstonian model for the dual pair (4IAX) discrimination method

The Institute for Perception, Richmond, Virginia In the dual pair method, the subject is presented with two stimuli in two pairs: One pair is composed of two samples of the same stimulus; the other pair is composed of two samples of different stimuli, one being the same as that in the identical pair. The task of the judge is to select the most different pair. The psychometric function for the dual pair method is derived and expressed in terms of a singly noncentral beta distribution. A table is provided that connects a measure of the degree of difference, d , to the probability of a correct response. This table assumes an unbiased observer and differencing decision rule. A table is provided to give an estimate of the variance of d¢, the experimental estimate of d. The power of the dual pair method is also investigated, and a formula to determine the sample size required to meet Type I and Type II error specifications is given. The dual pair method appears to be slightly less powerful than the duotrio and the triangular methods. Experimental investigation is needed to explore the dual pair in applied research work.     

Combining Information for Quantitative Decision‐making in Drug Development

Taking decisions during the development of a new drug requires combining many and varying pieces of information. The interconnections between these different pieces of information are often only partially known and in some cases merely conjectured. Despite this uncertainty, decisions must be taken – often with regard to the balance of risk and benefit – in order to make progress. A clear, consistent and efficient methodology for describing the structure of a project and the comprehensive state of knowledge at any point in time is required in order to add transparency to the decision process. A viable methodology must allow for a natural characterization of the uncertainty inherent in the drug development process and a relatively easy implementation. We present a possible solution that satisfies these requirements. The foundation of the proposed approach is based on a beta‐binomial update mechanism well known in Bayesian statistics. This work provides a consistent framework for solving hierarchical multicriteria decision problems. Copyright © 2014 John Wiley & Sons, Ltd.     

The Identity Issues Inventory: Identity Stage Resolution in the Prolonged Transition to Adulthood

The Identity Issues Inventory (I₃) uses an Eriksonian framework to assess identity stage resolution among those experiencing a prolonged transition to adulthood in terms of the developmental tasks of self-identity formation (integration and differentiation) and societal-identity formation (work roles and worldview). For this first analysis of this new measure, data were collected from two samples: (1) 196 people between the ages of 18 and 48 and (2) 1,489 participants between the ages of 18 and 41. Overall, the I₃ yields good factorial validity and reliability, and scores increase with age toward the “ceiling” of each task subscale, which represent anchors of a stable adult identity. Structural equation modeling assessed the relationships between these prominent identity issues and psychological health, revealing a positive relationship between the two constructs, providing evidence for predictive validity. An analysis of the second sample of 1,498 people confirmed these findings. The I₃ promises to be a useful tool in future investigations of identity stage resolutions for those aged 18 and above experiencing a prolonged transition to adulthood.     

Determinants of patient satisfaction with the medical consultation

Abstract

This study assessed patient satisfaction with the medical consultation in ambulatory settings. A multistage sampling method, stratified by geographical location in metropolitan Sydney and type of medical practice, was employed. Two hundred and seventy-two patients attending medical consultations completed a brief questionnaire and interview immediately following a medical consultation with either a general practitioner or a medical specialist. Factor analysis of the questionnaire indicated that 58% of the variance in patient satisfaction ratings was accounted for by the level of interpersonal warmth and respect and the amount of information communicated by the doctor. Other factors impacting on satisfaction included the number of patient requests perceived to be met by the doctor, and the characteristics of the medical encounter, such as the length of the consultation and whether the visit was a first or subsequent consultation. There was no association between level of satisfaction and gender of doctor or the type of medical practice attended.     

Gradual remapping results in early retinotopic and late spatiotopic inhibition of return

Here we report that immediately following the execution of an eye movement, oculomotor inhibition of return resides in retinotopic (eye-centered) coordinates. At longer postsaccadic intervals, inhibition resides in spatiotopic (world-centered) coordinates. These results are explained in terms of perisaccadic remapping. In the interval surrounding an eye movement, information is remapped within retinotopic maps to compensate for the retinal displacement. Because remapping is not an instantaneous process, a fast, but gradual, transfer of inhibition of return from retinotopic to spatiotopic coordinates can be observed in the postsaccadic interval. The observation that visual stability is preserved in inhibition of return is consistent with its function as a "foraging facilitator," which requires locations to be inhibited across multiple eye movements. The current results support the idea that the visual system is retinotopically organized and that the appearance of a spatiotopic organization is due to remapping of visual information to compensate for eye movements.     

An analysis of reading skill development using E-Z Reader

Previously reported simulations using the E-Z Reader model of eye-movement control suggest that the patterns of eye movements observed with children versus adult readers reflect differences in lexical processing proficiency. However, these simulations fail to specify precisely what aspect(s) of lexical processing (e.g., orthographic processing) account for the concurrent changes in eye movements and reading skill. To examine this issue, the E-Z Reader model was first used to simulate the aggregate eye-movement data from 15 adults and 75 children to replicate the finding that gross differences in reading skill can be accounted for by differences in lexical processing proficiency. The model was then used to simulate the eye-movement data of individual children so that the best-fitting lexical processing parameters could be correlated to measures of orthographic knowledge, phonological processing skill, sentence comprehension, and general intelligence. These analyses suggest that orthographic knowledge accounts for variance in the eye-movement measures that is observed with between-individual differences in reading skill. The theoretical implications of this conclusion will be discussed in relation to computational models of reading and our understanding of reading skill development.