Cardiovascular responses to avoidance conditioning in the dog: Effects of alpha adrenergic blockade

Laboratory dogs were trained to press a response panel to postpone shocks during daily one-hour avoidance conditioning periods. Each dog was also confined in the experimental environment for 5 hours prior to the avoidance periods. Blood pressure and heart rate were monitored continuously during these experiments from chronically indwelling arterial catheters. Extended training resulted in the emergence of a cardiovascular response pattern during the pre-avoidance interval characterized by gradual increases in blood pressure together with decreases in heart rate. Elevations in both blood pressure and heart rate were sustained during the avoidance periods. During sessions in which alpha adrenergic activity was suppressed by phenoxybenzamine, absolute levels of blond pressure were found to be lower than during control (non-drug) sessions, but a progressive rise in blood pressure continued to be observed during pre-avoidance. These results suggest that sustained cardiovascular responses during avoidance periods are associated with activation of the sympathetic nervous system, but that the gradual rise in blood pressure during pre-avoidance is due to other factors.     

Technical standards and performance standards in the pursuit of quality

The concept of standards lacks clarity because it is applied both to concrete specifications and to the assessment of quality. Confusion is reduced by introducing the notion of interchange expectancy. distinguishing transfer, coupling, and market success as components. Transfer expectancy depends upon the products to be transported or exchanged, but when there is a need to estimate transfer expectancy, a combination of technical standards and performance standards must be applied. Though performance standards are intended to produce quality, the quality of the instrumentation to measure performance standards is often neglected. The development of high-quality performance standards first requires the delineation of the relevant dimensions of performance quality. The process of giving precision to performance standards may lead to the emergence of more acceptable technical standards. To illustrate some of these points, data is presented from the CONDUIT system for quality evaluation of computer-based curriculum materials. The performance quality of these products includes the dimension of transfer expectancy, as well as educational and scientific merit. Increased specification and impact of technical standards may provide greater incentives to authors and hence lead to the invention of products which have higher educational and scientific quality.     

Islamic Legal, Ethical, and Political Theory: The Search for the Good Society and the Moral Law

Book reviewed:
Standing Trial: Law and the Person in the Modern Middle East , Baudouin Dupret (ed.), I.B. Tauris 2004 (1-86064-997-1), x + 382 pp., $75.00
Muslim Ethics: Emerging Vistas , Amyn B. Sajoo, I.B. Tauris 2004 (1-85043-550-2), xvi + 164 pp., $39.50     

One Family at a Time: A Prevention Program for At‐Risk Parents

The purpose of this study was to examine the effectiveness of a psychoeducational parenting program with at‐risk parents of young children. At‐risk was defined as excessive parental use of verbal and corporal punishment combined with low‐income status. All families were seen for 10 weeks, either individually or in very small groups. Results showed that compared with the control group, parents participating in the program significantly decreased their levels of verbal and corporal punishment, anger, stress, and reported child behavior problems; results were maintained at follow‐up. Implications for counselors are provided.     

Two bs or not two Bs? A signal detection theory analysis of repetition blindness in a counting task

Stimulus repetition usually benefits performance. A notable exception is repetition blindness (RB), in which subjects fail to report a repeated stimulus in a rapid serial visual presentation. Theories differ in attributing RB to either perceptual encoding or memory retrieval and to impaired discrimination versus response bias. In the present study, subjects judged whether one or two letters were imbedded in sequences of digits. Unlike previous studies, false guesses of two unrepeated letters were distinguished from false guesses of two repeated letters. When repeated- and unrepeated-letter trials were randomly intermixed (Experiment 1), RB was entirely attributable to response bias. However, when they were separately blocked (Experiments 2 and 3), RB was manifested in discriminability (d'). The results support perceptual-encoding accounts of RB but indicate that effects on discriminability depend on subjects' processing strategies.     

A Dissociation between Symbolic Number Knowledge and Analogue Magnitude Information

Semantic understanding of numbers and related concepts can be dissociated from rote knowledge of arithmetic facts. However, distinctions among different kinds of semantic representations related to numbers have not been fully explored. Working with numbers and arithmetic requires representing semantic information that is both analogue (e.g., the approximate magnitude of a number) and symbolic (e.g., what / means). In this article, the authors describe a patient (MC) who exhibits a dissociation between tasks that require symbolic number knowledge (e.g., knowledge of arithmetic symbols including numbers, knowledge of concepts related to numbers such as rounding) and tasks that require an analogue magnitude representation (e.g., comparing size or frequency). MC is impaired on a variety of tasks that require symbolic number knowledge, but her ability to represent and process analogue magnitude information is intact. Her deficit in symbolic number knowledge extends to a variety of concepts related to numbers (e.g., decimal points, Roman numerals, what a quartet is) but not to any other semantic categories that we have tested. These findings suggest that symbolic number knowledge is a functionally independent component of the number processing system, that it is category specific, and that it is anatomically and functionally distinct from magnitude representations.