A comparison of the effects of partial reinforcement schedules using a within-subject serial autoshaping procedure

Three experiments, each using a single group of pigeons, are reported. In Experiment 1 subjects were initially trained with two stimuli, one of which was always followed by food, the other being reinforced according to a 50% partial reinforcement schedule. Subsequently a serial procedure was adopted in which an additional stimulus, C, was consistently followed by the partially reinforced CS. A second additional stimulus, A, was followed on half of its occurrences by the continuously reinforced CS, its remaining presentations being followed by nothing. The rate of autoshaped keypecking was substantially greater during A than during C. In the remaining experiments subjects received first-order conditioning with a single stimulus that was either partially (Experiment 2) or continuously (Experiment 3) reinforced. The stimuli A and C were then again introduced for serial autoshaping. Stimulus A was occasionally paired with the CS and occasionally followed by nothing, whereas stimulus C was always followed by the CS. As in Experiment 1, the rate of responding during A was greater than during C. It is proposed that one influence on the rate of autoshaped keypecking during a CS is the accuracy with which the immediate consequences of that CS are predicted.     

Computer viruses: What they are,how they work,how they might get you,and how to control them in academic institutions

A computer virus is a program that replicates itself and spreads to computers with the goal of disrupting or destroying normal computer use. In academic computing, viruses represent a serious problem that costs millions of dollars in losses annually and hinders the free exchange of information so critical to education. Viruses operate in incubation, infection, and destroy phases. The nature, mechanisms, and preventive measures for personal-computer viruses are reviewed. Different procedures are recommended to protect research laboratories, instructional laboratories, and software lending libraries. Tradeoffs between providing adequate protection and not having the security become too burdensome are considered.     

Enhancing a standard experimental delivery system (MEL) for advanced psychological experimentation

Enhancements to the Micro Experimental Laboratory (MEL) and the ways in which they facilitate development of psychological experiments are discussed in this paper. New procedures are described for (1) presenting and manipulating pictorial graphics, (2) inputting response box, voice key, joystick, digitized speech, and mouse responses, (3) outputting lights, speech, and tone stimuli, (4) editing and analyzing digitized speech, and (5) implementing multitask processing. Methods for extending the language, developing test batteries, sequencing subjects, and managing and analyzing data are described.     

Topographic electroencephalographic alpha in recovered depressed elderly

Late-middle-aged and elderly normal volunteers with past histories of Major Depression according to the Diagnostic and Statistical Manual of Mental Disorders (third edition-revised) criteria were compared with sex- and age-matched control subjects using topographic electroencephalographic (EEG) indices. Healthy, euthymic recovered depressed subjects showed greater alpha amplitudes than controls. Delta, theta, and beta amplitudes did not reliably distinguish the groups. Considered in the context of previous research indicating that actively depressed subjects exhibit elevated EEG alpha compared to controls, these findings raise questions concerning state and trait conceptualizations of depression and EEG alpha.     

CLINICAL BEHAVIORAL PHARMACOLOGY: METHODS FOR EVALUATING MEDICATIONS AND CONTINGENCY MANAGEMENT

We evaluated methods for comparing the effects of dextroamphetamine (Dexedrine), thioridazine (Mellaril), and contingency management in the control of severe behavior problems. A reversal design was used in which medications were systematically titrated and assessed in unstructured as well as structured settings with three clients. Subsequently, behavioral procedures including timeout, differential reinforcement of other behavior, and visual screening, were used in a multiple-baseline design across settings. The assessment and design methods were useful in comparing the interventions. Dextroamphetamine decreased inappropriate behaviors and improved academic behaviors in one client, but no reliable effects were observed in the other two clients. Thioridazine was variable across clients, settings, behaviors, and dosages. Contingency management produced consistent decreases in inappropriate behaviors and small improvements in academic performance.