A high-gain,low-noise amplifier for EEG

This paper describes an amplifier for an electroencephalograph with gain of 1×10⁴ to 1×10⁶ and made entirely of commercially available IC components. The two-stage amplifier has a preamplifier stage with fixed gain of 1000, and a second stage with variable gain from 1 to 100. The final stage, an anti-aliasing filter, adds a gain of 10 to the signal. The circuit has high common mode rejection, low input bias current, very low noise characteristics, low offset voltages, and offset nulling capability built into the circuit.     

Beyond medical ethics: New directions for philosophy and medicine

A unique relationship exists between physicians and philosophers — one that expands on the constructive potential of the liaison between physicians and, for example, theologians, on the one hand, or, social workers on the other. This liaison should focus in the scientific aspects of medicine, not just the ethical aspects. Philosophers can provide physicians with a perspective on both the philosophy and the history of medicine through the ages — a sense of how medicine has adapted to the social cultural and ethical needs of each period. This perspective, while emphasizing medicine asscience, should not be limited to matters of methodology, or to criteria for distinguishing science from other intellectual pursuits, but should be concerned also with the history, sociology and politics of science. Both physicians and philosophers stand to gain from a strengthening of their active liaison now as never before; but most of all, the public will be the beneficiary.     

Converging evidence that fear of success is multidimensional

Fear of Success (FOS) was originally conceived as a unidimensional motive. However, there is both theoretical and empirical support for the hypothesis that FOS is multidimensional. We factor analyzed the responses of 236 undergraduates to twenty-oneConcern Over the Negative Consequences of Success items and found four factors. Our four factors show considerable overlap with dimensions based on theoretical accounts of FOS etiology as well as with the factor structures obtained from two other factor analytic studies. Thus, there is converging evidence that FOS is multidimensional. The relationship between multidimensional FOS and a multidimensional approach to achievement motivation is discussed.     

Explaining Choices in Procedural and Distributive Justice Across Cultures

A previous study (Leung, Bond, & Schwartz, 1990) established that an expectancy-valence model could be used effectively to explain behaviours in three social domains both within and across cultures. In this study the model was applied to the domains of resource allocation and conflict resolution in order to pinpoint which expectancies and which valences were carrying the explanatory weight of the respondents' behavioural strategies. For both Israeli and Hong Kong students the expectancies and, less strongly, the valences tapping harmony and performance quality were important for resource allocation; those tapping animosity reduction and process control, for conflict resolution. Suggestions were offered for broadening the net of explanatory constructs for future work aimed at specifying subjective factors associated with justice-related behaviours.     

Noncompliance with Persuasive Appeals for a Prosocial,Altruistic Act: Blood Donating1

Effects of persuasive messages, responsibility denial (RD), and attitude-accessing on blood-giving attitudes, intentions, moral obligations, and behavior were examined. In Study 1, participants (n= 84) who heard a message emphasizing moral reasons for donating indicated a more favorable postmessage attitude and stronger moral obligation to donate than participants exposed to a message aimed at reducing fear, a combined moral and fear- reduction message, or no message. Combined message participants showed greatest intent to donate, yet only 14% of all participants attended a campus drive. In Study 2, low (n= 52) and high (n= 60) RD individuals heard the message arguments and were asked to access their attitudes. Low compared to high RD individuals stated a stronger sense of moral obligation, particularly when they accessed their thoughts relevant to blood donating, and behavioral intention, especially in the combined message condition. Few participants attended a blood drive (12.5%), yet most were low RD individuals from the nonaccessed attitude condition (83%). Results suggest that few individuals will engage in the altruistic act of blood donating, despite the experimental use of persuasive messages and accessing issue-relevant attitudes.     

Effects of response requirement and alcohol on human aggressive responding.

Nine men participated in two experiments to determine the effects of increased response requirement and alcohol administration on free-operant aggressive responding. Two response buttons (A and B) were available. Pressing Button A was maintained by a fixed-ratio 100 schedule of point presentation. Subjects were instructed that completion of each fixed-ratio 10 on Button B resulted in the subtraction of a point from a fictitious second subject. Button B presses were defined as aggressive because they ostensibly resulted in the presentation of an aversive stimulus to another person. Aggressive responses were engendered by a random-time schedule of point loss and were maintained by initiation of intervals free of point loss. Instructions attributed these point losses to Button B presses of the fictitious other subject. In Experiment 1, increasing the ratio requirement on Button B decreased the number of ratios completed in 4 of 5 subjects. In Experiment 2, the effects of placebo and three alcohol doses (0.125, 0.25, and 0.375 g/kg) were determined when Button B presses were maintained at ratio values of 20, 40 and 80. Three subjects who reduced aggressive responding with increasing fixed-ratio values reduced aggressive responding further at higher alcohol doses. One subject who did not reduce aggressive responding with increasing fixed-ratio values increased aggressive responding at the highest alcohol dose. The results of this study support suggestions that alcohol alters aggressive behavior by reducing the control of competing contingencies.     

Choice with delayed and probabilistic reinforcers: effects of variability, time between trials, and conditioned reinforcers.

In a discrete-trials procedure with pigeons, a response on a green key led to a 4-s delay (during which green houselights were lit) and then a reinforcer might or might not be delivered. A response on a red key led to a delay of adjustable duration (during which red houselights were lit) and then a certain reinforcer. The delay was adjusted so as to estimate an indifference point--a duration for which the two alternatives were equally preferred. Once the green key was chosen, a subject had to continue to respond on the green key until a reinforcer was delivered. Each response on the green key, plus the 4-s delay that followed every response, was called one "link" of the green-key schedule. Subjects showed much greater preference for the green key when the number of links before reinforcement was variable (averaging four) than when it was fixed (always exactly four). These findings are consistent with the view that probabilistic reinforcers are analogous to reinforcers delivered after variable delays. When successive links were separated by 4-s or 8-s "interlink intervals" with white houselights, preference for the probabilistic alternative decreased somewhat for 2 subjects but was unaffected for the other 2 subjects. When the interlink intervals had the same green houselights that were present during the 4-s delays, preference for the green key decreased substantially for all subjects. These results provided mixed support for the view that preference for a probabilistic reinforcer is inversely related to the duration of conditioned reinforcers that precede the delivery of food.