An eight-channel computer-controlled scanning electromyograph

A measurement system is described for the computerized detection, digitizing, and storage of electromyographic (EMG) signals from up to eight muscle groups. The use of a channel scanning technique allows almost simultaneous multichannel recording with minimal circuit redundancy. Specifically, the scanning electromyograph allows several EMG preamplifiers to share expensive isolation, signal-conditioning, and interface circuitry. The design incorporates monolithic integrated circuit preamplifiers and includes optical isolation of the preamplifier circuitry for protection of the subject. Hybrid active filter modules allow convenient selection of system bandpass characteristics. Key measurement parameters are software programmable. The scanning electromyograph is inexpensively constructed from readily available componentry. Specifications for all functional blocks within the instrument are comparable to those of commercial instrumentation.     

Alcohol consumption by college women following exposure to unsolvable problems: Learned helplessness or stress induced drinking?

Three experiments were intended to examine the relationship between alcohol, depression and learned helplessness. In Study I, more female undergraduate heavy drinkers than light drinkers were found to have critically elevated scores on a depression index. A sex difference in the relationship between drinking and depression is suggested since male depressives were equally distributed among drinking categories. In Studies II and III, female undergraduates were given unsolvable problems in a learned helplessness paradigm. Relative to controls these subjects reported increased depressive and hostile affect and drank more beer in a taste rating task. However, we failed to find deficits in anagram solution with those subjects given the learned helplessness manipulation. Specific questions are raised regarding the boundary conditions of learned helplessness while implications bearing on stress-related alcohol consumption are discussed.     

A further analysis of the affective meanings associated with male and female sex-trait stereotypes

This study was concerned with the qualitative differences in the male and female sex-trait stereotypes. Previous research employing the item pool of the Adjective Check List (ACL) had indicated no relationship between the stereotype loading of the adjectives and their favorability ratings. In the present study, university students rated the ACL items for strength and activity, and these ratings were used to demonstrate that the male stereotype was appreciably stronger and more active than the female stereotype. It was found that the strength ratings were highly correlated with both activity and favorability ratings which were, themselves, unrelated. It was concluded that the principal qualitative difference between the stereotypes lay in the connotations of activity and passivity associated, respectively, with the male and female stereotype traits, and that any assertion of greater social desirability for the male stereotype was based on its greater activity and not, as is often supposed, on its greater favorability.     

Cognitive arithmetic: Evidence for right hemispheric mediation in an elementary component stage

Earlier studies involving the lateralization of arithmetic abilities have provided evidence for both right and left hemisphere superiorities. It is argued here that part of this inconsistency could be due to the complexity of the arithmetic computations which have been examined. The present studies examined a subprocess shown to be involved in more complex tasks, such as subtraction. The subprocess is the identification of which of two numbers is greater, and was tested by the flashing of a pair of digits to either the left or right visual field. Errors, reaction-times to make a decision, and examination of hand × visual field interactions all indicated that this subprocess is mediated by the right hemisphere. Correlational analysis was used to identify the operations underlying the observed lateralization of this ability. This analysis indicated that an operation indexed by the spatial order in which the digits were presented was effective in the right hemisphere but not the left hemisphere. Speculations on the nature of these operations were presented.     

Free classification: Element-level and subgroup-level similarity

Subjects classified sets of multidimensional stimuli into two groups in any way they wished. The sets were composed of 6 or 12 stimuli: 2 or 4 instances of 3 different stimuli (e.g., 2 blue circles, 2 green circles, 2 red circles). There were striking individual differences in the preferred classification. Some subjects maximized the similarity between subgroups by matching the composition of the subgroups--one instance of each stimulus was placed in each group. The other subjects maximized the similarity among stimuli within each subgroup by placing similar stimuli in each group (the blues and greens in one group, the reds in the other). The nature of the stimuli as well as the relationships among the three stimuli had little effect on classification. In this case, cognitive styles specific to individuals but general across diverse dimensions and stimulus sets determined classification.     

A set-theoretic random utility model of choice behavior

A random utility model of choice was developed by combining the basic ideas of the well-known theories of Thurstone and Restle. The new model has exactly the same number of free parameters as Tversky's Elimination-by-Aspects model. Furthermore, both models were found to fit, with equal accuracy, the data reported by Rumelhart and Greeno, and Tversky. It was concluded that although the two theories are not identical, they may be difficult to discriminate empirically.     

An Assessment of the Effectiveness of Two Tactics to Reduce Arousal in Crowded Mass Transit Settings1

Studies of crowding in various settings have shown that individuals are aroused and frequently suffer from ill health. Several studies have shown that it is possible to successfully intervene in residential, shopping, and classroom settings to reduce the negative effects of crowding. The present laboratory experiment assessed the effectiveness of two tactics commonly used by passengers in crowded mass transit settings. Results indicated that the two tactics, reading a newspaper or talking to others, failed to reduce arousal. An explanation for the failure of these tactics is offered.