Stevens Power Research Articles

Thaddeus Stevens: Nineteenth-Century Egalitarian (review)

BOOK REVIEWS145 The volumes in this series will be of great assistance to a variety of people. They may be used fruitfully in undergraduate and graduate classes as a means of introducing students to contemporary discourse occurring over crucial issues ; the letters may be a good starting point for any number of projects. Indeed , seasoned scholars may find these volumes useful for certain research topics. However, as the editor states, the Chase papers are voluminous and the ones published in this series are merely representative. For detailed research into a particular subject during the middle period, the microfilm collection—fortyfour reels—will have to be consulted. James L. Huston Oklahoma State University Thaddeus Stevens: Nineteenth-Century Egalitarian. By Hans L. Trefousse. (Chapel Hill: University of North Carolina Press, 1997. Pp. xiii, 312. $39.95.) Thaddeus Stevens is no longer the loathsome and daunting figure he once was. As Austin Stoneman in Thomas Dixon, Jr.'s novel, The Clansman (1905), and in D.W. Griffith's landmark film, Birth ofa Nation ( 1 9 1 5), Stevens, grim-faced as an executioner, unleased a reign of black terror on the conquered South. Nearly forty years after Fawn Brodie transformed Stevens's role in this racial melodrama, Hans L. Trefousse depicts a more prosaic figure and a less radical era. Stevens exerted little influence over what Trefousse describes as the moderate course of Reconstruction. A native ofVermont and a graduate of Dartmouth College, Stevens migrated south to Gettysburg, Pennsylvania. In his political and social associations Stevens joined with anti-Jacksonian factions to embrace temperance, antimasonry, nativism, and, finally, antislavery. Eschewing political consensus, Stevens exploited the fundamental instability of the second party system. He enjoyed his greatest success fighting the evil influence of the "slave power." In Pennsylvania , as elsewhere in the North, Jacksonians advanced their democratic reforms among white men at the same time that they denied equal rights to blacks. A delegate to the Pennsylvania constitutional convention in 1837, Stevens denounced "domestic slavery" as "the most disgraceful institution that the world had ever witnessed" (5 1 ). He supported limited black suffrage and opposed the extension ofthe franchise to white men who did not pay taxes. Bitterly opposed to the new constitution's provisions disenfranchising black men, Stevens refused to sign the document. In 1 842 Stevens moved from Gettysburg to the larger town ofLancaster where his law practice expanded and his political opportunities widened. It was in Lancaster that Stevens began to employ Mrs. Lydia Hamilton Smith as a housekeeper . Awidow with two children, Mrs. Smith, a mulatto, remained in Stevens's household and cared for him for the rest of his life. Rumors of their sexual I46CIVIL WAR HISTORY intimacy abounded. Trefousse discreetly limits his discussion of the matter to what clearly can be discerned from the evidence: Stevens and Mrs. Smith lived as domestic partners and Stevens provided well for her in his will. Stevens's political power reached its zenith during his tenure as chairman of the House Committee on Ways and Means, a position that he attained in 1 86 1 , at the age of sixty-nine. Trefousse insists that Stevens's outspokenness on emancipation enabled Lincoln "to continue his onward march toward freedom for the slave" (116). On issues of reconstruction, however, Trefousse grudgingly admits that differences between Stevens and Lincoln were fundamental and probably irreconcilable. Lincoln argued thatthe southern states remained within thejurisdiction of the Constitution. Stevens maintained that the act of rebellion invoked the laws of war and rendered the southern states conquered territories. Lincoln's reconstruction policies were limited by the Constitution; Stevens's were not. Stevens would "Strip a proud nobility of their bloated estates, reduce them to a level with plain republicans; send them forth to labor, and teach their children to enter the workshop or handle the plough." He would thus "humble the proud traitors" (172). On this issue Stevens had few followers. "His legacy was one of pointing the way," Trefousse concludes. "It was never one of domination " (238). Louis S. Gerteis University of Missouri-St. Louis Clara Barton: In the Service ofHumanity. By David Burton. (Westport, Conn.: Greenwood Press, 1995. Pp. 192. $49.95.) Clara Barton was a very...

A Psychophysical Evaluation of Frame Rate in Desktop Video Conferencing

The quality of digital video transmitted over computer networks can suffer from a variety of degradations. Little research has addressed perceptions of degraded digital video image quality. This paper reports on a study in which a psychophysical method, magnitude estimation, was used to develop a ratio scale of image quality for frame rates between 1 and 28 frames per second (fps). Five different scenes were used as stimuli, each varying in terms of filming speed, level of detail, and content. Results indicate that for non-traditional conferencing applications, image quality is not perceived to be better at rates greater than 10 fps. For a traditional conferencing application, a linear increase in image quality perception is associated with a linear increase in frame rate. Results are presented in terms of trend analysis, Steven's Power Function, and parametric statistics. Implications are made for the design of multimedia communication networks.

An Equiratio Mixture Model for non-additive components: a case study for aspartame/acesulfame-K mixtures.

The Equiratio Mixture Model predicts the psychophysical function for an equiratio mixture type on the basis of the psychophysical functions for the unmixed components. The model reliably estimates the sweetness of mixtures of sugars and sugar-alcohols, but is unable to predict intensity for aspartame/sucrose mixtures. In this paper, the sweetness of aspartame/acesulfame-K mixtures in aqueous and acidic solutions is investigated. These two intensive sweeteners probably do not comply with the model's original assumption of sensory dependency among components. However, they reveal how the Equiratio Mixture Model could be modified to describe and predict mixture functions for non-additive substances. To predict equiratio functions for all similar tasting substances, a new Equiratio Mixture Model should yield accurate predictions for components eliciting similar intensities at widely differing concentration levels, and for substances exhibiting hypo- or hyperadditivity. In addition, it should be able to correct violations of Stevens's power law. These three problems are resolved in a model that uses equi-intense units as the measure of physical concentration. An interaction index in the formula for the constant accounts for the degree of interaction between mixture components. Deviations from the power law are corrected by a nonlinear response output transformation, assuming a two-stage model of psychophysical judgment.

Improving Auditory Warning Design: Quantifying and Predicting the Effects of Different Warning Parameters on Perceived Urgency

The effects of four parameters (speed, fundamental frequency, repetition units, and inharmonicity) on perceived urgency were scaled using an application of Stevens's power law. From the exponents obtained, equal units of urgency change were calculated for three parameters. The units were combined in a set of stimuli, and the order of urgency was predicted. The obtained and predicted orders of urgency were highly correlated. The results also showed that even when equalized by psychophysical techniques, some parameters contribute more to perceived urgency than do others. This may be attributable to the different types of parameters scaled or the proportion of the usable range of each parameter that represents a unit change in urgency. The implication of the work for the design and improvement of auditory warnings is discussed.

Is Stevens's power law valid?

Is Stevens's power law valid?

Toward the unification of three visual laws and two visual models in brightness perception

A novel visual model of brightness perception is introduced to resolve apparent incompatibilities among Fechner's logarithmic relation, Steven's power law response, and psychophysical and electrophysiological K/sub m/*I/(I+S) experimental results. The proposed visual model, which is based on combining and extending two existing ones (the multiplicative and photoreceptor visual models), is shown to predict these results successfully. Thus a unification of three apparently conflicting visual laws emerges, and the versatility and validity of the visual model are demonstrated. >

SDLB adaptation and an approximation of Steven's power law

Initial curve fitting efforts having yielded similar results, data from four studies [E. Jerger, J. Acoust. Soc. Am. 29, 357–363 (1957); T. Palva and J. Karja, J. Acoust. Soc. Am. 45, 1018–1021 (1969); E. M. Weiler, M. Loeb, and E. A. Alluisi, J. Acoust. Soc. Am. 51, 638–643 (1972); and E. M. Weiler and J. D. Hood, Audiology 16, 499–506 (1977)] were combined to encompass intensities from 20 to 80 dB SL at 1 kHz. All studies used the classic method of simultaneous dichotic loudness balances (SDLB} as described by Hood [Acta. Oto‐Laryngol. Suppl. 92 (1950)] and Small [Modern Developments in Audiology, edited by J. Jerger (Academic, New York, 1963)]. A regression line was fit to the log values of stimulus intensity and log adaptation (dB). Converting to the form of Steven's power law, the resulting constant K by this approach was 0.9449 and the exponent of intensity N was 0.73953. For loudness magnitudes, N has often been reported as about 0.60.

Direct Estimation Considered within a Comparative Judgment Framework

Two experiments that employed the dimension of line length were conducted to support an interpretation of direct estimation within the framework of comparative judgment. It was reasoned that because memorial and processing demands increased, decreasing amounts of transmitted information should be found in discrimination, categorization, and estimation tasks when considered in that order. The data of the first experiment supported the prediction. However, external anchors provided to reduce demand in estimation had no apparent effect. A second study did indicate a marginal effect of anchors when subjects were instructed to employ them but, more strikingly, demonstrated that the shape of the psychophysical function was sensitive to the differential labels that accompanied the anchors. Labels derived from a Fechnerian assumption about psychophysical relations produced a Fechnerian function, whereas labels derived from the actual ratio of the stimulus line to the largest line produced a function consistent with Stevens's power law. It was concluded that the evidence favored a view of direct estimation consonant with cognitive interpretations rather than with the idea of a universal psychophysical function.

Utility Function for Money Determined Using Conjoint Measurement

Since Daniel Bernoulli's 1738 paper, there has been considerable controversy over how best to determine the utility function for money (see Lee, 1971, and Stigler, 1950, for reviews). Economists and others have generally agreed that the form of the function relating utility of a dollar (or any other constant amount of money) decreases as the amount in hand increases; i.e., an additional dollar is worth less to a rich person than to a poor person. The two forms most often mentioned as possibilities for a utility function are the logarithmic function orginally proposed by Bernoulli and the power function espoused by S. S. Stevens and others (Galanter, 1962; Stevens, 1975). Bernoulli's logarithmic function states that U(m) = a * log(m) + k, where m is money amount, U(m) is the psychological utility of that money amount, and a and k are constants. Stevens's power function, on the other hand, states U(m) = c * mb where U and m are as above and c and b are constants. It should be

Studies of the cognitive representation of spatial relations: II. A familiar environment.

This experiment tested the ability of people to recall the locations of buildings in a familiar campus setting. Ten graduate students represented the relative locations of buildings by pairwise distance judgments (on a 100-point scale) and by direct mapping of locations on a Tektronix cathode ray terminal. As evaluated by Stevens's power law, both methods led to accurate judgments of relative distance (the average exponent was close to 1). In addition, the pairwise judgments were analyzed by multidimensional scaling (MDS) and the buildings were located in a two-dimensional map. When asked to choose between the MDS representation and the map created directly on the Tektronix, all 10 subjects chose the latter as the more accurate. Moreover, 6 out of 10 subjects thought the direct map was more accurate than the actual map of the building locations. These results suggest that either pairwise judgment or direct mapping yield accurative representations of spatial relations in a familial environment, but that subjects favor the direct map.

Click-evoked response at the superior colliculus of the cat

Click-evoked response was recorded from deep layers of the superior colliculus of the cat for stimuli from 67 through 115 db SPL. The response was a biphasic waveform with a sharp initial negative peak. Magnitude of response as a function of intensity was a nonmonotonic function which could be fit by a theoretical equation based upon the interplay of excitatory and inhibitory processes. This equation yields Stevens's power law as a special case.

Loudness and the power series transformation. Preliminary model and measurements.

A nonlinear-algebraic approach to monaural intensity processing is proposed: the purpose is to integrate the conscious loudness attribute evoked by a pure tone with the power-series description of auditory distortion. The preliminary model consists of six postulates leading to a mathematical definition for loudness. To evaluate this equation, two task-specific sets of loudness judgments from each of seven subjects are examined. When linked to loudness-interval responses via the equisection assumption, the equation describes the behaviors quite well. Extrapolations into other intensity ranges predict similar responses with relatively slight overestimates. By relaxing the assumption that subjects will adjust the loudness proportions exactly as instructed, their ratio productions also can be described and predicted with sometimes surprising accuracy. Particularly striking is the prediction of overall levels and the curvilinearities of "doublings" from the "halvings". In addition, the theory proposes absolute loudness measurement, an explanation for the growth of loudness including the principle underlying Steven's Power Law, and might prove useful in examining some exceptions to this relationship. Several aspects of this model differ from traditional approaches to intensity processing, but it appears to warrent further critical evaluations.