Theoretical analysis of an alphabetic confusion matrix

A study was undertaken to acquire a confusion matrix of the entire upper-case English alphabet with a simple nonserifed font under tachistoscopic conditions. This was accomplished with two experimental conditions, one with blank poststimulus field and one with noisy poststimulus field, for six Ss run 650 trials each. Three mathematical models of recognition, two based on the concept of a finite number of sensory states and one being the choice model, were compared in their ability to predict the confusion matrix after their parameters were estimated from functions of the data. In order to ascertain the facility with which estimates of similarity among the letters could lead to a psychological space containing the letters, η_ij, the similarity parameter of the choice model was input to an ordinally based multidimensional scaling program. Finally, correlation coefficients were computed among parameters of the models, the scaled space, and a crude measure of physical similarity. Briefly, the results were: (1) the finite-state model that assumed stimulus similarity (the overlap activation model) and the choice model predicted the confusion-matrix entries about equally well in terms of a sum-of-squared deviations criterion and better than the all-or-none activation model, which assumed only a perfect perception or random-guessing state following a stimulus presentation; (2) the parts of the confusion matrix that fit best varied with the particular model, and this finding was related to the models; (3) the best scaling result in terms of a goodness-of-fit measure was obtained with the blank poststimulus field condition, with a technique allowing different distances for tied similarity values, and with the Euclidean as opposed to the city-block metric; and (4) there was agreement among the models in terms of the way in which the models reflected sensory and response bias structure in the data, and in the way in which a single model measured these attributes across experimental conditions, as well as agreement among similarity ami distance measures with physical Similarity.     

The multidimensional analysis of asymmetries in alphabetic confusion matrices: Evidence for global-to-local and local-to-global processing

This study examined the ability of an asymmetric multidimensional scaling program (DEDICOM) to reveal information about letter-perception processes. To demonstrate its potential, we applied it to the controversy concerning local-to-global versus global-to-local letter perception. These two theories lead to different predictions about stimulus confusion asymmetries. Since DEDICOM is capable of recovering the structure of asymmetric or directional patterns, it should reveal whether a stimulus-response confusion matrix contains patterns of asymmetry more consistent with one or the other perceptual theory. This was tested using two data sets. The first (from Lupker, 1979) revealed an additive hierarchy of asymmetry strongly consistent with global-tolocal processing, although unexpected additional structure and reliable anomalies indicated the need for a more refined theoretical account. The second (a full alphabetic confusion matrix combining data from Gilmore et al., 1979; Loomis, 1982; and Towasend, 1971) revealed five distinct patterns, each consisting of transformations attributable to the failure to detect specific local letter features. This solution strengthened support for local-to-global processing, in sharp contrast to the first analysis. Possible reasons for this divergence are discussed, including differences in the stimuli, exposure durations, and a hypothetical two-stage process of perception. Despite their differences, both solutions demonstrated how asymmetric scaling can reveal structure in asymmetries, which is relevant to perceptual theory and which would have been difficult to recover by other means.     

A confusion matrix for the study of taste perception

Taste stimulus identification was studied in order to more thoroughly examine human taste perception. Ten replicates of an array of 10 taste stimuli--NaCl, KCl, Na glutamate, quinine. HCl, citric acid, sucrose, aspartame, and NaCl-sucrose, acid-sucrose, and quinine-sucrose mixtures--were presented to normal subjects for identification from a list of corresponding stimulus names. Because perceptually similar substances are confused in identification tasks, the result was a taste confusion matrix. Consistency of identification for the 10 stimuli (T10) and for each stimulus pair (T2) was quantified with measures derived from information theory. Forty-two untrained subjects made an average of 57.4% correct identifications. An average T10 of 2.25 of the maximum 3.32 bits and an average T2 of 0.84 of a maximum 1.0 bit of information were transmitted. In a second experiment, 40 trained subjects performed better than 20 untrained subjects. The results suggested that the identification procedure may best be used to assess taste function following 1-2 training replicates. The patterns of taste confusion indicate that the 10 stimuli resemble one another to varying extents, yet each can be considered perceptually unique.     

Memory representation of alphabetic position and interval information.

The authors conducted 3 sets of experiments. In the 1st set of experiments, participants made alphabetic position estimations. In the 2nd set, participants made interletter distance estimations. In the 3rd set, they made comparative judgments of the alphabetic order of a pair of letters. The results showed that participants had highly accurate ordinal level information about the alphabet in memory but that interval level information was systematically distorted. In addition, alphabetic serial information was found to be used in 2 distinct modes in memory, depending on whether the representation could be contained within the span of immediate memory.     

Information underload: Recognition of slowly-presented alphabetic characters

The accuracy of identification of alphabetic letters was examined under three experimental procedures: slowly plotting all of the dots associated with a given display of letters in their correct spatial positions, but in a random temporal order; rapidly plotting one half of the dots associated with a display, and after a variable delay, rapidly plotting the other half of the dots; and rapidly plotting only a fraction of the total number of dots associated with the display. The accuracy of identification suffers as the rate of plotting is decreased and as the interval between the successive fields is increased. Therefore, a failure of spatial-temporal integration is inferred. The results of the separate procedures are partially consistent with an interpretation of a discrete, non-synchronized perceptual moment of 120–150 msec duration, assuming no accumulation of information across successive moments.     

Erratum to: Perseverance as an intellectual virtue

Much recent work in virtue epistemology has focused on the analysis of such intellectual virtues as responsibility, conscientiousness, honesty, courage, open-mindedness, firmness, humility, charity, and wisdom. Absent from the literature is an extended examination of perseverance as an intellectual virtue. The present paper aims to fill this void. In Sect. 1, I clarify the concept of an intellectual virtue, and distinguish intellectual virtues from other personal traits and properties. In Sect. 2, I provide a conceptual analysis of intellectually virtuous perseverance that places perseverance in opposition to its vice-counterparts, intransigence and irresolution. The virtue is a matter of continuing in one’s intellectual activities for an appropriate amount of time, in the pursuit of intellectual goods, despite obstacles to one’s attainment of those goods. In Sect. 3, I explore relations between intellectually virtuous perseverance and other intellectual virtues. I argue that such perseverance is necessary for the possession and exercise of several other intellectual virtues, including courage. These connections highlight the importance of perseverance in a comprehensive account of such virtues.     

The symbolic distance effect for alphabetic order judgements: A subjective report and reaction time analysis

The time needed to decide whether a pair of letters is in the correct alphabetic order varies inversely with alphabetic separation. This is an example of a phenomenon generally found with the comparison of ordered symbols or concepts, called the symbolic distance effect (Moyer and Bayer, 1976). It is argued that when letters are compared, an important determinant of this effect is the degree to which subjects subvocally run-through parts of the alphabet to determine the correctness of the order of a stimulus pair. A trial-by-trial introspection procedure coupled with reaction time measurements is used in the present experiment, in which letter order judgements were made over a range of separations. RTs increased with increasing number of letters in the reported run-through. At small letter separations, run-through occurred more frequently, and this was found to be the basis of the symbolic distance effect. For trials on which no run-through was reported the symbolic distance effect was absent. The data are summarized as a model in which comparisons are made from directly available order information from memory, or with an additional run-through process. The details of the run-through process suggest that groupings learned in childhood are probably involved in the selection of the starting letter for run-through.     

Models of group psychotherapy: sifting through confusion.

This editorial introduces a series of articles by leading proponents of the ten major models of group psychotherapy to appear in the International Journal of Group Psychotherapy. These theoretical contributions will be published throughout 1992 as a dedication to the American Group Psychotherapy Association's (AGPA) 50th anniversary. In the present article, the author reports results from a recent survey of senior clinicians within AGPA who expressed their opinions about the central issues that practitioners should understand during the working phase of group treatments. Statistical comparisons among action-oriented, interpersonal, and psychodynamic respondents to the questionnaire revealed striking differences in how therapeutic interventions were conceptualized. These findings are outlined as a preface to the first three articles in the series.     

Source confusion as an explanation of cultivation: a test of the mechanisms underlying confusion of fiction with reality on television

Cultivation studies have found evidence that heavy television viewers adopt a world view congruent with how the world is portrayed in fictional television programs. An explanation is that viewers may remember fictional TV stories as realistic stories or news (fiction-to-news confusion). Until now, fiction-to-news confusion was found only if at least a week evolved between watching TV and asking viewers what was remembered. The present study conducted with a purposive sample of students and employees of a college in The Netherlands (N=96; M age = 28.6 yr., SD = 10.9) indicates that fiction-to-news confusions can also occur almost immediately after watching. In addition, whereas earlier research suggests that fiction-to-news confusions are associated with heavy viewing, i.e., more confusion when more hours per day are spent on TV viewing in leisure time, and faulty memory, the present study more specifically suggests that participants make many fiction-to-news confusions when they are exposed to relatively many fictional TV fragments that contain threatening, violent events.     

Exorcising the double-nail confusion: a reply to Ono

Contrary to the claims of Ono it is argued that the principles and rules of direction vision do not account for the double-nail illusions, and that the 'ghost' concept is hidden rather than exorcised in Ono's approach.