Cortical steady-potential shifts in conditioning

Cortical steady-potential shifts obtained from nonpolarizing electrodes chronically implanted in freely moving cats and rats reveal cortical activation related to urgency of response to unconditional and conditional stimuli. Such shifts appear relatively independent of activation in the rhythmic electrocorticogram and are related to higher levels of activation. Shifting is found to be modulated by drive and level of learning, suggesting a correlation with the proposed reaction potential of Hull. Both approach and avoidance “urgency” are reflected in the onset slope and amplitude of SP shifts in a manner suggesting modulation of cortical activation by the effects of behavioral regulation of stimulus conditions.     

The effects of coding procedure on human information transmission

Three different coding schemes, i.e., transformations between stimuli and responses, were used in a continuous information transmission situation. The stimuli were groups of binary digits and S was required to transform these into verbal equivalents of combinations formed by taking various sets of the English letters. Three codes, one based on communication theory, one based on Miller’s (1956) chunking hypothesis, and a combination of the first two were used. In addition, two levels of stimulus redundancy, zero and 0.5 were used. Time to complete the task and errors were the de-pendent variables. The Ss were run for twelve days. The basic result was that Ss transmitted information at a constant rate regardless of the code or redundancy level used.     

A comparison of two psychophysical methods using animals

A discrimination box containing two levers with a light above each was used to train eight rats to press beneath the brighter light for a milk reinforcer. The brighter light was held constant and the comparison light was varied to produce 12 brightness differences. The animals were run under two experimental methods: the block method in which each brightness level comparison was presented for a block of 11 contiguous trials, and the staircase method in which the sequence of brightness comparisons was determined by the correctness of the response on the preceding comparison. The block method produced a smaller differential brightness threshold and a larger change in discrimination performance for stimulus magnitude changes than did the staircase method.     

Information and the memory span

Messages differing in number of symbols and symbol information load were presented tachistoscopically to 4 adult Ss. The messages were constructed by random drawing with replacement from an alphabet of 8 black form symbols and an alphabet of 32 colored form symbols. The number of symbols recalled varied as a function of alphabet; however, the information in recall was constant for all conditions. The number of symbols recalled and the information in recall was independent of message length.     

Variability in gustatory quality identification

A total of 60 male and 60 female non-smoking undergraduates were tested on two gustatory screening tasks in which solutions representing the four basic taste qualities were used. The solution concentrations chosen were low, but supposedly distinct as to their qualities. Only 16% of the males were able to identify all solutions correctly, i.e., to a criterion of 4 correct out of 7 presentations, as compared to 34% of the females. A further 28% of the males consistently confused the sour and bitter qualities as did 10% of the females. A correction procedure used in one part of the experiment did not prevent this confusion. We suggest that the sour-bitter confusion may be the gustatory analogue of abnormal color vision.     

Über den Zusammenhang zwischen Tüchtigkeit und Beliebtheit in Schulklassen

Zusammenfassung Es wurde an fünf Schulen ein hoher Zusammenhang zwischen Tüchtigkeit und Beliebtheit aufgezeigt, der mit steigendem Alter der Schüler allmählich absinkt.Relativ häufig sind die Tüchtigsten und die Beliebtesten in Schulklassen identisch; ein Zusammenhang mit dem Alter ist hierbei nicht nachzuweisen.Noch häufiger sind Beliebtheits- und Tüchtigkeitsstars identisch; in den unteren Klassen sind diese Identitäten signifikant zahlreicher als in den oberen Klassen.Die hohe Korrelation zwischen Tüchtigkeit und Beliebtheit kann nicht auf mangelnde Differenzierungsfähigkeit der Kinder zurückgeführt werden. Sie steht auch nicht im Zusammenhang mit dem Ranggradienten, der in allen Klassen relativ groß war.Wir sind Fräulein cand. phil. H. Heggemann für Erhebung und Auswertung eines Teils unseres Materials zu Dank verpflichtet⁶.     

God and free speech: A quaker perspective on the Satanic Verses controversy

This paper offers a Quaker perspective on the issues raised for British society by the Satanic Verses controversy. It is argued that the Quaker rejection of coercive power is founded upon the story of Jesus Christ. The origins of Quaker attitudes to free speech are located in seventeenth‐century Puritanism, arguing that Quakers share with Western secular defenders of free speech an internalization of the blasphemy taboo which issues in intolerance of anything held sacred. Furthermore, free speech rhetoric tends to ignore the power relations which sustain free speech in particular contexts. This is a neglect which, coupled with a secularized theory of race relations that ignores religious factors, renders its protagonists incapable of addressing anti‐Islamic prejudice, a phenomenon illustrated from press coverage of the controversy. The implications of this argument for British society and Quakers in particular are then considered. It is argued that an extension of legislation covering incitement to racial hatred to religion is the most appropriate legal response, but the greatest need is educational. Quakers and other Christian groups need to develop their own theological response to avoid passively replicating the dominant view in society.     

The many null distributions of person fit indices

This paper deals with the situation of an investigator who has collected the scores ofn persons to a set ofk dichotomous items, and wants to investigate whether the answers of all respondents are compatible with the one parameter logistic test model of Rasch. Contrary to the standard analysis of the Rasch model, where all persons are kept in the analysis and badly fittingitems may be removed, this paper studies the alternative model in which a small minority ofpersons has an answer strategy not described by the Rasch model. Such persons are called anomalous or aberrant. From the response vectors consisting ofk symbols each equal to 0 or 1, it is desired to classify each respondent as either anomalous or as conforming to the model. As this model is probabilistic, such a classification will possibly involve false positives and false negatives. Both for the Rasch model and for other item response models, the literature contains several proposals for a person fit index, which expresses for each individual the plausibility that his/her behavior follows the model. The present paper argues that such indices can only provide a satisfactory solution to the classification problem if their statistical distribution is known under the null hypothesis that all persons answer according to the model. This distribution, however, turns out to be rather different for different values of the person's latent trait value. This value will be called ability parameter, although our results are equally valid for Rasch scales measuring other attributes.As the true ability parameter is unknown, one can only use its estimate in order to obtain an estimated person fit value and an estimated null hypothesis distribution. The paper describes three specifications for the latter: assuming that the true ability equals its estimate, integrating across the ability distribution assumed for the population, and conditioning on the total score, which is in the Rasch model the sufficient statistic for the ability parameter.Classification rules for aberrance will be worked out for each of the three specifications. Depending on test length, item parameters and desired accuracy, they are based on the exact distribution, its Monte Carlo estimate and a new and promising approximation based on the moments of the person fit statistic. Results for the likelihood person fit statistic are given in detail, the methods could also be applied to other fit statistics. A comparison of the three specifications results in the recommendation to condition on the total score, as this avoids some problems of interpretation that affect the other two specifications.The authors express their gratitude to the reviewers and to many colleagues for comments on an earlier version.