Changes in the prevalence of alpha activity associated with the repetition,performance and magnitude of arithmetical calculations

Summary Changes in prevalence of alpha activity (defined as from 8 to 13 c.p.s.) immediately before and during the solution of twenty arithmetical tasks (multiplications and additions in Hard and Easy categories) by 61 normal subjects, with closed eyes, have been measured above a preset threshold voltage over noise level by a percent time alpha computer. An average prevalence of alpha activity of 64.75% before calculation reduced to an average prevalence of 49.01% during calculations. The prevalence of alpha activity during calculation was significantly increased by repetition of similar arithmetical tasks whereas the prevalence of alpha activity before calculation declined from the beginning to the end of the experiment, thus showing an opposite trend. Prevalence of alpha activity was not related to duration of calculations, but, in contrast, low prevalences of alpha activity during calculation were significantly associated with more numerous errors, particularly in additions. It was found that as the information content of a task increased so the prevalence of alpha activity during its solution declined, especially in additions and Easy multiplications. Calculation times and errors were strongly correlated with information content. These results are evaluated in terms of their possible behavioural significance and of the neurophysiological mechanisms underlying attenuation of alpha activity, although the precise theoretical context in which they should be viewed; whether they should be related to habituation, learning, fatigue or solely calculation, may require further clarification.

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Zusammenfassung Veränderungen in der Dominanz (Prävalenz) der Alpha-Aktivität (als 8–13 c.p.s. definiert) wurden kurz vor und während der Lösung von 20 arithmetischen Aufgaben (Multiplikation und Addition in Leichten und Schweren Serien) bei 61 normalen Personen, welche die Augen geschlossen hielten, studiert. Die Messung wurde bei einer festgesetzten (preset) Schwellenspannung über dem Geräuschniveau mit einem Alpha-Zeit-Computer ausgeführt. Dabei ergab sich eine Reduzierung der Alpha-Aktivität von 64,75% vor dem Rechnen auf 49,01% während des Rechnens. Die Alpha-Dominanz während des Rechnens wurde statistisch durch Wiederholung von ähnlichen Aufgaben erhöht; im Gegensatz dazu ging die Alpha-Dominanz vor dem Rechnen progressiv vom Anfang bis zum Ende des Experiments zurück.Die Alpha-Dominanz hatte keine Beziehung zur Dauer des Rechnens; andererseits waren niedrige Frequenzen von Alpha-Aktivität während des Rechnens mit Häufigkeit von Fehlern, vor allem beim Addieren, verbunden. Wenn sich der Informations-inhalt einer Aufgabe erhöhte, so verminderte sich die Alpha-Dominanz während ihrer Lösung, vor allem beim Addieren und bei leichten Multiplikationen. Sowohl Rechen-Zeit wie Fehler waren stark mit dem Informations-inhalt korreliert.Diese Ergebnisse werden hinsichtlich ihrer möglichen Beziehungen zum psychischen Verhaltens-Zustand (Behaviour) und zu den mit Abschwächung der Alpha-Aktivität verbundenen neuro-physiologischen Prozessen analysiert. Eine Klärung des präzisen theoretischen Zusammenhanges, in dem die Resultate gesehen werden sollten, sowie ihre Beziehungen zu Gewöhnung, Lernen, Ermüdung oder zum Rechnen allein, erfordert weiteres Studium.

     

<Emphasis Type="Italic">Doctor Anonymous</Emphasis>: Creating Contexts for Homosexuality as Mental Illness

In this essay, the author describes how he faced institutionalized homophobia during his psychiatric training, and how he later wrote a play inspired by the life of a gay psychiatrist. Despite Freud’s supportive stance, homosexuality aroused the antipathy of American organized psychiatry and psychoanalysis and came to be listed as an illness in the Diagnostic and Statistical Manual (DSM). Dr. John E. Fryer outed himself as “Dr. H Anonymous” at a 1972 meeting of the American Psychiatric Association, and the next year homosexuality was removed from the DSM. The 2014 play Doctor Anonymous offers a fictionalized account of this watershed moment in the history of the gay rights movement. The author discusses his own psychotherapeutic work with gay male patients, including those who had previously been treated with conversion therapy, and explores how the play mirrors his own life experience and the experience of his patients.     

Pattern of Neuropsychological Deficit at Age Five Years Following Neonatal Unilateral Brain Injury

The pattern of language deficit following left-hemisphere brain injury and visual/spatial deficit following right-hemisphere injury in an adult or older child is well recognized, but has been inconsistently reported following presumed neonatal brain injury. Our prospective study of 24 children at age 5 with documented neonatal unilateral brain injury lends support to the theory of hemisphere specialization at the time of birth. Twelve children who had unilateral left-hemisphere lesion were compared to 12 children with unilateral right-hemisphere lesion of similar timing and severity. Relative visual/spatial deficit following right-hemisphere lesion and receptive language deficit following left-hemisphere lesion were identified. Lateralized measures of grip strength, fine motor speed, and fine motor dexterity were not significantly different between the groups for either hand in this nonhemiparetic study sample. Only one child with a left-hemisphere lesion was left-handed, and only one child (right-lesion) had a hemiparesis.     

Brief report: Compliance in the classroom: Using the „thumbs up”︁ procedure to increase student compliance to teacher requests

This study assessed the effectiveness of a program designed to increase compliance with teacher commands in a regular 5th grade math class. A reversal design (A-B-B'-A-B') was employed. The teacher used a discriminative stimulus to signal the students as to the availability of an opportunity to earn a point towards a reinforcer. To receive the point the students were required to return the signal and initiate compliance. The entire class was involved in the program; however, data were recorded on two students, one identified by the teacher as noncompliant; the other served as a control. The results indicated that the program was effective in increasing initiation of compliance to teacher commands. However, serious questions were raised about the generalizability of such a program.     

Inference to the best explanation: does it track truth?

In the form of inference known as inference to the best explanation there are various ways to characterise what is meant by the best explanation. This paper considers a number of such characterisations including several based on confirmation measures and several based on coherence measures. The goal is to find a measure which adequately captures what is meant by ‘best’ and which also yields the truth with a high degree of probability. Computer simulations are used to show that the overlap coherence measure achieves this goal, enabling the true explanation to be identified almost as often as an approach which simply selects the most probable explanation. Further advantages to this approach are also considered in the case where there is uncertainty in the prior probability distribution.