When two limbs are weaker than one: Sensorimotor syncopation with alternating hands

This study addresses the demands of alternating bimanual syncopation, a coordination mode in which the two hands move in alternation while tapping in antiphase with a metronomic tone sequence. Musically trained participants were required to engage in alternating bimanual syncopation and five other coordination modes: unimanual syncopation where taps are made (with the left or right hand) after every tone; unimanual syncopation where taps are made after every other tone; bimanual synchronization with alternating hands; unimanual synchronized tapping with every tone; and unimanual tapping with every other tone. Variability in tap timing was greatest overall for alternating bimanual syncopation, indicating that it is the most difficult. This appears to be due to instability arising from the simultaneous presence of two levels of antiphase coordination (one between the pacing sequence and the hands, the other between the two hands) rather than factors relating to movement frequency or dexterity limits of the nonpreferred hand.     

ILLUSTRATING FEMINIST THEORY

Feminist theory holds that many of the pathological behaviors observed in patients result from their position in the social hierarchy. The goals of the demonstration detailed in this article are to show the impact of current gender roles on the psychological well-being of women and men and to generate understanding and discussion of the problems that relative status can create in the therapeutic relationship. This teaching demonstration draws parallels between the Zimbardo (1971) prison experiment and the impact that assignment to low-and high-power roles can have on the psychological health of women and men. Students are asked to rate men and women on some of the diagnostic criteria that the Diagnostic and Statistical Manual of Mental Disorders (American Psychiatric Association, 1994) associates with Axis I and II diagnoses. The students watch a video of Zimbardo's prison study and then rate the prisoners and guards. This demonstration provides another explanation for gender patterns in psychopathology by demonstrating that psychologically healthy White males will develop different patterns of psychopathology depending on whether they are placed in a dominant or subordinate role. When placed in the subordinate role, they exhibit behaviors typically seen in women clients; when placed in a dominant role they exhibit behaviors commonly associated with male clients. This exercise demonstrates the unhealthy nature of the gender roles for both women and men.     

Two ways of learning associations

How people learn chunks or associations between adjacent items in sequences was modelled. Two previously successful models of how people learn artificial grammars were contrasted: the CCN, a network version of the competitive chunker of Servan‐Schreiber and Anderson [J. Exp. Psychol.: Learn. Mem. Cogn. 16 (1990) 592], which produces local and compositionally‐structured chunk representations acquired incrementally; and the simple recurrent network (SRN) of Elman [Cogn. Sci. 14 (1990) 179], which acquires distributed representations through error correction. The models' susceptibility to two types of interference was determined: prediction conflicts, in which a given letter can predict two other letters that appear next with an unequal frequency; and retroactive interference, in which the prediction made by a letter changes in the second half of training. The predictions of the models were determined by exploring parameter space and seeing howdensely different regions of the space of possible experimental outcomes were populated by model outcomes. For both types of interference, human data fell squarely in regions characteristic of CCN performance but not characteristic of SRN performance.