Muscle coordination and force variability during static and dynamic tracking tasks

This study examined muscular activity patterns of extensor and flexor muscles and variability of forces during static and dynamic tracking tasks using compensatory and pursuit display. Fourteen volunteers performed isometric actions in two conditions: (i) a static tracking task consisting of flexion/pronation, ulnar deviation, extension/supination and radial deviation of the wrist at 20% maximum voluntary contraction (MVC), and (ii) a dynamic tracking task aiming at following a moving target at 20% MVC in the four directions of contraction. Surface electromyography (SEMG) from extensor carpi ulnaris, extensor carpi radialis, flexor carpi ulnaris and flexor digitorum superficialis muscles and exerted forces in the transverse and sagittal plane were recorded. Normalized root mean square and mutual information (index of functional connectivity within muscles) of SEMGs and the standard deviation and sample entropy of force signals were extracted. Larger SEMG amplitudes were found for the dynamic task (p < .05), while normalized mutual information between muscle pairs was larger for the static task (p < .05). Larger size of variability (standard deviation of force) concomitant with smaller sample entropy was observed for the dynamic task compared with the static task (p < .01 for both). These findings underline a rescaling of the muscles’ respective contribution influencing force variability relying on feedback and feed-forward control strategies in relation to display modes during static and dynamic tracking tasks.     

Eye movement suppression interferes with construction of object-centered spatial reference frames in working memory

The brain’s frontal eye fields (FEF), responsible for eye movement control, are known to be involved in spatial working memory (WM).In a previous fMRI experiment (Wallentin, Roepstorff & Burgess, Neuropsychologia, 2008) it was found that FEF activation was primarily related to the formation of an object-centered, rather than egocentric, spatial reference frame. In this behavioral experiment we wanted to demonstrate a causal relationship between eye movement control and manipulation of spatial reference frames. Sixty-two participants recalled either spatial (“Was X in front of Y?”) or non-spatial (“Was X darker than Y?”) relations in a previously shown image containing two to four objects, each with an intrinsic orientation and unique luminance. During half of all recall trials a moving visual stimulus was presented, which participants had to ignore, thus suppressing eye movement. Response times were significantly slower for spatial relations with distraction while there was no effect on non-spatial relations. There was no effect on accuracy, i.e. WM maintenance. This is consistent with the hypothesis that in spatial representations the FEFs are involved in WM content manipulation, such as establishing an object-centered spatial frame of reference.     

Indispensability and Holism

It is claimed that the indispensability argument for the existence of mathematical entities (IA) works in a way that allows a proponent of mathematical realism to remain agnostic with regard to how we establish that mathematical entities exist. This is supposed to be possible by virtue of the appeal to confirmational holism that enters into the formulation of IA. Holism about confirmation is supposed to be motivated in analogy with holism about falsification. I present an account of how holism about falsification is supposed to be motivated. I argue that the argument for holism about falsification is in tension with how we think about confirmation and with two principles suggested by Quine for construing a plausible variety of holism. Finally, I show that one of Quine’s principles does not allow a proponent of mathematical realism to remain agnostic with regard to how we establish that mathematical entities exist.     

Coming out of the Hasidic closet: Jiří Mordechai Langer (1894–1943) and the fashioning of homosexual-Jewish identity

This essay inaugurates the historical study of the modern homosexual Jewish experience before Stonewall. I begin with a historiographic introduction to the emerging subfield of gay Jewish history. I then turn to reintroduce Jiri Langer, a homosexual and Hasidic writer affiliated with the interwar "Prague circle" (and friend of Franz Kafka and Max Brod) into the purview of modern Jewish Studies. I take up two questions: first, how Langer reconciled his homosexual and Orthodox religious identity; and second, why Langer"s homosexuality became exigent as a Jewish question at this particular historical moment. In his key text, Die Erotik der Kabbala, Langer engages with the dominant interwar debates on homosexuality, but most directly with the work of Hans Blüher, the major theoretician of the German Wandervogelbewegung. In the course of correcting Blüher's antisemitic claims about Jews and homosexuality, Langer managed to delineate a specifically homosexual Jewish identity by renegotiating the relationship between homosexuality and Judaism and by adumbrating a history of "gay" Jews. I contextualize this long-neglected text within Langer's fascinating biography; the debates in the early homosexual rights movement; the particular cultural features of the "Prague circle" in which Langer wrote; and the dislocation and devastation of Langer's beloved eastern-European Hasidic communities caused by World War I—communities that Langer experienced as deeply homoerotic.     

Career-related goal pursuit among post-high school youth: Relations between personal control beliefs and control strivings

The present research reveals the bi-directional relationship between career-related control beliefs and strivings, and their predictive relationship with hours of gainful employment. Three waves of data of a longitudinal study of 532 graduating high school seniors from four ethnically diverse schools in the Los Angeles Unified School District were analyzed using structural equation modeling. The results show individuals?? career-related personal control beliefs in effort and social connections, but not in ability or luck, were significantly predictive of career-related control strivings 1?year later. Thus, only personal control beliefs in causal factors that are contingent on an individual??s primary control strivings to enact effects are predictive of active motivational engagement in pursuit of career-related goals. Regarding the inverse direction of influence (i.e., strivings predict beliefs), career-related control strivings were significantly predictive of career-related personal control beliefs in ability, effort, and social connections, but not luck, 1?year later. These results support the idea that active goal engagement creates an implemental mindset that optimistically biases individuals?? beliefs in their personal control over causal factors relevant to attaining a pursued career-related goal. In addition, the results show that career-related control strivings, but not career-related personal control beliefs, are significantly positively associated with the number of hours of gainful employment worked 1-year later, supporting a beliefs-strivings-outcome sequential relationship.     

The Indispensability Argument for Mathematical Realism and Scientific Realism

Confirmational holism is central to a traditional formulation of the indispensability argument for mathematical realism (IA). I argue that recent strategies for defending scientific realism are incompatible with confirmational holism. Thus a traditional formulation of IA is incompatible with recent strategies for defending scientific realism. As a consequence a traditional formulation of IA will only have limited appeal.     

The power of the past: nostalgia as a meaning-making resource

In three experiments we tested whether nostalgia bolsters meaning in life relative to two other modes of autobiographical thought: imagining a desired future experience and recalling a positive past experience. In Experiment 1 participants thought about a nostalgic or desired future experience and then completed a presence of meaning scale. Thinking about a nostalgic (compared to desired future) experience increased perceived presence of meaning. In Experiment 2 we examined whether nostalgia can additionally reduce the search for meaning. Participants thought about a nostalgic, desired future or recent positive experience, and then completed a search for meaning scale. Nostalgia, relative to both comparison conditions, decreased the search for meaning. Finally we tested whether, by virtue of its capacity to increase meaning, nostalgia can mitigate threats to meaning. In Experiment 3 participants were exposed to either absurd or representational art, under the guise that they would later have to interpret its meaning, and then thought about either a nostalgic or a recent positive experience. Meaning was subsequently measured. The absurd art interpretation condition decreased the perceived presence of meaning but nostalgic reflection attenuated this effect.     

Do we conceptualize every color we consciously discriminate?

Mandik understands color-consciousness conceptualism to be the view that one deploys in a conscious qualitative state concepts for every color consciously discriminated by that state. Some argue that the experimental evidence that we can consciously discriminate barely distinct hues that are presented together but cannot do so when those hues are presented in short succession suggests that we can consciously discriminate colors that we do not conceptualize. Mandik maintains, however, that this evidence is consistent with our deploying a variety of nondemonstrative concepts for those colors and so does not pose a threat to conceptualism. But even if Mandik has shown that we deploy such concepts in these experimental conditions, there are cases of conscious states that discriminate colors but do not involve concepts of those colors. Mandik's arguments sustain only a theory in the vicinity of conceptualism: The view that we possess concepts for every color we can discriminate consciously, but need not deploy those concepts in every conscious act of color discrimination.