In this article, I discuss manuscript material written by Petrus van Musschenbroek related to his first experiments with the Leiden jar. Despite the importance of the discovery of the Leiden jar for the history of electricity and the questions that still surround its discovery, a detailed treatment of this manuscript material is lacking in the literature. The main aim of this paper is to provide an outline of the manuscript material and to contextualize van Musschenbroek’s first experiments with the Leiden (...) jar. I show how the experiment fits within his research program on electricity and I discuss van Musschenbroek’s initial reactions to and analysis of the phenomenon. Before doing so, I first provide a short overview of the treatment of the early history of the Leiden jar in the secondary literature. After that, I discuss van Musschenbroek’s treatment of the topic of electricity in the textbooks he published in the years before the discovery of the device. Van Musschenbroek repeatedly emphasized that not enough experimental results were available for an informed theoretical treatment of the phenomenon of electricity to be possible. I then turn to the manuscript material, where I give a general description of the contents of the manuscript and van Musschenbroek’s experimental practice. The manuscript material further confirms recent work on the Leiden jar by Silva and Heering, and provides new insights into the way van Musschenbroek himself reacted to the discovery. (shrink)

Teaching is an important aspect of scientific practice. However, it has only recently become the subject of detailed historical and philosophical analyses. In this paper, I argue that Joseph Rouse’s philosophy of scientific practice has important implications for the study of scientific education. Rouse’s dynamic conception of scientific knowledge entails that education should occupy a central place in our analyses of scientific practices, as it is crucial in guaranteeing their temporal extension and sustenance. However, Rouse’s reconceptualization of scientific knowledge also (...) has implications for our understanding of scientific education itself. I will work out these implications, focussing on Rouse’s non-subject-centered account of scientific practices. More generally, I show how Rouse’s philosophy of science entails that the study of scientific education should take the form of an integrated history and philosophy of scientific education. (shrink)

In this article, we discuss the development of the concept of a ‘law’ (of nature) in the work of the Dutch natural philosopher and experimenter Petrus van Musschenbroek (1692–1761). Since Van Musschenbroek is commonly described as one of the first ‘Newtonians’ on the Continent in the secondary literature, we focus more specifically on its relation to Newton’s views on this issue. Although he was certainly indebted to Newton for his thinking on laws (of nature), Van Musschenbroek’s views can be seen (...) to diverge from Newton’s on crucial points. We show, moreover, how his thinking on laws of nature was shaped by both international and local factors. We start with a brief discussion of Newton’s concept of ‘laws of nature’ in order to set the stage for Van Musschenbroek’s. We then document the development of Van Musschenbroek’s views on laws of nature in chronological order. We demonstrate how his thinking on laws of nature was tied to institutional, theological and scientific factors. We conclude by pointing to the broader significance of this case study for our understanding of the development of the concept ‘law of nature’ during the eighteenth century. (shrink)

We present data and argument to show that in Tetris—a real-time interactive video game—certain cognitive and perceptual problems are more quickly, easily, and reliably solved by performing actions in the world rather than by performing computational actions in the head alone. We have found that some translations and rotations are best understood as being used to implement a plan, or to implement a reaction. To substantiate our position we have implemented a computational laboratory that lets us record keystrokes and game (...) situations, as well as allows us to dynamically create situations. Using the data of over 30 subjects playing 6 games, tachistoscopic tests of some of these subjects, and results from our own successful efforts at building expert systems to play Tetris, we show why knowing how to use one’s environment to enhance speed and robustness are important components in skilled play. (shrink)

Eighty-four undergraduate male subjects were tachistoscopically exposed either to an experimental message designed to arouse anxiety , or to a neutral control message , at 4 ms or 200 ms durations. Electrodermal responses were recorded before, during and after exposure to the critical messages. Three measures of awareness of 4 ms stimuli were used; recall, recognition and discrimination. No evidence of stimulus awareness was found on any of these measures. Only subjects exposed to the experimental message at 4 ms durations (...) showed a significant increase in EDR from pre-exposure to message exposure period. These results support Silverman's hypothesis that drive-related stimuli must be presented subliminally in order to produce significant effects on behavior, and are consistent with Bornstein's hypothesis that stimulus awareness inhibits responding to drive- and affect-related stimuli. (shrink)

Neurobiological and cognitive models of unconscious information processing suggest that subconscious threat detection can lead to cognitive misinterpretations and false alarms, while conscious processing is assumed to be perceptually and conceptually accurate and unambiguous. Furthermore, clinical theories suggest that pathological anxiety results from a crude preattentive warning system predominating over more sophisticated and controlled modes of processing. We investigated the hypothesis that subconscious detection of threat in a cognitive task is reflected by enhanced ''false signal'' detection rather than by selectively (...) enhanced discrimination of threat items in 30 patients with panic disorder and 30 healthy controls. We presented a tachistoscopic word-nonword discrimination task and a subsequent recognition task and analyzed the data by means of process-dissociation procedures. In line with our expectations, subjects of both groups showed more false signal detection to threat than to neutral stimuli as indicated by an enhanced response bias, whereas indices of discriminative sensitivity did not show this effect. In addition, patients with panic disorder showed a generally enhanced response bias in comparison to healthy controls. They also seemed to have processed the stimuli less elaborately and less differentially. Results are consistent with the assumption that subconscious threat detection can lead to misrepresentations of stimulus significance and that pathological anxiety is characterized by a hyperactive preattentive alarm system that is insufficiently controlled by higher cognitive processes. (shrink)

Freud proposes that in unconscious processing, logical connections are also (heavily) based upon phonological similarities. Repressed concerns, for example, would also be expressed by way of phonologic ambiguity. In order to investigate a possible unconscious influence of phonological similarity, 31 participants were submitted to a tachistoscopic subliminal priming experiment, with prime and target presented at 1ms. In the experimental condition, the prime and one of the 2 targets were phonological reversed forms of each other, though graphemically dissimilar (e.g., “nice” (...) and “sign”); in the control condition the targets were pseudo-randomly attributed to primes to which they don’t belong. The experimental task was to “blindly” pick the choice most similar to the prime. ERPs were measured with a focus on the N320, which is known to react selectively to phonological mismatch in supraliminal visual word presentations. The N320 amplitude-effects at the electrodes on the midline and at the left of the brain significantly predicted the participants’ net behavioral choices more than half a second later, while their subjective experience is one of arbitrariness. Moreover, the social desirability score (SDS) significantly correlates with both the behavioral and the N320 brain responses of the participants. It is proposed that in participants with low SDS the phonological target induces an expected reduction of N320 and this increases their probability to pick this target. In contrast, high defensive participants have a perplexed brain reaction upon the phonological target, with a negatively peaking N320 as compared to control and this leads them to avoid this target more often. Social desirability, which is understood as reflecting defensiveness, might also manifest itself as a defense against the (energy-consuming) ambiguity of language. The specificity of this study is that all of this is happening totally out of awareness and at the level of very elementary linguistic distinctions. (shrink)

The ArgumentThis essay addresses the historiographical question of how to study scientific instruments and the connections between them without rigidly determining the boundaries of the object under historical scrutiny beforehand. To do this, I will explore an episode in the early history of the tachistoscope — defined, among other things, as an instrument for the brief exposure of visual stimuli in experimental psychology. After looking at the tachistoscope described by physiologist Volkmann in 1859, I will turn to the gravity chronometer, (...) constructed by Cattell at Wundt's Leipzig institute of psychology in the 1880s. Taking Wittgenstein's notion of family resemblances as a methodological suggestion to travel from one member to another to find out just how members relate to one another, I will investigate part of the family to which both the tachistoscope and the gravity chronometer turn out to belong. A detailed analysis of these instruments, using both historical sources and historical accounts of psychological instruments, may demonstrate that the instrument is not a standard package that, if well applied, will simply secure good results. Each package needs to be assembled again and again; the particular package that is assembled may differ on different occasions. Thus an alternative is developed to an understanding of instruments as univocally functioning material means. (shrink)