Physico-mathematics and the search for causes in Descartes’ optics—1619–1637

One of the chief concerns of the young Descartes was with what he, and others, termed “physico-mathematics”. This signalled a questioning of the Scholastic Aristotelian view of the mixed mathematical sciences as subordinate to natural philosophy, non explanatory, and merely instrumental. Somehow, the mixed mathematical disciplines were now to become intimately related to natural philosophical issues of matter and cause. That is, they were to become more ’physicalised’, more closely intertwined with natural philosophising, regardless of which species of natural philosophy one advocated. A curious, short-lived yet portentous epistemological conceit lay at the core of Descartes’ physico-mathematics—the belief that solid geometrical results in the mixed mathematical sciences literally offered windows into the realm of natural philosophical causation—that in such cases one could literally “see the causes”. Optics took pride of place within Descartes’ physico-mathematics project, because he believed it offered unique possibilities for the successful vision of causes. This paper traces Descartes’ early physico-mathematical program in optics, its origins, pitfalls and its successes, which were crucial in providing Descartes resources for his later work in systematic natural philosophy. It explores how Descartes exploited his discovery of the law of refraction of light—an achievement well within the bounds of traditional mixed mathematical optics—in order to derive—in the manner of physico-mathematics—causal knowledge about light, and indeed insight about the principles of a “dynamics” that would provide the laws of corpuscular motion and tendency to motion in his natural philosophical system.     

Bridging a yawning chasm: EEG investigations into the debate concerning the role of the human mirror neuron system in contagious yawning

Ongoing debate in the literature concerns whether there is a link between contagious yawning and the human mirror neuron system (hMNS). One way of examining this issue is with the use of the electroencephalogram (EEG) to measure changes in mu activation during the observation of yawns. Mu oscillations are seen in the alpha bandwidth of the EEG (8–12 Hz) over sensorimotor areas. Previous work has shown that mu suppression is a useful index of hMNS activation and is sensitive to individual differences in empathy. In two experiments, we presented participants with videos of either people yawning or control stimuli. We found greater mu suppression for yawns than for controls over right motor and premotor areas, particularly for those scoring higher on traits of empathy. In a third experiment, auditory recordings of yawns were compared against electronically scrambled versions of the same yawns. We observed greater mu suppression for yawns than for the controls over right lateral premotor areas. Again, these findings were driven by those scoring highly on empathy. The results from these experiments support the notion that the hMNS is involved in contagious yawning, emphasise the link between contagious yawning and empathy, and stress the importance of good control stimuli.     

Effects of cage mesh on pointing: hand shapes in chimpanzees (<Emphasis Type="Italic">Pan troglodytes</Emphasis>)

It has been speculated that cage mesh exerts a shaping influence on reaching behavior by captive apes, which is then misconstrued as pointing by human observers. Although this notion is clearly falsified by the pointing of captive language-trained apes—who point in the absence of intervening cage mesh—nevertheless, the degree to which cage mesh might influence pointing hand shapes by captive great apes in other housing environments remains relatively unexplored. We examined 259 pointing gestures displayed in archival footage from over 18 h of observation by three nonlanguage-trained chimpanzees housed at a biomedical research center. We coded points in relation to how close to the boundaries of the diamond-shaped cage mesh their points were displayed. We found that points with the whole hand were significantly more likely to be displayed away from the mesh boundaries, relative to points with the index finger or other single-digit points. However, points of each hand shape were displayed at each location, demonstrating that these physical parameters do not fully account for the number of fingers extended while pointing by chimpanzees.     

Biblical Literalism: A Test of the Compensatory Schema Hypothesis Among Anglicans in England

The compensatory schema hypothesis (Hoffmann and Bartkowski, Soc Forces 86:1245–1272, 2008) has been used to explain why women seem to have higher levels of biblical literalism than men in some Christian denominations. Based on social structuration and gender theories, it proposes that biblical literalism is a key social schema in some denominations that deny women access to institutional power. Women compensate for the lack of access to institutional social resources (leadership) by stressing the accepted schema (literalism) more strongly than men. The theory was tested using two samples from the Church of England, one lay (N = 394) and one ordained (N = 1,052). Laywomen were more literal than laymen among evangelicals and Anglo-catholics, where opposition to women’s ordination is highest, but in both cases the difference was largely explained by differences in education levels between the sexes. Clergywomen, with access to leadership resources, were less literal than clergymen in both Anglo-catholic and evangelical traditions. The results offer rather weak support for the compensatory schema hypothesis, and alternative explanations of the findings are discussed.     

Kepler’s optics without hypotheses

This paper argues that Kepler considered his work in optics as part of natural philosophy and that, consequently, he aimed at change within natural philosophy. Back-to-back with John Schuster’s claim that Descartes’ optics should be considered as a natural philosophical appropriation of innovative results in the tradition of practical and mixed mathematics the central claim of my paper is that Kepler’s theory of optical imagery, developed in his Paralipomena ad Vitellionem (1604), was the result of a move similar to Descartes’ by Kepler. My argument consists of three parts. First, Kepler borrowed a geometrical model and experiment of optical imagery from the mélange of mixed and practical mathematics provided in the works of the sixteenth-century mathematicians Ettore Ausonio and Giovanni Battista Della Porta. Second, Kepler criticized the Aristotelian theory of light and he developed his own alternative metaphysics. Third, Kepler used his natural philosophical assumptions about the nature of light to re-interpret the model of image formation taken from Della Porta’s work. Taken together, I portray Kepler’s theory of optical imagery as a natural philosophical appropriation of an innovative model of image formation developed in a sixteenth-century practical and mixed mathematical tradition which was not interested in questioning philosophical assumptions on the nature of light.     

Midlife Sexuality Among Thai Adults: Adjustment to Aging in the Thai Family Context

The objective of the study is to assess views of age related changes in sexual behavior among married Thai adults age 53–57. Results are viewed in the context of life course theory. In-depth interviews were conducted with 44 Thai adults in Bangkok and the four regions of Thailand. Topics covered include changing sexual behavior with age, adjustment to this change, gender differences in behavior, attitudes toward commercial sex and other non-marital sexual partners, and condom use. Most respondents were aware of this change and saw a decrease in sexual activity and desire more often among women compared to men. At the same time, many respondents viewed sexuality as important to a marriage. Some respondents accepted the decrease in sexual activity and focused more on work, family and temple activities. Thai Buddhism was seen as an important resource for people who were dealing with changes due to aging. Other persons turned to other partners including both commercial and non-commercial partners. The influence of the HIV epidemic that began in the 1990s was seen in concerns about disease transmission with extramarital partners and consequent attitudes toward condom use. The acceptability of extramarital partners in the family and community ranged from acceptance to strong disapproval of extramarital relationships.     

In perfect harmony: synchronizing the self to activated social categories

The self-concept is one of the main organizing constructs in the behavioral sciences because it influences how people interpret their environment, the choices they make, whether and how they initiate action, and the pursuit of specific goals. Because belonging to social groups and feeling interconnected is critical to human survival, the authors propose that people spontaneously change their working self-concept so that they are more similar to salient social categories. Specifically, 4 studies investigated whether activating a variety of social categories (i.e., jocks, hippies, the overweight, Blacks, and Asians) increased associations between the self and the target category. Whereas Studies 1 and 2 focused on associations between stereotypic traits and the self, Studies 3 and 4 examined self-perceptions and self-categorizations, respectively. The results provide consistent evidence that following social category priming, people synchronized the self to the activated category. Furthermore, the findings indicate that factors that influence category activation, such as social goals, and factors that induce a focus on the interconnectedness of the self, such as an interdependent vs. independent self-construal, can impact this process. The implications of changes to the working self-concept for intergroup relations are discussed.     

Carry on: spontaneous object carrying in 13-month-old crawling and walking infants

Carrying objects requires coordination of manual action and locomotion. This study investigated spontaneous carrying in 24 walkers who were 13 months old and 26 crawlers who were 13 months old during 1-hr, naturalistic observations in the infants' homes. Carrying was more common in walkers, but crawlers also carried objects. Typically, walkers carried objects in their hands, whereas crawlers multitasked by using their hands simultaneously for holding objects and supporting their bodies. Locomotor experience predicted frequency of carrying in both groups, suggesting that experienced crawlers and walkers perceive their increased abilities to handle objects while in motion. Despite additional biomechanical constraints imposed by holding an object, carrying may actually improve upright balance: Crawlers rarely fell while carrying an object, and walkers were more likely to fall without an object in hand than while carrying. Thus, without incurring an additional risk of falling, spontaneous carrying may provide infants with new avenues for combining locomotor and manual skills and for interacting with their environments.     

Social class differences in N400 indicate differences in spontaneous trait inference

An emerging literature indicates that dispositional bias in causal attribution of social behavior is weaker for people with working-class (vs. middle-class) backgrounds. However, it is unknown whether this difference is also present in spontaneous forms of trait inference. In the current work, American undergraduates were asked to merely memorize many pairings of a target face and a trait-implying behavior. In a subsequent lexical judgment task, after each face was presented as a fixation, either an implied trait or its antonym was given as a target. As expected, participants with college-educated parents (middle class) showed a strong N400 event-related potential component to the antonym (vs. the implied trait), suggesting spontaneous trait inference during the memorization phase. In contrast, those with high-school-educated parents (working class) showed no such effect. It is important to note that the N400 spontaneous trait inference effect was associated with perceived significance of dispositions in accounting for social behaviors.     

Human sensitivity to the magnitude and probability of a continuous causal relation in a video game

Continuous causation, in which incremental changes in one variable cause incremental changes in another, has received little attention in the causal judgment literature. A video game was adapted for the study of continuous causality in order to examine the novel cues to causality that are present in these paradigms. The spatial proximity of an object to an "enemy detector" produced auditory responses as a function of the object's proximity. Participants' behavior was a function of the range of the effect's auditory sensitivity and the moment-to-moment likelihood of detection. This new paradigm provides a rich platform for examining the cues to causation encountered in the learning of continuous causal relations.