西医——中医挥之不去的他者

中西医的论证是医学哲学与医学史研究的热点问题。后现代哲学可以为理解两种医学之间的关系提供一个新的视角。本文运用后现代哲学中的“他者”观念回顾了中西医之间张力的演变,指出在整个过程中“中医”未能摆脱“西医”作为“他者”的注视。并从后现代医学的角度对这种张力的未来进行展望。     

Effect of exposure to lithium-paired or amphetamine-paired saccharin solution on open arm avoidance in an elevated plus maze

Recent evidence suggests that drug-induced conditioned taste avoidance may be mediated by conditioned fear (e.g., Parker, 2003). The experiments reported here evaluated the effect of exposure to a drug-paired flavor on open arm exploration in an elevated plus maze (EPM), a measure of fear. When rats were tested on a familiar (trial 2) EPM, but not on a novel (trial 1) EPM, prior exposure to a lithium-paired saccharin solution enhanced open arm activity relative to saline-paired saccharin. On the other hand, when rats were exposed to lithium-paired saccharin during plus maze exposure, they displayed suppressed open arm activity relative to unpaired controls when tested in a familiar maze. The pattern of results was specific to the conditional affective properties of the taste, because exposure to unconditional sickness produced by administration of lithium, and unconditionally unpalatable quinine solution did not produce this pattern. These results were interpreted in terms of the opponent process model of motivation; that is, exposure to a lithium-paired flavor elicits conditioned fear which is immediately followed by conditioned relief when the exposure is terminated. On the other hand, exposure to an amphetamine-paired flavor either before or during EPM testing enhanced open arm exploration. Since the strength of taste avoidance did not differ among amphetamine and lithium conditioned rats, these results provide further evidence that the nature of a saccharin-lithium association differs from that of a saccharin-amphetamine association.     

Failure of serial taste-taste compound presentations to produce overshadowing of extinction of conditioned taste aversion

Two experiments were conducted to study overshadowing of extinction in a conditioned taste aversion preparation. In both experiments, aversive conditioning with sucrose was followed by extinction treatment with either sucrose alone or in compound with another taste, citric acid. Experiment 1 employed a simultaneous compound extinction treatment and found results indicative of overshadowing of extinction. By contrast, Experiment 2, in which extinction treatment involved serial compound presentations, failed to obtain evidence of overshadowing of extinction. The results of Experiment 2 indicate that the serial presentation of two tastes was processed as equivalent to the separate presentation of the tastes. The results are discussed in relation to: (1) Convergent evidence from research on latent inhibition, (2) competing theories of learning and, (3) their possible adaptive value in food-selection learning.     

Optimal correction for guessing in multiple-choice tests

Subjects’ decisions in multiple-choice tests are an interesting domain for the analysis of decision making under uncertainty. When the test is graded using a rule that penalizes wrong answers, each item can be viewed as a lottery where a rational examinee would choose whether to omit (sure reward) or answer (take the lottery) depending on risk aversion and level of knowledge. We formalize students as heterogeneous decision makers with different risk attitudes and levels of knowledge. Building on IRT, we compute the optimal penalty given students’ optimal behavior and the trade-off between bias and measurement error. Although MCQ examinations are frequently used, there is no consensus as to whether a penalty for wrong answers should be used or not. For example, examinations for medical licensing in some countries include MCQ sections with penalty while in others there is no penalty for wrong answers. We contribute to this discussion with a formal analysis of the effects of penalties; our simulations indicate that the optimal penalty is relatively high for perfectly rational students but also when they are not fully rational: even though penalty discriminates against risk averse students, this effect is small compared with the measurement error that it prevents.     

Watch Where You're Going? Interferer Velocity and Visual Behavior Predicts Avoidance Strategy During Pedestrian Encounters

Pedestrians can avoid collisions with other pedestrians by modifying some combination of their velocity and their path. The authors investigated how path constraints (constrained or unconstrained), interferer velocity (slow or fast), and vision (looking or not looking; time spent looking at the interferer) influenced collision avoidance to an oblivious interferer walking on a perpendicular path. Ten participants walked 6 m to either a point or line target on either a constrained or unconstrained path while wearing an eye-tracking device and avoiding an oblivious interferer that walked at 2 speeds. Looking behavior and interferer velocity were reliable predictors of determining whether a pedestrian would pass in front of or behind the interferer, while path constraints were less reliable. These findings highlight the degeneracy in human movement systems and suggest that, in complex environments, behavior may not always be optimized for efficiency.     

The Association Between the Attitude of Food‐Waste‐Aversion and BMI: An Exploration in India and the United States

This research proposes the existence of a hitherto undocumented attitude related to food wastage: the attitude of food‐waste‐aversion. We develop a 6‐item scale including affective, cognitive, and conative components to measure this attitude and empirically investigate its properties in two countries using novel datasets. We test for food‐waste‐aversion scale's convergent validity by demonstrating that it is correlated in the expected direction with five theoretically related constructs—frugality, social responsibility, spendthriftness, self‐control, and materialism (Studies 1a and 1b)—and with BMI (Studies 2 and 3). We provide more indirect evidence of the scale's convergent validity by documenting that the link between food‐waste‐aversion and BMI is attenuated among those who practice refrigerating leftovers (Study 3). We also document that the food‐waste‐aversion scale is distinct from general waste aversion and external meal‐cessation rules, thus providing evidence of discriminant validity (Studies 1a, 1b, and 1c). Taken together, these results provide construct validity for the novel construct of food‐waste‐aversion. We discuss the theoretical and substantive contributions of our findings.     

Exploiting Listener Gaze to Improve Situated Communication in Dynamic Virtual Environments

Beyond the observation that both speakers and listeners rapidly inspect the visual targets of referring expressions, it has been argued that such gaze may constitute part of the communicative signal. In this study, we investigate whether a speaker may, in principle, exploit listener gaze to improve communicative success. In the context of a virtual environment where listeners follow computer‐generated instructions, we provide two kinds of support for this claim. First, we show that listener gaze provides a reliable real‐time index of understanding even in dynamic and complex environments, and on a per‐utterance basis. Second, we show that a language generation system that uses listener gaze to provide rapid feedback improves overall task performance in comparison with two systems that do not use gaze. Aside from demonstrating the utility of listener gaze in situated communication, our findings open the door to new methods for developing and evaluating multi‐modal models of situated interaction.     

Eye Movements in Strategic Choice

In risky and other multiattribute choices, the process of choosing is well described by random walk or drift diffusion models in which evidence is accumulated over time to threshold. In strategic choices, level‐k and cognitive hierarchy models have been offered as accounts of the choice process, in which people simulate the choice processes of their opponents or partners. We recorded the eye movements in 2 × 2 symmetric games including dominance‐solvable games like prisoner's dilemma and asymmetric coordination games like stag hunt and hawk–dove. The evidence was most consistent with the accumulation of payoff differences over time: we found longer duration choices with more fixations when payoffs differences were more finely balanced, an emerging bias to gaze more at the payoffs for the action ultimately chosen, and that a simple count of transitions between payoffs—whether or not the comparison is strategically informative—was strongly associated with the final choice. The accumulator models do account for these strategic choice process measures, but the level‐k and cognitive hierarchy models do not. © 2015 The Authors. Journal of Behavioral Decision Making published by John Wiley & Sons Ltd.     

Eye gaze influences working memory for happy but not angry faces

Previous research has shown that angry and happy faces are perceived as less emotionally intense when shown with averted versus direct gaze. Other work reports that long-term memory (LTM) for angry (but not happy) faces was poorer when they were encoded with averted versus direct gaze, suggesting that threat signals are diluted when eye contact is not engaged. The current study examined whether gaze modulates working memory (WM) for angry and happy faces. In stark contrast to LTM effects, WM for angry faces was not significantly modulated by gaze direction. However, WM for happy faces was significantly enhanced when gaze was averted versus direct. These findings suggest that in WM – when rapid processing and an immediate response is required – averted gaze may alter the meaning behind a smile, and make this kind of expression particularly salient for short-term processing.     

Out of mind,out of sight? Investigating abnormal face scanning in autism spectrum disorder using gaze‐contingent paradigm

Diminished social motivation is hypothesized to explain abnormal face scanning pattern in individuals with autism spectrum disorder (ASD), especially reduced eye‐looking time in ASDs than typically developing (TD) people. Here, we tested an alternative explanation that children with ASD may use a compensatory strategy to avoid direct eye contact by processing the eyes through peripheral vision. We compared the face scanning patterns of children with and without ASD in two conditions: in the clear condition, the face was completely visible; in the blur condition, by using the gaze‐contingent paradigm, the whole face was blurred except for a small region being fixated at, thus children could not rely on the peripheral information to process the eyes. We found that children with ASD fixated less on the eyes than TD children in both conditions. Temporal‐course analyses further revealed the possible motivation‐based guidance of attention to process the eyes in the TD group but not in the ASD group. Additionally, we found that children with ASD scanned faces more randomly and less strategically than TD children. These results have ruled out the alternative hypothesis that the abnormal face scanning pattern in ASDs was due to their compensatory strategy to process eyes through peripheral vision, furthering our understanding of the mechanisms underlying their abnormal face scanning.