The Δ–∑ hypothesis: How contrast and reinforcement rate combine to generate suboptimal choice

When given a choice between two alternatives, each offering food after the same delay with different but signaled probabilities, pigeons often prefer the low probability alternative. This preference is surprising because pigeons fail to maximize the rate of food intake; they exhibit a suboptimal preference. We advance a new explanation, the Δ–∑ hypothesis, in which the difference in probability of reinforcement within terminal links (Δ) and the overall reinforcement probability rate of each alternative (∑) are the key variables responsible for such suboptimal preference. We tested the Δ–∑ hypothesis in two experiments. In Experiment 1, we manipulated the Δs while maintaining constant all other parameters of the task, in particular the ∑s. We predicted a preference for the alternative with the larger Δ. In Experiment 2, we examined the effect of the overall reinforcement probabilities, the ∑s, while maintaining constant all other parameters of the task, in particular the Δs. We predicted a preference for the larger ∑. The results of both experiments support the Δ–∑ hypothesis.     

The Effect of Mindfulness on Heart Rate Control

An experiment was conducted to test the hypothesis that mindful attention to change regarding heart rate (HR) would result in greater control over HR. Experimental groups monitored the changing or stable nature of HR, respectively. All participants’ HR slowed during the decrease phase. Participants whose attention was directed to the stable nature of HR performed the worst on the increase phase of the HR control task. These results suggest that mindfulness, instantiated here as attention to variability, is a means to increasing control.

The effect of a collision warning system on the driving performance of young drivers at intersections

This study investigated the manner in which the driving performance of young people was affected by a collision warning system when they encountered a driver running a red light at an intersection. Furthermore, the causal relationship among driving performance, traffic factors and intersection accidents was examined using Path Analysis. Participants drove a driving simulator with an intersection collision warning system (ICWS) in a simulated urban area. The driving performance measures recorded were reaction time, speed, lateral position deviation and crash events. Experimental results indicated that drivers who drove a vehicle with an ICWS audio signal at an intersection had a shorter reaction time, a lower speed and a reduced accident rate than those observed while driving a vehicle without ICWS audio signal. Furthermore, Path Analysis showed that the ICWS had an indirect effect on accident rate reduction through improved driving performance. The location of intersection accident had both direct and indirect effects on the accident rate. The number of driving days per week had a direct effect on accident rate reduction.     

Heart rate variability predicts self‐control in goal pursuit

The aim of our study was to investigate the effects of a failure experience on the exercise of self‐control in goal pursuit. We hypothesized that tonic heart rate variability (tonic HRV), a possible physiological marker of inhibitory capacity, increases the exercise of self‐control in the pre‐ and post‐actional phase in goal pursuit after failure. Participants received feedback for an alleged intelligence test and subsequently worked on the same test again. As indicators of exercised self‐control, we assessed self‐confidence in the pre‐actional phase and rumination in the post‐actional phase. As hypothesized, tonic HRV was positively associated with pre‐ and post‐actional self‐control, even after controlling for the effect of neuroticism. We discuss the implications of our results for the self‐regulatory strength model. Copyright © 2009 John Wiley & Sons, Ltd.     

医务工作者对剖宫产率增高影响的分析

剖宫产率的过快增加已经成为了一个全球性的问题,不仅是一个医疗问题,而且是一个社会问题、伦理问题。与剖宫产率增高相关的因素是多方面的,本文重点探讨医源性因素对剖宫产率增高的影响,分析从医院及医生方面控制剖宫产率增高的措施。     

French native speakers in the making: From language-general to language-specific voicing boundaries

By examining voice onset time (VOT) discrimination in 4- and 8-month-olds raised in a French-speaking environment, the current study addresses the question of the role played by linguistic experience in the reshaping of the initial perceptual abilities. Results showed that the language-general −30- and +30-ms VOT boundaries are better discriminated than the 0-ms boundary in 4-month-olds, whereas 8-month-olds better discriminate the 0-ms boundary. These data support explanations of speech development stressing the effects of both language-general boundaries and linguistic environment (attunement theory and coupling theory). Results also suggest that the acquisition of the adult voicing boundary (at 0 ms VOT in French vs. +30 ms VOT in English) is faster and more linear in French than in English. This latter aspect of the results might be related to differences in the consistency of VOT distributions of voiced and voiceless stops between languages.     

Are You Alive? Sensor Data as a Resource for Social Interaction

This paper presents findings from the field test of a prototype device that collects heart rate sensor data and displays it for users. The prototype was tested on a football team, including teenage players, their parents and coaches. The findings include notes on user expectations related to the technology and detailed analyses of the social interactions that took place during the test. The paper concludes with design implications relating to this application, but also poses challenges for context-aware computing and machine intelligence in general.

恶性肿瘤高发态势与肿瘤学教学现状的思考

恶性肿瘤的发病率及病死率日渐增高,成为21世纪威胁人类健康、导致死亡的主要疾病。在我国,肿瘤已经成为常见病。本文从肿瘤高发的态势与肿瘤学飞速发展的现状出发,分析我国肿瘤诊治整体水平与医学院校肿瘤学课程设置及教学相对滞后的状况,阐述了新形势下加强医学院校在本科生基础医学教育中强化与改革肿瘤学课程的重要性和必要性。     

Slower eating rate reduces the food intake of men, but not women: implications for behavioral weight control

This study tested a central tenet of behavioral weight control: does slower eating rate reduce food intake and positively affect appetite ratings. This study used direct behavioral observation of participants' (n=48; 25BMI35) eating behavior using Universal Eating Monitors. Food intake and ratings of "desire to eat" (collected each minute during meals) were represented as a function of time. Based on an acclimation meal, participants' eating rate was modified by instructing them to eat a bite of food when prompted by a computer, which generated three types of meals: (1) baseline (eating rate was the same as the acclimation meal), (2) reduced-rate (eating rate was reduced by 50%), and (3) combined-rate (eating rate at the beginning of the meal was identical to that of the acclimation meal, subsequently eating rate was reduced by 50%). All meals were ad libitum. Slower eating rate during the reduced-rate and combined-rate meals resulted in less food intake compared to the baseline meal for men, but not women. Ratings of desire to eat, normalized for the amount of food consumed, were lower during the combined-rate meal for men and women. Thus, this basic premise of behavioral weight control was supported for men, but not for women.     

How are base‐rates used,when they are used: a comparison of additive and Bayesian models of base‐rate use

Previous research has uncovered many conditions that encourage base‐rate use. The present research investigates how base‐rates are used when conditions are manipulated to encourage their use in the lawyer/engineer paradigm. To examine the functional form of the response to base‐rate, a factorial design was employed in which both base‐rate and the individuating information were varied within‐subject. We compared the performance of several models of base‐rate use, including a model that allows base‐rate and individuating information to be combined in a strictly additive fashion, and a model which presumes that respondents use Bayes' Rule in forming their judgments. Results from 1493 respondents showed that the additive model is a stronger predictor of base‐rate use than any other model considered, suggesting that the base‐rate and individuating information are processed independently in the lawyer/engineer paradigm. A possible mechanism for this finding is discussed. Copyright © 1999 John Wiley & Sons, Ltd.