Using a virtual reality system to study balance and walking in a virtual outdoor environment: a pilot study.

Falls and fall-related injuries are a major problem for elderly persons. Most falls occur during walking and turning, and the risk of falling increases when attention is diverted to something besides walking. It is often difficult to standardize methods for testing balance and fall tendency in a clinically relevant setting. We describe the development of a system using a virtual environment (VE) to assess how attention demanding and unexpected events influence a person's capacity to control balance and movement. The hardware in the system consists of a head-mounted display (HMD), a magnetic tracker system, and two SGI computers. The software consists of the image generation of the VE and the management and visualization of motion tracking data. In a preliminary pilot study eight subjects (age 23-80) participated. Each subject walked on a normal floor and was visually presented a familiar outdoor environment in the HMD. They were exposed to different unexpected events, such as a virtual snowfall and tilting of the VE. Disturbances of balance and walking patterns such as changes in speed, stride length and balance reactions like slipping were observed. Two subjects experienced symptoms of cyber sickness with a SSQ score above 25 points. Walking with sensors only did not affect walking time, but in VE the subjects generally walked more slowly. Virtual tilting of the environment had an impact on balance performance during walking. This effect was not observed while the test subjects were walking in a virtual snowfall. The model needs further development but may hold a potential for clinical use.     

工作应激与个体归因特点关系的研究

工作应激一直是组织行为中的热点问题,但综观前人研究,很少有研究者从归因的视角揭示其产生过程。本研究从个体的应激源感受性出发,探讨了个体归因特点与其工作应激的关系,建构了相应的模型,并结合压力管理问题,对研究进行了有益展望。     

Body image and body change strategies among adolescent males and females from Fiji, Tonga and Australia

The current study was designed to investigate the body image and body change strategies of adolescents from Fiji, Tonga and Australia. Participants were 628 Fijians, 463 Indo-Fijians, 598 Tongans and 535 European Australians. Adolescents completed measures of height, weight, body dissatisfaction, strategies to lose weight, increase weight and increase muscles. The results demonstrated that overweight adolescents were more dissatisfied with their bodies than those who were normal weight. Overweight Fijians and Tongans were more satisfied with their body than Indo-Fijian or Australian adolescents. Tongans, followed by Fijians and Indo-Fijians, were more likely to engage in strategies to lose weight, increase weight and increase muscles. These results are consistent with the focus in Fiji and Tonga on the value of the large body ideal, but may also reflect the recent focus on the attainment of a healthy body size.     

The Social Production of Altruism: Motivations for Caring Action in a Low-Income Urban Community

Contemporary social science paints a bleak picture of inner-city relational life. Indeed, the relationships of low-income, urban-residing Americans are represented as rife with distress, violence and family disruption. At present, no body of social scientific work systematically examines the factors that promote loving or selfless interactions among low-income, inner-city American individuals, families and communities. In an effort to fill that gap, this ethnographic study examined the motivations for altruism among a sample of adults (n = 40) who reside in an economically distressed housing community (i.e., housing project) in New York City. Content analyses of interviews indicated that participants attributed altruism to an interplay between 14 motives that were then ordered into four overarching categories of motives: (1) needs-centered motives, (2) norm-based motives deriving from religious/spiritual ideology, relationships and personal factors, (3) abstract motives (e.g., humanism), and (4) sociopolitical factors. The implications of these findings are discussed.     

语言产生中词频效应老化的神经基础与时间进程

词频效应指语言产生中人们对高频词汇的加工比低频词汇更快更准确的一种现象,它可能发生在语言产生中的不同阶段。对青年人和老年人词频效应的不同特点和加工机制进行比较,可以考察语言产生的认知老化机制。通过语言产生理论可对词频效应的老化进行预测,提出词频效应在个体发展和老化阶段的相对稳定性,分析老化导致词频效应相关的神经基础和加工时间进程的改变。未来研究可进一步分离词频效应与习得年龄效应对语言产生老化的影响,并扩展至神经退行性疾病患者中。     

Distance perception and the ambiguity of visual stimulation: A theoretical note

Certain current views postulate that visual perception, especially of distance, is a function of optical stimulation alone. It is shown here that the optical array does not, in fact, specify absolute distance unambiguously, for either a stationary or a moving O. In view of this ambiguity of optical information, a more complex theory, comprising both visual and nonvisual information, as needed to explain, veridical perception.     

FACTORS INFLUENCING TWO-DIMENSIONAL FORM PERCEPTION

The perceived shape of a circle and ellipse has been studied as influenced by the size of the figure, size of the reference frame, contrast and intensity. It was found that these factors have a systematic influence upon form perception. The data are considered within the context of the shape slant invariance hypothesis and are interpreted as providing evidence against this hypothesis as applied to the proximal form.