Rational analyses of information foraging on the web

This article describes rational analyses and cognitive models of Web users developed within information foraging theory. This is done by following the rational analysis methodology of (a) characterizing the problems posed by the environment, (b) developing rational analyses of behavioral solutions to those problems, and (c) developing cognitive models that approach the realization of those solutions. Navigation choice is modeled as a random utility model that uses spreading activation mechanisms that link proximal cues (information scent) that occur in Web browsers to internal user goals. Web-site leaving is modeled as an ongoing assessment by the Web user of the expected benefits of continuing at a Web site as opposed to going elsewhere. These cost–benefit assessments are also based on spreading activation models of information scent. Evaluations include a computational model of Web user behavior called Scent-Based Navigation and Information Foraging in the ACT Architecture, and the Law of Surfing, which characterizes the empirical distribution of the length of paths of visitors at a Web site.     

The challenge of raising ethical awareness: A case-based aiding system for use by computing and ICT students

Students, the future Information and Communication Technology (ICT) professionals, are often perceived to have little understanding of the ethical issues associated with the use of ICTs. There is a growing recognition that the moral issues associated with the use of the new technologies should be brought to the attention of students. Furthermore, they should be encouraged to explore and think more deeply about the social and legal consequences of the use of ICTs. This paper describes the development of a tool designed to raise students’ awareness of the social impact of ICTs. The tool offers guidance to students undertaking computing and computer-related courses when considering the social, legal and professional implications of the actions of participants in situations of ethical conflict. However, unlike previous work in this field, this tool is not based on an artificial intelligence paradigm. Aspects of the theoretical basis for the design of the tool and the tool’s practical development are discussed. Preliminary results from the testing of the tool are also discussed. An earlier version of this paper was presented by one of the authors at the First International Conference on Teaching Applied and Professional Ethics in Higher Education, Federal University of Surrey Centre for Applied Ethics, Southlands College, Roehampton, London, 2–4 September, 2003.     

Pacing strategy in trail running: A cognitive subtractive model of the affective balance between effort and pleasure?

The objective of the present study was to undercover the cognitive rules developed by athletes in pacing strategy during a trail running competition. Fifty participants completed a questionnaire on how decisions were made around pacing. Each questionnaire consisted of 12 scenarios that featured the two components of affective balance (effort and pleasure) as information cues. We applied repeated-measures analyses of variance and Tukey’s post hoc tests to the data. The results showed that pleasure and effort had a significant effect on deciding to reduce the pace and deciding to maintain the pace. The type of cognitive rule depended on the pacing outcome, with a subtractive integration rule when deciding to maintain the pace and a conjunction integration rule when deciding to reduce the pace. The presence of two different cognitive rules emphasized the importance of information integration in pacing strategy.     

在亮度对比和颜色对比下立体视知觉的定量研究

研究了在亮度对比与等亮度颜色对比的条件下,受试者分辨随机点阵立体图对的立体视敏度（最小视差）．结果表明：（１）在亮度对比条件下,立体视敏度随对比度的增加而增加,１０％的对比度即可引起立体视知觉,对比度大于３０％时达到饱和;（２）在亮度对比与等亮度颜色对比两种不同的条件下,受试者的立体视敏度不存在有统计学意义的差异;（３）当双眼分别接受不同颜色的等亮度立体图刺激时,与亮度对比条件相比,受试者的立体视敏度无明显差异;（４）当受试者双眼分别接受由亮度对比和颜色对比形成的立体图刺激时,只有当颜色对比图中图形与背景间的对比度超过等亮度值３８％以上时,才能形成立体视知觉．以上结果提示,大、小细胞系统（包括斑点系统与斑点间系统）均参与立体视知觉信息的传递．     

Expected performance at the human/computer interface as a function of user proficiency and system power

How do managers expect the proficiency of users and the power of the computers to determine overall performance? Five different models are proposed: (a) a matching model in which optimal performance is achieved when the power of the system is judged to be compatible with the proficiency of the user, (b) an averaging model in which expected performance is the average of the values of user proficiency and system power, (c) a multiplying model in which performance is the product of the values of user proficiency and system power, (d) a human/computer ratio model in which performance is determined by the ratio of system power over total effort, and (e) a computer/human ratio model in which performance is determined by the ratio of user proficiency over total effort. The applicability of these models was assessed by having managers and students of management predict performance in human/computer systems from information about the user's proficiency with computers and the power of the system. Participants rated 16 combinations of user proficiency and system power from a 4 × 4 factorial design. The pattern of ratings indicated that 51 per cent used a multiplying model and 25 percent used an averaging model; whereas, only 6 percent used the matching model and 4 percent used a ratio model. The remaining 14 percent did not follow any model clearly. Implications of these results were discussed for the design of the human/ computer interface, training and selection of users, and the cost-benefit tradeoffs for investment in user training versus equipment acquisition.     

品牌印象研究述评

品牌印象是消费者基于对品牌信息的感知和体验而在头脑中留下的品牌部分或整体信息。品牌印象形成涉及到类别信息加工和个别化信息加工两方面,其认知加工模式还存在争议。品牌印象实证研究主要存在以品牌主观形象为核心的品牌印象研究和以品牌拟人化特征为焦点的品牌印象研究两条线路。在分析比较的基础上,我们认为无论是品牌形象研究线路还是品牌人格研究线路,探讨的都是品牌的客观特性在消费者头脑中留下的主观印象,其本质都是对消费者品牌印象的研究。品牌印象是品牌与消费者的关系基础。品牌建设的任务就是在深刻把握消费者品牌印象形成机制的基础上,通过调节和控制消费者对品牌的认知、联想、态度、信任和忠诚来积累品牌资产。     

Myopic loss aversion: Demystifying the key factors influencing decision problem framing

Advancement of myopic loss aversion theory has been hamstrung by conflicting results, methodological inconsistencies, and a piecemeal approach toward understanding the key factors influencing decision problem framing. A series of controlled experiments provides a more holistic view of the variables promoting myopia. Extending the information horizon promotes broad framing, which propels risk. Evaluation frequency and decision frequency interact regardless of information horizon, supporting the notion that restricting either mechanism alleviates myopia. When conducting evaluations infrequently, neither segregating nor aggregating retrospective returns significantly alters risk preferences. Moreover, students and real retirement plan participants exhibit comparable appetites for risk, implying that both groups frame decision problems similarly. Explanations for these findings and avenues for future research are discussed.     

Good friendships,bad friends: Friendship factors as moderators of the relation between aggression and social information processing

The primary objective was to examine whether the associations between aggression and social information processing was moderated by friendship quality and the aggressiveness of the best friend. Drawn from a larger normative sample of 5th and 6th graders, 385 children (180 boys) completed questionnaires pertaining to friendship quality and social information processing. Friendship and peer nominations of behaviours were collected. Results revealed positive associations between aggressive behaviour and the endorsement of aggressive coping strategies in cases where the protagonist was an unfamiliar peer. However, one important exception emerged: no significant associations between aggression and aggressive coping were revealed for children with high-quality friendships with aggressive peers. In cases where the protagonist was the best friend, there was a significant relation between aggression and vengeful coping, but only for those participants who had a low-quality friendship with an aggressive friend.     

Contrast constancy revisited: The perceived contrast of sinusoidal gratings above threshold

The contrast sensitivity function of the human visual system, measured with sinusoidal luminance gratings, has an inverted U shape with a peak around 2–4?c/deg. Above threshold, it is thought that luminance gratings of equal physical contrasts but of distinguishably different spatial frequencies are all perceived as having similar contrasts, a phenomenon that has been termed contrast constancy. However, when suprathreshold contrast matches were measured for pairs of luminance gratings whose spatial frequencies were indistinguishable, the matching curves were not flat and followed a similar inverted U shape form as the contrast sensitivity function at threshold. It was therefore suggested that contrast constancy may only be revealed when matching the contrasts of clearly distinguishable spatial frequencies. Here, observers matched the perceived contrasts of suprathreshold luminance gratings of similar but visibly different spatial frequencies between 0.25 and 16?c/deg. The results show that, much like the contrast sensitivity function at threshold, observers are more sensitive to intermediate spatial frequencies (1–6?c/deg) than they are to either higher or to lower spatial frequencies. This tuning is evident when matching reference contrasts of 30–80%, implying a significant role in everyday vision. To demonstrate that these results were not due to local adaptation, the experiment was repeated with shorter stimulus duration, producing the same results. The extent of departure from contrast constancy found in the present study is compared to previously reported suprathreshold measurements. The results are also discussed with consideration to limitations with display apparatus such as monitor blur.