Acquisition of cognitive compiling

Language involves both structure and process. Giving each its due, we present a cognitive process model and show how its empirical success is related to claims about syntactic structure. Innate constraints on syntax are a central issue in linguistic theory, so it is a matter of concern that a widely accepted view of phrase structure constraints (X-bar theory) appears to be violated in some recent comprehension experiments with children. However, what is directly observed in the experiments is not a syntactic structure but the execution of a plan. We present a language of process for representing such plans and thereby provide a unified explanation of several developmental phenomena, including the results of the above experiments and of new experiments suggested by our approach. The explanation is in terms of the cognitive resources required to formulate and execute a plan. Since the explanation is based on nonsyntactic processing, the children's syntax need no longer be held faulty. This conclusion invigorates the claim that the range of phrase structures available to children is biologically constrained.     

Delayed signal detection, differential reinforcement, and short-term memory in the pigeon.

In two discrete-trial delayed-detection experiments, six pigeons were trained on dependent concurrent variable-interval schedules. Pecking a red side key was reinforced when the brighter of two white lights (S1) had been presented on the center key, and pecking a green side key was reinforced when the duller of two white lights (S2) had been presented on the center key. Incorrect responses were red side-key pecks following S2 presentations and green side-key pecks following S1 presentations; these resulted in three-second blackouts. In Experiment 1, the time between presentation of S1 or S2 on the center key and the onset of the red and green side keys was varied nonsystematically from 0.06 seconds to 19.69 seconds across experimental conditions. Stimulus discriminability decreased as the stimulus-choice delay increased. A rectangular-hyperbolic function better described this decrease in discriminability over time than did a negative-exponential function. In Experiment 2, at each of three stimulus-choice delays (0.06, 3.85, and 10.36 seconds), relative reinforcer frequency for correct responses to the red and green side keys was varied by changing the values of the dependent concurrent variable-interval schedules. The sensitivity of choice to relative reinforcer frequency was independent of the decrease in stimulus discriminability with increasing stimulus-choice delay.     

Students' perceptions of personality needs and environmental press as a function of program separation

A sample of 1,877 high school seniors completed the Activities Index and High School Characteristics Index. The student responses were used to identify personality needs and environmental press differences across program and degree of program separation variables.It was concluded that: (1) College preparatory students perceived high personality needs for intellectual endeavors, while vocational students had needs for the tangible and concrete. (2) The personality differences across degrees of program separation suggested the physical proximity of the two program groups affected students' interpersonal relationships. (3) Several of the environmental press were exactly opposite the students' perceived personality needs. (4) The nonsignificant needs-press relationships suggested that high school environments were not facilitating the personality needs of students. (5) Comprehensive high schools seemed the most viable administrative configuration for servicing the diverse needs of today's high school students.     

Uncertainty about the rest of the sentence

A word-by-word human sentence processing complexity metric is presented. This metric formalizes the intuition that comprehenders have more trouble on words contributing larger amounts of information about the syntactic structure of the sentence as a whole. The formalization is in terms of the conditional entropy of grammatical continuations, given the words that have been heard so far. To calculate the predictions of this metric, Wilson and Carroll's (1954) original entropy reduction idea is extended to infinite languages. This is demonstrated with a mildly context-sensitive language that includes relative clauses formed on a variety of grammatical relations across the Accessibility Hierarchy of Keenan and Comrie (1977). Predictions are derived that correlate significantly with repetition accuracy results obtained in a sentence-memory experiment (Keenan & Hawkins, 1987).     

Suboptimal tradeoffs in information seeking

Explicit information-seeking actions are needed to evaluate alternative actions in problem-solving tasks. Information-seeking costs are often traded off against the utility of information. We present three experiments that show how subjects adapt to the cost and information structures of environments in a map-navigation task. We found that subjects often stabilize at suboptimal levels of performance. A Bayesian satisficing model (BSM) is proposed and implemented in the ACT-R architecture to predict information-seeking behavior. The BSM uses a local decision rule and a global Bayesian learning mechanism to decide when to stop seeking information. The model matched the human data well, suggesting that adaptation to cost and information structures can be achieved by a simple local decision rule. The local decision rule, however, often limits exploration of the environment and leads to suboptimal performance. We propose that suboptimal performance is an emergent property of the dynamic interactions between cognition and the environment.     

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．