Direct brain communication: neuroelectric and metabolic approaches at Tübingen

The brain–computer interface (BCI) provides users with the possibility of sending messages and commands to the external world without using their muscles, thus enabling communication to occur independent of movement. Such a possibility is of utmost importance for paralyzed patients who may otherwise lose their ability to communicate. Enhanced methodology and the development of faster computers have substantially improved applications and offer new possibilities in this field. To date, there have been over 20 BCI research groups working on different approaches. In this paper, we review our studies of BCI based on electric and metabolic activity of the brain.     

Spatial reasoning with external visualizations: what matters is what you see, not whether you interact

Three experiments examined the effects of interactive visualizations and spatial abilities on a task requiring participants to infer and draw cross sections of a three-dimensional (3D) object. The experiments manipulated whether participants could interactively control a virtual 3D visualization of the object while performing the task, and compared participants who were allowed interactive control of the visualization to those who were not allowed control. In Experiment 1, interactivity produced better performance than passive viewing, but the advantage of interactivity disappeared in Experiment 2 when visual input for the two conditions in a yoked design was equalized. In Experiments 2 and 3, differences in how interactive participants manipulated the visualization were large and related to performance. In Experiment 3, non-interactive participants who watched optimal movements of the display performed as well as interactive participants who manipulated the visualization effectively and better than interactive participants who manipulated the visualization ineffectively. Spatial ability made an independent contribution to performance on the spatial reasoning task, but did not predict patterns of interactive behavior. These experiments indicate that providing participants with active control of a computer visualization does not necessarily enhance task performance, whereas seeing the most task-relevant information does, and this is true regardless of whether the task-relevant information is obtained actively or passively.     

Modeling how, when, and what is learned in a simple fault-finding task

We have developed a process model that learns in multiple ways while finding faults in a simple control panel device. The model predicts human participants' learning through its own learning. The model's performance was systematically compared to human learning data, including the time course and specific sequence of learned behaviors. These comparisons show that the model accounts very well for measures such as problem-solving strategy, the relative difficulty of faults, and average fault-finding time. More important, because the model learns and transfers its learning across problems, it also accounts for the faster problem-solving times due to learning when examined across participants, across faults, and across the series of 20 trials on an individual participant basis. The model shows how learning while problem solving can lead to more recognition-based performance, and helps explain how the shape of the learning curve can arise through learning and be modified by differential transfer. Overall, the quality of the correspondence appears to have arisen from procedural, declarative, and episodic learning all taking place within individual problem-solving episodes.     

Formation of partially and fully elaborated generalized equivalence classes

Most complex categories observed in real-world settings consist of perceptually disparate stimuli, such as a picture of a person's face, the person's name as written, and the same name as heard, as well as dimensional variants of some or all of these stimuli. The stimuli function as members of a single partially or fully elaborated generalized equivalence class when they occasion the mutual selection of each other after the establishment of some subset of relations among the stimuli. Indeed, it is these generalized relations among stimuli that enable an individual to respond appropriately to the inevitable flux of natural environments. The present experiments involved procedures for producing both types of generalized equivalence class and for evaluating their retention. Granting the formal and functional similarities that exist between generalized equivalence classes and natural categories, natural kinds, and fuzzy superordinate classes, the variables responsible for the emergence of the former might also account for the emergence of the latter three phenomena. In Experiment 1, After forming an A'-B' class, a B'-C relation was trained and generalization tests were conducted with B'-C, C-B', A'-C, and C'-A. Two of 5 participants passed the tests documenting the formation of A'-B'-C classes. Failures occurred in the A'-C and C-A' tests but not the B'-C and C-B' tests. Failures were also correlated with time between A'-B' class formation and C-based testing and with the absence of baseline confirmation when training and testing were separated by about one week. Experiment 2 replicated Experiment 1 but presented baseline confirmation probes immediatley prior to testing when training and testing were separated by one week; all participants then formed partially elaborated generalized equivalence classes. In Experiment 3, 5 of 6 participants formed fully elaborated generalized equivalence classes, represented as A' = B' = C'.     

Instructional effects on performance in a matching-to-sample study

Conducting studies using an undergraduate participant pool is fraught with difficulties. Among them are problems with adequately motivating subjects both to come to the study, and once there, to actively engage the experimental task. Thirty-one college students participated in a matching-to-sample (MTS) study involving substantial training, testing, retraining, and retesting of conditional discriminations and equivalence relations among four 4-member classes of nonsensical words. The study was conducted during the end of the semester, when performance often had been observed to be poorer than at other points in the semester. Eleven of the participants, in addition to standard instructions about the task, received additional instructions specifying molar consequences for high rates of "correct" responses throughout the procedure. This subset of participants displayed markedly improved performance as compared to those who did not receive the additional instructions. Results suggest that specification of molar contingencies improves participants' sensitivity to molecular contingencies within the study. Instructions that specify and increase the consequential functions of feedback provided during MTS trials may be one means of reducing unwanted variability in human MTS performance.     

眼动交互中边框和视标对作业绩效的影响研究

研究人计算机界面设计中的眼动交互反馈方式,为优化基于视线追踪技术的人计算机界面设计提供工效学依据。12名被试在交互对象有无边框提示和当前注视位置有无视标反馈的四种组合条件下,通过眼动交互完成目标选择任务,由计算机自动记录作业时间、选择错误和超时数目。结果发现,有无当前注视位置的视标反馈对作业时间有显著影响,有视标反馈可加速目标字母的搜索与定位过程和目标激活过程,由视标反馈所产生的作业时间下降,主要由目标定位时间的缩短所致;边框提示对用户的作业绩效无显著影响。根据上述结果可得以下结论:对当前注视位置提供视标反馈是一种有效的反馈方式,基于视线追踪的人机交互系统应为用户提供这种反馈信息。     

Open Problems in the Philosophy of Information

Abstract: The philosophy of information (PI) is a new area of research with its own field of investigation and methodology. This article, based on the Herbert A. Simon Lecture of Computing and Philosophy I gave at Carnegie Mellon University in 2001, analyses the eighteen principal open problems in PI. Section 1 introduces the analysis by outlining Herbert Simon's approach to PI. Section 2 discusses some methodological considerations about what counts as a good philosophical problem. The discussion centers on Hilbert's famous analysis of the central problems in mathematics. The rest of the article is devoted to the eighteen problems. These are organized into five sections: problems in the analysis of the concept of information, in semantics, in the study of intelligence, in the relation between information and nature, and in the investigation of values.     

Computer Modeling and the Fate of Folk Psychology

Although Paul Churchland and Jerry Fodor both subscribe to the so-called theory-theory – the theory that folk psychology (FP) is an empirical theory of behavior – they disagree strongly about FP's fate. Churchland contends that FP is a fundamentally flawed view analogous to folk biology, and he argues that recent advances in computational neuroscience and connectionist AI point toward development of a scientifically respectable replacement theory that will give rise to a new common-sense psychology. Fodor, however, wagers that FP will be largely preserved and vindicated by scientific investigations of behavior. Recent findings by developmental psychologists, I argue, will push both Churchlandians and Fodorians toward the pessimistic view that FP is a misguided theory that will never be displaced, because it is, so to speak, built into our cognitive systems. I explore the possibility of preserving optimism by rejecting the theory-theory and adopting the simulation theory , a competing view developed by Robert Gordon, Alvin Goldman, and Jane Heal. According to simulationists, common-sense interpretation of behavior is accomplished by means of pretense-like operations that deploy the cognitive system's own reasoning capabilities in a disengaged manner. Since on this view no theory-like set of principles would be needed, the simulation theory seems to enjoy a simplicity advantage over the theory-theory. Steven Stich and Shawn Nichols, however, contend that as the cognitive system would require special mechanisms for disengaged operation, the simplicity question cannot be resolved until suitable computational models are developed. I describe a set of models I have constructed to meet this need, and I discuss the contribution such models can make to determining FP's fate.     

Book Reviews

Books reviewed:
James Campbell, Recovering Benjamin Franklin
Elliot L. Jurist, Beyond Hegel and Nietzsche: Philosophy, Culture, and Agency