An experiment based on Allen's calculus and its transfer to qualitative spatial reasoning, was conducted. Subjects had to find a conclusion X r 3 Z that was consistent with the given premises X r 1 Y and Y r 2 Z. Implications of the obtained results are discussed with respect to the mental model theory of spatial inference. The results support the assumption that there are preferred models when people solve spatial three-term series problems. Although the subjects performed the task surprisingly well overall, there were significant differences in error rates between some of the tasks. They are discussed with respect to the subprocesses of model construction, model inspection, validation of the answer, and the interaction of these subprocesses.

The authors outline a theory of conditionals of the form If A then C and If A then possibly C. The 2 sorts of conditional have separate core meanings that refer to sets of possibilities. Knowledge, pragmatics, and semantics can modulate these meanings. Modulation can add information about temporal and other relations between antecedent and consequent. It can also prevent the construction of possibilities to yield 10 distinct sets of possibilities to which conditionals can refer. The mental representation of a conditional normally makes explicit only the possibilities in which its antecedent is true, yielding other possibilities implicitly. Reasoners tend to focus on the explicit possibilities. The theory predicts the major phenomena of understanding and reasoning with conditionals. You reason about conditional relations because much of your knowledge is conditional. If you get caught speeding, then you pay a fine. If you have an operation, then you need time to recuperate. If you have money in the bank, then you can cash a check. Conditional reasoning is a central part of thinking, yet people do not always reason correctly. The lawyer Jan Schlictmann in a celebrated trial (see Harr, 1995, pp. 361–362) elicited the following information from an expert witness about the source of a chemical pollutant trichloroethylene (TCE):

The past five years, spent working towards a Ph. D., have been among the best periods of my life. I am truly grateful to everyone who made it so. Thanks everybody! This is a genuine acknowledgment of the highly appreciated and extremely valuable contributions made by these persons. It is not a feeble attempt to curry favor with people, such as one’s thesis committee, family, and potentially powerful and influential friends. I’d like to start with acknowledging the guidance, suggestions, support, and encouragement provided by Dr. Max. Egenhofer and members of my thesis committee,

Although it is natural to suppose that visual mental imagery is important in human deductive reasoning, the evidence is equivocal. This article argues that reasoning studies have not distinguished between ease of visualization and ease of constructing spatial models. Rating studies show that these factors can be separated. Their results yielded four sorts of relations: 1. visuo-spatial relations that are easy to envisage visually and spatially; 2. visual relations that are easy to envisage visually but hard to envisage spatially; 3. spatial relations that are hard to envisage visually but easy to envisage spatially; and 4. control relations that are hard to envisage both visually and spatially. Three experiments showed that visual relations slow down the process of reasoning in comparison with control relations, whereas visuo-spatial and spatial relations yield inferences comparable to those of control relations. We conclude that irrelevant visual detail can be a nuisance in r...

We propose a computational model for spatial reasoning by means of mental models. Our SRM model (Spatial Reasoning by Models) maps spatial working memory to a twodimensional array and uses a spatial focus that places objects in the array, manipulates the position of objects, and inspects the array to find spatial relations that are not given in the premises. The SRM model results in a computational complexity measure that relies on the number of operations in the array and the number of relations that must be handled. The performance of the SRM model is compared to the performance of human subjects reported in the literature and in our own study.

Software visualization is nifty stuff; but is it the powerful cognitive tool it is often assumed to be? This chapter attempts to moderate the understandable enthusiasm for software visualization and to raise some of the questions for which the discipline doesn't yet have answers. The chapter is structured as a list of questions with discussion. The questions are not a comprehensive analysis of cognitive challenges in software visualization. Rather, the chapter attempts to provide a list sufficiently provocative to give designers pause, in order: (a) to establish that good software visualization isn't simply a matter of mimicking paper-based tasks or doing what is technically easy---and certainly isn't `solved' yet; but also (b) even simple tools can improve software comprehension, if they're the right ones.

Inferences about spatial, temporal, and other relations are ubiquitous. This article presents a novel model-based theory of such reasoning. The theory depends on 5 principles. (a) The structure of mental models is iconic as far as possible. (b) The logical consequences of relations emerge from models constructed from the meanings of the relations and from knowledge. (c) Individuals tend to construct only a single, typical model. (d) They spontaneously develop their own strategies for relational reasoning. (e) Regardless of strategy, the difficulty of an inference depends on the process of integration of the information from separate premises, the number of entities that have to be integrated to form a model, and the depth of the relation. The article describes computer implementations of the theory and presents experimental results corroborating its main principles.

Abstract. This paper examines capacity limits in mental animation of static diagrams of mechanical systems and interprets these limits within current theories of working memory. I review empirical studies of mental animation that examined (1) the relation of spatial ability to mental animation (2) the effects of working memory loads on mental animation, (3) use of external memory in mental animation and (4) strategies for task decomposition that enable complex mental animation problems to be accomplished within the limited capacity of working memory. The effects of capacity limits on mental animation are explored by implementing a simple production system model of mental animation in the 3CAPS production system architecture, limiting the working memory resources available to the model, and implementing strategies for managing scarce working memory resources. It is proposed that mental animation involves the visual-spatial and executive components of working memory and that individual differences in mental animation reflect the operation of these working memory components. 1

When second-price auctions have been conducted in the laboratory, most of the observed bids have been “overbids ” (bids that exceed the bidder’s value) and there are very few underbids. Few if any of the subjects in those experiments had any prior experience bidding in auctions. We report on sealed-bid second-price auctions that we conducted on the Internet using subjects with substantial prior experience: they were highly experienced participants in eBay auctions. Unlike the novice bidders in previous (laboratory) experiments, the experienced bidders exhibited no greater tendency to overbid than to underbid. However, even subjects with substantial prior experience tend not to bid their values, suggesting that the non-optimal bidding of novice subjects is robust to substantial experience in non-experimental auctions. A key determinant of bidding behavior was whether a subject had ever been a seller on eBay. We thank Greg Crawford, Ron Harstad, John Kagel, and Dan Levin for helpful comments. We are

Abstract. Research spanning decades has generated a long list of phenomena associated with human spatial information processing. Additionally, a number of theories have been proposed about the representation, organization and processing of spatial information by humans. This paper presents a broad account of human spatial competence, integrated with the ACT-R cognitive architecture. Using a cognitive architecture grounds the research in a validated theory of human cognition, enhancing the plausibility of the overall account. This work posits a close link of aspects of spatial information processing to vision and motor planning, and integrates theoretical perspectives that have been proposed over the history of research in this area. In addition, the account is supported by evidence from neuropsychological investigations of human spatial ability. The mechanisms provide a means of accounting for a broad range of phenomena described in the experimental literature.