Variability of the MAX and MIN Statistic: A Theory of the Quantile Spread as a Function of Sample Size

The maximum and minimum of a sample from a probability distribution are extremely important random variables in many areas of psychological theory, methodology, and statistics. For instance, the behavior of the mean of the maximum or minimum processing time, as a function of the number of component random processing times (n), has been studied extensively in an effort to identify the underlying processing architecture (e.g., Townsend & Ashby, 1983; Colonius & Vorberg, 1994). Little is known concerning how measures of variability of the maximum or minimum change with n. Here, a new measure of random variability, the quantile spread, is introduced, which possesses sufficient strength to define distributional orderings and derive a number of results concerning variability of the maximum and the minimum statistics. The quantile spread ordering may be useful in many venues. Several interesting open problems are pointed out. This work was supported by an NIH Grant R01 MH57717 to the first author. Some of the collaboration took place during the year 2000 while J.T. Townsend was a Fellow at the Hanse Institute for Advanced Study (HWK), sponsored by H. Colonius at Oldenburg University.     

Dispersion-weighted kappa: An integrative framework for metric and nominal scale agreement coefficients

The rater agreement literature is complicated by the fact that it must accommodate at east two different properties of rating data: the number of raters (two versus more than two) and the rating scale level (nominal versus metric). While kappa statistics are most widely used for nominal scales, intraclass correlation coefficients have been preferred for metric scales. In this paper, we suggest a dispersion-weighted kappa framework for multiple raters that integrates some important agreement statistics by using familiar dispersion indices as weights for expressing disagreement. These weights are applied to ratings identifying cells in the traditional inter-judge contingency table. Novel agreement statistics can be obtained by applying less familiar indices of dispersion in the same wayThis revised article was published online in August 2005 with the PDF paginated correctly.     

On Revising Fuzzy Belief Bases

We look at the problem of revising fuzzy belief bases, i.e., belief base revision in which both formulas in the base as well as revision-input formulas can come attached with varying degrees. Working within a very general framework for fuzzy logic which is able to capture certain types of uncertainty calculi as well as truth-functional fuzzy logics, we show how the idea of rational change from “crisp” base revision, as embodied by the idea of partial meet (base) revision, can be faithfully extended to revising fuzzy belief bases. We present and axiomatise an operation of partial meet fuzzy base revision and illustrate how the operation works in several important special instances of the framework. We also axiomatise the related operation of partial meet fuzzy base contraction.This paper is an extended version of a paper presented at the Nineteenth Conference on Uncertainty in Arti.cial Intelligence (UAI’03).     

A Contextual Approach to Scientific Understanding

Achieving understanding of nature is one of the aims of science. In this paper we offer an analysis of the nature of scientific understanding that accords with actual scientific practice and accommodates the historical diversity of conceptions of understanding. Its core idea is a general criterion for the intelligibility of scientific theories that is essentially contextual: which theories conform to this criterion depends on contextual factors, and can change in the course of time. Our analysis provides a general account of how understanding is provided by scientific explanations of diverse types. In this way, it reconciles conflicting views of explanatory understanding, such as the causal-mechanical and the unificationist conceptions.     

Reversibility of the other-race effect in face recognition during childhood

Early experience with faces of a given racial type facilitates visual recognition for this type of face relative to others. To assess whether this so-called other-race effect can be reversed by subsequent experience with new types of faces, we tested adults of Korean origin who were adopted by European Caucasian families when they were between the ages of 3 to 9. The adoptees performed a face recognition task with photographs of Caucasian and Asian faces. They performed exactly like a control group of French participants, identifying the Caucasian faces better than the Asiatic ones. In contrast, a control group of Koreans showed the reverse pattern. This result indicates that the face recognition system remains plastic enough during childhood to reverse the other-race effect.     

Towards a bio-psycho-social model of autobiographical memory

Self-awareness and identity are important cornerstones of thinking in social psychology. On the basis of current knowledge and theories from the social, cultural, and biological sciences, this paper attempts to outline an integrative approach to the phenomena of memory and reminiscence. Reference to psychodynamic argumentation is made in addition, where appropriate. The central topic to our argumentation is autobiographical memory, which we analyse according to evolutionary, neuroscientific, and cultural findings. The emotional context and the ontogenetic development of reminiscences (or memories directly relating to one's own self) provide the preliminary framework for an integrated view which includes interactions between the life span, brain development, the social and cultural environment, and genetic predispositions.     

Word frequency of irrelevant speech distractors affects serial recall

In this study, participants memorized frequent or rare target words in silence or while ignoring frequent or rare distractor words. Distractor words impaired recall performance, but low-frequency distractor words caused more impairment than did high-frequency distractor words. We demonstrate how to solve the identifiability problem for Schweickert's (1993) multinomial processing tree model of immediate recall, and then use this model to show that irrelevant speech affected both the probability with which intact target word representations were available for serial recall and the probability of successful reconstruction of item identities based on degraded short-term memory traces. However, the type of irrelevant speech--low-versus high-frequency words--selectively affected the probability of intact target word representations. These results are consistent with an explanation of the irrelevant speech effect within the framework proposed by Cowan (1995), and they pose problems for other explanations of the irrelevant speech effect. The analyses also confirm the validity of Schweickert's process model.     

On the speed of intuition: Intuitive judgments of semantic coherence under different response deadlines

Intuition is the ability to judge stimulus properties on the basis of information that is activated in memory but not consciously retrieved. We investigated one central feature of intuitive judgments--namely, their speed. Participants judged whether or not three clue words were coherent in the sense that they were weakly associated with a common fourth concept. To restrict the time available for conscious deliberation of possible solution words, participants had to synchronize their judgments with a response signal appearing at different lags after the clue words. In two experiments, participants discriminated coherent and incoherent triads reliably better than chance, even when they did not consciously retrieve the solution word and the lag between clue words and response signal was as short as 1.5 sec. Results indicate that intuitive judgments can indeed be made very fast and without extended conscious deliberation. Possible mechanisms underlying intuitive judgments are discussed.