A model for detection and recognition with signal uncertainty

A model for signal detectability suggested by Luce is extended to situations in which the observer is uncertain of some important characteristic of the signal, such as frequency. By making a single assumption concerning the observer's covert response behavior, two solutions are obtained corresponding to qualitatively different behavior. Decrements in detectability and in recognition with uncertainty are shown to be particular functions of discriminability and detectability of the stimuli in other situations. Relevant experimental data are considered.This work was supported by grant NSF-G5544 from the National Science Foundation. The author is indebted to R. Duncan Luce for critical discussion of the content and helpful suggestions concerning the form of this paper. Useful comments have been made by David M. Green, Francis W. Irwin, Roger M. Shepard, and W. P. Tanner, Jr.     

Agricultural policy and strategic investment in information technology

In this article the perspective shifts to the “upstream” end of the agricultural knowledge and information system (AKIS). Because knowledge policy and strategic decision-making are not the prerogative of the public sector, organizations such as cooperative unions and multinational companies are included. After considering the influence of the changing environment on the nature of the AKIS, the role of knowledge management and policy in the emerging knowledge and information market is examined. Special attention is given to public and private R&D. The article then looks where information technology (IT) fits in and what considerations determine strategic investment in IT projects and sustained services. Some of the European experiences with this strategic investment are evaluated.     

PIGEONS ARE SENSITIVE TO THE SPATIAL ORGANIZATION OF COMPLEX VISUAL STIMULI

Abstract— Two experiments investigated the role of spatial organisation in the discrimination and generalization of complex visual stimuli by pigeons. In Experiment 1, after pigeons had been trained to discriminate line drawings of four objects, they were tested with novel pictures in which the same component parts of the objects were spatially rearranged. The spatially scrambled pictures led to a dramatic drop in recognition accuracy, hut responding remained above chance. In Experiment 2, pigeons reached a high level of discriminative performance when required to choose among four different spatial arrangements of the same object parts. These results confirm Cerella's (1980) conclusion that pigeons discriminate the component parts of complex visual stimuli, but. unless it is assumed that the scrambling deleted or created emergent features, the results disconfirm his conclusion that spatial organization plays no role in pigeons' picture perception.     

ELI: An Interactive Elicitation Technique for Subjective Probability Distributions

Uncertain knowledge about continuous quantities is usually formalized through subjective probability distributions (SPD′s). However, results from past experimental research have often pointed to the rather poor quality of SPD′s. Moreover, previous attempts to improve SPD quality frequently appeared to be only partly successful; overconfidence especially proved to be an exceptionally persistent phenomenon. In the present study, method-induced biases in particular are considered to be responsible for the poor quality of SPD′s, and an alternative means for eliciting uncertain knowledge was designed to meet fundamental quality criteria to a more satisfactory degree. The direct realization of a proper scoring rule in a graphically oriented interactive computer program is one of the central features of this new elicitation technique, ELI. An experiment with 48 subjects was carried out to evaluate ELI performance and to compare it with the performance of (a) an existing elicitation technique and (b) a simple technique that only asks for a best guess and a lower and upper bound. The three techniques were evaluated and compared with respect to their contribution to reliable and valid SPD′s and with respect to their practical usefulness. The results indicated that for ELI the fundamental requirements were realized to a great extent. Furthermore, compared with the two other techniques, ELI performance appeared to be superior. In particular, only with the support of ELI did overconfidence appear to be almost absent.     

Order effects in belief updating with consistent and inconsistent evidence

The current study tests for the presence of differential order effects in evaluation tasks with consistent and inconsistent evidence as predicted by the Hogarth and Einhorn (1992) belief-adjustment model. The results, based on both between-subjects and within-subjects experiments, demonstrate that there were significant recency effects with inconsistent evidence as predicted, larger recency effects when the inconsistent evidence was farther apart in subjective value as predicted, and significant recency effects even when subjects were given training designed to both help them understand the task as completely as possible and to be better able to assess the pieces of evidence. By including a within-subjects design, we were able to demonstrate that the difference in subjective value between two pieces of evidence is the primary factor influencing the magnitude of the recency effect, regardless of whether the evidence is consistent or inconsistent. This latter finding is unique and contrary to previous research and theory.     

The prediction of adjustment at age 7 from activity level at age 5

One-hundred and ninety-two children (equally split between boys and girls) were studied when they were 5 years old in two settings, school and home. The children were observed in playgroups and at home, and were rated on activity level by their parents on the Rothbart Child Behavior Questionnaire. At age 7, the children were tested in our laboratory on the Harter Test of Perceived Competence and on an achievement task, and parents filled out the Child Behavior Checklist, the Child Behavior Questionnaire, and the Conners Parent Rating Scale. Home observations of activity level were significantly related to parent ratings of activity level, but not to school observations. Activity level at age 5 was related to parents' ratings of aggression and hyperactivity and to girls' learning problems at age 7. Activity level was not related to the children's self-perceived competence, but mothers' rating of high activity level at age 5 was related to low reading comprehension at age 7.Preparation of this paper was supported in part by the Center for Research for Mothers and Children, NICHD, U.S. PHS grant HD 19739 to Beverly I. Fagot.