An alternative assessment of children's comprehension of relative clauses

Methodological difficulties are identified in the assessment of children's comprehension of relative clauses (RCs) by means of the standard acting-out procedure. An alternative experimental task is proposed which attempts to minimize these difficulties while exploring the advantages of the acting-out technique. An experiment is reported in which Portuguese-speaking 3- to 6-year olds were tested by means of this alternative task. The results show children being affected by both the position and the focus of the RC in the same way adults have been reported to be and an error analysis suggests that most of children's difficulties can be ascribed to memory overload while RCs are processed as noun modifier sentences. These results contradict the view that there are developmental differences with regard to the way sentences with RCs are parsed and that processing load induces errors particularly manifested in right-branching subject focus sentences. Developmental changes taking place between the ages of 3 and 6 are considered and questions are raised concerning development from the age of 5.The research reported here was carried out while the author read for the PhD degree at the University of London. The writing up of this paper was financially supported by a postdoctoral grant from the Brazilian Research Council (CNPq: 302103-86.4).     

Cut-free sequent and tableau systems for propositional Diodorean modal logics

We present sound, (weakly) complete and cut-free tableau systems for the propositional normal modal logicsS4.3, S4.3.1 andS4.14. When the modality is given a temporal interpretation, these logics respectively model time as a linear dense sequence of points; as a linear discrete sequence of points; and as a branching tree where each branch is a linear discrete sequence of points.Although cut-free, the last two systems do not possess the subformula property. But for any given finite set of formulaeX the superformulae involved are always bounded by a finite set of formulaeX* _L depending only onX and the logicL. Thus each system gives a nondeterministic decision procedure for the logic in question. The completeness proofs yield deterministic decision procedures for each logic because each proof is constructive.Each tableau system has a cut-free sequent analogue proving that Gentzen's cut-elimination theorem holds for these latter systems. The techniques are due to Hintikka and Rautenberg.Presented byDov M. Gabbay     

Local and global factors of similarity in visual search

Effects of the similarity between target and distractors in a visual search task were investigated in several experiments. Both familiar (numerals and letters) and unfamiliar (connected figures in a 5 × 5 matrix) stimuli were used. The observer had to report on the presence or absence of a target among a variable number of homogeneous distractors as fast and as accurately as possible. It was found that physical difference had the same clear effect on processing time far familiar and for unfamiliar stimuli: processing time decreased monotonically with increasing physical difference. Distractors unrelated to the target and those related to the target by a simple transformation (180° rotation, horizontal or vertical reflection) were also compared, while the physical difference was kept constant. For familiar stimuli, transformational relatedness increased processing time in comparison with that fort unrelated stimulus pairs. It was further shown in a scaling experiment that this effect could be accounted for by the amount of perceived similarity of the target-distractor pairs. For unfamiliar stimuli, transformational relatedness did have a smaller and less pronounced effect. Various comparable unrelated distractors resulted in a full range of processing times. Results from a similarity scaling experiment correlated well with the outcome of the experiments with unfamiliar stimuli. These results are interpreted in terms of an underlying continuum of perceived similarity as the basis of the speed of visual search, rather than a dichotomy of parallel versus serial processing.     

Beyond belief bias: Reasoning from conceptual structures by mental models manipulation

Mental models constitute an alternative to the rule-based systems in the explanation of human reasoning (Johnson-Laird, 1983). In this paper, we claim that the concept of believability generally used to categorize content and context effects is of little use within a semantic theory. Thus, we propose the use of categories that are directly extracted from subjective relations among concepts within the reasoning problem. We demonstrate that manipulations based on this kind of categorization produce predictable patterns of responses in reasoning problems. We present two experiments to test our predictions, using conditional and syllogistic reasoning problems, and in both cases, we demonstrate the influence of conceptual knowledge not only in natural contexts, but also in experimentally created artificial contexts.     

Detachment and defeasibility in deontic logic

The purpose of the paper is to present a logical framework that allow to formalize a kind of prima facie duties, defeasible conditional duties, indefeasible conditional duties and actual (indefeasible) duties, as well as to show their logical interconnections.     

Empirically defined symptom scales using the DISC 2.3

Empirically defined scales of depressive, attention deficit hyperactivity disorder, oppositional-defiant disorder, and conduct symptoms from the lay-administered National Institute of Mental Health (NIMH) Diagnostic Interview Schedule for Children (DISC), version 2.3, and evidence of their reliability and validity, are presented. The scales were developed using factor analyses of data obtained from an epidemiologic survey of over 1,200 children drawn from four sites across the U.S. and Puerto Rico (the NIMH Methods for the Epidemiology of Child and Adolescent Mental Disorders, or MECA Study). Their psychometric properties were tested in a subsample of children reinterviewed by clinicians. The findings support the use of these continuous measures. The scales are strongly related to the diagnostic categories and show good test-retest reliability. The scales can be used to characterize severity in children with diagnoses and to describe problems and symptoms in children without diagnoses. Because these scales can measure gradations in symptomatology, they may be more useful than categorical measures. Like categorical measures, the scales based on the DISC are greatly influenced by the informant, whether child or parent.This research was supported by grant MH-46732 from the National Institute of Mental Health, Bethesda, Maryland.The MECA Program is an epidemiologic methodology study performed by four independent research teams in collaboration with staff of the Division of Clinical Research, which was reorganized in 1992 with components now in the Division of Epidemiology and Services Research and the Division of Clinical and Treatment Research, of the NIMH, Rockville, Maryland. The NIMH Principal Collaborators are Darrel A. Regier, MD, MPH, Ben Z. Locke, MSPH, Peter S. Jensen, MD, William E. Narrow, MD, MPH, and Donald S. Rae, MA; the NIMH Project Officer was William J. Huber. The Principal Investigators and Coinvestigators from the four sites are as follows: Emory University, Atlanta, Georgia, UO1 MH46725: Mina K. Dulcan, MD, Benjamin B. Lahey, PhD, Donna J. Brogan, PhD, Sherryl Goodman, PhD, and Elaine Flagg, PhD; Research Foundation for Mental Hygiene at New York State Psychiatric Institute (Columbia University), New York, New York, UO1 MH46718: Hector R. Bird, MD, David Shaffer, MD, Myrna Weissman, PhD, Patricia Cohen, PhD, Denise Kandel, PhD, Christina Hoven, PhD, Mark Davies, MPH, Madelyn S. Gould, PhD, and Agnes Whitaker, MD; Yale University, New Haven, Connecticut, UO1MH46717: Mary Schwab-Stone, MD, Philip J. Leaf, PhD, Sarah Horwitz, PhD, and Judith H. Lichtman, MPH; University of Puerto Rico, San Juan, Puerto Rico, UO1 MH46732: Glorisa Canino, PhD, Maritza Rubio-Stipec, MA, Milagros Bravo, PhD, Margarita Alegría, PhD, Julio Ribera, PhD, Sarah Huertas, MD, and Michael Woodbury, MD.The authors gratefully acknowledge Zenaida González and José Martínez who performed the data nalayses, as well as Elizabeth Pastrana, and Felícita Laboy, secretaries, for their valuable contributions to this work.