The Perception of a Colored Translucent Sheet on a Background

Metelli's theory of the perception of translucency models the effective reflectance of a translucent sheet on a background as a partitive mixture of the color of the sheet and the color of the background. In the achromatic case, the usable (that is, scale-invariant) rules governing the apparent reflectances are the same as those that would emerge from the Kubelka-Munk theory. For chromatic translucency, the relationships are more complex, but a set of rules still emerge from the partitive-mixture theory that are invariant to tradeoffs between illuminant and reflectances. This column sets forth the rules in the hopes that they will have graphical applications, both on computer VDUs and in hardcopy.     

On finding optimal and near-optimal lineal spanning trees

The search for good lineal, or depth-first, spanning trees is an important aspect in the implementation of a wide assortment of graph algorithms. We consider the complexity of findingoptimal lineal spanning trees under various notions of optimality. In particular, we show that several natural problems, such as constructing a shortest or a tallest lineal tree, are NP-hard. We also address the issue of polynomial-time, near-optimization strategies for these difficult problems, showing that efficient absolute approximation algorithms cannot exist unlessP = NP.This author's research was supported in part by the Sandia University Research Program and by the National Science Foundation under Grant M IP-8603879.This author's research was supported in part by the National Science Foundation under Grants ECS-8403859 and MIP-8603879.     

The Effect of Run Time on the Inter-Unit Uniformity of Aqueous Film Coating Applied to Glass Beads in a Hi-Coater

Coating experiments were conducted to assess the inter-unit uniformity using individual weight gains of glass beads. Applying more aqueous film coating and prolonging the film-coating process by diluting the coating suspension did improve the coating variability among glass beads. It appears that run time is an important underlying factor which affecting the inter-unit coating uniformity.     

Has psychology ever been a science of behavior? A comment on Skinner.

Argues that B. F. Skinner (see record 1988-00027-001) failed to recognize the role of behaviorism in the failure of psychology to become a science of behavior. The authors state that behaviorism has generated laws concerning the impact of behavior on certain environments instead of laws of behavior. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Expressed emotion and subclinical psychopathology observable within the transactions between schizophrenic patients and their family members.

The authors examined whether young, recently discharged schizophrenic patients from high (n?=?34) and low (n?=?14) expressed emotion (EE) families differ in their level of subclinical symptomatology during a direct interaction task. Compared with patients from low-EE homes, patients from high-EE homes showed significantly more odd and disruptive behavior with family members. High-EE relatives were more likely than low-EE relatives to respond with criticism to the first unusual thought verbalized by the patient; when this occurred, the probability of a second unusual thought was augmented. Results suggest that high-EE family members may display negative attitudes toward patients in part because they are exposed to higher levels of unusual or disruptive behavior than low-EE relatives. The data also support a bidirectional, transactional model of the relationship between relatives' EE and patient psychopathology. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Cognitive science: Making the whole different from the sum of its parts.

Reviews the book, From models to modules: Studies in cognitive science from the McGill workshops edited by I. Gopnik and M. Gopnik (1986). This book is only moderately successful in conveying the exciting advances that are beginning to appear as a result of the interdisciplinary efforts in cognitive science. The book's emphasis on language processes and linguistics will seriously limit its potential readership, although there are some contributions from outside that domain. Moreover, many of the chapters were not prepared with a general audience in mind, and to appreciate a number of the chapters fully the reader must have a strong linguistic background. A more severe problem is that the chapters are based on a series of workshops held at McGill University in 1982 and 1983. The sad consequences are that (a) the book is badly out of date (few references are more recent than 1983), (b) most of the contributions were not original but were based on ideas and results that were or were about to be in print at the time the workshops were held, and (c) many of the chapters are so short that they do not provide adequate depth of coverage. At this late date, the value of the book may be as a summary of a few of the early issues and methodologies that have captured the attention of cognitive scientists. (PsycINFO Database Record (c) 2010 APA, all rights reserved)