The role of spatial-frequency channels in the perception of local and global structure

Adaptation and reaction-time techniques were used to examine the role of different spatial-frequency channels in the perception of local and global structure. Subjects were shown figures consisting of a large C composed of smaller Cs and asked to identify the orientation of either the global C or its local elements. Prior to performing the task subjects were adapted to different spatial frequencies and the effect on subsequent performance was assessed. Two main results were found. First, the adapting frequency that most affected the global task was often lower than that most affecting the local task, suggesting that high and low frequencies independently code the structure of an image. Second, reaction time to global figures was often faster than to local figures at all levels of detectability, again suggesting a role of low-frequency channels in global processing.     

Visual object recognition in patients with right-hemisphere lesions: axes or features?

An investigation is reported of the ability of normal subjects and patients with right-hemisphere lesions to identify 3-D shadow images of common objects from different viewpoints. Object recognition thresholds were measured in terms of angle of rotation (through the horizontal or vertical axis) required for correct identification. Effects of axial rotation were very variable and no evidence was found of a typical recognition threshold function relating angle of view to object identification. Although the right-hemisphere-lesion group was consistently and significantly worse than the control group, no qualitative differences between the groups were observed. The findings are discussed in relation to Marr's theory that the geometry of a 3-D shape is derived from axial information, and it is argued that the data reported are more consistent with a distinctive-features model of object recognition.     

Building higher-order units in tachistoscopic identification: A test of two models

Summary Subjects were shown eight-letter pseudowords tachistoscopically and were asked to report as many letters as possible. The pseudowords, examples of either first- or fourth-order approximation to English, were printed in normal or reversed spelling and were presented in either normal of mirror-imaged letters. Finally subjects were either free to report in any order they wished, or they were instructed to report from left to right or from right to left. With normal letters, the familiarity effect was controlled by the spelling direction, not by the direction of report or the match between direction of report and spelling direction. With mirrored letters, however, order of approximation to English had no effect. The results contradict two existing theories: Mewhort's theory claims that the familiarity of fourth-order materials aids processing at a postcategorical level; it has trouble explaining why the familiarity effect disappeared with mirrored letters and normal spelling. Wolff's theory claims that familiarity aids processing at the feature level; it has trouble explaining why the familiarity effect disappeared with mirrored letters and reversed spelling.     

Child of divorce: An overview

Children of divorce represent a diverse population at risk for subsequent psychological problems, whose interests are insufficiently understood or protected by the legal system or the mental health community. Although many children weather the stress of marital breakdown without psychopathological sequelae, a significant number show lasting difficulties. Information concerning the psychological adaptation of these children has increased rapidly during the past decade, but it remains unequel to the task of guiding family policy in this arena. Current knowledge identifies child gender and developmental stage as crucial factors that interact with the chronic stresses of postdivorce family life to produce short-and long-range impediments to the maturation of these vulnerable young people. There is a critical need to facilitate understanding and cooperation between the behavioral sciences and the legal profession on behalf of children in divorced families. The major research tasks relevant to enlightened public policy lie ahead.     

A guide to family/school interventions for the family therapist

When presented with a behavioral problem or symptom expression that involves two systems, such as a serious school-related problem, the therapist needs to design an approach that will intervene effectively and expeditiously in both systems. This paper offers a guide to stages of problem escalation and therapeutic intervention that is intended to aid the problem-solver's thinking processes in approaching a troubled situation that involves two systems, the school and the home.     

Induction,trance, and ritual in family mythologizing

The authors put forward a theory of family mythologizing as a process of induction, trance, and ritual. These phenomena, in the context of expressive language, comprise myths. Mythologizing is assumed to be part of normative development. All individuals and families employ myths as schemata for organizing highly complex yet cognitively inexplicable relationships. The authors propose a systemic explanation for the operations of mythologizing and present case illustrations.     

Apple II assembly language routines for digital data acquisition and contingency control

Modifications and corrections to Rayfield’s (1982) assembly language routines for data acquisition and experimental control using the Apple II computer are described. The modified routines, together with an optoisolated hardware interface, provide a reliable, accurate, and easy to use microcomputer system for experimental control and data acquisition.     

Microcomputer-based scalp topography mapping of event-related potentials

A microcomputer-based technique to evaluate the scalp topography of event-related potentials is described. This technique uses only four electrode locations and produces a 24 × 24 element color matrix of the topography of scalp electrical activity across time. The program also displays the coordinates, latency, and value of the maximum point within the matrix. The program is implemented on an Apple II+/IIe computer and is adaptable to other computers with graphic capabilities.     

RSCORE-J: Pooled rating-method data: A computer program for analyzing pooled ROC curves

RSCORE-J, a computer program for a signal-detection analysis of pooled rating-method data, is listed and described. RSCORE-J computes jackknife estimates of ROC parameters and their standard errors from rating-method data pooled over a group of observers.