Linguistic negation in autistic and normal children

Young, severely maladaptive autistic children with some speech competence were compared to normally developing 3-year-old children of lower and middle class and 5-year-olds of lower class on negation tasks. All subjects were shown 12 sets of cards depicting negative contrasts designed to elicit semantic categories of nonexistence, denial, and rejection and were tested for production, imitation, and comprehension. Syntactic and semantic analysis revealed that autistic children were superior imitators and poor producers but showed skills in comprehension comparable to a 4-year-old's level of functioning. While retarded in some functions, the experimental group produced syntactic structures that were more rigid, suggesting the significantly greater use of imitation as a major strategy in linguistic coding.This work was done at the NYU-Bellevue Medical Center with partial support by NIMH Grant No. MH 07331 to R. K.     

YEPS: Running real-time experiments on a timesharing system

The Yale experimental programming system is described. This system consists of user-callable subroutines and a set of modifications to the UNIX operating system which support the development and execution of real-time psychology experiments. The interactions between a timesharing operating system and the provision of real-time facilities for experiments are discussed.     

Interviewee perceptions of an organisational careers guidance scheme

A study was carried out during the early stages of the introduction of a career development scheme in a large government department. Information relating to aspects of various careers counselling issues was gathered from staff who had received such counselling and from personnel staff responsible for its provision. The study shows, amongst other things, that the interviewers were perceived to use some counselling skills, that the interviewers claimed they experienced few problems of role conflict, but that the staff tended to identify the interviewers with management. The findings are discussed relation to the appropriateness of interviewing style and to the broader context of how individuals might influence their career development within the opportunities provided by the organisation.     

BAND AID: First steps toward an ICAI system

BANDAID is an intelligent computer-assisted instruction (ICAI) system designed for students learning to program in BASIC. The major thesis is that beginning students need a friendly environment, that is, one in which information about the language and the system are immediately available. The system accepts most commands without switching levels: BASIC lines are parsed on input with very specific error messages. An editor allows corrections of BASIC lines. The program can be traced while running, and an indefinite number of HELP comments can be written for the system. Without leaving the BASIC environment, the user can interact with the CMS monitor of the main machine running the program. Although no English language comments or questions are allowed, the system is modular so that additions of restrictive dialogue interaction and guided tutoring are possible. Illustrations are presented showing the capabilities of the system. The paper also presents some of the implementation details of BANDAID. A flexible system requires implementation in LISP, so examples of how the system programmer interacts with LISP during debugging are given. Although still incomplete, the system runs satisfactorily and can be used easily by beginning students and by psychologists interested in how people learn complex subjects.     

A two-stage detection model applied to skilled visual search by radiologists

Harvard Medical School and Peter Bent Brigham Hospital, Boston, Massachusetts 02115 The model treats the detection of targets in a visual search task as a concatenation of two serial detection stages. Preattentive visual mechanisms in the initial stage function as a filter, selecting specific features of a visual pattern for the observer’s explicit attention and final cognitive evaluation. The model uses bivariate normal distributions to represent the decision variables for the two serial stages, assuming different parameters for the target and nontarget features in a test set. The model is applied to the detection performance of radiologists interpreting chest x-rays under various conditions of search. It accounts for the substantial improvement in radiologists’ ability to distinguish between target and nontarget test features when they had to search the x-ray images, compared to their performance without visual search. A change in the ROC curve between two different search tasks could be interpreted as a shift in the selection cutoff used by the preattentive filter.     

Picture perception: An analysis of visual compensation

Although geometric information is altered when a picture’s viewing point is changed, such changes often do not affect perception. Two experiments assessed pictorial perception relative to the distortions introduced by viewing point dislocation. Results provide a psychophysical demonstration of pictorial compensation and suggest that it is based on the discrepancy between the actual and an assumed-correct viewing position. An explanation of pictorial compensation is offered that could be applied to direct picture perception and to picture-in-a-picture perception.     

A mutual inductance shocker

A simple dc shock-generating device is described. The principle of operation relies upon the mutual inductance effect between the primary and secondary coils of a transformer.