A user-interactive graphics-based computer system for analysis of the EEG

Computer technology provides a powerful high-resolution tool for the analysis and understanding of the electroencephalogram (EEG). A system of user-interactive graphics-based computer programs analyzing the power spectral density (PSD), coherence, and phase-angle relationships of the EEG is described, along with the mathematical algorithms used. The analytic variables inherent in coherence analysis are reviewed. These variables include choices of sampling parameters, auto- and cross-spectral algorithms, smoothing techniques, and use of the γ²(f) or γ(f) value for coherence. These variables in the analysis itself have a net interactive effect on the calculated results that often makes comparability of data across studies impossible. Thus, it is proposed that studies include a graph showing the authors’ derived coherence values for a set of standard test signals to enhance scientific communication.     

A statistical analysis system (SAS) computer program for Markov chain analysis

A computer program for Markov chain analysis is presented and discussed. The program is written in the language of the Statistical Analysis System (SAS) but detailed knowledge of SAS is not required for its use. The program tests hypotheses about the goodness of fit of first- and second-order Markov models. It also tests if transition probabilities are homogeneous between the first and the second half of each sequence.Presented, in part, at the Association for the Advancement of Behavior Therapy Convention, November 1984.     

Statistical power analysis for one-way analysis of variance: A computer program

To facilitate the computation of statistical power for analysis of variance, Cohen developed the index of effect sizef, defined as theSD between groups divided by theSD within groups. A microcomputer program for statistical power allows the user to compute the value off in any of several ways: by specifying the mean andSD for every cell in the ANOVA; by specifying the mean value for the two extreme cells and the pattern of dispersion for the remaining cells; by estimating the proportion of variance in the dependent variable that will be explained by group membership; and/or with reference to conventions for small, medium, and large effects. The program will compute power for any single set of parameters; it will also allow the user to generate tables and graphs showing how power will vary as a function of effect size, sample size, andα.     

A computer system for processing eye-movement records

A computer system using the LINC-8 computer was developed to process eye-movement records from two 16-mm cine film input sources : the Mackworth stand camera and the Mackworth wide-angle camera. Data reduction was accomplished by projecting the films onto an X-Y plotting table. An operator marked, using a cursor, either the eyespot, in the case of the stand camera, or the pupil and display center, in the case of the wide-angle camera, in order to digitize the locus of the gaze. This information was normalized and stored on magnetic tape as: ordinal fixation number, fixation duration, and fixation coordinates (X and Y). A software library was created to analyze the three eye-movement measures. One program calculates interfixation distance, fixation time, and dispersion of fixations about a point. A second program operates on data matrices to: calculate area covered by a fixation pattern, frequency of redundant fixations in a fixation pattern, and distribution of fixations over features of the visual display. Data are displayed on either scope or the Calcomp plotter.     

A system for computer control of auditory stimuli

A computer system for generation of auditory stimuli is described. The system produces natural-speech or software-generated stimuli for monaural, binaural, or dichotic presentation. Stimuli have been generated for experiments run both on-line and off-line.     

multiTree: A computer program for the analysis of multinomial processing tree models

Multinomial processing tree (MPT) models are a family of stochastic models for psychology and related sciences that can be used to model observed categorical frequencies as a function of a sequence of latent states. For the analysis of such models, the present article presents a platform-independent computer program called multiTree, which simplifies the creation and the analysis of MPT models. This makes them more convenient to implement and analyze. Also, multiTree offers advanced modeling features. It provides estimates of the parameters and their variability, goodness-of-fit statistics, hypothesis testing, checks for identifiability, parametric and nonparametric bootstrapping, and power analyses. In this article, the algorithms underlying multiTree are given, and a user guide is provided. The multiTree program can be downloaded from http://psycho3.uni-mannheim.de/multitree.     

Human content in affect-inducing stimuli: A secondary analysis of the international affective picture system

We report a secondary analysis of the international affective picture system (IAPS), the broadest available standardized sample of emotional stimuli, which confirmed our prediction that the distribution of slides across the valence and arousal dimensions would be related to human versus inanimate slide content. Pictures depicting humans are over-represented in the high arousal/positive and high arousal/negative areas of affective space as compared to inanimate pictures, which are especially frequent in the low arousal/neutral valence area. Results pertaining to dominance ratings and gender differences in valence and arousal ratings further suggest that there are qualitative differences between emotional reactions to animal or human slide content and responses to nonsocial still photos. Researchers need to be mindful of this distinction when selecting affect-inducing stimuli.

A device for the computer processed analysis of video frames

This article briefly describes a system of analyzing movement sequences extracted from video images. The system uses an IBM-PC or compatible computer, equipped with a CGA screen and a mouse, and a videotape recorder and monitor. The coordinates of the points selected from the images with the mouse are stored in an ASCII-format file by a computer program. The principle behind this system is that it projects video images on a computer screen through a one-way mirror while avoiding parallax effects.     

A computer system for automatically constructing stimulus material

A FORTRAN system for constructing various kinds of stimulus materials is described. A user enters the basic components of an experiment (stimulus items, presentation parameters, trial identifiers, etc.) as files, and uses the system to combine the basic files, automatically constructing the desired stimuli. The system contains file-manipulation functions for combining files (including factorial combination), functions for separating out parts of a file, and functions for randomizing files. The user can use the standard FORTRAN function-embedding and function-definition features to easily specify elaborate operations on the basic files to construct complex stimulus files.     

A semiautomatic system for preparing computer data cards

A system is described which eliminates manual coding and punching of computer data cards in a psychophysical experiment. Conventional relay logic is used to control the operation of a card punch and to enter data in selected card columns.     

A 6809 single-board computer system for the control of behavioral experiments

A computer system consisting of a 6809 single-board computer in conjunction with an IBM-compatible Personal Computer (PC) is described for the control of behavioral experiments. The single-board computer uses the C programming language to program experimental events. Each component of the system (the single-board computer, a digital interface, the PC, and the software) is outlined with its capabilities and drawbacks noted.     

A coefficient of imbalance for content analysis

This article presents a Coefficient of Imbalance applicable to any type of communication that may be classified into favorable content, unfavorable content, neutral content, and non-relevant content. The combined influence of the average presentation of relevant content and the average presentation of total content is reduced to two components, the coefficients of favorable imbalance and of unfavorable imbalance. A precise definition of imbalance is developed and measured against ten criteria.The authors wish to express their appreciation to Mr. Harold Elsten, Dr. Natan C. Leites, and Mr. Ithiel Pool for valuable suggestions and criticisms.     

RASP: A system for the analysis of memory tasks

The purpose of this paper is to introduce a system for the analysis of memory tasks. The system involves four basic task dimensions, derived from an ecological analysis of memory functioning: Reproductivity (R), Acquisition (A), Sufficiency (S), and Productivity (P). Three studies are reported in which professional memory psychologists were asked to rate sets of standard laboratory and more ecologically relevant memory tasks in terms of the four RASP dimensions. In general, results implied independence across the two sets of tasks between the four dimensions. Interrater reliabilities were found to be modest to high. However, it was suggested that RASP best be used as a tool for understanding the meaningful relations that exist among dimensions within general sets or pools of tasks, for different classes of tasks, as well as for prototypical tasks. We argue that, especially when the relationship between RASP profiles for two particular tasks is crossvalidated by behavioral data, and conflict with assumptions about what memory systems or processes are involved, then there is a potential for conceptual refinement. This refinement could be attained either through an increased theoretical generalization, or through an increased theoretical precision. Based on obtained RASP information at the level of classes of tasks (e.g., episodic vs. semantic) as well as at a prototypical task level (e.g., word recall vs. prose recall), several intriguing memory phenomena are discussed. Finally, we suggest that RASP may serve as a tool for reducing the number of task-specific assumptions of what systems and processes mediate memory performance.