Computing interrater reliability on the Apple Macintosh computer

A program is described for computing interrater reliability by averaging, for each rater, the correlations between one rater’s ratings and every other rater’s ratings. For situations in which raters rate more than one ratee, raters’ reliabilities can be computed for either each item or each ratee. The program reads data from a text file and puts the reliability coefficients in a text file. The standard Macintosh interface is implemented. The Quick-BASIC program is distributed both as a listing and in compiled form; it can be run with advantage with math coprocessors.     

PsychLib: A library of machine language routines for controlling psychology experiments on the Apple Macintosh computer

The hardware and system software of the Apple Macintosh computer are described, and their implications for conducting psychological research is discussed. A library of machine language routines for presenting auditory and visual stimuli and recording response latencies is described.     

A review of scientific visualization software for the Macintosh computer

Many programs are available for the Macintosh that provide advanced visualization tools. Some of the tools are individual applications, and some are part of mathematical packages. This paper reviews the capabilities, functionality, and ease of use of visualization tools within six software packages: Mathematica, Spyglass Transform/View, Spyglass Dicer, JMP, MacSpin, and SYSTAT.     

Response time accuracy in Apple Macintosh computers

The accuracy and variability of response times (RTs) collected on stock Apple Macintosh computers using USB keyboards was assessed. A photodiode detected a change in the screen’s luminosity and triggered a solenoid that pressed a key on the keyboard. The RTs collected in this way were reliable, but could be as much as 100 ms too long. The standard deviation of the measured RTs varied between 2.5 and 10 ms, and the distributions approximated a normal distribution. Surprisingly, two recent Apple-branded USB keyboards differed in their accuracy by as much as 20 ms. The most accurate RTs were collected when an external CRT was used to display the stimuli and Psychtoolbox was able to synchronize presentation with the screen refresh. We conclude that RTs collected on stock iMacs can detect a difference as small as 5–10 ms under realistic conditions, and this dictates which types of research should or should not use these systems.     

Real-time color-frame animation for visual psychophysics on the Macintosh computer

Psychophysical experiments involving moving stimuli require the rapid presentation of animated sequences of images. Although the Macintosh computer is widely used as a color graphics computer in research laboratories, its animation capabilities are generally ignored because of the speed limitations of drawing to the screen. New off-screen color graphics structures help to avoid the speed limitations so that real-time color or gray-scale visual motion stimuli may be generated. Precomputed animation frames are stored in off-screen memory and then rapidly transferred to the screen sequentially. The off-screen graphics structures may also be saved to disk in “Picture” form as “resources” for later retrieval and playback, allowing the experimenter to build in advance a collection of moving stimuli to use in future experiments. Code examples in the C programming language are provided, and the relative strengths and weaknesses of Macin-tosh color-frame animation for psychophysical experimentation are discussed.     

Using digitized auditory stimuli on the Macintosh computer

Hardware/software packages that digitize sound on the Apple Macintosh can help researchers prepare and present auditory materials needed for their experiments. Common features and benefits of commercially available sound digitizing packages are discussed in terms of some possible applications to cognitive psychology experiments.     

Demonstration experiments in perception and cognitive psychology for the Macintosh computer

A package of programs demonstrating psychology experiments widely cited in perception and cognitive psychology textbooks is described. The programs are suitable for laboratory research projects and in-class demonstrations. An attractive feature of the programs is that they have provisions for changing experimental parameters to allow students to design different experiments from the original programs. Iconic memory, memory scanning (using the additive factors approach), lexical decision, target detection, speeded classification, picture recognition/picture memory, and the Phi phenomenon can be demonstrated.     

Using HyperCard to administer a figural test on the Apple Macintosh

To date, applications of automated assessment techniques in personality testing have largely been limited to objective personality instruments with text stimuli; few assessment applications have involved graphic stimuli. Although projective personality instruments generally include ambiguous graphic or pictorial stimuli, computer applications with these procedures have been limited to automated scoring and interpretation, administration of sentence completion devices employing text stimuli, and the use of mechanical methods rather than computer graphics to display visual stimuli. In the present report, we describe a Macintosh HyperCard application for administering an objective personality test with visual stimuli, the Barron-Welsh Revised Art Scale of the Welsh Figure Preference Test. This test consists of a series of figural stimuli and a binary “like”/“dislike” response format, and it thus represents an administration procedure between standard objective self-report inventories involving text stimuli and a “true”/“false” response or variant, and tests such as the Rorschach or TAT that are both figural and free-response. The HyperCard language provides a variety of promising techniques useful for microcomputer test administration.     

Software for the generation and display of random-dot cinematograms on the Macintosh computer

The software packageDotMovie 1.3.8 was designed to create and display dynamic random-dot cinematograms for studies of motion perception on Macintosh II microcomputers. In each frame of the cinematogram, some dots move in random uncorrelated directions, while other dots move with constant speed in one direction. As the relative number of dots moving in a correlated direction increases, the observer sees flow in the direction of the movement. The software described facilitates the creation of random-dot cinematograms, their presentation, and collection of data from subjects’ responses.     

An external millisecond timer for the Apple Macintosh with applications to cross-modal lexical priming

The circuit and program described in this report allow researchers to use Macintosh personal computers to conduct research that requires timing with millisecond accuracy. This is accomplished with external response keys and an external clock that sends characters through the Macintosh’s serial port. For researchers interested in cross-modal lexical priming tasks, a tachistoscopic slide shutter is incorporated to allow for accurately timed presentation of visual stimuli. Because the visual display and response keys are external to the computer, display and reaction times are not subject to the timing constraints inherent to the keyboard or the Macintosh Event Manager. All circuit diagrams and code are in the public domain.     

Extendable high-speed stimulus generation and recording on the Macintosh computer

A new visual electrophysiology and eye-movement laboratory was developed with three goals in mind: (1) rapid execution speed for quick acquisition of data from infant subjects, (2) ease of operation by experimenters, and (3) modularity and flexibility. A powerful system composed of two linked Macintosh computers was constructed in which one computer was used solely to generate visual stimuli and the second solely to record subjects’ responses, allowing recording to execute at maximum speed without being slowed by stimulus graphics generation. A single program on the recording computer allowed the experimenter to choose the stimulus and recording parameters. The two computers intercommunicated via a local EtherNet network to coordinate recording and signal averaging. This paper presents design principles and specific programming techniques relevant to any Macintosh system that must rapidly acquire physiological recordings while simultaneously displaying sensory stimuli.     

MacPsych: An electronic discussion list and archive for psychology concerning the Macintosh computer

MacPsych is an electronic mail discussion list and an electronic archive for those using the Macintosh in psychology. The discussion list allows psychologists from around the world to ask questions and discuss issues relating to the use of the Macintosh in psychology. The archive is a place where list members may share software and other files of relevance. The Society for Computers in Psychology sponsors the discussion list, and the journalBehavior Research Methods, Instruments, & Computers has designated the archive as the distribution site for Macintosh software and files described in its pages. Those interested may join the list by sending electronic mail to macpsych-request@stolaf.edu. The archive can be accessed via anonymous ftp at ftp.stolaf.edu in the directory pub/macpsych.