Millisecond timing on the Apple Macintosh: Updating Drexel’s MilliTimer

In 1986, we published inBehavior Research Methods, Instruments, & Computers a small library of assembler code for the public domain that permitted accurate millisecond timing for Apple’s Macintosh computer. That version of MilliTimer used the Versatile Interface Adapter chip’s Timer 1 (VIA T1), which is part of the standard Macintosh hardware configuration. The VIA T1, however, is also used by the Sound Manager, and thus the use of sound and accurate millisecond timing were incompatible. We offer for the public domain a new version labeled MilliTimer 2.2, which permits psychologists and other researchers to use the full capabilities of the Macintosh. MilliTimer 2.2 is compatible with popular teaching, research, and clinical tools such as Hyper-Card and MacLaboratory. MilliTimer 2.2 employs the Macintosh Time Manager, which is a part of the Macintosh operating system and is supported by Apple for the 512KE, Plus, SE, and Macintosh II machines. MilliTimer 2.2 is hardware-independent and automatically self-corrects for other operating system activities that also use the Time Manager. The self-correcting function is limited, however, and can result in a nonaccumulating error averaging about ?3 msec. To preserve compatibility with earlier machines that do not contain the Time Manager, a simple mode parameter allows MilliTimer 2.2 to use the older, more accurate timing method.     

Accurate millisecond timing on Apple’s Macintosh using Drexel’s MilliTimer

Many of the timed functions that concern psychologists, such as perceptual presentations and reaction time, are sensitive to a maximum variability in display timing caused by screen-refresh characteristics. For the Apple Macintosh, the screen operating speed is 60 Hz, which translates to an average of 8.33-msec variability. For microcomputers other than the Macintosh, a variety of hardware and software modifications to generate millisecond timing have become standard (e.g., Reed, 1979). Other than Reed College’s (1985) implementation in Rascal, which requires the Rascal development language, there has been no method of which we were aware to synchronize experimental timing with display presentation on the Macintosh. This limitation in the usefulness of the Macintosh as an otherwise excellent research tool can be overcome using Drexel University’s MilliTimer. The assembler code which follows should be considered in the public domain and can be readily adapted to any of the Macintosh-based languages.     

MacLaboratory Controller: A switch and A/D interface between Apple’s Macintosh and peripheral apparatus

Apple’s Macintosh microcomputer has advantages over other systems used for laboratory control and data acquisition, especially because of its graphic and user-friendly features. However, a major perceived limitation has been its closed architecture. We describe an interface using the RS 422 modem port that supports up to 64 input/output (I/O) functions including analog-to-digital 4–12 channel input. The Controller software supplies an easily edited authoring tool in which functional relationships, logical operators, timing (millisecond accuracy), and counting functions are established through simple mouse and menu commands. Data from I/O functions may be displayed or saved as tab-delimited files that can be opened by various Macintosh statistical and spreadsheet packages and that are transportable to some mainframe applications.     

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.     

MacLab: A Macintosh system for psychology labs

MacLab, a program that turns the Apple Macintosh into a psychology laboratory tool, is described. MacLab combines intelligent editors, a millisecond timer, MacPaint pictures, and the ease of use of the Macintosh user interface to create a system with which experimental psychologists can quickly create and run powerful experiments with no need of any knowledge of programming.     

Combining EEG,MIDI, and motion capture techniques for investigating musical performance

This article describes a setup for the simultaneous recording of electrophysiological data (EEG), musical data (MIDI), and three-dimensional movement data. Previously, each of these three different kinds of measurements, conducted sequentially, has been proven to provide important information about different aspects of music performance as an example of a demanding multisensory motor skill. With the method described here, it is possible to record brain-related activity and movement data simultaneously, with accurate timing resolution and at relatively low costs. EEG and MIDI data were synchronized with a modified version of the FTAP software, sending synchronization signals to the EEG recording device simultaneously with keypress events. Similarly, a motion capture system sent synchronization signals simultaneously with each recorded frame. The setup can be used for studies investigating cognitive and motor processes during music performance and music-like tasks—for example, in the domains of motor control, learning, music therapy, or musical emotions. Thus, this setup offers a promising possibility of a more behaviorally driven analysis of brain activity.     

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.     

Toolbox-based routines for Macintosh timing and display

Pascal routines are described for several real-time operations on Macintosh computers. Methods are presented for millisecond timing and for high-speed transfer of arbitrary bit-image displays to the screen. All routines are based on Toolbox procedures available on virtually all Macintosh computers.     

InputLogger: General-purpose logging of keyboard and mouse events on an Apple Macintosh

Event logging, particularly logging of event-timing information, is often used in human-computer interaction research in investigations of the ways in which people use computers and in the evaluation of input devices and applications. This paper describes InputLogger, a low-level input-event recorder for the Apple Macintosh. It differs from other keystroke loggers in that it records accurate timing information for all keyboard and mouse events while being application independent. It is capable of logging any Macintosh session. InputLogger has been used to gather data on the difficulties experienced by people with motor disabilities using ordinary keyboards and mice. It would be appropriate for many other experimental applications.     

ArtWare: Macintosh multimedia software for aesthetics research

This paper describes ArtWare, a HyperCard stack for the Apple Macintosh that allows researchers to configure and run simple experiments in visual aesthetics. ArtWare allows researchers to (1) choose paintings or other works of art from commercially available laser discs to use as stimuli, (2) create and edit sets of semantic differential response scales, and (3) create an experiment stack that randomizes the presentation of stimuli and scales as well as collects data from subjects. In addition, the paper discusses revisions planned for the current software to broaden its utility to areas beyond visual aesthetics.     

A simple graphical technique for assessing timer accuracy of computer systems

Timing accuracy is of perennial concern to researchers conducting reaction time studies, especially for those using computers that were not designed with millisecond accuracy in mind. Inaccuracies can manifest themselves in the form of quantization of the continuous time data stream. The method proposed here is simply to inspect the graph of the order statistics because quantization is readily apparent in such graphs. The method is illustrated with timing measurements of keypresses on an IBM PC.     

A Commodore 64-based interface system for the operant laboratory

A system of interfaces for the Commodore 64 (C-64) microcomputer for use in the operant laboratory is described. This system frees the experimenter from limitations on the number of I/O lines available on the user port of the C-64 and offers the control of operant chambers for a low cost. Subroutines in machine code to control the interfaces, offering millisecond timing of external events, are presented. A sample BASIC program demonstrates how the subroutines are called from BASIC to run a simple discrimination experiment.     

Measuring keyboard response delays by comparing keyboard and joystick inputs

The response characteristics of PC keyboards have to be identified when they are used as response devices in psychological experiments. In the past, the proposed method has been to check the characteristics independently by means of external measurement equipment. However, with the availability of different PC models and the rapid pace of model change, there is an urgent need for the development of convenient and accurate methods of checking. The method proposed here consists of raising the precision of the PC’s clock to the microsecond level and using a joystick connected to the MIDI terminal of a sound board to give the PC an independent timing function. Statistical processing of the data provided by this method makes it possible to estimate accurately the keyboard scanning interval time and the average keyboard delay time. The results showed that measured keyboard delay times varied from 11 to 73 msec, depending on the keyboard model, with most values being less than 30 msec.     

Listener: A tool for client-side investigation of hypermedia navigation behavior

Behavioral researchers have employed hypermedia-based software applications in their experiments for some time. More recently, interest in the World-Wide Web has developed among researchers in the social sciences, and popular use of this new medium continues to grow at an incredible rate. This paper describes Listener, a tool developed to log users’ hypermedia and World-Wide Web navigation behavior using Apple Macintosh computers in a laboratory setting. Listener is able to capture navigation actions through cached documents, overcoming some of the problems associated with analyzing standard web server logs.     

A BASIC program for computing Cronbach’s accuracy components

Accuracy is a measure of the extent of agreement between a rater’s ratings and the ratings of experts or the responses of ratees. Cronbach (1955) argued that accuracy research should focus on components of accuracy rather than on an overall measure. However, complex calculations are required to compute Cronbach’s accuracy components. A program is presented that provides a convenient way of computing all four components of accuracy (elevation, differential elevation, stereotype accuracy, and differential accuracy), as well as the associated correlation components, on an Apple Macintosh computer. The standard Macintosh interface is used to obtain all necessary information. The program will read data in a standard text file and will run faster on computers with math coprocessors.     

Graphing multivariate data with Chernoff''s faces

Chernoff's faces is one of several icon graphics routines accessible through the SYGRAPH module available through SYSTAT Inc. SYSTAT is a very sophisticated statistics package that has been previously reviewed in the Journal of School Psychology (Roberts, D. M. JSP 25, 313–318, 1987). SYSTAT and SYGRAPH are available for both the IBM PC and the Apple Macintosh computers. The output from this example was produced with SYSTAT 5.1 on a Macintosh computer.     

Toward an Experimental Timing Standards Lab: Benchmarking precision in the real world

Much discussion has taken place over the relative merits of various platforms and operating systems for real-time data collection. Most would agree that, provided great care is taken, many are capable of millisecond timing precision. However, to date, much of this work has focused on the theoretical aspects of raw performance. It is our belief that researchers would be better informed if they could place confidence limits on their own specific paradigms in situ and without modification. To this end, we have developed a millisecond precision test rig that can control and time experiments on a second presentation machine. In this paper, we report on the specialisthardware and software used. We elucidate the importance of the approach in relation to real-world experimentation.