A microcomputer interface for control of real-time experiments in cognitive psychology

A microcomputer system for real-time control of experiments in cognitive psychology is described. The microcomputer serves as an interface that allows a remote timesharing computer to control the timed display of textual material on CRTs and collect response times accurate to 1 msec. It can control two CRT subject stations presenting the same or different experiments and control other devices such as slide projectors and tape recorders. It is argued that such special-purpose microcomputer interfaces provide a real-time laboratory with significantly less effort than does the more traditional laboratory minicomputer.     

An MS-DOS-compatible data logger for recording subjects’ self-ratings

Some research designs require subjects to make ratings of their own internal cognitive or affective states or the behavior of other subjects. An ideal device for this purpose should allow for electronic data storage and be easy to use for research subjects. The communication box (Markman & Poltrock, 1982) has been popular for this purpose but consists of dated technology. Other data-logging devices are too complicated for subjects’ use. This paper describes an electronic data logger which uses readily available hardware. A dual-tone multiple-frequency (DTMF) telephone keypad encoder is used to generate unique tones that are stored on the audio track of a videotape or on an audio tape. A DTMF receiver decoder IC is used to decode the audio signals. The decoded signals can be read on a light-emitting diode display or entered directly into a personal computer file via an RS-232 serial interface.     

Limitations of high-level microcomputer languages in software designed for psychological experimentation

The execution times of microcomputer high-level-language commands can be long enough to be of concern in experiments in which precise timing is a consideration. The problems in developing standard BASIC timing routines are addressed. A technique for using the Model III TRS-80 real-time clock to calibrate BASIC timinig routines is described, and representative execution times of selected commands are reported. It is concluded that high-level languages are too slow and that execution times are too variable for critical timing in experiments. On the other hand, machine language programs can provide the needed precision and control.     

The role of elaborations in learning a skill from an instructional text

In these studies, we examined the role of elaborations for subjects learning a procedural skill (viz., using a personal computer) from an instructional text. In Experiment 1, we compared two sources of elaborations: those provided by the author and those generated by learners while reading. In the latter condition, subjects were given advance information about the tasks they were to perform so that they would generate more specific task-related elaborations while reading. Each source of elaborations facilitated skill performance. This result contrasts with results of the past experiments testing declarative knowledge in which author-provided elaborations were found to hurt performance. In Experiment 2, the author-provided elaborations were classified into those illustrating the syntax of the operating system commands and those explaining basic concepts and their applicability. Syntax elaborations produced significant facilitation for experienced and novice computer users. Concept elaborations produced no reliable improvement.     

nodeGame: Real-time,synchronous, online experiments in the browser

nodeGame is a free, open-source JavaScript/ HTML5 framework for conducting synchronous experiments online and in the lab directly in the browser window. It is specifically designed to support behavioral research along three dimensions: (i) larger group sizes, (ii) real-time (but also discrete time) experiments, and (iii) batches of simultaneous experiments. nodeGame has a modular source code, and defines an API (application programming interface) through which experimenters can create new strategic environments and configure the platform. With zero-install, nodeGame can run on a great variety of devices, from desktop computers to laptops, smartphones, and tablets. The current version of the software is 3.0, and extensive documentation is available on the wiki pages at http://nodegame.org.     

Perceptual organization of behavior: a hierarchical control model of coordinated action

The behavior of individual subjects is compared with a hierarchical control system model of behavioral organization. Subjects varied the position of two control handles simultaneously to keep the distance constant between two pairs of lines. Three variations on this basic experiment that illustrate some fundamental properties of coordinated action are shown: first, how independent actions, compensating for unpredictable and undetectable disturbances, can produce a single behavioral result; second, how the ability to produce a particular result is maintained when the connection between action and result is changed; and third, how two independent outputs can appear to be related as coordinative structures when one output disturbs a result being controlled by the other. The correlation between the behavior of subjects and model in all experiments is typically on the order of .99. A detailed examination of the operation of the model shows that actions are structured by perception, not by central commands or equations of constraint.     

SPLIT: A sound editor for a PDP-8 computer

SPLIT is a program that helps prepare sounds for use in psychological experiments. Analog signals are converted to digital form and stored on a disk in real time. Digital sound files can be viewed on an oscilloscope display and played back for on-line auditory inspection. Interactive commands allow the user to segment and combine sounds with precise temporal control.     

A multiprogram approach to real-time experimentation

A technique for implementing real-time experiments utilizing several separate and independent programs is discussed. The technique can be employed when the experimental procedure is divided into real-time and nonreal-time program units. These program units are executed in the most appropriate computing environment, and the resulting output is directed to a sequential file. The nonreal-time program issues commands to the real-time program by means of keywords that are inserted in the sequential file output at those points where real-time operations are required. These commands are interpreted by the real-time program which processes the sequential file. While the nonreal-time program is experiment-specific, the real-time program is independent of the particular experiment performed. The applications of this multiprogram approach to real-time experimentation are considered.     

Controlling experiments with a general-purpose time-sharing system

For many experiments in the behavioral and biomedical sciences, there is no substitute for an experimental-control computer with true real-time capabilities. However, if an experimenter can tolerate timing errors of several seconds, then he can reap the benefits of computer control by buying time on a general-purpose time-sharing system. There can be little doubt that a self-contained computer-controlled laboratory will be more economical if a fair number of experiments are contemplated. But when only a few experiments are planned, the researcher may find that he can run them with a general-purpose time-sharing system at only a fraction of the cost of establishing a     

Investigating temporal properties of covert shifts of visual attention using the attentional walk task

The attentional walk task was used to investigate the temporal properties of covert shifts of attention. Observers shifted attention within arrays of identical items in response to a series of auditory commands and reported the color of the final disk. The density of the arrays and the timing of the shift commands varied. Performance decreased as density increased, and the minimal amount of time needed to shift attention depended on the density of the display, varying from 350 to 750 msec. In addition, the observers were able to maintain attentional focus for at least 3,500 msec without a decline in performance, regardless of density. Thus, although the ability to maintain attention at a given position was found to be independent of the precision with which that location was defined, more precise attentional shifts required more time to execute.     

Additive and interactive effects in memory for subject-performed tasks

Abstract

Three experiments were carried out to explore reasons for the superior recall and recognition of subject-performed tasks (SPTs) relative to memory for the equivalent verbal commands. In Experiment 1, list structure was varied; list structure affected recall, but the variable did not interact with the SPT/command manipulation. The same absence of an interaction was found in Experiment 2 with respect to different retrieval conditions and also with respect to the age of adult subjects. Experiment 3 confirmed that the age difference was as large for SPTs as it was for verbal commands. In addition, an interaction between SPT/command and levels of processing was found in Experiment 3. Differences between the additive and interactive patterns of results are discussed in terms of SITS contributing both additional (possibly motoric) information and also conceptual information that overlaps with information added by other variables.     

A general experiment programming system for the IBM 1800

A system is described that meets some user requirements of programming ease, general applicability, and simultaneous multiple S and laboratory operation. The system is based on an extremely flexible time-sharing real-time monitor and a user-level task-oriented programming language which together free the user from all multiple S bookkeeping programming. The conceptually simple language consists of simple commands for operations at the level of experimental procedure, such as displaying stimuli, collecting and timing responses, providing time delays, and recording data. Other commands support string manipulation, arithmetic, and disk I/O. The system is programmed only for the IBM 1800; however, it represents a successful approach to laboratory computerization.     

Experimental RunTime System: Software for developing and running reaction time experiments on IBM-compatible PCs

The Experimental RunTime System (ERTS) is a recent addition to the small collection of commercial software packages available for writing and running reaction time experiments on IBM-compatible PCs. Experiments are written using any text editor and a relatively small set of ERTS commands. Millisecond timing is provided by a software timer with no additional hardware requirements. All displays are in high-resolution VGA graphics. The Creative Labs Soundblaster card is supported in 16-bit mode, but is not required for simple tone generation. Voice-key support is available via the Soundblaster card. Keyboard, mouse, and external keys may be used as reaction keys, and the mouse or a joystick may be used as a tracking device. The stimulus-centered design and powerful display control commands of ERTS make it appropriate for developing a wide range of trial-based experiments.     

Tachistoscopic presentation and millisecond timing on the IBM PC/XT/AT and PS/2: A Turbo Pascal unit to provide general-purpose routines for CGA,Hercules, EGA,and VGA monitors

A review of the literature on adopting microcomputers for use in tachistoscopic research paradigms illustrates the need for a comprehensive package to effectively deal with the wide variety of video displays and microcomputers used in experimental settings. In addition, because of the large number of possible configurations created when video displays and computer systems are combined, there is a need to be able to efficiently drive any such combination without rewriting program code. A Turbo Pascal unit is presented to provide standard tachistoseopic routines compatible with monochrome, CGA, Hercules, EGA, and VGA video technology. Procedures that synchronize both text and graphics mode stimuli with the vertical retrace pulse are given, as are routines to provide access to a timer with better than millisecond precision. Pascal code is described that will run on the IBM PC, XT, AT, or PS/2, as well as on any compatible machine. The versatility of the unit allows the experimenter to use generic video and timer commands that will automatically adapt at run time to the system that is being used, without further experimenter intervention.     

An IBM XT-compatible,computer-based,slide-projector laboratory

In the present paper, we describe the software and hardware of an on-line, visual-memory laboratory running under Turbo Pascal on an IBM PC XT-compatible computer. The display system includes one Kodak random access projector and four standard Kodak carousel projectors, all equipped with tachistoscopic shutters and luminance-control devices. The response system consists of eight 16-key response boxes. The laboratory can be used for any experiment in which 35-mm slides are to be used as stimuli, and in which precise display times, stimulus luminances, and reaction times are required. The laboratory is particularly well suited to picture-perception and picture-memory experiments.     

Attentional Tracking in the Perception of Apparent Motion: Evidence from Sequential Blanking Displays

Perception of sequential blanking displays was studied in a series of three experiments investigating factors that influence whether “shadow motion” or “item motion” is seen in a display. In addition to the duration of the blanking interval (BI) itself, three other such factors were identified: the eccentricity at which the display is viewed, the spacing of items in the display, and the type of motion that subjects are instructed to try to see. It is argued that these and other previously reported results are explicable without the need to invoke any kind of visual integration period. Instead, they are interpreted in terms of a first-order system of automatic luminance detectors and a second-order tracking system involving both voluntary and involuntary attention. The relationship of these findings to other recent work in apparent motion and visual attention and to other bistable motion displays is discussed.     

A method for utilizing a single port for multiple functions on the IBM PC or compatible system

Psychological experiments often require the control of a large number of output lines; unfortunately, the IBM PC provides only 32 8-bit ports through which communication may be implemented without risk of conflict with other software/hardware. A single 8-bit port may be used to control a large number of devices by adding appropriate decoder logic between the computer’s port and the devices that are to be controlled. Software and hardware are presented that illustrate this technique by controlling an 8-digit light-emitting diode display with a single IBM PC output port.