Digital readouts superimposed electronically on televised pictures

A display module is described that allows numeric data to be superimposed on televised pictures and recorded as an adjunct to the televised information. The device is inexpensive, versatile, and electrically compatible with most closed circuit television systems. It employs standard, large-scale integrated (LSI) circuits, commonly used in commercial television receivers to display time and channel number. Additional circuits are presented that connect these LSI circuits to those of a conventional television camera and videotape recorder, allow variables other than time and channel number to be displayed, reduce the size of the readouts, and produce more than one set of time and channel number readouts.     

PSARP,a programmable signal and response processor

Experiments on perceptual-motor skills often ask for complex application of standard devices. Combinations of the usual electric or electronic instruments such as signal generators, simple time counters and response recorders cannot always be used to form a sufficiently flexible system for a particular set of experiments. In general, an apparatus specially built for a specific experiment does not satisfy the requirements of related investigations and the same device is seldom used again. This paper gives an outline of the principles of a flexible and programmable system which meets the requirements of a considerable number of variables. Some first applications of the system are described.     

N-channel tachistoscopes

Two 10-channel tachistoscopes are described. In one the optical system is based upon fiber optic light guides; channel and interchannel time control is provided by Tektronix pulse and waveform generators. In the other the optical system uses 10 8-mm variable power projector lens systems. Timing control is obtained from an Iconix timebase generator and preset counters. Two methods of programming the equipment are described and some experimental applications are considered.     

An application of the poisson race model to confidence calibration

In tasks as diverse as stock market predictions and jury deliberations, a person's feelings of confidence in the appropriateness of different choices often impact that person's final choice. The current study examines the mathematical modeling of confidence calibration in a simple dual-choice task. Experiments are motivated by an accumulator model, which proposes that information supporting each alternative accrues on separate counters. The observer responds in favor of whichever alternative's counter first hits a designated threshold. Confidence can then be scaled from the difference between the counters at the time that the observer makes a response. The authors examine the overconfidence result in general and present new findings dealing with the effect of response bias on confidence calibration.     

A first order approximation of satiation time: (IRT)2/Rt

Habituation, satiation, adaptation, and boredom are a few of the words used to label the behavioral consequences of a fundamental operation: repeated and protracted presentation of a stimulus. The cumulative measure of the response associated with that stimulus is expected to display an inflection at some time Ti after which the slope approaches zero. Ti can be estimated by dividing the square of the interresponse time (IRT)2 by the duration of the response associated with reinforcement (Rt), where Rt is expressed in the nearest whole temporal unit of interresponse time. Calculated TiS for habituation to the same sexual, aggressive, or social stimuli are compatible with general observation.     

Apple II/FIRST-Corvus networks

Our Apple II/FIRST hardware-software configuration is a cost-effective, powerful, and efficient system for experimental control, data collection, and signal analysis of research in conditioning, neurophysiology, psychopharmacology, and psychophysiology. The present report describes the enhancement of our data-processing capabilities by the addition of peripheral hardware configured to form Corvus multiplexer networks. These networks have transformed our array of Apple II/FIRST systems into multiprocessor facilities possessing the data-processing power and flexibility of far larger and more costly mainframe systems while retaining the benefits of the markedly reduced cost, great flexibility, and high processing speed of microprocessor-based systems.     

A FORTRAN 77 program for a nonparametric item response model: The Mokken scale analysis

A nonparametric item response theory model—the Mokken scale analysis (a stochastic elaboration of the deterministic Guttman scale)—and a computer program that performs this analysis are described. Three procedures of scaling are distinguished: a search procedure, an evaluation of the whole set of items, and an extension of an existing scale. All procedures provide a coefficient of scalability for all items that meet the criteria of the Mokken model and an item coefficient of scalability for every item. Four different types of reliability coefficient are computed both for the entire set of items and for the scalable items. A test of robustness of the found scale can be performed to analyze whether the scale is invariant across different subgroups or samples. This robustness test serves as a goodness of fit test for the established scale. The program is written in FORTRAN 77. Two versions are available, an SPSS-X procedure program (which can be used with the SPSS-X mainframe package) and a stand-alone program suitable for both mainframe and microcomputers.     

Throughput: A simple performance index with desirable characteristics

Throughput is a corrected response rate measure giving the number of successes per unit of discretionary time. It is a simple but general index applicable to psychomotor, behavioral, and cognitive tasks in which response times are measured. This measure has several attractive features: (1) It allows comparisons to be made across various tasks in which speed and accuracy are meaningful and measurable, independently of temporal differences in hardware, software, and procedures; (2) under conditions in which both speed and accuracy decline (or improve), throughput will be a more sensitive index of performance than either alone will be; and (3) in those tasks in which the speed—accuracy trade-off phenomenon operates, throughput will tend to be relatively less variable than either component alone will be. The measure allows both behavioral and information-processing interpretations of data and may be useful as a simple composite index, a measure of effectiveness or of cognitive consistency in studies investigating performance degradation or enhancement.     

Explicitly modeling the effects of aging on response time

Research into the effects of aging on response time has focused on Brinley plots. Brinley plots are constructed by plotting mean response times for older subjects against those for young subjects for a set of experimental conditions. The typical result is a straight line with a slope greater than 1 and a negative intercept. This linear function has been interpreted as showing that aging leads to a general slowing of cognitive processes. In this article, we show that the slope of the Brinley plot is actually a measure of the relative standard deviations of older versus young subjects’ response times; it is not a measure of general slowing. We examine current models of the effects of aging on mean response time and show how they might be reinterpreted. We also show how a more comprehensive model, Ratcliff’s diffusion model (1978), can account for Brinley plot regularities and, at the same time, provide an account of accuracy rates, the shapes of response time distributions, and the relative speeds of error and correct response times, aspects of the data about which models designed to account for Brinley plots are mute. We conclude by endorsing a research approach that applies explicit models to response time data in aging in order to use the parameters of the model to interpret the effects of aging.     

A power-law model of psychological memory strength in short- and long-term recognition

A classic law of cognition is that forgetting curves are closely approximated by power functions. This law describes relations between different empirical dependent variables and the retention interval, and the precise form of the functional relation depends on the scale used to measure each variable. In the research reported here, we conducted a recognition task involving both short- and long-term probes. We discovered that formal memory-strength parameters from an exemplar-recognition model closely followed a power function of the lag between studied items and a test probe. The model accounted for rich sets of response time (RT) data at both individual-subject and individual-lag levels. Because memory strengths were derived from model fits to choices and RTs from individual trials, the psychological power law was independent of the scale used to summarize the forgetting functions. Alternative models that assumed different functional relations or posited a separate fixed-strength working memory store fared considerably worse than the power-law model did in predicting the data.     

The Binary Additivity of Subjective Probability Does not Indicate the Binary Complementarity of Perceived Certainty

People's numeric probability estimates for 2 mutually exclusive and exhaustive events commonly sum to 1.0, which seems to indicate the full complementarity of subjective certainty in the 2 events (i.e., increases in certainty for one event are accompanied by decreases in certainty for the other). In this article, however, a distinction is made between the additivity of probability estimates and the complementarity of internal perceptions of certainty. In Experiment 1, responses on a verbal measure of certainty provide evidence of binary noncomplementarity in the perceived likelihoods of possible scenario outcomes, and a comparison of verbal and numeric certainty estimates suggests that numeric probabilities overestimated the complementarity of people's certainty. Experiment 2 used a choice task to detect binary noncomplementarity. Soliciting numeric probability estimates prior to the choice task changed the participants' choices in a direction consistent with complementarity. Possible mechanisms yielding (non)complementarity are discussed.     

FIT: An iterative parameter-estimation function in LISP

A nested parameter-estimation program (FIT), written in LISP, is described. FIT searches an n-dimensional parameter space for the set of parameter values associated with either a minimum or a maximum criterion score. The range of the parameters is cut in half on each iteration. Two versions of FIT, one suitable for use on large, mainframe systems and the other designed for small microprocessors, appear in the appendices.     

A microcomputer-controlled complex reaction time instrument

An inexpensive microcomputer system that measures complex reaction time to a visual stimulus is described. This system can determine the rate of gain of information by utilizing a two-, four-, or eight-choice reaction time task encompassed within the same unit. The system turns on randomly chosen lights and monitors the time required for the subject to depress a corresponding switch. Information describing the stimulus and the subject’s response are printed on a Teletype after each response.     

Bootstrap-Calibrated Interval Estimates for Latent Variable Scores in Item Response Theory

In most item response theory applications, model parameters need to be first calibrated from sample data. Latent variable (LV) scores calculated using estimated parameters are thus subject to sampling error inherited from the calibration stage. In this article, we propose a resampling-based method, namely bootstrap calibration (BC), to reduce the impact of the carryover sampling error on the interval estimates of LV scores. BC modifies the quantile of the plug-in posterior, i.e., the posterior distribution of the LV evaluated at the estimated model parameters, to better match the corresponding quantile of the true posterior, i.e., the posterior distribution evaluated at the true model parameters, over repeated sampling of calibration data. Furthermore, to achieve better coverage of the fixed true LV score, we explore the use of BC in conjunction with Jeffreys’ prior. We investigate the finite-sample performance of BC via Monte Carlo simulations and apply it to two empirical data examples.     

Development of a puff- and suction-type pressure stimulator for human tactile studies

In this study, we developed a tactile stimulator capable of administering either puff- or suction-type stimuli. The system is composed of three parts: a control unit, an air-handling unit, and a stimulation unit. The control unit controls the type, intensity, and time of stimulation. The air-handling unit delivers the stimulation power quantitatively to the stimulation unit, as commanded by the control unit. The stimulation unit stably administers either type of pressure to the skin, without any change of the tactor. Although the design of the stimulator is simple, it allows for five levels of control of the stimulation intensity (2–6 psi) and 0.1-s steps of control of the stimulation time, as we confirmed by tests. Preliminary electroencephalographic and event-related potential (ERP) studies of our system in humans confirmed the presence of N100 and P300 waves at standard electrode position C3, which are related to perception and cognition, respectively, in the somatosensory area of the brain. In addition, different stimulation types (puff and suction) and intensities (2 and 6 psi) were reflected in different peak-to-peak amplitudes and slopes of the mean ERP signal. The system developed in this study is expected to contribute to human tactile studies by providing the ability to administer puff- or suction-type stimuli interchangeably.     

Contributions to the mathematical theory of human relations. IV

An attempt is made to define and treat analytically the concept of individual freedom in a society. Two possible definitions are briefly discussed. One takes as a measure of freedom the ratio (w ₀ –w)w ₀, wherew ₀ is the maximum amount of work that a person can physically perform per unit time andw is the amount of work which he has actually to perform per unit time in a given society. The other definition takes as a measure of freedom that fraction of an individual's time during which he can indulge in any activity of his own choice without interfering with other individuals. Expressions are derived by way of illustration, giving the individual freedom in terms of other parameters which characterize the social structure.     

Switching time between overt and covert speech: Generative attention

Four experiments investigated a new phenomenon: the existence of a very large switching time effect that occurs from rapidly alternating between overt and covert (mouthed) speech. This is referred to as an intensity switching effect, and the time taken for each switch is, in itself, long enough for a spoken or mouthed character (letter or digit) to be produced. In Experiments 1 and 2, the intensity switching effect was shown to be different from the switching that occurs between categories of materials (letters and digits) because it is both much larger and much more resistant to practice effects. The intensity switching effect was also shown to be distinct from a memory load effect, since it holds even for perceptually available lists. In Experiments 3 and 4, the issue of a peripheral vs. a central origin of intensity switching was addressed. Evidence was found for a central origin. In addition, two models -of response intensity representation were contrasted: a symbolic or digital model, with intensity altered by parameter substitution, and an analog model, with intensity represented by a moving pointer on an intensity continuum. The results supported the symbolic model. It is concluded that the intensity switching effect is a measure of control processes at work in altering the intensity parameters of the vocal response system.     

An evaluation of statistical software for research and instruction

A variety of microcomputer statistics packages were evaluated. The packages were compared on a number of dimensions, including error handling, documentation, statistical capability, and accuracy. Results indicated that there are some very good packages available both for instruction and for analyzing research data. In general, the microcomputer packages were easier to learn and to use than were mainframe packages. Furthermore, output of mainframe packages was found to be less accurate than output of some of the microcomputer packages.     

Interfacing Apple and IBM computers for the analysis of clinical biofeedback

This paper demonstrates a method of transferring research data from a remote clinic to a large university mainframe for data manipulation and statistical analysis. Data collected by an Apple //e computer were transferred to an IBM 3031 mainframe by sending data files to an IBM PC by telephone modem or by direct hardwire connection to the PC. The IMB PC performed data-formatting routines and then uploaded the files to the mainframe for storage. Advantages and disadvantages of sending data over telephone lines via a modem are discussed.     

Concurrent variable-ratio schedules: Implications for the generalized matching law

Rats' responses were reinforced on concurrent variable-ratio variable-ratio schedules in which responses on one lever incremented the ratio counter and responses on a second lever changed the schedule and correlated stimulus. The relative frequency of reinforcement was varied from .10 to .99. In one set of conditions, responding on the main lever incremented both ratio counters, but reinforcement required a response in the presence of the stimulus correlated with the ratio that had been completed. In a second set of conditions, responses on the main lever incremented only the ratio correlated with the stimulus that was currently present. When main-lever responses incremented both ratio counters, subjects distributed responding and time in a manner consistent with the generalized matching law. When responses on the main lever incremented only the schedule currently in effect, the rats responded almost exclusively on the schedule producing the higher frequency of reinforcement. These results extend the applicability of the generalized matching law to dependent ratio schedules.