A low-cost spatial contrast sensitivity display driver

The circuit described here can provide the line and frame signals to drive anx, y display scope or oscilloscope at high resolution (1,000 lines) and repetition rate (50 Hz). Synchronizing circuitry at the input of the circuit allows the raster scan to be locked to an input signal, such as the square-wave output from a function generator, while another waveform from the same function genera-tor, the sine output, drives the z (intensity) input of the display scope. A stable spatial contrast display results. Spatial contrast depth is a direct function of z input modulation voltage. Spatial frequency is a direct function of the function generator frequency. The circuit can be used with a programmable function generator under computer control.     

A clock pulse generator (CPG) for behavioral time research

A device is described which (1) generates very accurate time calibration tones suitable for tape recording along with experimental behaviors, and (2) creates from such a recorded tone an easy-to-read structured pulse train for oscillographic tracings. Calibration tones at 1-, 5-, and 10-kHz pulse rates are derived from a crystal oscillator module and are made available for tape recording at one output of the device. The second output produces a four-level structured pulse train in which there is one pulse for each cycle of the calibration tone (every 10th is a little larger, every 100th a little larger yet, and every 1,000th larger still). An example of the use of this device in speech, timing research is given.     

An optically isolated digital interface for the SKED system

A digital interface to support the SKED software system in recent versions of the PDP-8 computer. One printed circuit card of interface logic and optical isolators can be installed in the OMNIBUS to provide 24 input and 36 output lines to external panels containing input simulation switches and input or output indicators.     

When causality does not imply correlation: more spadework at the foundations of scientific psychology

Experimental research in psychology is based on an open-loop causal model which assumes that sensory input causes behavioral output. This model was tested in a tracking experiment where participants were asked to control a cursor, keeping it aligned with a target by moving a mouse to compensate for disturbances of differing difficulty. Since cursor movements (inputs) are the only observable cause of mouse movements (outputs), the open-loop model predicts that there will be a correlation between input and output that increases as tracking performance improves. In fact, the correlation between sensory input and motor output is very low regardless of the quality of tracking performance; causality, in terms of the effect of input on output, does not seem to imply correlation in this situation. This surprising result can be explained by a closed-loop model which assumes that input is causing output while output is causing input.     

A microcomputer system for controlling classical conditioning experiments

A microcomputer-based laboratory system for controlling stimulus presentations and data acquisition in classical conditioning experiments is described. The system comprises an Intel 386/486-based microcomputer and a commercially obtained low-cost counter/timer board with input/output lines for stimulus timing and external device control. A simple, yet versatile custom-designed structured programming language is provided for performing an unlimited number of stimulus configurations and their sequences. In electrophysiological studies, the system can be flexibly connected to computer-controlled signal conditioning systems for the amplification and filtering of multiunit and evoked field potential responses and to high-speed data acquisition systems for sampling and analyzing the responses. The costs of reserving an entire microcomputer for experiment control are well compensated for by the simplicity and efficiency of programming and transportability of the control protocols between different setups and laboratories. Furthermore, a data acquisition and analysis system most suitable for the aims of a research project can be selected.     

Controlling the Tektronix 4006 graphics terminal with OS/8 BASIC

Several BASIC-callable assembler subroutines are described that permit relatively straight-forward interaction with a Tektronix 4006 or equivalent graphics terminal. These routines enable input, alphanumeric output, and graphic output with or without automatic coordinate transformation. The routines can be used for the graphic presentation of data or, with additional laboratory routines, for stimulus presentation in psychological experiments.     

Using the IBM-compatible microcomputer’s serial port as an input-output interface

A general purpose input-output interface is an essential tool in many common research situations. This article describes a simple way to set up the IBM-compatible microcomputer’s RS-232 serial port as an interface with up to four inputs and two outputs. First, aspects of the serial port relevant to its use as an input-output interface are discussed. Next, port access commands needed to control output lines and monitor input lines in the appropriate way are described, and examples in the Turbo Pascal 5.0 language are provided. Finally, a schematic diagram and a discussion of a simple circuit to implement the interface are provided.     

The effect of representations of binary variables on judgment of influence

Studies concerned with judgments of contingency between binary variables have often ignored what the variables stand for. The two values of a binary variable can be represented as a prevailing state (nonevent) or as an active state (event). Judgments under the four conditions resulting from the combination of a binary input variable that can be represented as event-nonevent or event-event with an outcome variable that can be represented in the same way were obtained. It is shown in Experiment 1, that judgments of data sets which exhibit the same degree of covariation depend upon how the input and output variables are represented. In Experiment 2 the case where both the input and output variables are represented as event-nonevent is examined. Judgments were higher when the pairing of the input event was with the output event and the input nonevent with the output nonevent that when the pairing was of event with nonevent, suggesting a causal compatibility of event-event pairings and a causal incompatibility of event-nonevent pairings. Experiment 3 demonstrates that judgments of the strength of the relation between binary input and output variables is not based on the appropriate statistical measure, the difference between two conditional probabilities. The overall pattern of judgments in the three experiments is mainly explicable on the basis of two principles: (1) judgments tend to be based on the difference between confirming and disconfirming cases and (2) causal compatibility in the representation of the input and output variables plays a critical role.     

A “hand-shaking” multiplexer for the IBM 1800

An instrument is described which is used to multiplex the “ready” and “external sync” lines of an IBM 1800’s data channel to 15 external devices. Used with the digital output registers of the computer, the device facilitates the interfacing of non-IBM peripheral devices to the 1800. The multiplexer can be used in any application in which a pair of lines needs to be shared among several devices.     

A powerful,inexpensive experiment controller or IBM PC interface and experiment control language

A very powerful, but inexpensive, advanced technology (16 MHz 80C188EB) experiment controller is described. It can be programmed in either a BASIC-like (ECBASIC) or an ALGOL-like (ECL) procedure specification language. It provides 1-msec resolution, optional transparent total data logging, and is designed to function as a remote peripheral processor in a network with virtually any computer acting as the network supervisor (e.g., IBM compatible or Macintosh). Each serial port on the host computer can support up to 10 simultaneous experiments. The various optional I/O modules provide for opto-isolated normally open or normally closed switch operation input, high current output, as well as D/A and A/D functions. Our I/O modules can also be plugged directly into an IBM PC parallel port by using a small adaptor board. In this way, the advantages of using ECBASIC or ECL to control experiments are available to researchers who wish to simply interface their host computer directly to the apparatus in order to minimize expense.     

A logarithmic electronic integrator for activity transducers

A solid state integrator having an optional logarithmic or linear input/output function, high input impedance, de input, high sensitivity, low drift, and contact-closure output is described.     

Graphic bar display of on-line physiological data using a minicomputer,DAC, and conventional servo recorder

A method is described for providing an on-line bar graph display of physiological data. A conventional servo recorder is coupled with an 8-bit digital-to-analog converter, and provides a low-cost, hard-copy graphic display peripheral that can be added to any laboratory type minicomputer system with buffered output data lines. The graphic display technique requires minimal memory allocations and a simple software algorithm to provide a flexible graphic system that can accommodate various types of biological data.     

Instrumentation for an electrocutaneous communication device

The device described is a prototype that uses spatiotemporal resolution for electrocutaneous stimulation. Signals initiated through a keyboard activate a matrix of four electrodes that may be applied to the fingers, forearm, abdomen, back, or other parts of the integument. The instrumentation described includes a pulse generator, the active time and delay time controls, the control of the total length of a pulse train, and the constant-current generators whose output is fed into the electrodes. This device may be used as an interface with an alphanumeric device (e.g., a calculator or computer) and as a basic instrument in research investigating the spatial and temporal resolving capacities of the skin senses.     

A bit-addressable I/O interface for microcomputers

An input/output (I/O) interface design based on the 6522 VIA is described. This design is enhanced with additional circuitry to provide such features as latched input, bit-addressable I/O line control, and provisions for expansion.     

When can information from ordinal scale variables be integrated?

Many theoretical constructs of interest to psychologists are multidimensional and derive from the integration of several input variables. We show that input variables that are measured on ordinal scales cannot be combined to produce a stable weakly ordered output variable that allows trading off the input variables. Instead a partial order is obtained in which the amount of ordering depends on the number and nature of the input variables and the relationship between them. However, if trade-offs are excluded, it is still possible to obtain a weak order using lexicographic ordering of the input variables. An implication is that psychological processes that integrate information from different input variables and that produce consistent output require that the input variables be measured on more than ordinal scales. A further implication is that the level of measurement of the input variables affects the kind of psychological model that can be applied to the process.     

Constraints for Input/Output Logics

In a previous paper we developed a general theory of input/output logics. These are operations resembling inference, but where inputs need not be included among outputs, and outputs need not be reusable as inputs. In the present paper we study what happens when they are constrained to render output consistent with input. This is of interest for deontic logic, where it provides a manner of handling contrary-to-duty obligations. Our procedure is to constrain the set of generators of the input/output system, considering only the maximal subsets that do not yield output conflicting with a given input. When inputs are authorised to reappear as outputs, both maxichoice revision in the sense of Alchourrón/Makinson and the default logic of Poole emerge as special cases, and there is a close relation with Reiter default logic. However, our focus is on the general case where inputs need not be outputs. We show in what contexts the consistency of input with output may be reduced to its consistency with a truth-functional combination of components of generators, and under what conditions constrained output may be obtained by a derivation that is constrained at every step.     

An infrared device to monitor discrete ambulatory and stereotypic behaviors

An electronic device that can detect discrete ambulatory and stereotypic behaviors of animals is described. The system involves a minimum of two infrared (IR) beams, each connected to a set/reset flip-flop or latch. The initial occlusion of an IR beam simultaneously sets a latch, delivers a locomotion pulse output, and resets any previously set latch whose IR beam is not occluded. A set latch causes its associated IR beam to be refractory to further locomotion movements until reset by the occlusion of a second IR beam. All beams are continuously responsive to stereotypic activity.     

Independent control of dual video subsystems on the IBM PC and compatibles

Two methods for generating video output on multiple video monitors are described. The first method involves splitting the signal from a single video adaptor card-so that multiple video monitors may be attached. Although this method is simple and relatively cost-effective, it is limited to adaptors that produce only digital video signals, thus precluding the use of VGA systems and composite displays. The second method involves the installation and programming of video adaptors: Two sample programs, which control a secondary adaptor by means of either BIOS routines or direct commands via C code, are described. Although more complex, this second method allows output to each display to be controlled independently. Furthermore, output to one screen may consist of graphics information while output to the second screen consists of text. Together, both methods can be used to create an experimental system composed of multiple data-collection stations and an independent experimenter console.     

Isolating cognitive modules with the dual-task paradigm: Are speech perception and production separate processes?

A dual-task paradigm is used to investigate whether the auditory input logogen is distinct from the articulatory output logogen. In the first two experiments it is shown that the task of detecting an unspecified name in an auditory input stream can be combined with reading aloud visually presented words with relatively little single- to dual-task decrement. The stimuli for both tasks are independent streams of random words presented at rapid rates. A series of control experiments suggest that the first task places a considerable information processing load on the auditory input logogen, the second a considerable load on the phonological output logogen, and that subjects do not switch between the two tasks. The fact that the two tasks can be combined with ease is therefore interpreted as supporting the view that the systems underlying reading aloud and listening are separate. The ease of performance when the input streams are in different modalities, compared to the difficulties when they are in the same, has implications for general models of attention.