Efficient estimation of sensory thresholds

Laboratory computers permit detection and discrimination thresholds to be measured rapidly, efficiently, and accurately. In this paper, the general natures of psychometric functions and of thresholds are reviewed, and various methods for estimating sensory thresholds are summarized. The most efficient method, in principle, using maximum-likelihood threshold estimations, is examined in detail. Four techniques are discussed that minimize the reported problems found with the maximum-likelihood method. A package of FORTRAN subroutines, ML-TEST, which implements the maximum-likelihood method, is described. These subroutines are available on request from the author.     

Adaptation effects on evoked electrical taste

In spite of a clear increment in absolute thresholds as an effect of self-adaptation, the electrically provoked taste sensation does not show a reduction in subjective intensity during the protracted stimulation time. Chemical cross-adaptation effects on the threshold and suprathreshold levels of electrical taste are observed only when the adapting solutions are electrolytes regardless of their taste qualities. It seems that the stability of perceived intensity during current flow is principally due to some irritation of the sensitive tissue of the tongue, whereas cross-adaptation effects may be attributed to the potential changes across the excitable membranes caused by electrical properties of adapting electrolytic solutions.     

A comparison of chinchilla auditory evoked response and behavioral response thresholds

The auditory sensitivity of the chinchilla was measured by both a behavioral and auditory evoked-response (AER) procedure. There was no significant difference in either the waveform or the threshold of the AER recorded over the tentorium from awake and anesthetized chinchillas. The chinchilla threshold for pure tones appears to be more sensitive when measured by the behavioral technique than by the AER method. Both the AER and behavioral response of three chinchillas exposed to a 105 dB SPL octave band of noise centered at 2 KHz for 3 h shifted markedly after the exposure. However, the difference between the AER and behavioral response threshold was reduced or absent. During the process of recovery the difference between the two responses begins to reappear.     

A computer-controlled system for training and testing primates

The hardware and software for a computer-controlled training and testing system for primates are described. The computer (DDP-116 in the Computer-Controlled Psychology Laboratory at Carnegie-Mellon University) controls all stimulus presentation, reinforcement, and records data in a form ready for analysis on a larger computer.     

FOCLAB: A language for computer-controlled psychology research

The FOCLAB system, a dialect of FOCAL, provides complete real-time experiment control and data acquisition capabilities in the area of experimental psychology. The language provides digital and analog input/output, graphics (including alphanumerics) on a refresh CRT, and a powerful set of time measurement operations. With these facilities FOCAL may be used in cognitive and operant, as well as psychophysiological research. FOCLAB will operate with either PDP-8 or PDP-12 systems, and can control most of the currently existing lab interface options for these computers. The system will operate on 8K core-only machines, as well as under OS/8.     

A computer-controlled laboratory for studying infant event perception

An integrated software package for testing infants in a habituation procedure is described. The software is written for an Apple II computer with a minimum of 64K of memory. Additional interface cards are required for timing responses and displaying dynamic stimuli. The software is divided into four independent modules: (1) Configure Experiment allows the experimenter to design a specific experiment. (2) Run Experiment controls the running of a previously configured habituation experiment. (3) Calculate Reliability allows a second observer to score the subject for the purpose of computing reliability. (4) Data Summary and Formatting provides a summary of the results and allows the user to flexibly format the data for reading by various statistical packages.     

APCOL: A programming system for computer-controlled psychology laboratories

The development of on-line computer systems can be facilitated by higher-level programming languages that are more powerful and easier to learn than machine-level Assembly languages. In general, it is not possible to speak ofa programming language without also describing the operating system and functional problem domain of the small computer system for which it is intended. This is because of the great variety in the architecture and configuration of small computers. However, it is possible to state more general requirements and design criteria for on-line computer languages in psychology. APCOL is an example of an integrated programming system. One of the important distinguishing features of the system is that it is implemented both on the small-scale laboratory computer and on a large general-purpose computer linked to the smaller machine via a high-speed communications network. This arrangement permits firsthand access to interactive program construction with immediate test of program function by using the on-line implementation as well as access to the text-editing and mass storage facilities of the large-scale machine.     

Magnitude production and magnitude estimation of taste intensity

Magnitude productions of sodium chloride (salty), quinine hydrochloride (bitter), and sucrose (sweet) yielded steeper psychophysical functions than those obtained with magnitude estimation. Hydrochloric acid (sour) produced the opposite effect. The results are discussed with respect to previous findings in taste intensity scaling and to general psychophysical considerations.     

A computer-controlled olfactometer for fMRI and electrophysiological studies of olfaction

A design for an inexpensive and reliable olfactometer is presented. The design has several advantages for fMRI and electrophysiology investigators. These advantages include relatively rapid odorant rise times, computer control, multiple odor administration, and no ferrous materials near the subjects. In addition, the device is contamination resistant, and, because the air is neither warmed nor humidified, it is unlikely to become an incubator for bacteria. The olfactometer is constructed of off-the-shelf chromatography parts that require little modification.     

A computer-controlled administration of the matching familiar figures test

The Kagan Matching Familiar Figures Test of Impulsivity/Reflectivity was modified to allow computer control of stimulus presentation and data acquisition via IBM-compatible systems. The comparability of computer administration and traditional hand administration was examined in a split-half study with a sample of 58 students (ages, 18–39 years). Analyses of variance revealed no significant differences between the administration techniques for latency and a small but significant difference for accuracy. Correlations between the two administration techniques were .61 for latency and .40 for error scores. Internal consistency coefficients for computer administration exceeded those for hand administration on both latency and accuracy. These data compare favorably with results reported by others and suggest that computer administration offers a viable alternative to traditional hand administration of the MFFT in research applications.     

A modular,computer-controlled system for olfactory stimulation in the MRI environment

Although the cerebral networks involved in sensory perception are of general interest in neuroscience, registration of the effects of olfactory stimulation, especially in a magnetic resonance imaging (MRI) environment, presents particular problems and constraints. This article presents details of a reliable and portable system for olfactory stimulation that is modular in design and based on microcontroller technology. It has the following characteristics: (1)?It is under software control; (2)?the presentation of olfactory stimulation can be synchronized with respiration; (3)?it can be manually controlled; and (4)?it is fully compatible with an MRI environment. The principle underlying this system is to direct an odor to the subject’s nostrils by switching airflow to different odor diffusers. The characteristics of this system were established using (1)?ultraviolet (UV) spectroscopy, to measure its response time, and (2)?gas chromatography, to measure the repeatability of odor presentation in terms of gas concentration. A response time of 200?± 25 ms was obtained for the system, and the standard deviations of the gas concentration delivered during stimulation ranged from 1.5% to 22%, depending on the odor, the airflow, and the dilution of the odor used. Since it is portable, controlled by software, and reliable, on the basis of the results we obtained, this system will lend itself to a wide range of applications in olfactory neuroscience.     

A computer-controlled matrix system for presentation to the skin of complex spatiotemporal patterns

A system for presenting complex spatiotemporal patterns to the skin is described. The computer-controlled device consists of a matrix of 64 piezoceramic benders mounted in a support system that can be fitted to steeply contoured skin surfaces such as the thigh. Vibrotactile patterns that include movement across the skin’s surface and/or intensitive variation within or across display epochs are programmed and presented in a frame-by-frame manner, similar to the production of motion pictures. Patterns can be predefined, or modified by observers’ responses to allow for an interactive haptographic display. Design considerations for the construction of the tactile matrix, computer interface, and software are discussed.     

A computer-controlled language training system for investigating the language skills of young apes

A computer-controlled language training system was designed and constructed to enhance the objectivity and efficiency of inquiry into the language-relevant behaviors of apes. The system allows the S to gain control over the events of the 24-h day in direct correspondence with its competence in using a keyboard on which each key represents a word. Various incentives can be obtained through the selection and depression of appropriate keys in accordance with rules of sentence structure monitored by a computer. The system is flexible and allows for eventual conversation between man and ape, with the computer as the intermediary. A Teletype records all that transpires. Achievements of the chimpanzee S over the course of the first 8 months of the system’s operation attest to the worth of the system and training methods.