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Methods of stimulating the skin by capacitive electrical discharges are described and properties of the stimulus waveforms are discussed. A neural excitation model is invoked to account for electrocutaneous sensitivity. The model gives a good account of threshold data from several experiments in which the methods of stimulation are compared. Sensitivity is shown to be charge-dependent for stimuli that are brief relative to the exponential time constant of the neural membrane model. Systematic departures from charge-dependence occur when the stimulus discharge time constant is made to exceed a depolarization time constant: these departures follow a strength]duration relationship predicted by the model.

This paper presents research on the sensory and electrical properties of human subjects in response to electrical stimuli from highvoltage capacitive discharges. Threshold data for single monophasic transient stimuli are analyzed. The psychophysical measurements are related to a neuroelectric model with parameters that depend on some of the basic properties of excitable membranes.

An experimental simulation technique is introduced to study memory constraints affecting comprehension of embedded sentences. Memory for embedded structure is measured in a pairing task that simulates requirements imposed by sentence comprehension. With increasing memory load (number of embeddings), the rate of performance decline is consistent across all (recall and comprehension) conditions, and reflects a loss of order (as opposed to item) information. Short-term memory overload, rather than linguistic complexity, appears sufficient to account for comprehension difficulty. Performance was imperfect even with singly embedded constructions. Recall showed no abrupt failure with multiple embeddings, indicating that memory constraints are not as discontinuous as English syntax might suggest.

A model for partial masking and other threshold-elevation effects is presented in the context of a sensation-matching paradigm. The model is applied to an electrocutaneous experiment in which the subjects adjusted stimulus intensity on the right-hand fingertip to match sensation levels of standard stimuli presented to the left fingertip. Concurrent mechanical stimulation on the right fingertip masked sensation magnitude in a way consistent with the model. Similarities between this tactile masking effect and analogous auditory phenomena are explored. When applied to loudness matching, the model describes the general shape of loudness contours and it shows that the steep slopes observed in auditory masking and "recruitment" can be a consequence of a threshold shift alone, without a supranormal growth in loudness. The model also shows that a small response bias can distort plots of sensation matching, leading to the suggestion that some varieties of loudness recruitment may not have a sensory basis.

Uncertain frequency detection of brief sinusoids in noise was studied in a special Yes-No paradigm that included single-frequency trials randomly interleaved with trials on which either of two frequencies could be presented. Contrary to implications from previous studies, and to sensory filter models of attention, the Os’ deliberate attempts to impose narrow- or wide-band listening had only a small effect on the relative detectability of signals at 500 Hz and at 1100 Hz. If frequency selectivity is to be understood as sensitivity adjustment (rather than as a recognition process), the relevant parameters may be entirely stimulus determined.