A programmable relay and amplifier I/O interface for the PDP-8/E computer

Use of the Digital Equipment Corporation DR8 digital input/output buffer for the PDP-8/E computer is common. However, by itself the DR8 has inadequate output-driving capability for even the smallest laboratory device. A flexible low-cost control network designed to enable a DR8 interface to control any of 12 pico-reed relays for output driving or 8 programmable amplifiers for auditory signal presentation is described.     

Dark adaptation and the Hermann grid illusion

The latency of the perception of the dark spot at the intersection of a Hermann grid was measured before and after dark adaptation. It was found that dark adaptation significantly increased the latency of perception of the spot while light adaptation had no effect. This finding was predicted from the Jung and Spillman account of the Hermann grid illusion and from the Kuffler et al. finding that inhibitory receptive fields of the cat’s retinal ganglion ceils are reduced in size and responsiveness after dark adaptation. The significance of this finding in relation to other simultaneous contrast phenomena is discussed.     

A disfluency descriptor digest for clinical use

A clinical form to be used in identifying which of a set of fluency eliciting techniques might be used most advantageously in therapy with individual stutterers is described.     

Motor perseverative behavior in adult stutterers and nonstutterers

The performances of 22 adult stutterers and 22 adult nonstutterers on motor tasks requiring the graphic reproduction of a sequence of alternating figures following the production of a series of nonalternating figures were studied. The finding that there were no differences in the performance of the two groups on the alternating motor tasks was interpreted as challenging the validity of previous observations that motor perseverative behavior exists in stutterers and is indicative of a central neurological deficit in that population.     

Clinical notes: Masking devices and The Edinburgh Masker—Clinical applications within a prison setting

This paper outlines portions of the writer's therapeutics in the field of stuttering with emphasis upon use of masking the hearing of stutterers as a part of a total therapeutic approach. Commencing with devices providing continuous noise to override the voice of the stutterer so that he cannot hear himself and, thus, eliciting fluency. Described is the use of the voice actuated Edinburgh Auditory Masker within an intensive stuttering program in a prison setting since September 1978. It is concluded that the use of masking and the Edinburgh device has been helpful and productive with severe stutterers.     

A semiautomatic system for preparing computer data cards

A system is described which eliminates manual coding and punching of computer data cards in a psychophysical experiment. Conventional relay logic is used to control the operation of a card punch and to enter data in selected card columns.     

The growth of the equidistance tendency over time

To determine the manner in which the equidistance tendency (ET) varies as a function of time, 10 Ss tracked the perceived position of a monocular test object viewed in a binocular field consisting of two rectangles which differed in perceived size and distance.Variables investigated were the temporal order of rectangle appearance and disappearance which determined whether or not opposingETs existed, luminance and repetition interval of the 20 msec test object. It was found thatET effects occur gradually over time, that opposingETs retard the rate at which the test object changes its perceived locus, and that elapsed time rather than total observation time was critical in determining how great a change in perceived locus of the test object occurred. Implications of these findings were discussed.     

Brightnesses,luminances, and Fechner’s paradox

Monocular brightnesses were varied, without varying monocular luminances, both by means of simultaneous contrast and by means of changes in the level of adaptation. Binocular brightness was shown to change in accord with monocular brightness, independent of monocular luminances.