An electronic audio switch

This article describes an electronic switch that allows presentation of sine wave stimuli without the often undesirable transient thump, thud, or click usually caused by ordinary electromechanical switches.     

Air-puff-elicited startle: Habituation over trials and measurement of a hypothetical emotional response

In the first of two experiments, it was demonstrated that an air puff elicited a reliable startle reflex in rats which showed no habituation over 50 trials. In the second study an attempt was made to measure an emotional response by recording startle reactions to the air puff during presentation of a presumed fear-eliciting CS. It was concluded that the air-puff-elicited startle reflex can be employed as an indirect measure of a hypothetical emotional response.     

The semiautomatic Wisconsin general test apparatus

A semiautomatic version of the Wisconsin General Test Apparatus is described along with circuitry. Comparison data are provided for the semiautomatic and manual WGTA obtained under comparable procedures and conditions. Response latencies are given for go/no-go object discrimination problems and subsequent retention tests.     

EMG waveform duration: A validation method for the surface electromyogram

The electromyogram (EMG) recorded with surface electrodes was examined using a triggered oscilloscope technique. When all but the high-amplitude waveforms in a given segment of activity were excluded from analysis, it was found that the duration of the remaining waveforms was specific to the muscle that produced them. That is, waveforms of a given duration were recorded whenever conventional indices-observable contraction, joint movement. needle recordings-showed activity in a specific muscle. This led to the suggestion that waveform duration might be used to validate the surface EMG. The suggestion. which is limited by the need to control posture and electrode placement, both of which may influence waveform duration, was illustrated in application to psychological research.     

Subjective uncertainty,the orientation reaction,and the reinforcement of an instrumental response

In Experiment 1, Ss were exposed to slides of intermediate blur for 5, 10, 30, or 60 sec and were asked to guess the identity of the blurred object and to estimate how confident they were of each guess. The S’s task in Experiment 2 was merely to view the blurred slides while S’s EEG waves were being recorded. After being exposed to a blurred slide for a certain duration, in Experiment 3, Ss were required, by means of a key press, to choose to view either a clear version of the blurred slide or an unrelated clear picture. Uncertainty/second, EEG desynchronization/’second, and related choices were all found to be a negatively sloped function of viewing duration.