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.     

Tables of event sequences for sequential analyses of data in psychological experiments containing two-class events

Tables of sequences of two-class events are presented for use in programming psychological experiments in which behavior on trial n may be a function of the events of trials n ? 1, n ? 2, and/or n ? 3. Various factors related to schedule generation are discussed, i.e., restrictions on trial-block length which accompany sequential balance, interrelationships of trial blocks in the multiblock experiment, relationships between run length and r-tuple occurrences, and alternation behavior. Following a consideration of various methods of schedule generation for the two-class experiment, it was concluded that no method can result in schedules that possess all properties considered desirable in psychological experiments. However, the present sequences allow for sequential balance and analysis, and thus should prove useful in producing schedules in some contexts that are standard with regard to sequential influences.     

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.     

Dimensional salience as a function of educational attainment and method of discrimination training

The effects of three methods of selective-attention training with 4-sided forms on the salience of an invagination physical dimension in discrimination judgments with a stimulus domain of 12-sided forms were examined for 6-year-old Ss of low and high educational attainment. The results demonstrated that training procedures involving perceptual demonstration or manipulation increase the invagination dimension salience in the 12-sided stimulus domain more than a verbal training procedure for low educational attainment Ss. Implications for the psychophysical study of relatedness of stimulus domains are discussed.     

Redistributing control between the elements of a compound stimulus

Twenty-eight pigeons were given discrimination training. Four groups were run in which for 0, 2, 4 and 9 sessions of training colour was an irrelevant cue and tone was relevant. Generalization tests were given in extinction; the training colour (C₁) and another colour (C₂) were presented with tone (T) and noise (N). Responding to these four stimulus combinations, TC₁, TC₂, NC₁ and NC₂, allowed the assessment of control by colour and tone. A reduction of control by colour and an increase in control by tone were found to be positively related to the amount of training with colour irrelevant. Tests showed a strong inverse relationship between control by colour and tone.