Cross-task validation of functional measurement

Ss judged average heaviness of two unseen lifted weights on a 20-step rating scale. They also rated heaviness of a single visible object of variable size and weight. The data for each task obeyed the parallelism prediction of the linear integration model. This within-task consistency validates jointly the model and the response scale. Functional measurement procedure yielded independent scales of subjective heaviness from each task. These were linearly related, a criterion of external consistency. The plot of subjective heaviness against objective weight was slightly negatively accelerated. These results disagree with those that have been obtained with magnitude estimation. Since the rating data satisfy both internal and external consistency, they constitute the true measure of sensation. Magnitude estimation, in contrast, must be biased and invalid.     

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.     

Awide range timing circuit with two independent controls

The timer described in this note is an example of how a small increase in engineering complexity can lead to a marked increase in user convenience and overall system accuracy.     

Two types of short-term visual storage

Seven-letter words were flashed repetitively at various durations above and below the recognition threshold for single flashes. One form of a short-term storage effect was studied by measuring the interstimulus interval between flashes at which S reported that the stimulus became phenomenally discontinuous in time. Storage times reached a maximum of about 300 msec in this task. A second form of storage effect was measured by decreasing the interstimulus interval until S could correctly recognize a repeated stimulus whose duration was below the single-flash recognition threshold; this effect extended to 900 msec in some cases. Each of these effects was reliably obtained for both rare and frequent words. Both forms of storage were increased by providing a dark rather than a lighted adapting field between presentations of the test stimulus. Implications for Information processing of brief displays are discussed.     

Two parameters of a temporally defined schedule of negative reinforcement

Temporal schedules of negative reinforcement were derived in a manner analogous to those for positive reinforcement, and two parametric studies were carried out with two of the three defining variables. With some limiting values of the defining variables, escape schedules result and data obtained at these values were similar to those obtained in escape studies. At other values of the defining variables avoidance behavior was generated.     

Job Satisfaction Researches of 1964–65

This annual review of job satisfaction researches is the 23rd in a series and covers reports published in 1964–65 plus earlier studies not previously dealt with in this journal. The format—findings and conclusions, topics investigated, per cent dissatisfied, current emphases, and summaries of studies—has become standard in this series of articles.     

The effect of repetition on the perception of single letters

Single letters were presented for from one to five flashes, with S required to report what he saw after each flash. The clarity of the letter increased sharply with repetition. Since the letters were no larger than one-third of a degree in size, clarity could not have been increased by S making different fixations from flash to flash and combining them into a total percept. Nor was S guessing, since this could be ruled out by other indicators. Thus, it was concluded that repetition of the stimulus can have a direct effect on the clarity of a S’s percept of that stimulus.