An ideal signal generator for time-sampling observation procedures

Systematic observation of behavior has been used in a variety of naturalistic and laboratory situations by both ethologists and psychologists. Many of the recording techniques used in these situations involve time-sampling procedures in which observed and recorded events are sampled during specified time units. Such an approach is particularly appropriate when frequency measures, rather than response duration, behavior sequences, etc., are of primary interest. Time sampling can take several forms, but in each case preselected behavioral categories are recorded at regular time intervals. These time intervals are usually signaled by an external stimulus, such as the click of a metronome. Although widely used, such procedures have a number of limiting deficiencies. Most profoundly, the presence of an external signal not only defines time units for the 0, but also serve as an extraneous source of stimulation for the observed Ss. Such sources of potential distraction may distort environmental conditions in important unknown ways. In addition, devices such as metronomes have only a limited short range of time intervals, while some time-sampling procedures require relatively large time intervals. Then, too, available devices are often large or require an external power source, making it awkward or even impossible to use in field investigations. The present paper describes an inexpensive signal generator which has none of these deficiencies. It is a small compact instrument, which can fit comfortably into a shirt or jacket pocket and be taken anywhere, is battery operated, is infinitely variable from about 5 pulses/sec to at least 30 sec, and delivers a tone signal only to the O. As such, it is ideally suited for both laboratory and field investigations which require time-sampling observation procedures. The device is constructed around two Signetics