A deglitching circuit for the AA50 D/A converter

Switching transients or “glitches” are frequently encountered in signal processing applications involving digital-to-analog (D/A) conversion. A low-cost “deglitching” circuit is described and implemented for the Digital Equipment Corporation AA50 D/A converter option on the PDP-8/e minicomputer. Switching transients were eliminated using a noninverting, unity-gain sample-and-hold circuit (employing Datei System’s SHM-IC-1). Switching transients were reduced to below-noise levels across a wide range of output levels and sampling rates.     

A cognitive-behavioral perspective on intelligence

The present editorial has two purposes. The first purpose is to indicate a parallel trend in two seemingly disparate areas of research which upon closer examination have interesting possible ties. These research areas are information processing and cognitive-behavior modification (CBM). The second purpose is to highlight the role that affect plays in intellectual functioning, noting some of the implications which then follow for the assessment of intelligence.     

Pupillometric assessment of retrieval operations in factual long-term memory

The process involved in recall from long-term memory were studied through the use of a general knowledge questionnaire and the technique of pupillometry. Degree of processing of the components of the retrieval process was inferred from second-by-second monitoring of pupil size. Measurements were recorded during subjects' attempts to retrieve the answer to the query, or if unsuccessful, from clues of the target (first and last letters), and if still unsuccessful, to recognize the presented target word as being associated with the question (the “Of course”, or “That's it!” experience). Pupil size differed according to the nature of the three task demands. Additionally, there were differences based on the type of outcome within the question trial (e.g., between target known but blocked — feeling-of-knowing/tip-of-tongue — and target not known), and the answer trial (recognize vs not recognize the question—answer relationship). The results were related to the search and decisional processes of retrieval.     

Conversion of a printing calculator to an inexpensive printing counter

A procedure is described for simple conversion of a printing calculator to an inexpensive printing counter. The unit is particularly useful for unattended data collection. A timing circuit controls printout of accumulated data at specified time intervals.     

Televised classroom events as distractors for reading-disabled children

Three experiments examined the influence of videotaped classroom events on the academic performance and study behavior of reading-disabled and normally reading children in grades 1 through 6. In experiments 1 and 2a an experimenter-controlled presentation of these distractors resulted in performance decrements, the magnitude of which was greater for higher difficulty tasks. The distractor effects were similar for the two groups in this condition. However, when the children themselves were allowed to control their degree of exposure to the same distractors in experiment 2b, the reading-disabled children were less likely to act to escape the distraction. Results are discussed in terms of children's metacognitive awareness of distraction, and implications for the classroom are considered.     

Personality Factors Related to Black Teenage Pregnancy and Abortion

Forty-eight pregnant adolescents who applied for therapeutic abortions (TAs) were compared with 55 adolescents who planned to have their babies (Terms) and 67 adolescents who were not pregnant (Controls) on the California Psychological Inventory (CPI). All the subjects were single, Black, and aged 15 or 16. CPI results point to psychological differences with the Controls being most socialized, followed by the TAs, and then the Terms. Term girls seem to be experiencing a void and appear to be trying to fill it and assume an adult role by having a baby; the TAs do not seem to have these same needs. In addition, girls who became pregnant and described the relationship with the putative father as casual, appear on the CPI to have more daily problems, lack socialization, be less clear thinking, and have poor self-control. Pregnant girls who have good communication with their mothers showed no differences on the CPI from girls with poor communication with their mothers.     

A stochastic model for test-retest correlations

A simple stochastic model is formulated in order to determine the optimal time between the first test and the second test when the test-retest method of assessing reliability is used. A forgetting process and a change in true score process are postulated. The optimal time between tests is derived by maximizing the probability that the respondent has not remembered the response on the first test and has not had a change in true score. The resulting test-retest correlation is then found to be a linear function of the true reliability of the test, where the slope of this function is the key probability of not remembering and having no change in true score. Some numerical examples and suggestions for using the results in empirical studies are given. Specific recommendations are presented for improved design and analysis of intentions data.This research was made possible by a grant from the Center for Food Policy Research, Graduate School of Business, Columbia University, New York, New York, 10027.