Classically conditioned heart rate and respiratory-motor activity in newborn and neonatal pygmy goats

Classical discrimination conditioning of heart rate (HR) and respiratory-motor (RM) activity was examined in 16 newborn (average age = 1 day) and 8 neonatal (average age = 2 weeks) pygmy goats over 4 days of conditioning involving an electric shock US and auditory CSs. On the 4th day, one-half of the animals in each group received a low to moderate dose of ethanol to test the resistance of the CRs to drug effects. Discriminated conditioning of RM activity but not HR occurred in the newborn group, indicating an absence of close coupling between skeletal-motor activity and HR at this early age. While the newborn group failed to show recognizable HR reactions to the CSs during the 4 days of testing, it did show a long-latency brady-cardia UR beginning at 2 days of age that may have been secondary to baroreceptor reflex actions. The neonatal group displayed conditioning of both HR and RM activity. The similar latencies of the two types of CRs during the CS suggested that they may have been related to each other. However, the fact that the RM CR developed a day before the HR CR, combined with the observation that ethanol modified the HR CR but not the RM CR, supports the view that there was considerable independence between the two types of CRs.     

Inescapable shock interferes with the acquisition of a low-activity response in an appetitive context

This study investigates the effects of exposure to inescapable shock on the acquisition of a low-activity appetitive response using a trial procedure. Inescapable shock was found to interfere with the acquisition of a nose-poke response to obtain food as compared with animals exposed to either escapable shock or no shock. In addition, general activity levels were measured separately during the trial and the intertrial interval during the appetitive test. Inescapably shocked animals were less active during the trial component than were either the escapably shocked or the nonshocked animals. However, no differential levels of activity were observed during the intertriai interval component of the appetitive test. The relevance of these findings for both the learned helplessness and the learned inactivity hypotheses is discussed.     

Teacher engagement in core components of an effective,early childhood professional development course: Links to changes in teacher–child interactions

This study built on prior research regarding the effectiveness of the National Center for Research in Early Childhood Education (NCRECE) course by exploring the individual course components. Core aspects of course engagement and performance were described and examined in relation to improvements in the observed quality of teacher–child interactions. Teacher characteristics were also examined as predictors of course engagement and performance. A sample of 150 preschool teachers participated in a semester-long, credit-bearing, college course designed to improve the quality of their emotional, organizational, and instructional interactions with children. Teachers’ participation and performance in the course were high on average. Teachers’ skill level in accurately and specifically explaining other teachers’ instances of effective teacher–child interactions was related to improvements in their own observed teacher–child interactions. Finally, teachers with an early childhood major and those endorsing child-centered beliefs displayed better skills in detecting other teachers’ high-quality interactions with children. Results are discussed in relation to designing more effective early childhood professional development programs.     

Göttingen in retrospect

Participant assessment is one of the processes which can be used to evaluate the success of educational exchange programs. This study was conducted in 1972 with University of California students who attended the University of Göttingen, Federal Republic of Germany, during the 1965–66 academic year. Participants were asked about their subsequent use of language, as well as their assessment of the academic, intellectual, personal, social and cultural dimensions of the program. This paper reports the results of the Göttingen questionnaire and, hopefully, contributes to a better understanding of the kinds of enduring student benefits that can result from an educational experience abroad.     

The erasure of reinstated fear

Three experiments investigated the reinstatement of fear to a previously conditioned and extinguished CS as a result of separate presentation of the original US. That reinstatement was found to be sharply attenuated by nonreinforcement of a second fear elicitor between presentations of the US and testing of the CS. This “erasure” of reinstatement depended upon the fear-eliciting power of the intervening stimulus and, under some circumstances, was essentially complete. Moreover, erasure reduced not only the response to the CS but also the extinction it underwent as a result of subsequent nonreinforcement. It is argued that neither the conditioning of background stimuli nor stimulus generalization among explicit CSs provides an adequate account of these reinstatement and erasure results. Rather, they are interpreted in terms of the construction and destruction of a nonassociative representation of the US during conditioning, extinction, reinstatement, and erasure. In that context, some inferences can be made about the rules governing these nonassociative changes and the ways in which they interact with modifications in associations.     

AN ASSESSMENT OF THE CONTENT OF MEDICAL PRACTICE IN THE UNITED STATES: PROFILES OF PHYSICIANS IN FIVE SPECIALITIES

The University of Southern California has conducted a series of 24 surveys of the professional activities of physicians and surgeons in the United States. The surveys encompass more than 10,000 respondents representing 65.8% of all practising physicians in the United States and its territories. Using a specially‐developed “log‐diary” recording instrument, these physicians reported data on the care they provided during hundreds of thousands of encounters with their patients. This article provides an exposition of the study's unique methodology, presents illustratative data for 5 of the 24 specialities surveyed (cardiology, family practice, general internal medicine, orthopaedic surgery and psychiatry), and discusses the study's relevance and implications for medical education.     

Classroom age composition and the early learning of preschoolers

Data from 1,407 preschoolers were used to examine the implications of classroom age composition for the early learning and development of 4-year-olds in classrooms with 3- and 5-year-olds also in attendance. Results suggest that a greater number of younger classmates did not detract from 4-year-olds’ language development, literacy performance, or inhibitory control, nor did having older peers consistently facilitate learning in these domains. However, 4-year-olds who entered school with low inhibitory control and print knowledge demonstrated greater gains in both domains when attending classrooms with more same-age or older classmates than when in classrooms with more younger peers. When taken together, these results suggest that classroom age composition, in prekindergarten programs serving mostly 4-year-olds, for the most part has little consequence except for those 4-year-olds entering school with lower skill levels in key domains, in which case having older peers is of benefit.