The interaction of conditioned taste aversions and schedule-induced polydipsia: Availability of alternative behaviors

Animals poisoned following exposure to saccharin subsequently avoided the schedule-induced consumption of saccharin. While this suppression was transient for subjects who had access only to the saccharin solution during the free-food presentations, recovery of schedule-induced saccharin consumption was significantly retarded for subjects who had concurrent access to saccharin and a running wheel. It has been suggested that the transient suppression of schedule-induced polydipsia by conditioned taste aversions results from the pellet-induced tendency to drink within the schedule-induced polydipsia procedure. That access to the running wheel reduces schedule-induced polydipsia in general and prolongs the suppression of schedule-induced polydipsia by taste aversions supports this view.     

The effect of worked examples on student learning and error anticipation in algebra

Instructional Science - The present study examines the effectiveness of incorporating worked examples with prompts for self-explanation into a middle school math textbook. Algebra 1 students...     

Two-year-olds use the generic/nongeneric distinction to guide their inferences about novel kinds

These studies investigated two hundred and forty-four 24- and 30-month-olds' sensitivity to generic versus nongeneric language when acquiring knowledge about novel kinds. Toddlers were administered an inductive inference task, during which they heard a generic noun phrase (e.g., Blicks drink milk) or a nongeneric noun phrase (e.g., This blick drinks milk) paired with an action (e.g., drinking) modeled on an object. They were then provided with the model and a nonmodel exemplar and asked to imitate the action. After hearing nongeneric phrases, 30-month-olds, but not 24-month-olds, imitated more often with the model than with the nonmodel exemplar. In contrast, after hearing generic phrases, 30-month-olds imitated equally often with both exemplars. These results suggest that 30-month-olds use the generic/nongeneric distinction to guide their inferences about novel kinds.     

Extinction and food-reinforced inhibition of conditioned salivation in dogs

The present experiment compared two methods of eliminating a classically conditioned response in dogs, extinction and reinforcement of nonsalivation, using both a within- and between-subjects experimental design. Eighteen dogs were trained for 16 days in Phase I, 16 days in Phase II, and 8 days in Phase III. In Phase I, each subject received classical conditioning training to two stimuli. In Phase II, Group 1 received extinction training to one stimulus and reinforcement of nonsalivation to the other stimulus. Group 2 received continued classical conditioning training to one stimulus and reinforcement on nonsalivation training to the other. Group 3 received continued classical conditioning training to one stimulus and extinction training to the other. In both the within- and between-subjects comparisons, responding to the stimulus associated with extinction was eliminated faster than responding to the stimulus associated with reinforcement of nonsalivation.     

The Application of Computer Technology to Education—Innovative Projects of the U.S. Office of Education

Dr. Reddick discusses four promising educational research projects currently being funded by the Bureau of Research.     

Neonatal Stress Reactivity: Predictions to Later Emotional Temperament

To investigate the relations among popular measures of neonatal stress and their link to subsequent temperament, 50 full-term newborns from a normal care nursery were examined responding to a heelstick blood draw. Baseline and heelstick measures of behavioral state, heart period, vagal tone, and salivary cortisol were obtained. Recovery measures of behavioral and cardiac activity were also analyzed. Mothers completed Rothbart's Infant Behavior Questionnaire when their infants reached 6 months of age. Baseline vagal tone predicted cortisol in response to the heelstick, suggesting that baseline vagal tone reflects the infants' ability to react to stressors. Greater reactivity to the heelstick (more crying, shorter heart periods, lower vagal tone, and higher cortisol) was associated with lower scores on "Distress-to-Limitations" temperament at 6 months. This finding was consistent with the expectation that the capacity to react strongly to an aversive stimulus would reflect better neurobehavioral organization in the newborn. Recovery measures of cardiac activity approximated and were correlated with baseline measures indicating the strong self-righting properties of the healthy newborn. Finally, vagal tone and salivary cortisol measures were not significantly related, suggesting the importance of assessing both systems in studies of the ontogeny of stress-temperament relations.     

Adults’ Learning about Science in Free‐choice Settings

This paper synthesizes findings from three studies to answer a general question: What do casual, adult visitors learn about science from their science‐related experiences in free‐choice settings? Specifically we asked whether there are changes in how people think about science in their daily lives, the nature and use of scientific knowledge, and its communication by scientists. The three studies involved samples of visitors to an interactive science centre, visitors to a traditional natural history museum, and attendees at a series of public lectures, each given by an expert scientist in human genetics. Pretest and post‐test data collected by parallel questionnaires indicated that, despite the different nature of their experience in the three different settings, participants became more positive about the value of science and the work done by scientists and their ability to communicate with the public. At all venues, however, participants became less scientific in their thinking about the nature of scientific knowledge, becoming more likely to believe it to be infallible. The consistency of these findings was surprising, and participants’ changed views about the nature of scientific knowledge were unexpected. Possible explanations for theses outcomes were suggested in terms of participants’ reasons for attending the venue, the nature of their engagement, and the non‐controversial ways in which the exhibitions and lectures were structured. The findings suggest that the educational role of free‐choice settings should be considered carefully, particularly with regard to the representation of science.