The removal and restoration of stimulus control

When a well-learned circle versus ellipse discrimination was made impossibly difficult for the subjects (rhesus monkeys), the controlling stimulus-response topographies were replaced by competing topographies. The identification of two training conditions sufficient to reinstate the original discrimination permitted the following inferences: the original controlling topography had merely decreased in probability of occurrence, whereas the "strength" of the stimulus-response relation remained unchanged; discriminations along the apparently continuous circle-ellipse dimension actually involved several distinct stimulus-control topographies.     

The comprehension of rate-incremented aural coding

Stimulus and psychological measures of a battery of 36 rate-manipulated versions of an extended message indicate that optimization of the efficiency of aural coding beyond that previously reported can be accomplished by the simultaneous application of a combination of natural and artificial distortions of the durational characteristics of speech. Peak efficiency of listening was successfully pushed to 400 wpm (words per minutes) primarily by means of a selective reduction of speech pause time. Regression estimates predicting the influence of pause time, total duration, and talker rate upon judgments of speech rate and comprehension are presented and implications for listening strategies and speech apperception drawn.This research was supported by grant HD02417 from the National Institute of Child Health and Human Development.     

Longitudinal analysis of the relationship between changes in smoking and changes in drinking in a community sample: the Winnipeg Health and Drinking Survey.

Smoking cigarettes and drinking alcohol are positively correlated in cross-sectional studies of the general population. However, it is unclear whether changes in quantity of drinking over time are related to changes in amount of smoking over time. This investigation examined, with structural equation modeling, the relationship of changes in drinking to changes in smoking over 2 years among 344 adults who reported cigarette smoking and alcohol use at baseline in 1989-1990 or at follow-up in 1991-1992 or both. Surprisingly, no significant relationships were found between changes in smoking and changes in drinking. This lack of effect suggests that changes in the quantity or intensity of drinking and of smoking are not related in any important way in nonclinical populations.