Effects of neutral and positive stimuli on stuttering: “Calling attention to stuttering” revisited

This study investigated the effects of presumably positive and neutral response-contingent stimuli on the occurence of stuttering. Eight adult stutterers spoke spontaneously during a 60-min experimental session, which was divided into three 20-min periods. During Condition I no stimuli were delivered. During Condition II a digital counter and a pair of yellow lights were activated each time the subject stuttered. During Condition III these same response-contingent stimuli were delivered, but with the additional factor that the subject would earn 5¢ each time the counter moved forward and the lights were illuminated. Conditions II and III were counterbalanced across subjects. The experimenter was unaware of which of the two contingencies were operative during Conditions II and III. Results showed no significant changes in occurence of stuttering due to either response-contingent stimulus. A discussion of theoretical and experimental implications is given.     

A set-theoretic random utility model of choice behavior

A random utility model of choice was developed by combining the basic ideas of the well-known theories of Thurstone and Restle. The new model has exactly the same number of free parameters as Tversky's Elimination-by-Aspects model. Furthermore, both models were found to fit, with equal accuracy, the data reported by Rumelhart and Greeno, and Tversky. It was concluded that although the two theories are not identical, they may be difficult to discriminate empirically.     

Delayed alternation in the rat: Effect of contextual stimuli on proactive interference

The effect of contextual stimuli on proactive interference in the rat was investigated in three experiments. The task was a modified delayed alternation procedure in which the rat was initially forced to one side of a T maze (the interfering forcing) followed by a forcing to the opposite side (the target forcing). A free choice run followed the target forcing in which a turn in either direction could be made. In order to obtain reinforcement on the free choice run, the rat was required to turn in the direction opposite that of the target forcing (i.e., in the same direction as the interfering forcing). Manipulation of the context prevailing during the interfering forcing, target forcing, and free choice runs revealed that free choice accuracy was (a) greater when the interfering and target forcings were conducted in different contexts than when they were conducted in the same context and (b) influenced only slightly, if at all, by whether the free choice context coincided with that prevailing during the interfering forcing or with that prevailing during the target forcing.     

Some effects of lick-contingent delays on the development of schedule-induced polydipsia

Experiments 1 and 2 examined the effects of various durations of lickcontingent delays of reinforcement on the development of schedule-induced polydipsia. Food was provided every 1 min in the absence of licking. Delays of 1 min or more effectively disrupted the development of the licking behavior. In Experiments 3 and 4 a lick-contingent stimulus was provided in addition to the delay of food delivery. A light, which was turned on by a lick and turned off by food, greatly enhanced the development of polydipsia under delays that had previously prevented such development. A tone proved less effective than the light in promoting the development of polydipsia. Adventitious reinforcement and conditioned punishment explanations of these results were considered. A distinction was drawn between the mechanism responsible for the development of schedule-induced behavior and that responsible for its maintenance.     

Role of intertrial interval following an escape or avoidance response in bar-press avoidance

In three experiments, rats learned bar-press avoidance as a function of the intertrial interval following an escape or an avoidance. The general hypothesis is that the length of these intervals affects bar-press avoidance differentially, depending on whether an avoidance follows an escape (avoidance/escape) or an avoidance (avoidance/avoidance) on the previous trial. Specifically, it is proposed that short escape ITIs will facilitate avoidance/escape and avoidance/avoidance, while avoidance ITIs will have no effect on avoidance responding. The results tend to support this hypothesis. The shorter the intertrial interval following an escape, the higher the probability of both measures: avoidance/escape and avoidance/avoidance. No effect of avoidance interval was found on avoidance/avoidance. Unpredictedly, however, it was found that in comparison to a very short intertrial interval following an avoidance (0.5 sec), relatively long intervals (5 and 45 sec) facilitate avoidance/escape. These results were interpreted as mainly reflecting nonassociative factors such as shock-produced activity.     

Common items and reliability in personality measurement

Most psychological tests and inventories, particularly in personality and attitude measurement, contain common items, that is, various subscales of the test or inventory may share one or more items in common. Surprisingly, the role of common items in such a fundamental personality test attribute as reliability is not known. The present report specifically considered common-item contributions to test internal consistency reliability using extant data from the California Psychological Inventory. No negative contribution of item overlap was found. To the contrary, it was concluded that the use of common items is an economical technique for increasing the total number of items in the scales, thus increasing scale internal reliabilities without increasing the overall number of items in the inventory.     

Cortical stimulation and speech timing: A preliminary observation

Audio recordings of the speech of seven patients receiving cortical stimulation during epilepsy surgery were acoustically analyzed, and duration measurements of the sound /s/ under stimulation and nonstimulation conditions were compared. It was found that in the dominant hemisphere, stimulation tended to significantly increase the duration of /s/; but not all stimulation sites were comparably affected. Stimulation of frontal lobe locations was also observed to more frequently result in durational increases than when temporal or parietal sites were stimulated. However, for sites affected, the actual magnitude of durational increase was comparable among the three lobes.     

Environmental dispositions and the evaluation of architectural interiors

The Environmental Response Inventory (ERI) was developed, in part, to assess dispositions toward everyday physical environments and to aid in explaining variance in response to settings. The eight ERI scales were examined and resultant hypotheses were tested in a design involving evaluative ratings of 10 everyday public building interiors briefly presented in sequences of color slides to 118 participants. Settings were arranged in three levels of generality. Results support the ERI as a promising tool. Biographical items also correlate with ratings. Environment evaluation is discussed as a complex phenomenon, in which rater differences play a significant part.