Case report of stuttering acquired in association with phenytoin use for post-head-injury seizures

Previous research indicates that stuttering and deficits in motor performance may be associated with the use of phenytoin (Dilantin). The present report concerns a case of stuttering acquired in association with phenytoin use for post-head-injury seizures. The extent and nature of dysfluencies and the motor performance of speech and nonspeech muscle systems were evaluated over an extended period during which changes in anticonvulsant medication were made. Reductions in dysfluency levels and improved motor performance were observed following a medication change from phenytoin to carbamazepine. Performance on tests assessing nonmotor functions, such as memory and attention, was equivalent before and after the medication change. The apparent association between dysfluency levels, motor performance deficits, and phenytoin suggest that in the present case stuttering resulted in part from a general impairment in motor control.     

One answer to the demand for accountability: Selection utility as an investment decision

An examination of selection utility models demonstrates that they bear a considerable resemblance to capital budgeting models well established in the finance literature. Five applications of capital budgeting to selection utility are suggested and discussed. Capital budgeting concepts are recommended as a rich source of further practical and theoretical development of selection Utility models.     

Object tracking and search in infancy: A review of data and a theoretical evaluation

Most research on infants' development of object and spatial concepts is based on object search tasks or visual tracking studies. In this review, it is concluded that many phenomena, particularly the tracking data, can be accounted for in terms of objective spatial perception in early infancy. However, some phenomena, particularly the stage IV search error, cannot be explained in these terms. A theoretical framework is put forward that integrates aspects of theory of direct perception with constructionist theory. First, it is proposed that objective properties of the basic spatial array are directly perceived, but that because perception is derived from action in the environment, there are initial limits to the scope and coherence of perception that diminish as the infant gains effective motor control. Second, it is proposed that in attempts to decipher the structure of social interchanges over objects, infants construct functional categorizations of objects that allow them to overcome limited awareness of their physical properties. Finally, it is suggested that these functional concepts provide an adequate means of interpreting the world, so that concepts based on the physical properties of objects, including their permanence, are relatively late developments.     

Sign-tracking behavior in aversive conditioning: Its acquisition via a Pavlovian mechanism and its suppression by operant contingencies

When rats are presented with Pavlovian backward pairings in which shock is the unconditioned stimulus (US) and an elevated platform the conditioned stimulus (CS), they show a strong tendency to approach the platform. Attempts were made at evaluating the nature of the associative mechanisms responsible for the acwuisition and maintenance of the approach behavior. In Experiment 1, following a baseline period when platform presentations were given in the absence of shocks, first (training I), approach to the platform was prevented and subjects were exposed to either backward, forward, or random presentations of shock and platform: this procedure attempted to minimize the effects of response learning on the acquisition of approach behavior. Then (training II), all subjects received backward shock-platform pairings and had access to the platform. Approach to the platform was stronger in animals previously exposed to backward pairings than in the animals of the other two groups. Also, animals preexposed to forward platform-shock pairings showed suppression of approach behavior on the first trial of training II relative to their performance on the last trial of baseline. These data suggest that a stimulus-reinforcer learning mechanism alone is sufficent for the acquisition of approach. Experiments 2a and 2b evaluated the effects of “punishing” operant contingencies on Pavlovian-produced approach behavior. The results showed that approach can be eliminated, but only after repeated exposure to an operant contingency which consisted of the immediate closure of the platform upon approach responding. These data suggest that approach behavior produced by Pavlovian contingencies can be modified by operant contingencies. Taken together, these data provide additional support for a sign-tracking notion in aversive conditioning.     

Probability learning and coping in dysphoria and obsessive-compulsive tendencies

The processing of stress-relevant categorical events and their contributions to subsequent probability judgments were examined among subjects who were psychometrically categorized as dysphoric, obsessive-compulsive, or “control.” stress-relevant symptomatology of depression was considered to be characterized by a deficit of active counterstress coping activity and obsessive-compulsiveness by ritualistic efforts which have little or no direct effect on stress occurrence. Subjects were presented with a sequence of stressful (loud white noise) and benign (illumination of a green light) events in association with a series of discrete stimuli (alphabetic letters) in three conditions of counterstress activity. Results generally supported the predicted tendency to learn probability information primarily in conditions which reflected the subjects' characteristic ways of responding to stress. Obsessive-compulsives acquired the information primarily in a “ritualistic” context, controls in an active coping context, and dysphorics in both a coping deficit context and unexpectedly in an active coping context. The role of enhanced stressor predicability in maintaining typical stress response patterns of the three groups was discussed.     

The interaction model of anxiety and dental treatment

An empirical test of the interaction model of anxiety was provided by assessing the state anxiety and trait anxiety of 20 female and 7 male dental patients undergoing periodontal surgery. Measures of A-State (PARQ IV), A-Trait (S-R GTA), and perceptions (PSRF) were administered in both a high-stress condition (30 min prior to surgery) and a low-stress condition (4 to 6 days after surgery). It was hypothesized that undergoing periodontal surgery would be perceived as a combination ambiguous/physical danger situation. Accordingly it was predicted that high-ambiguous A-Trait subjects would experience greater decreases in A-State than low-ambiguous A-Trait subjects in proceeding from the high-stress to the low-stress condition. Similarly it was predicted that high-physical danger A-Trait subjects would show greater decreases in A-State than low-physical danger A-Trait subjects. Significant A-Trait × stress condition interactions were not expected to occur for noncongruent A-Trait facets (social evaluation and innocuous). Results indicated that, while the high-stress condition was perceived as an ambiguous/physical danger situation, the A-Trait × stress condition interactions were not significant for ambiguous, physical danger, or innocuous A-Trait facets. Contrary to prediction, a significant interaction was observed between social evaluation A-Trait and stress condition. This finding was explained in terms of the complex relationship between situation perception and situation reaction.     

A statistical approach to Saaty's scaling method for priorities

This paper investigates the logarithmic least squares (LLSM) approach to Saaty's (Journal of Mathematical Psychology, 1977, 5, 234–281) scaling method for priorities in hierarchical structures. It is argued that statistical criteria are important in deciding the scaling method controversy. It is shown that LLSM is statistically optimal under a number of realistic and practical models. Variances and covariances of parameter estimates are derived. The covariance matrix associated with overall priority differences is also developed. These results allow for a significance analysis of apparent priority differences.     

Speech rate and the development of short-term memory span

Two experiments are reported which examine the effects of word duration on memory span in subjects of different ages. The same linear function relating recall to speech rate (assessed by the speed of repeating words) fits the results of subjects ranging in age from 4 years old to adulthood. It is concluded that developmental increases in short-term memory span can be explained in terms of increases in speech rate and that there is no evidence for an increase in short-term memory capacity. Analyses of the children's speech suggests that increases in speech rate with age reflect increases in the speed of articulation of individual words, rather than any change in the duration of pauses between successive words or changes in coarticulation between words.