Prenatal testosterone treatment potentiates the aggression‐inhibiting effect of the neurosteroid dehydroepiandrosterone in female mice

The neurosteroid dehydroepiandrosterone (DHEA) is a powerful inhibitor of aggression in murine models when given for 15 days and potentially may be useful in the management of inappropriate human aggression. Although the biosynthesis and metabolism of DHEA have been described, little is known about the potential effect of the steroidal environment during sexual differentiation on the subsequent response to DHEA. Whether prenatal androgen exposure influences the subsequent response to DHEA was assessed by comparing the effect of DHEA (80 μg/d) on aggression in female offspring where dams were treated with 1, 10, or 100 μg of testosterone (T) on days 15 to 18 of gestation (Experiment I) or that developed in different uterine positions (Experiment II). The results showed that DHEA decreased attack behavior in general and that the 100‐μg prenatal T treatments enhanced the antiaggressive effect of this neurosteroid. Neither the lower doses of exogenously administered T nor the uterine position led to an enhanced response to DHEA. In addition, whether DHEA produced changes in social and nonsocial activities was examined. In the 100‐μg T females, DHEA increased the duration of the former and decreased the frequency and duration of the latter, indicating that it was not a general decrement in behavioral expression that mediated the enhanced response to the antiaggressive effect of DHEA. In the second experiment, DHEA treatment led to increased frequencies of social nonaggressive and nonsocial activities. However, the uterine positions × treatment interactions were not significant, demonstrating that contiguity to male fetuses did not differentially affect the response to DHEA. Aggr. Behav. 27:130–138, 2001. © 2001 Wiley‐Liss, Inc.     

Onset and termination of accessory facial movements during stuttering

In this study the onset and offset times of seven types of accessory facial movements during oral and silent prolongations were described in three severe stutterers. For each observed facial movement the onset and offset times were determined by means of slow motion analysis of video-recorded speech samples. For two of the three subjects significant differences in the onset and offset times at the various facial movements were found; however, no consistent patterns in the separate facial movements could be observed. On the contrary, the onset of most facial movements appeared to be located at the very start and their offset at the end of the stuttering moment. The implications of these findings with respect to the function of accessory facial movements in stuttering are discussed.     

Student learning as the basis for reinforcement to the instructor

The present study reinforced the two instructors of two students with profound mental retardation first for the instructors' training behaviors, then for improved student learning in a multiple baseline across responses design. Reinforcement of the instructors' training behaviors increased their training behaviors, replicating the findings of previous studies, but had no effect on student learning. When the reinforcement for the instructors was instead made contingent upon student learning, the student learning improved and the instructors' high level of training behaviors was maintained. In addition, the instructors began to request training for themselves. These findings suggest that staff motivation programs for instructors might usefully base the reinforcers not only on the instructor's performance, but on the progress of their students.     

Variability in the initiation of articulatory movements in the speech of stutterers and normal speakers

This study was designed to investigate the differences between stutterers and normal speakers in phonatory and articulatory timing during the initiation of fluent utterances of monosyllabic words. Electromyographic recordings of four articulatory muscles and recordings of glottal vibrations were made of repetitive utterances of a series of monosyllabic words by 15 stutterers and 17 nonstutterers. These data were analyzed in terms of average interval times between voice onset and onset of EMG activity and between onset of EMG activity in each articulator and in terms of the intrasubject variability of these durational measures. Results showed that there were no significant differences between stutterers and nonstutterers in average interval times and that stutterers, in general, were significantly more variable in their speech onset timing. Findings are discussed in terms of recent hypotheses concerning the role of timing disturbances as the main source of speech disruption in stutterers.     

Simulation study of a decision-making model of squash competition, phase one: The analysis of the protocol

This study aims at specifying some of the cognitive processes underlying decision-making in squash competition. More specifically, the study focuses on the strategy of the defending player (D) when chosing among three categories of preparation (total preparation for one particular event, partial preparation in favor of one event and absence of biased preparation). D is viewed as an information processing system (IPS) placed in a problem-solving situation, the problem being what decision to reach. The results obtained in a preceding investigation about the nature of the information processed by a player to anticipate and prepare for the opponent's shot in a real game setting, are used to determine a typical protocol of the behavior of D. The analysis of this protocol allows one to formally define (in Backus-Normal-Form) the problem space of D which is also D's internal representation of the task environment. From the problem space are derived (1) the problem behavior graph depicting the search of D through his problem space for a solution, and (2) the production system (a set of conditional statements, each expressing what to do under specific conditions) defining the logic of the search. The results of this first phase of the simulation study of a decision-making model of squash competition show that the cognitive strategy of D is based upon the use of a specific preformed algorithm. This algorithm could be stored in some long-term memory and activated by the current state of information in short-term memory. Finally, the proposed model also leads to the suggestion that the cognitive strategy of the performer may be influenced by a variety of factors such as the experience of the player, the time pressure, the expectancies, the performer's confidence in his predictions and the mistakes caused by incorrect predictions.     

Eye movements and visual imagery in free recall

The relationship between eye movements and visual imagery has almost exclusively been studied by treating eye movements as the dependent variable while an imagery task is being performed. In the present experiment three eye-movement treatment conditions were manipulated, within Ss, as the independent variable in order to study their effects on the free recall of nouns which Ss had to store by means of imagery. The imagery-evoking capacity (I) of nouns was varied over three levels within lists of Dutch nouns (Low, Medium and High I). Ss were instructed to generate a visual image to each separate noun under the following treatment conditions: (a) while they looked over and scanned their image as if they were looking at the real object: (b) while they received concurrent visual stimulation from a checkerboard pattern; (c) while they fixated on a target. Reliable, but minor effects of treatment conditions on the recall scores were found. The results were discussed in terms of possible theories about the nature of the relationship between eye movements and visual imagery.     

A stochastic growth model applied to repeated tests of academic knowledge

In the course of the medical program at the University of Limburg, students complete a total of 24 progress tests, consisting of items drawn from a constant itembank. A model is presented for the growth of knowledge reflected by these results. The Rasch model is used as a starting point, but both ability and difficulty parameters are taken to be random, and moreover the logistic distribution is replaced by the normal. Both individual and group abilities are estimated and explained through simple linear regression. Application to real data shows that the model fits very well.     

Some effects of congenital spasticity on fundamental frequency

5 normal speakers and 5 speakers with congenital upper motor-neuron damage repeatedly spoke a three-work sentence stressing the first, second, or third words. Fundamental frequency was measured for each word and over each sentence. Analysis showed that the spastics' mean fundamental frequency was significantly higher than the normals', regardless of utterance. Also, spastics were more restricted in their prosodic maneuvering above this average fundamental frequency. Despite this finding, the spastics were capable of producing consistent stress patterns with normal variability.