The role of the GABA(A) agonist muscimol on memory performance: reward contingencies determine the nature of the deficit

A matching-to-position (MTP) paradigm was altered to influence the type of associations a rat would use to solve the task. Our main behavioral manipulation was the application of the differential outcomes procedure (DOP). The DOP involves correlating each to-be-remembered event with a distinct reward condition. This procedure results in the development of unique reward expectancies that enhance and guide choice behavior. Such distinct reward expectancies are not formed when either a common or random assignment of reward is used (a non-differential outcomes procedure [NOP]). Intracerebroventricular infusions of the amnestic agent muscimol (GABA(A) agonist) or aCSF were delivered to male rats trained on a delayed MTP task that implemented either the DOP or the NOP. Muscimol impaired performance in a dose dependent fashion in both groups--but the nature of the deficit differed as a function of reinforcement contingencies. Rats trained with the DOP displayed a non-mnemonic delay-independent impairment: performance at all delay intervals was disrupted. In contrast, NOP-trained rats displayed a delay-dependent impairment demonstrating that muscimol can also have memory-disrupting effects. The difference in pattern of impairment appears to be a function of the associations formed during training and the type of cognitive strategies involved in maintaining behavior on a conditional delayed discrimination task when reinforcement contingencies are varied. Thus, these results demonstrate that increasing GABA(A) receptor activation impairs a range of associative and memory functions.     

Relationship between response rate and reinforcement frequency in variable-interval schedules: II. Effect of the volume of sucrose reinforcement

Three rats were exposed to variable-interval schedules specifying a range of different reinforcement frequencies, using three different volumes of .32 molar sucrose (.10, .05, and .02 milliliters) as the reinforcer. With each of the three volumes, the rates of responding of all three rats were increasing, negatively accelerated functions of reinforcement frequency, the data conforming closely to Herrnstein's equation. In each rat the value of the constant K_H, which expresses the reinforcement frequency needed to obtain the half-maximal response rate, increased with decreasing reinforcer volume, the values obtained with .02 milliliters being significantly greater than the values obtained with .10 milliliters. The values of the constant R_max, which expresses the theoretical maximum response rate, were not systematically related to reinforcer volume. The effect of reinforcer volume upon the relationship between response rate and reinforcement frequency is thus different from the effect of the concentration of sucrose reinforcement: In a previous experiment (Bradshaw, Szabadi, & Bevan, 1978) it was found that sucrose concentration influenced the values of both constants, R_max increasing and K_H decreasing with increasing sucrose concentration.     

Maximum likelihood estimation in multidimensional scaling

A variety of distributional assumptions for dissimilarity judgments are considered, with the lognormal distribution being favored for most situations. An implicit equation is discussed for the maximum likelihood estimation of the configuration with or without individual weighting of dimensions. A technique for solving this equation is described and a number of examples offered to indicate its performance in practice. The estimation of a power transformation of dissimilarity is also considered. A number of likelihood ratio hypothesis tests are discussed and a small Monte Carlo experiment described to illustrate the behavior of the test of dimensionality in small samples.The research reported here was supported by grant number APA 320 to the author by the National Research Council of Canada.     

Confirmation of linear system theory prediction: Changes in Herrnstein's k as a function of changes in reinforcer magnitude

Eight human subjects pressed a lever on a range of variable-interval schedules for 0.25¢ to 35.0¢ per reinforcement. Herrnstein's hyperbola described seven of the eight subjects' response-rate data well. For all subjects, the y-asymptote of the hyperbola increased with increasing reinforcer magnitude and its reciprocal was a linear function of the reciprocal of reinforcer magnitude. These results confirm predictions made by linear system theory; they contradict formal properties of Herrnstein's account and of six other mathematical accounts of single-alternative responding.     

Self-compassion reduces parental burnout: Mediation roles of parental psychological control and support

This study investigated the mediating role of parental psychological control (PPC) and support in the relationship between self-compassion and parental burnout syndrome. The study participants included 1185 Vietnamese parents who completed questionnaires regarding demographic information, parental burnout, self-compassion, parental support of the child, and PPC. We used data analyses, including structural equation modeling, to test the mediation roles of PPC and parental support of the child. Our main findings include: (1) self-compassion had a significant negative effect on parental burnout; (2) the mediation roles of PPC and parental support of the child were also significant. These results suggest that parents with high self-compassion tend to provide more support for children in daily parenting, which helps reduce parental burnout. In contrast, parents with low self-compassion were more likely to use PPC, which exacerbated their burnout. The results from this study provide suggestions for creating effective interventions in the family context to reduce parental burnout and improve parenting effectiveness.     

The mediational role of motivation in the model of motor development in childhood: A longitudinal study

The aim of this study was twofold: first, to examine the stability of the hypothesized conceptual model of motor development (without and with including various types of motivation) when children are followed up one-year later, and second to examine longitudinally whether changes in one model variable predict changes in other variables, according to the hypothesized pathways in the model. A sample of 361 Spanish students (50.7% girls, 8–11 years old) voluntarily participated in this study. In relation to the first aim, structural equation modeling revealed the expected positive relationship between the model variables in both measurement times. That is: actual motor competence (MC) predicted physical activity (PA) (p < .001), perceived MC mediated the relationship between actual MC and PA (p < .001), and autonomous motivation mediated the relationship between perceived MC and PA (p < .05). Moreover, the comparison of the invariance analysis showed non-practical differences between the unconstrained model and the constrained model, supporting the stability of the model over time. In relation to the second aim, the hypothesized model in Time 2 controlling for Time 1 values showed that changes in children’s actual MC positively predicted changes in their perceived MC (p < .001), which in turn, predicted changes in their autonomous motivation (p < .001), and PA (p < .001) at Time 2. Based on these findings Physical Education teachers are recommended to foster children’s actual and perceived MC as well as their autonomous motivation over time in order to promote PA strategies for lifelong health.     

Exploring psychological factors of mobile phone use while riding among motorcyclists in Vietnam

Mobile phone use while riding is one of the five most common risky behaviors of motorcycle riders in Vietnam. This study investigated motorcyclist’s mobile phone use while riding intention and behavior based on the extended Theory of Planned Behavior (TPB) framework. Based on this framework, attitude, subjective norm, perceived behavioral control, habits, and health motivation underlying the rider’s mobile phone use while riding intentions and behavior were included in a questionnaire and captured by direct and indirect measurements. Small-displacement motorcycle riders (N = 291) completed the extended TPB based questionnaire. An exploratory factor analysis technique identified the selected factors (e.g., attitude, habit, etc.). Moreover, Structural Equation Modeling results showed moderate to good fits to the observed data. Therefore, the results supported the utilization of extended TPB framework in identifying factors of mobile phone use while riding intention and behavior. Specifically, negative attitude, perceived behavioral control, and mobile phone use while riding habit related to the intention to use a mobile phone while riding of small-displacement motorcyclists. Meanwhile, habit and behavioral intention related to the behavior to use a mobile phone while riding of small-displacement motorcycle riders. Especially, the correlation between behavioral intention and self-reported behavior was very strong. This finding embraced previous research indicating that intention was a major motivational component of behavior. Based on the results, safety intervention implications for small-displacement motorcycle riders were discussed.     

Factor structure and measurement invariance of the multidimensional driving style inventory across gender and age: An ESEM approach

The Multidimensional Driving Style Inventory (MDSI) is the most comprehensive measure of typical driving behavior to date and has been frequently used to compare driving styles across different groups of drivers, particularly between gender- and age-related groups. However, the factor structure of MDSI has not been clearly established and its measurement invariance has not been demonstrated. The goal of the present study was to examine the internal structure and measurement invariance of the MDSI across gender and age. A sample of 1277 drivers from Argentina responded to the Argentinian version of the MDSI. Exploratory structural equation modeling (ESEM) was used to test the factor structure and measurement invariance across females (n = 602) and males (n = 675), and across young (18–29, n = 558), adult (30–49, n = 395) and older (50 and older, n = 317) drivers. The results showed that a 36-item six-factor ESEM model represented by risky, angry, dissociative, anxious, distress-reduction and careful and patient driving styles was the best model based on fit indices and interpretability. Configural, weak and strong invariance of the six-factor ESEM model across gender and age was also supported. The MDSI in its Argentinian version is equivalent across gender and age, supporting the validity of previous research findings examining gender and age differences in driving styles. Future studies should examine the measurement invariance of the MDSI across other relevant driving-related variables.