Many construction buildings and Structural barrier members that was built before 90s in USA, they weren’t designed for Seismic resistance until Federal Emergency Management Agency FEMA started to do seismic evaluation and rehabilitation... more
Many construction buildings and Structural barrier members that was built before 90s in USA, they weren’t designed for Seismic resistance until Federal Emergency Management Agency FEMA started to do seismic evaluation and rehabilitation and suggested reinforcement methods. In this article we evaluate FRP sheet reinforcement.
Engineers are often faced with construction of pavement structures over soft and highly compressible subgrade. Such conditions render the structures unable to withstand the required design loads and susceptible to high settlements with... more
Engineers are often faced with construction of pavement structures over soft and highly compressible subgrade. Such conditions render the structures unable to withstand the required design loads and susceptible to high settlements with associated excessive distress, leading to pavement damage. Because using imported quality fill to improve the load-bearing capacity of the subgrade has limited benefits, an alternative construction approach is needed to ensure the required strength of the soil structure is reached. The use of geosynthetics in soil to improve bearing capacity and stability offers a better alternative to imported fill. This research was conducted to determine the degree of improvement of the load-bearing capacity and reduction in settlement as a result of the geosynthetic reinforcement of soft clay overlain by granular material. Compression tests on the unreinforced clay subgrade and geosynthetic-reinforced two-layered soil composite were conducted at bench-scale using a Universal Compression Machine at the University of Cape Town Geotechnical Engineering Laboratory. The geosynthetic products used to reinforce the soil structure in this study included geogrids and geotextiles. The reinforcement layer was placed alternatively within the layer of granular material and at the interface of the soil and a range of fill thicknesses and depths of placement were tested to determine their influence on mobilized strength. The use of these composites could potentially lead to reduced construction costs as a result of less aggregate material used, an extension in the design life of the pavement structure and, consequently, a reduced necessity for maintenance work.
The principal aim of this study is to determine the relative contribution of genetic and environmental factors to the constructs of the Revised Reinforcement Sensitivity Theory. The sample comprised 184 twins of both sexes, aged 18 to 41... more
The principal aim of this study is to determine the relative contribution of genetic and environmental factors to the constructs of the Revised Reinforcement Sensitivity Theory. The sample comprised 184 twins of both sexes, aged 18 to 41 (96 monozygotic and 88 dizygotic). Reinforcement Sensitivity Questionnaire (29 items), measuring 5 rRST constructs (BIS, BAS, Fight, Flight, and Freezing), was applied in the study. Heritability of five personality dimensions was examined using full univariate ACE twin models. All models (except for Freezing) have satisfactory fit. Non-shared environment has largest contributions to all dimensions’ variances (55% to 73%). Additive genetic contributions are the largest for Freezing (32%) and BAS (20%), while shared environment contributes most substantially to Flight (25%), Fight (21%) and BAS (20%). The results particularly point to crucial role of environmental factors in shaping the reactions to both signals of reward and signals of punishment.
Gray’s (1970) reinforcement sensitivity theory (RST) was recently updated (Gray & McNaughton, 2000), but the changes have not received extensive empirical validation. The study tests three novel predictions of the revised RST. First, the... more
Gray’s (1970) reinforcement sensitivity theory (RST) was recently updated (Gray & McNaughton, 2000), but the changes have not received extensive empirical validation. The study tests three novel predictions of the revised RST. First, the behavioral activation system (BAS) is expected to be sensitive to both con- ditioned and unconditioned incentives. Second, the behavioral inhibition system (BIS) is expected to be sensitive to conflicting incentives such as between unconditioned and conditioned stimuli, and not to avoidance responses or aversive stimuli alone. Third, during approach-avoidance conflicts only, BAS is expected to moderate BIS responses to conflict such that individuals with high BAS show the strongest effect of BIS. In order to test these hypotheses, we developed a novel incentive task that crosses approach/avoidance conditioned responses to appetitive/aversive unconditioned stimuli. Conflict between unconditioned and conditioned stimuli occurred on the approach-aversive and avoid-appetitive trials. Results confirm the predictions and provide support for the revised RST.
ABSTRACT In this article, we attempt to integrate Dickman's (1990) descriptive concept of Functional Impulsivity (FI) with Gray's (1970, 1991) Reinforcement Sensitivity Theory (RST). Specifically, we consider that FI bears great... more
ABSTRACT In this article, we attempt to integrate Dickman's (1990) descriptive concept of Functional Impulsivity (FI) with Gray's (1970, 1991) Reinforcement Sensitivity Theory (RST). Specifically, we consider that FI bears great conceptual similarity to Gray's concept of reward-reactivity, which is thought to be caused by the combined effects of a Behavioral Activation System (BAS) and Behavioral Inhibition System (BIS). In our first study, we examine the construct validity and structural correlates of FI. Results indicate that FI is related positively to measures of BAS and Extraversion, negatively to measures of BIS and Neuroticism, and is separate from Psychoticism and typical trait Impulsivity, which Dickman calls Dysfunctional Impulsivity (DI). In our second study, we use a go/no-go discrimination task to examine the relationship between FI and response bias under conditions of rewarding and punishing feedback. Results indicate that FI, along with two measures of BAS, predicted the development of a response bias for the rewarded alternative. In comparison, high DI appeared to reflect indifference toward either reward or punishment. We consider how these findings might reconcile the perspectives of Gray and Dickman and help clarify the broader understanding of Impulsivity.
Since 1964, the relationship between personality and criminal behaviour has been extensively studied. However, studies, which have examined the Eysenckian dimensions of extraversion, neuroticism and psychoticism have produced mixed... more
Since 1964, the relationship between personality and criminal behaviour has been extensively studied. However, studies, which have examined the Eysenckian dimensions of extraversion, neuroticism and psychoticism have produced mixed results. Gray's [Gray, J. A. (1970). The psychophysiological basis of introversion–extroversion. Behavior Research and Therapy, 8, 249–266] Reinforcement Sensitivity Theory provides an alternative conceptualisation of the role of personality in criminal behaviour, and has generally produced more consistent findings. This study aimed to examine the relationship between reinforcement sensitivity and delinquent behaviour in a sample of 259 adolescents, and to examine the role that coping strategies play in this relationship. Hierarchical regression analyses revealed that use of problem solving mediated the relationship between reward sensitivity and delinquent behaviour, while use of non-productive coping strategies moderated the relationship between BAS drive and delinquency. Consequently, it was suggested that coping skills training could be an effective early intervention for delinquent behaviour.
The new presented Butterfly-PSO technique (or BF-PSO) is basically originated by Particle Swarm Optimization (PSO). The Butterfly-PSO technique (BF-PSO) appears as a new growing star among all optimization techniques. The proposed... more
The new presented Butterfly-PSO technique (or BF-PSO) is basically originated by Particle Swarm Optimization (PSO). The Butterfly-PSO technique (BF-PSO) appears as a new growing star among all optimization techniques. The proposed ‘Butterfly- Particle Swarm Optimization (Butterfly or BF-PSO)’ is inspired by butterfly natural intelligence, character, behavior, intelligent network and intelligent communication during the nectar search process. The BF-PSO introduces new parameters such as sensitivity of butterfly (s), probability of food (nectar) (p), the degree of the node and the time varying probability coefficient (α). These parameters improve the searching ability, excellent convergence and the overall performance of the Butterfly-PSO effectivly. The BF-PSO optimizations results have been presented for various functions with the multi-dimension problems.
The child version of the Carver and White (1994) BIS/BAS-scales (Muris et al., 2005) was used to assess sensitivity of the Behavioral Inhibition and the Behavioral Activation System in clinically anxious and non-anxious youth (n = 175,... more
The child version of the Carver and White (1994) BIS/BAS-scales (Muris et al., 2005) was used to assess sensitivity of the Behavioral Inhibition and the Behavioral Activation System in clinically anxious and non-anxious youth (n = 175, ages 8–18 years, 70 boys). Results supported the hypothesis that clinical anxiety is associated with overactivity in the BIS (Gray, 1982). Consistent with the revised Reinforcement Sensitivity Theory (Gray & McNaughton, 2000) the BIS-scale consists of two subscales, one measuring BIS_Anxiety and one measuring FFFS_Fear. BIS-scores were higher in the anxious sample than in the non-anxious sample. BAS-scores were equal. Higher levels of BIS-activity were related with an increase in symptoms of anxiety and depression. BIS-scores were higher in girls than in boys, there were no gender differences in BAS-scores.
Gray's Reinforcement Sensitivity Theory (RST) presupposes individual differences in the sensitivity of basic brain systems that... more
Gray's Reinforcement Sensitivity Theory (RST) presupposes individual differences in the sensitivity of basic brain systems that respond to punishing and reinforcing stimuli. These differences are thought to underlie the personality dimensions of anxiety and impulsivity, and to have relevance for psychopathology. The present article aims at reviewing RST-based research on personality-psychopathology associations. First, RST and its revisions are described and the link between RST systems and personality dimensions is discussed. Second, studies investigating associations between RST systems and specific types of psychopathology are summarized. Although the available research yields a rather consistent picture with respect to constellations of BIS/BAS sensitivity that are associated with specific types of psychopathology, it also provides a clear indication that much work remains to be done. The discussion section highlights several topics that deserve future research attention.
Previous research has shown that the startle reflex is potentiated during experimentally induced anxiety (fear-potentiated startle). In the present study, the magnitude and time course of the startle blink reflex were examined among 35... more
Previous research has shown that the startle reflex is potentiated during experimentally induced anxiety (fear-potentiated startle). In the present study, the magnitude and time course of the startle blink reflex were examined among 35 undergraduates scoring one standard deviation above (n = 14) or below (n = 21) the mean in a self-report measure of sensitivity to punishment (SP) in a paradigm involving the anticipation of electric shocks. Contrary to our predictions, SP did not relate to differences in the magnitude or in the time course of fear-potentiated startle. Our data do not support an association between this individual differences variable and the fear-potentiated startle.
Individual differences in behavioral dispositions, values and motivation systems have been investigated in relative isolation from each other. We investigated the network structure of indicators derived from Reinforcement Sensitivity... more
Individual differences in behavioral dispositions, values and motivation systems have been investigated in relative isolation from each other. We investigated the network structure of indicators derived from Reinforcement Sensitivity Theory, Five-Factor Model and Basic individual values in a large sample of young adults (N = 749). The network showed evidence of a small world structure indicating a small number of densely connected networks is sufficient to describe human personality. We identified a number of nodes (indicators) that were central within the network. An Exploratory Graph Analysis suggested ten distinct network clusters, which varied in terms of behavioral approach versus inhibition; exploration vs constraint and self/ego vs social orientation, demonstrating the complexity of individual differences from a motivational-situational perspective. A more complex dimensional exploration of personality networks allows for a more nuanced understanding of how personality systems can be motivated within specific environments and towards different internal or external targets.
Background: Both Reinforcement Sensitivity Theory and Social Cognitive Theory have been applied to understanding drinking behaviour. We propose that theoretical relationships between these models support an integrated approach to... more
Background: Both Reinforcement Sensitivity Theory and Social Cognitive Theory have been applied to understanding drinking behaviour. We propose that theoretical relationships between these models support an integrated approach to understanding alcohol use and misuse. Objectives: We aimed to test an integrated model in which the relationships between reward sensitivity and drinking behaviour (alcohol consumption, alcohol-related problems and symptoms of dependence) were mediated by alcohol expectancies and drinking refusal self-efficacy. Methods: Online questionnaires assessing the constructs of interest were completed by 443 Australian adults (M age = 26.40, sd = 1.83) in 2013 and 2014. Results: Path analysis revealed both direct and indirect effects and implicated two pathways to drinking behaviour with differential outcomes. Drinking refusal self-efficacy both in social situations and for emotional relief was related to alcohol consumption. Sensitivity to reward was associated with alcohol-related problems, but operated through expectations of increased confidence and personal belief in the ability to limit drinking in social situations. Conversely, sensitivity to punishment operated through negative expectancies and drinking refusal self-efficacy for emotional relief to predict symptoms of dependence. Conclusions: Two pathways relating reward sensitivity, alcohol expectancies and drinking refusal self-efficacy may underlie social and dependent drinking, which has implications for development of intervention to limit harmful drinking.
The Reinforcement Sensitivity Theory proposes that a neurobiological system, the Behavioral Activation System, defines individual differences on the subject’s sensitivity and reactivity to appetitive stimuli associated with... more
The Reinforcement Sensitivity Theory proposes that a neurobiological system, the Behavioral Activation System, defines individual differences on the subject’s sensitivity and reactivity to appetitive stimuli associated with mesocorticolimbic structures, while this system does not mediate aversive stimulus processing. However, Jeffrey A. Gray’s model also predicts the system’s antagonism between this appetitive system and another aversive stimulus sensitive system, the Behavioral Inhibitory System/Fight-Flight-Freeze System, mostly associated with limbic structures. Therefore, direct modulation of brain activation during appetitive stimulus processing should be expected from the Behavioral Activation System, while inverse modulation during aversive stimulus processing may be expected to reflect the system’s antagonism. Using the Sensitivity to Reward scale of the SPSR questionnaire to assess individual differences in the activity of the reward system, we present different behavioral and neuroimaging data to illustrate our view. The first experiment was based on a simple letter-judgment task while viewing erotic and aversive pictures selected from the International Affective Picture System. A second experiment employed a task performed by participants to detect infrequent aversive (i.e., stop) signals when responding to reward. The results from these studies were consistent with the idea that Behavioral Activation System-related personality traits mediate the brain activation associated with appetitive stimulus processing in reward-related areas, while it also showed its antagonism to aversive systems through a negative mediation on the limbic cortex activation. To conclude, sensitivity to reward may be understood as a form of impulsivity related to both better appetitive learning and poorer aversive learning.
Previous studies have linked perfectionism to differences in reinforcement sensitivity, but findings have been mixed. The present study explored the relationships between three forms of perfectionism (self-oriented, other-oriented,... more
Previous studies have linked perfectionism to differences in reinforcement sensitivity, but findings have been mixed. The present study explored the relationships between three forms of perfectionism (self-oriented, other-oriented, socially prescribed) and components of the revised Reinforcement Sensitivity Theory of personality in relation to the experience of positive and negative affect. In a sample of 388 university students, we found consistent evidence of significant bivariate and semipartial correlations controlling for the overlap between the three forms of perfectionism: self-oriented perfectionism showed positive relationships with the behavioral approach system (BAS), the behavioral inhibition system (BIS), and the fight-flight-freeze system (FFFS); other-oriented perfectionism showed a negative relationship with the BIS (and was unrelated to the FFFS); and socially prescribed perfectionism showed positive relationships with the BIS and BAS impulsiveness, and a negative relationship with BAS goal-drive persistence (and was unrelated to the FFFS). Furthermore, mediation analyses indicated that the reinforcement sensitivity components (BIS and BAS, but not FFFS) explained differences in how the three forms of perfectionism predicted recent positive and negative affect. These findings open up new empirical avenues in suggesting that fundamental emotion-motivational systems play a key role in the relationship of perfectionism and affective experiences.
This study examined the nature of the relationship between adult attachment and sensitivities of the Behavioural Approach System (BAS), Fight-Flight-Freeze System (FFFS), and the Behavioural Inhibition System (BIS) as defined by Gray and... more
This study examined the nature of the relationship between adult attachment and sensitivities of the Behavioural Approach System (BAS), Fight-Flight-Freeze System (FFFS), and the Behavioural Inhibition System (BIS) as defined by Gray and McNaughton’s (2000) revised Reinforcement Sensitivity Theory (r-RST). A total of 225 first year psychology students completed the Experiences in Close Relationships-Revised scale (ECR-R) as an index of adult attachment; along with Carver and White’s (1994) BAS scale (CW-BAS), Fear Survey Schedule (FSS), State-Trait Anxiety Inventory (STAI), and Reinforcement Sensitivity Theory Personality Questionnaire (RST-PQ) as indices of reinforcement sensitivity. Hierarchical multiple regressions revealed that both attachment dimensions are significantly related to BIS sensitivity, which suggests that motivational ambivalence is a central feature of attachment insecurity. This study contributes to the understanding of adult attachment behaviour in relationship to more fundamental motivational systems.