My way or the highway: High narcissism and low self-esteem predict decreased support for democracy.

In two studies, we analysed the relationships between different types of self-evaluation (i.e., narcissism and self-esteem) and support for democracy. Support for democracy requires the ability to respect the views and opinions of others, even if one disagrees with them. Classic studies have linked support for democracy with high self-evaluation, which should assume psychological security and, thus, the ability to trust others. However, not all forms of high self-evaluation are secure. Narcissists have high feelings of self-worth, but tend to be defensive: They are easily threatened by criticisms or conflicting views. We then expected that while support for democracy should be positively predicted by secure, non-narcissistic self-evaluation, it should be negatively predicted by narcissistic self-evaluation. In two studies, conducted in the United States (Study 1, n = 407) and in Poland (Study 2, n = 405), support for democracy was positively predicted by self-esteem and negatively predicted by narcissism. Study 2 additionally demonstrated that interpersonal trust mediated the effects of self-esteem on support for democracy. We discuss the role of psychological predispositions in understanding support for democratic systems.

Importance of associative learning processes for one-trial behavioral sensitization of preweanling rats.

During adulthood, associative learning is necessary for the expression of one-trial behavioral sensitization; however, it is uncertain whether the same associative processes are operative during the preweanling period. Two strategies were used to assess the importance of associative learning for one-trial behavioral sensitization of preweanling rats. In the initial experiments, we varied both the sequence and time interval between presentation of the conditioned stimulus (CS, novel environment) and unconditioned stimulus (US, cocaine). In the final experiment, we determined whether electroconvulsive shock-induced retrograde amnesia would disrupt one-trial behavioral sensitization. Results showed that robust-sensitized responding was apparent regardless of the sequence in which cocaine and the novel environment (the presumptive CS) were presented. Varying the time between CS and US presentation (0, 3, or 6 h) was also without effect. Results from experiment 3 showed that single or multiple electroconvulsive shock treatments did not alter the expression of the sensitized response. Therefore, these data indicated that one-trial behavioral sensitization of preweanling rats was exclusively mediated by nonassociative mechanisms and that associative processes did not modulate sensitized responding. These findings are in contrast to what is observed during adulthood, as adult rats exhibit one-trial behavioral sensitization only when associative processes are operative.

One-trial behavioral sensitization in preweanling rats: differential effects of cocaine, methamphetamine, methylphenidate, and D-amphetamine.

RATIONALE: Preweanling rats exhibit robust one-trial cocaine-induced behavioral sensitization; however, it is uncertain whether other psychostimulants can also induce sensitization in young rats using the one-trial procedure. OBJECTIVE: The purpose of this study was to determine whether methamphetamine, methylphenidate, and D: -amphetamine are capable of inducing one-trial locomotor sensitization in preweanling rats. METHODS: In a series of four experiments, rats were pretreated with cocaine (30 mg/kg), methamphetamine (2-12 mg/kg), methylphenidate (5-20 mg/kg), or amphetamine (5 mg/kg) before being placed in a novel activity chamber or the home cage on PD 19. Rats were then challenged with the same psychostimulant (20 mg/kg cocaine, 1-8 mg/kg methamphetamine, 2.5-7.5 mg/kg methylphenidate, or 1-2 mg/kg amphetamine) on PD 21, with distance traveled being measured for 180 min. In a separate experiment, rats were pretreated with methamphetamine on PD 16-19 and challenged with methamphetamine on PD 21. RESULTS: Only cocaine, but not various dose combinations of other psychostimulants, was able to produce one-trial behavioral sensitization in preweanling rats. Context-dependent locomotor sensitization was also evident if rats were pretreated with methamphetamine on PD 16-19 and tested on PD 21. CONCLUSIONS: It is uncertain why only cocaine was able to induce one-trial locomotor sensitization in preweanling rats, but it is possible that: (a) the neural circuitry mediating sensitization differs according to psychostimulant, (b) cocaine is more readily associated with environmental contexts than other psychostimulants, or (c) affinity and pharmacokinetic factors may underlie cocaine's ability to induce one-trial behavioral sensitization in preweanling rats.