Acquired affective-evaluative value: conservative but not unchangeable

In a previous study on Evaluative Conditioning it was found that unlike signal-learning, evaluative learning is resistant to extinction. In the present experiment we tried to replicate and corroborate this finding. In addition, we investigated the effectiveness of a counterconditioning procedure to alter acquired evaluative value. On a within-subject base (n = 30), it was found that the mere contingent presentation of neutral with (dis)liked pictures of human faces was sufficient to change the affective-evaluative tone of the originally neutral stimuli in (negative) positive direction. Next, we replicated the finding that an extinction procedure does not have any influence on the acquired evaluative value of the originally neutral stimuli, and this even in subjects fully aware of the extinction presentations. We demonstrated the effectiveness of a counterconditioning procedure to alter acquired evaluative value, and in addition, found some evidence that awareness of the counterconditioning manipulations is not a prerequisite for its effectiveness. The theoretical consequences of these findings are phrased in terms of a fundamental distinction between signal-learning and evaluative learning, and some important implications for the behavioral treatment of affective-emotional disorders are suggested.     

The locus of intersensory facilitation of reaction time

When an imperative visual stimulus is paired with an auditory (accessory) stimulus, RT is generally faster than with the imperative stimulus alone. Three experiments using additive-factors logic tested an energy-summation view of the accessory, where effects are due to increased rate of information build-up in sensory stages, and a preparation-enhancement view which holds that the accessory serves an alerting function. Experiment 1 found no interaction between the accessory presence and (visual) stimulus brightness, suggesting no role of the accessory in stimulus identification. Experiment 2 found no interaction between accessory presence and spatial S-R compatibility, arguing that the accessory operated in stage(s) other than response selection. Experiment 3 produced an interaction between the accessory and movement complexity, arguing for accessory effects in a response-programming stage. The data generally favored preparation-enhancement, and offered no support for an energy-summation view.     

The rationality of conditional cooperation

InMorals by Agreement, David Gauthier (1986) argues that it is rational to intend to cooperate, even in single-play Prisoner's Dilemma games, provided (1) your co-player has a similar intention; (2) both intentions can be revealed to the other player. To this thesis four objections are made. (a) In a strategic decision the parameters on which the argument relies cannot be supposed to be given. (b) Of each pair ofa-symmetric intentions at least one is not rational. But it is impossible to form symmetric intentions to cooperate conditionally. For the condition on which the decision depends cannot be fulfilled without deciding. (c) If one's intention has to be ascertained on the basis of information about one's past performance, it is straightforwardly rational to intend to cooperate, but there is no reason to do so in a single-play PD. (d) The argument cannot be extended ton-person games which are Gauthier's principal concern.     

On becoming a leader: Effects of gender and cultural differences on power distance reduction

The present research focused on power processes in a simulated organizational structure consisting of three hierarchical levels occupied by different numbers of mules and females. Subjects were presented with a chart showing the organizational hierarchy of which they were a member placed at the lowest level, and asked to nominate any person for the leader position vacated by the current incumbent. The results of Experiment I (n = 88 Dutch male and female university students) showed that male subjects strongly overnominated themselves, whereas a majority of the female subjects nominated either self or another female. Of the others that were nominated by both males and females, almost all were occupants of positions immediately below the leader position, indicating the normative influence of a bureaucratic rule of leader succession. Experiment 2 was a replicational study carried out in a different culture (n = lOl Polish male and female university students). Polish subjects adhered to the bureaucratic rule more strongly than their Dutch counterparts, and both females and males nominated mostly males. Results are discussed with reference to gender self-stereotypes and cultural differences.     

An on-line assessment of causal reasoning during comprehension

Fletcher and Bloom (1988) have argued that as readers read narratives, clause by clause, they repeatedly focus their attention on the last preceding clause that contains antecedents but no consequences in the text. This strategy allows them to discover a causal path linking the text's opening to its final outcome while minimizing the number of times long-term memory must be searched for missing antecedents or consequences. In order to test this hypothesis, we examined the reading times of 25 subjects for each clause of eight simple narrative texts. The results show that: (1) causal links between clauses that co-occur in short-term memory (as predicted by the strategy) increase the time required to read the second clause; (2) potential causal links between clauses that never co-occur in short-term memory (again as predicted by the strategy) have no effect on reading time; and (3) reinstatement searches are initiated at the end of sentences that are causally unrelated to the contents of short-term memory or that contain clauses that satisfy goals no longer in short-term memory. These results support the claim that subjects engage in a form of causal reasoning when they read simple narrative texts.     

Les Principes Philosophiques Du Christianisme

Sans résumé     

Cardiovascular responses to open-field stress in rats: sex differences and effects of gonadal hormones

We studied sex differences in cardiovascular responses to stress using a new radio-telemetry model in which freely-moving Spontaneously Hypertensive rats (SHR) are exposed to open-field novelty stress. This model allowed simultaneous assessment of cardiovascular and behavioural responses to psychological stress. Female SHR in the diestrous stage of their estrous cycle had markedly greater pressor and tachycardic responses to open-field exposure when compared to either female rats not in diestrous or male SHR. Treatment of ovariectomized SHR with estrogen alone had no significant effect on cardiovascular reactivity, while a combined treatment of estrogen and progesterone slightly, but significantly attenuated their pressor response to open-field stress. In addition, treatment of castrated male rats with testosterone significantly enhanced their pressor responses to stress when compared to values obtained before treatment. None of the hormone treatments had any significant effect on heart rate responses to stress. Neither at different stages of the estrous cycle nor after hormone treatments were there any marked changes in behavioural responses in the open-field, making it unlikely that the differences in cardiovascular stress responses were caused by changes in behavioural activity. These data demonstrate differences in cardiovascular stress responses that seem to be dependent on the stage of the estrous cycle. They suggest that particularly androgens, such as testosterone, may enhance pressor responses to stress. On the other hand, a combination of estrogen and progesterone, rather than estrogen alone, may have a small attenuating effect on cardiovascular reactivity.     

Estimating the mean effect size in meta-analysis: Bias,precision, and mean squared error of different weighting methods

Although use of the standardized mean difference in meta-analysis is appealing for several reasons, there are some drawbacks. In this article, we focus on the following problem: that a precision-weighted mean of the observed effect sizes results in a biased estimate of the mean standardized mean difference. This bias is due to the fact that the weight given to an observed effect size depends on this observed effect size. In order to eliminate the bias, Hedges and Olkin (1985) proposed using the mean effect size estimate to calculate the weights. In the article, we propose a third alternative for calculating the weights: using empirical Bayes estimates of the effect sizes. In a simulation study, these three approaches are compared. The mean squared error (MSE) is used as the criterion by which to evaluate the resulting estimates of the mean effect size. For a meta-analytic dataset with a small number of studies, theMSE is usually smallest when the ordinary procedure is used, whereas for a moderate or large number of studies, the procedures yielding the best results are the empirical Bayes procedure and the procedure of Hedges and Olkin, respectively.     

War stress and late-life mortality in World War II male civilian resistance veterans

The mental and physical health of 146 Dutch males exposed to severe war stress during their young adulthood were examined in 1986-1987 when they were at ages 61 to 66 years. The veterans' data were compared with a randomly selected population-based sample of same-aged males. In 2005, 70% of the war stress veterans had died, and only 35% of the comparison group. The baseline quality of life was significantly poorer in the war stress veterans than in the comparison group. Baseline variables explained 42% of the increased risk of mortality among war stress veterans. Smoking was the largest single contributor to mortality.     

Parental communication appears not to be an effective strategy to reduce smoking in a sample of Dutch adolescents

This longitudinal study examined the reciprocal effects of the frequency of parent–adolescent communication on tobacco-related issues (smoking-specific communication), and adolescents’ smoking. Participants were 428 Dutch older and younger siblings between 13 and 16 years old. Smoking-specific communication did not affect youth smoking in general; however, among younger, but not older, siblings, smoking-specific communication was associated with a higher likelihood of smoking over time. In addition, when adolescents already smoked parents started to talk more frequently about smoking-related issues with their older and younger adolescents later on. Neither the quality of smoking-specific communication, the quality of parent–adolescent relationship, nor parental smoking moderated these reciprocal effects. In conclusion, prevention campaigns encouraging parents to undertake smoking-specific communication might not be desirable.