The effect of sleep deprivation on signal detection parameters

Twelve subjects performed a high signal rate vigilance task, once after a night's sleep, and once after a night without sleep. Raw scores were transformed into the signal detection parameters, d' and β. After sleep deprivation, detection performance was significantly impaired. This was reflected in a fall of d', whereas β was not significantly altered. Analysing the control data alone for comparison with other vigilance studies revealed a decrement in % signals detected and d', and an increase in β from the first to the second half of the test.     

The spiral of distrust: (Non‐)cooperation in a repeated trust game is predicted by anger and individual differences in negative reciprocity orientation

This study investigated state anger and individual differences in negative reciprocity orientation as predictors of individuals' willingness to cooperate with strangers. In order to observe real behaviour, we used a trust game that was played over six periods. In the trust game, a first player (sender) determines how much of a certain endowment she/he wants to share with a second player (trustee), who then can give something back. We varied whether participants received feedback [feedback (yes, no)] about the trustee's behavioural decision (amount sent back). Supporting our hypotheses, the results suggest that feedback compared with no feedback about the trustee's behaviour increased anger. Specifically, information about low back transfers triggered anger and non‐cooperation in return. Importantly, participants with a strong negative reciprocity orientation reported higher levels of anger and were less willing to cooperate with the trustee compared with those with low negative reciprocity orientation. Moreover, even when anger was low, individuals with a strong negative reciprocity orientation were less willing to cooperate compared with those with a low negative reciprocity orientation. Thus, negative reciprocity orientation seems to arouse a spiral of distrust. Theoretical and practical implications of these findings are discussed.     

Mortality salience effects on reckless driving intentions in a motorcyclist sample: The moderating role of group riding

Campaigns against reckless driving often mention the risk of dying. Research on terror management theory indicates that death claims may backfire and foster reckless driving. Here, we studied such mortality salience effects in a motorcyclist sample. Two moderating variables, particularly interesting regarding the sample of motorcyclists, were considered: group riding (vs. riding alone) and driving‐related self‐esteem. Motorcyclists were exposed to a campaign, either highlighting mortality or not. Orthogonally, cyclists were primed with riding in a group (vs. riding alone). Driving‐related self‐esteem was assessed via a questionnaire. We predicted that reminders of riding in a group would buffer against ironic mortality effects. Supporting this hypothesis, mortality salience effects interacted with the group prime. The results indicate that death appeals are likely to backfire with cyclists riding alone rather than cyclists riding in a group, especially if motorcycling is relevant to the self.     

Swedish Acceptance and Action Questionnaire (SAAQ): a psychometric evaluation

Psychological inflexibility and experiential avoidance are equivalent (with somewhat different connotations) concepts and refer to an unwillingness to remain in contact with particular private events. This concept is most often measured by the Acceptance and Action Questionnaire (AAQ-II) and is strongly related to psychopathology and behavioral effectiveness. In this study, the preliminary psychometric properties of the Swedish version of the AAQ-II (Swedish Acceptance and Action Questionnaire—SAAQ) are presented. The study is done in two steps. In the first step, the 10-item version of the AAQ-II is investigated through principal component analysis (n = 147). Secondly, due to problems with the component structure, the instrument is reduced to a six-item version and its validity and internal consistency are investigated (n = 154). The six-item version shows good concurrent and convergent validity as well as satisfying internal consistency (α = .85). Furthermore, the Swedish six-item version of the AAQ-II showed one strong component. Test–retest reliability was satisfactory (r = .80; n = 228). In future research, predictive and external validity would be important to investigate in order to further ensure that the SAAQ is a useful measure for clinical research. In conclusion, the SAAQ has satisfactory psychometric properties, but more data need to be gathered to further explore the possibilities for the instruments in Swedish contexts.     

The road to the unconscious self not taken: Discrepancies between self‐ and observer‐inferences about implicit dispositions from nonverbal behavioural cues

To what extent can individuals gain insight into their own or another person's implicit dispositions' We investigated whether self‐perceivers versus neutral observers can detect implicit dispositions from nonverbal behavioural cues contained in video feedback (cue validity) and whether these cues are in turn used as a valid basis for explicit dispositional inferences (cue utilization). Across three studies in the domains of extraversion and anxiety we consistently obtained reliable cue validity and cue utilization for neutral observers but not for self‐perceivers. An additional measure of state inferences in Study 3 showed that one reason for the lack of mediation in self‐perceivers is their reluctance to use their state inferences as a basis for more general trait inferences. We conclude that people have a ‘blind spot’ with respect to the nonverbal behavioural manifestations of their unconscious selves, even though neutral observers may readily detect and utilize this information for dispositional inferences. Copyright © 2009 John Wiley & Sons, Ltd.     

Is Phosphorus Hesperus?

It is argued that philosophers who adopt the perdurance theory of persistence and who subscribe to the principle of Unrestricted Mereological Composition (UMC) are in a position to regard “Phosphorus is Hesperus” as false.     

Functional hemispheric differences for the categorization of global and local information in naturalistic stimuli

Up to now functional hemispheric asymmetries for global/local processing have mainly been investigated with hierarchical letters as stimuli. In the present study, three experiments were conducted to examine whether corresponding visual-field (VF) effects can also be obtained with more naturalistic stimuli. To this end, images of animals with a pattern placed on their body were displayed as stimuli. The task for the global level and for the local level was to categorize the animals and the patterns, respectively. As a result, VF-effects were also found for these stimuli and tasks. It is concluded that the hemispheric differences observed for hierarchical letters also hold for naturalistic stimuli.