Completeness of S4 for the Lebesgue Measure Algebra

We prove completeness of the propositional modal logic S4 for the measure algebra based on the Lebesgue-measurable subsets of the unit interval, [0, 1]. In recent talks, Dana Scott introduced a new measure-based semantics for the standard propositional modal language with Boolean connectives and necessity and possibility operators, ^[¯]\Box and \Diamond\Diamond. Propositional modal formulae are assigned to Lebesgue-measurable subsets of the real interval [0, 1], modulo sets of measure zero. Equivalence classes of Lebesgue-measurable subsets form a measure algebra, M\mathcal M, and we add to this a non-trivial interior operator constructed from the frame of ‘open’ elements—elements in M\mathcal M with an open representative. We prove completeness of the modal logic S4 for the algebra M\mathcal M. A corollary to the main result is that non-theorems of S4 can be falsified at each point in a subset of the real interval [0, 1] of measure arbitrarily close to 1. A second corollary is that Intuitionistic propositional logic (IPC) is complete for the frame of open elements in M\mathcal M.     

What the tip-of-the-tongue (TOT) says about homophone frequency inheritance

The present study uses tip-of-the-tongue (TOT) states as a unique source of evidence to test the hypothesis of lexical access benefits for homophones--that is, whether low-frequency homophones, such as tee, inherit the lexical access benefits of their high-frequency homophonic counterparts, such as tea. We compared retrieval success rates for low-frequency homophones, for matched low-frequency controls, and for high-frequency controls with the combined frequency of the homophone set. In correct retrievals, low-frequency homophones behaved according to their specific frequency, not differing from the low-frequency controls. However, retrieval failures revealed a different kind of homophone effect. When retrieval failed for targets with a homophone partner, access difficulties tended to be less profound than for low-frequency controls, ending closer to target retrieval more often than low-frequency controls (at Step 2; in a self-resolved TOT or in a TOT with a strong feeling of knowing), and ending far away from target retrieval less often than low-frequency controls (at Step 1; in a notGOT). These results provide evidence against the notion of shared word-form representations for homophonic targets but leave open a door for a weaker form of homophone effects, possibly arising from feedback activation that influences retrieval only when access is sufficiently slowed (as when retrieval fails).     

Faces in the face of death: Effects of exposure to life-threatening events and mortality salience on facial expression recognition in combat and noncombat military veterans

Soldiers in war zones often experience life-threatening events that put their lives at stake. The present study examined how these exposures shape soldiers' social behavior, manifested by recognition of facial expressions. In addition, we investigated how explicit awareness of one's eventual death affects sensitivity to facial expressions. Veterans of elite military combat units were exposed to conditions of mortality or pain salience and later requested to label the emotions depicted in threatening and nonthreatening faces. Combat veterans were more accurate than noncombat veterans in identifying threatening expressions, both in mortality or pain salience induction (Experiment 1) or under no induction at all (Experiment 2). In addition, noncombat veterans primed with mortality salience identified fear expressions more accurately than those primed with pain salience. Finally, mortality salience improved accuracy for nonthreatening expressions for all veterans. The present results demonstrate that fear of death, resulting from exposure to concrete life-endangering perils or from thoughts on human's inevitable death, influences perception of facial expressions, which is critical for successful interpersonal communication. (PsycINFO Database Record (c) 2012 APA, all rights reserved).     

A disadvantage in bilingual sentence production modulated by syntactic frequency and similarity across languages

Bilingual speakers access individual words less fluently, quickly, and accurately than monolinguals, particularly when accessing low-frequency words. Here we examined whether the bilingual speech production disadvantage would (a) extend to full sentences above and beyond single word retrieval and whether it would be modulated by (b) structural frequency and (c) syntactic properties of the bilingual speakers’ other language. English monolinguals, Spanish–English bilinguals and Mandarin–English bilinguals were tested in a sentence production task conducted exclusively in English. Response times were modulated by bilingualism, structural frequency, and structural similarity across the bilingual speakers’ two languages. These results refine our knowledge regarding the scope of the bilingual disadvantage, demonstrate that frequency effects apply to syntactic structures, and also suggest that syntax is partially shared across bilinguals’ two languages.     

Mental and Motor Switching in Parkinson's Disease

Switching difficulties in Parkinson's disease (PD) are expressed in both mental and motor tasks. The authors of the present study investigated whether those deficits coexist in the same patient and are positively correlated. They tested 8 nondemented PD patients and 6 age-matched control participants by using the modified Wisconsin Card Sorting Test and a motor switching paradigm that is based on the task of reaching toward visual targets, the location of which could unexpectedly be altered within the reaction time. In both mental and motor tasks, patients performed significantly worse than controls. There were no significant correlations between the two types of pathology in individual patients. Mental and motor switching deteriorate in PD patients, but the deficits are not necessarily of parallel severity.

basal ganglia     

Career counsellors' perceptions of the severity of career decision-making difficulties

Individuals differ in the type and severity of the difficulties they face when making a career decision. Relying on the Gati, Krausz, and Osipow (1996) taxonomy of career decision-making difficulties, we elicited the judgements of 28 career counselling experts about factors that contribute to the perceived severity of the difficulties. Difficulties attributed to an internal or emotional cause were judged as more severe than difficulties attributed to an external or cognitive cause. With respect to the consequences, difficulties that prevent making a decision, or those that require long-term treatment, were judged as more severe than difficulties that may lead to a non-optimal decision, and those that require a short-term treatment. The analysis revealed that the factor that most affected the experts' severity judgements was the expected length of treatment. Treatment priority was affected only partially by severity, reflecting the role of other considerations.     

Mispredicting distress following romantic breakup: Revealing the time course of the affective forecasting error

People evidence significant inaccuracies when predicting their response to many emotional life events. One unanswered question is whether such affective forecasting errors are due to participants’ poor estimation of their initial emotional reactions (an initial intensity bias), poor estimation of the rate at which these emotional reactions diminish over time (a decay bias), or both. The present research used intensive longitudinal procedures to explore this question in the wake of an upsetting life event: the dissolution of a romantic relationship. Results revealed that the affective forecasting error is entirely accounted for by an initial intensity bias, with no contribution by a decay bias. In addition, several moderators of the affective forecasting error emerged: participants who were more in love with their partners, who thought it was unlikely they would soon enter a new relationship, and who played less of a role in initiating the breakup made especially inaccurate forecasts.     

Coincidence and Common Cause

According to the traditional view of the causal structure of a coincidence, the several parts of a coincidence are produced by independent causes. I argue that the traditional view is mistaken; even the several parts of a coincidence may have a common cause. This has important implications for how we think about the relationship between causation and causal explanation—and in particular, for why coincidences cannot be explained.     

Disappointment expression evokes collective guilt and collective action in intergroup conflict: the moderating role of legitimacy perceptions

Research on intergroup emotions has largely focused on the experience of emotions and surprisingly little attention has been given to the expression of emotions. Drawing on the social-functional approach to emotions, we argue that in the context of intergroup conflicts, outgroup members’ expression of disappointment with one’s ingroup induces the complementary emotion of collective guilt and correspondingly a collective action protesting ingroup actions against the outgroup. In Study 1 conducted immediately after the 2014 Gaza war, Jewish-Israeli participants received information about outgroup’s (Palestinians) expression of emotions (disappointment, fear, or none). As predicted, outgroup’s expression of disappointment increased collective guilt and willingness to participate in collective action, but only among those who saw the intergroup situation as illegitimate. Moreover, collective guilt mediated the relationship between disappointment expression and collective action, moderated, again, by legitimacy perception. In Study 2, we replicated these results in the context of racial tension between Black and White Americans in the US. We discuss the theoretical and applied implications of the findings.