Rationality and indeterminate probabilities

We argue that indeterminate probabilities are not only rationally permissible for a Bayesian agent, but they may even be rationally required. Our first argument begins by assuming a version of interpretivism: your mental state is the set of probability and utility functions that rationalize your behavioral dispositions as well as possible. This set may consist of multiple probability functions. Then according to interpretivism, this makes it the case that your credal state is indeterminate. Our second argument begins with our describing a world that plausibly has indeterminate chances. Rationality requires a certain alignment of your credences with corresponding hypotheses about the chances. Thus, if you hypothesize the chances to be indeterminate, your will inherit their indeterminacy in your corresponding credences. Our third argument is motivated by a dilemma. Epistemic rationality requires you to stay open-minded about contingent matters about which your evidence has not definitively legislated. Practical rationality requires you to be able to act decisively at least sometimes. These requirements can conflict with each other-for thanks to your open-mindedness, some of your options may have undefined expected utility, and if you are choosing among them, decision theory has no advice to give you. Such an option is playing Nover and Hájek??s Pasadena Game, and indeed any option for which there is a positive probability of playing the Pasadena Game. You can serve both masters, epistemic rationality and practical rationality, with an indeterminate credence to the prospect of playing the Pasadena game. You serve epistemic rationality by making your upper probability positive-it ensures that you are open-minded. You serve practical rationality by making your lower probability 0-it provides guidance to your decision-making. No sharp credence could do both.     

The Effect of Family Size on Spanish Simple and Complex Words

This study presents the results of three experiments in which the Family Size (FS) effect is explored. The first experiment is carried out with no prime on simple words. The second and third experiments are carried out with morphological priming on complex words. In the first experiment a facilitatory effect of FS is observed: high FS targets produced faster responses than low FS targets. However, an inhibitory effect of Stem-FS is observed in the second experiment: low Stem-FS targets produced faster responses than high Stem-FS targets. In the third experiment a facilitatory effect is observed when the Affix-FS is manipulated: high Affix-FS targets produced faster responses than low Affix-FS targets. Overall data confirms that the effect of FS plays an important role in lexical access in Spanish. The results also show that the effect of FS is modulated by the lexical nature of the prime (lexical or sublexical) and by the number of candidates activated. Finally, it is suggested that the nonwords employed were decisive in obtaining the results mentioned.     

Development of the Social Behavior of Two Mice Species With Contrasting Social Systems

The house mouse (Mus musculus) and the mound‐building mouse (M. spicilegus) differ in their mating and social systems. The M. musculus is polygynous and females tend to breed cooperatively while M. spicilegus is known to be monogamous and famous for its unique cooperative behavior; the communal overwintering. Mus spicilegus is considered as a highly aggressive species in the genus Mus. In the present study, we attempted to analyze the development of aggressive and sociable behavior in these species and to discover how familiarity with the target moderates the development of sociable and aggressive behaviors and moderates the differences between the species. Dyadic social interaction tests in neutral cages were performed on 21‐, 60‐, and 120‐day‐old mice of both genders and both species. Each individual was tested against a sibling and an unfamiliar individual at all three ages. Our results showed that the development of aggressive and sociable behavior with age differed between the species and sexes; however, familiarity with the other mouse moderated the effect of species on aggression. At 21 days, both genders of M. spicilegus were more aggressive against strangers than siblings. This became true of both species at 60 days. When facing a stranger, both sexes of M. spicilegus were more aggressive than M. musculus at 120 days. However, when facing a sibling, neither gender of M. spicilegus was more agonistic than M. musculus, indicating that either kinship or early social experiences elicit tolerance. Aggr. Behav. 38:288‐297, 2012. © 2012 Wiley Periodicals, Inc.     

Eye movements blink the attentional blink

When presented with a sequence of visual stimuli in rapid succession, participants often fail to detect a second salient target, a phenomenon referred as the attentional blink (AB; Raymond, Shapiro, & Arnell, 1992; Shapiro, Raymond, & Arnell, 1997). On the basis of a vast corpus of experiments, several cognitive theories suggest that the blink results from a discrete structuring of attention, sampling information from temporal episodes during which several items can access encoding process (Wyble, Bowman, & Nieuwenstein, 2009; Wyble, Potter, Bowman, & Nieuwenstein, 2011). The objective of this work is to explore the AB when multiple items are presented at the fovea during ocular movements. The authors reasoned that each fixation may cohesively form an episode and hence expected that the blink may vanish within a single fixation. In turn, they expected saccades to accentuate episodic borders and hence shorten the regime of interference when 2 targets are presented fovealy in successive fixations. Evidence is provided in favor of this hypothesis, showing that the blink vanishes when both targets are presented in the core of a single fixation (far from the saccadic boundaries) and that it recovers more rapidly in successive fixations. These studies support current views that episodes should have an effect on the AB and provide evidence that eye movements play an important role in the formation of episodes.     

Eye gaze versus arrows as spatial cues: two qualitatively different modes of attentional selection

This study aimed to evaluate the type of attentional selection (location- and/or object-based) triggered by two different types of central noninformative cues: eye gaze and arrows. Two rectangular objects were presented in the visual field, and subjects' attention was directed to the end of a rectangle via the observation of noninformative directional arrows or eye gaze. Similar experiments with peripheral cues have shown an object-based effect: faster target identification when the target is presented on the cued object as compared to the uncued object, even when the distance between target and cue was the same. The three reported experiments aimed to compare the location- and object-based attentional orienting observed with arrows and eye gaze, in order to dissociate the orienting mechanisms underlying the two types of orienting cues. Results showed similar cueing effects on the cued versus oppositely cued locations for the two cue types, replicating several studies with nonpredictive gaze and arrow cues. However, a pure object-based effect occurred only when an arrow cue was presented, whereas a pure location-based effect was only found for eye-gaze cues. It is suggested that attention is nonspecifically directed to nearby objects when a noninformative arrow is used as cue, whereas it is selectively directed to a specific cued location when noninformative eye gaze is used. This may be mediated by theory of mind mechanisms.     

Are the pathogens of out-groups really more dangerous?

We question the plausibility of Fincher & Thornhill's (F&T's) argument that localised pathogen-host coevolution leads to out-groups having pathogens more damaging than those infecting one's own family or religious group.     

Is an optimistic memory less easily influenced by negative than by positive emotions?

This work examines whether a positive personality trait, such as optimism, can reduce bias in differential words recalled after inducing a certain emotion. After showing a list of words with various emotional valences to a group of 59 subjects, a specific emotional state was induced. Subsequently, the subjects were asked to recall the list of words. The results obtained indicated that less optimistic subjects had a tendency to recall and recognize a greater number of negative words when in a negative emotional condition. Statistical significance was reached in the female group's negative word recognition when experiencing negative emotion.     

Effects of category label activation about the elderly

The present research focuses on the study of behavioral effects of non-conscious activation of categories among outgroup (young people) and ingroup members (elderly people). Specifically, non-conscious activation of labels that designate the same group, but with different valence (old vs. elderly), showed an effect on a behavior not directly related to interaction with elderly. The first study with young individuals (N= 62) shows that, after non-conscious activation of a negative label (old), participants displayed longer RTs in the first phase of the task than in the case of positive label (elderly) priming. The second study (N= 40), performed with elderly people, shows a similar result, after non-conscious activation of a negative label (old), elderly people showed longer RTs in the first phase of the task, compared with the group in the non-conscious positive label activation condition. Results concerning the theoretical and practical implications are discussed.     

Parenting style in Spanish parents with children aged 6 to 14

The aim of this paper was to establish which parenting style of Spanish families is associated with optimum children's outcomes. A random Spanish sample of 1,103 parents of children and teenagers from 6 to 14 years of age, of whom 47% were females, reported on their child-rearing practices. Families were classified into 1 of 4 groups (authoritative, authoritarian, indulgent, or neglectful) based on the parents' answers. Socialization outcomes were 6 indicators of interpersonal relationship quality, 9 indicators of psychological adjustment, 7 indicators of personal competence, and 12 indicators of behavior problems. Results showed that indulgent and authoritative parenting styles were associated with better outcomes than authoritarian and neglectful parenting. Overall, our results supported the idea that, in Spain, the optimum parenting style is the indulgent one, as scores in the four sets of socialization outcomes among children and teenagers from indulgent families were always equal to, or even better than, the authoritative parenting style.