A pinch or a lesion: a reconceptualization of biting consequences in mice

Intruder and resident male colony mice exhibit an array of distinct defensive and offensive behaviors. Intruders typically show more boxing, flight, defensive sideways position, on the back position and general locomotion, while residents exhibit higher levels of attack, olfactory investigation, aggressive grooming, and biting, with a preference for dorsal bite locations. Here, analysis of bite locations on the body of the intruder mice showed that the majority of bites produced few lesions (i.e. actual puncturing of the skin) when compared to scrapes or no markings. Most bites were directed to the back of the opponent animal with very few bites directed towards the opponents' vulnerable ventrum. In particular, bites directed at the relatively hairless ventrum produced no lesions. These findings, along with previous work on mice and rats, suggest that intraspecific offense with preferred target sites for biting, facilitates an effective but largely nonwounding interaction between resident and intruder mice. Furthermore, bruise and wound analyses suggest an association between bite targets and tissue damage. The preference for specific bite locations may be complimented by a differential intensity of attack, with the back attracting the strongest bites and the ventrum the weakest. This apparent nonwounding fighting pattern contradicts the current evaluation of rodent wounding severity in this paradigm and can therefore refine the usage of this model and of the protocols associated with it.     

Choosing to switch: Spontaneous task switching despite associated behavioral costs

The literature shows that switching among simple cognitive tasks is difficult and involves a performance cost. Accordingly, cost-benefit considerations seem to predict that task switching would not occur spontaneously. Here we show that spontaneous task switching is a robust phenomenon, despite its costs. In Experiment 1, participants had to judge shapes according to one of three possible dimensions. Importantly, they were given the option to choose another relevant dimension or let the computer program change the dimension for them, but only if they wanted to do so. The results showed that spontaneous task switching was prevalent, despite robust switching costs. Experiment 2 extended this finding in showing spontaneous switching from an easy task to a more difficult task. The authors provide two possible explanations for the phenomenon that posit that spontaneous switching may be unpreventable or even advantageous.     

Reporting intentional rating of the primes predicts priming effects in the affective misattribution procedure

In the affective misattribution procedure (AMP), pairs of prime and target stimuli appear rapidly in succession. Attitudes toward the prime influence the evaluation of the target despite instructions to avoid this influence. Because this priming effect presumably happens without people's knowledge, the AMP is used to study automatic evaluation. Participants in four studies performed the AMP and reported their perception of the priming effect. The authors found that the priming reflected reliable and valid attitudes toward the primes mostly among participants who reported that the priming occurred and that they intentionally rated the primes instead of the targets. The authors conclude that the AMP hardly captures attitude effects that escape people's knowledge. The AMP's good psychometric qualities as an attitude measure rely mainly on a small subset of participants who believe that they intentionally caused the attitude effect.     

Post-traumatic stress disorder symptom severity in service members returning from Iraq and Afghanistan with different types of injuries

IntroductionRisk for post-traumatic stress disorder (PTSD) varies in part due to the nature of the traumatic event involved. Both injury and return from combat pose high risk of PTSD symptoms. How different injuries may predispose towards PTSD is less well understood. METHODS: A retrospective record review was conducted from 1402 service members who had returned to Naval Medical Center San Diego from Iraq or Afghanistan and who had completed the PTSD Checklist as part of their post-deployment screening. Rates of PTSD were examined in relation to mechanism of injury. RESULTS: Of those without injury, 8% met Diagnostic and Statistical Manual criteria for PTSD. Thirteen percent of those with a penetrating injury, 29% with blunt trauma, and 33% with combination injuries met criteria for PTSD. PTSD severity scores varied significantly according to type of injury.DiscussionThe World War I concept of "shell shock" implied that blast-related injuries were more likely to result in psychological symptoms than were other injuries. These data may support that idea. Circumstance of injury, population differences, and reporting bias could also have influenced the results.ConclusionThese results suggest that service members with blunt or combination injuries merit particular attention when screening for PTSD.     

Towards a model theory of diagrams

A logical system is studied whose well-formed representations consist of diagrams rather than formulas. The system, due to Shin [2, 3], is shown to be complete by an argument concerning maximally consistent sets of diagrams. The argument is complicated by the lack of a straight forward counterpart of atomic formulas for diagrams, and by the lack of a counterpart of negation for most diagrams.The authors are grateful to Jon Barwise and an anonymous referee for valuable comments and suggestions.     

Leader-Member Exchange and Employee Creativity: Test of a Multilevel Moderated Mediation Model

Using multisource data, this article examined the relationship of two types of employee perceptions of overall fairness (i.e., fairness of the organization and fairness of the department), with supervisor ratings of in-role task performance and organizational citizenship behaviors (OCB). We also examined whether high-quality leader-member exchange (LMX) relationships compensate for negative effects of fairness on job performance and citizenship behaviors. Focusing on a sample of 154 health care workers, we found that only employee perceptions of overall fairness regarding the department were related to supervisory ratings of OCB and in-role task performance. Moreover, LMX moderated the relationships between fairness perceptions and (a) task performance, (b) organization-focused OCB, but not (c) individual-focused OCB. We discuss implications for research and the potential for reducing negative effects of low fairness perceptions on job performance through positive LMX.     

The paradox of evolution

In the second (and expanded) version of Origin of the Species, Darwin introduces the term “advanced progressive development” in an attempt to describe the development of the more complex species from the simpler ones. More than 100 years have passed since Darwin tried to qualify and conceptualize the directional question of evolution, and very little progress has been made regarding the subject. The appearance of the species, from the simple to the more complex, is today an empirical fact, one which is no longer dependent upon any theory, including that of Darwin. This work examines the subject of advanced development in evolution by attempting to answer a few basic questions: What parameters may be used to evaluate complexity? Can any rules or order be identified as to the development of the species? Is the mechanism of “natural selection” sufficient to explain the direction or ‘purpose’ of evolution? Can the human race be included within the “rules” of Darwin's evolutionary theory?

The purpose of this essay is to develop and represent a new conceptual framework. Through this, it will be possible to offer a principle answer to all four questions.