Species ecology explains the spatial components of genetic diversity in tropical reef fishes.

Generating genomic data for 19 tropical reef fish species of the Western Indian Ocean, we investigate how species ecology influences genetic diversity patterns from local to regional scales. We distinguish between the α, ß and γ components of genetic diversity, which we subsequently link to six ecological traits. We find that the α and γ components of genetic diversity are strongly correlated so that species with a high total regional genetic diversity display systematically high local diversity. The α and γ diversity components are negatively associated with species abundance recorded using underwater visual surveys and positively associated with body size. Pelagic larval duration is found to be negatively related to genetic ß diversity supporting its role as a dispersal trait in marine fishes. Deviation from the neutral theory of molecular evolution motivates further effort to understand the processes shaping genetic diversity and ultimately the diversification of the exceptional diversity of tropical reef fishes.

Examining mental simulations of uncertain events.

A great deal of research into the experiential nature of language has demonstrated that our understanding of events is facilitated through mental simulations of the described linguistic input. However, to date little is understood about how contextual uncertainty about the described event might influence the content and strength of these mental representations or the cognitive effort involved. In this article, we report a single experiment in which participants read sentences such as "The old lady [knows/thinks] that the picnic basket is open." Following a delay of 250 or 1,500 ms, they responded to pictures that varied in the physical form of the target object (matching vs. mismatching). Results revealed an expected facilitation effect for matching images, but more important, they also showed interference effects (longer reaction times) at the shorter interstimulus interval (ISI; 250 ms) following the uncertain verb thinks, as compared with the certain verb knows. At the longer ISI, this effect was no longer present. This suggests that at the short ISI, uncertain conditions required extra time to construct and map a simulation of events onto the available image. Results are discussed in terms of the mechanisms involved in representing possible events and with reference to related literature on perspective taking.