Attitudinal ambivalence has been found to increase processing of attitude-relevant information. In this research, the authors suggest that ambivalence can also create the opposite effect: avoidance of thinking about persuasive messages. If processing is intended to reduce experienced ambivalence, then ambivalent people should increase processing of information perceived as proattitudinal (agreeable) and able to decrease ambivalence. However, ambivalence should also lead people to avoid processing of counterattitudinal (disagreeable) information that threatens to increase ambivalence. Three studies provide evidence consistent with this proposal. When participants were relatively ambivalent, they processed messages to a greater extent when the messages were proattitudinal rather than counterattitudinal. However, when participants were relatively unambivalent, they processed messages more when the messages were counterattitudinal rather than proattitudinal. In addition, ambivalent participants perceived proattitudinal messages as more likely than counterattitudinal messages to reduce ambivalence, and these perceptions accounted for message position effects on amount of processing.

Declines in animal body sizes are widely reported and likely impact ecological interactions and ecosystem services. For harvested species subject to multiple stressors, limited understanding of the causes and consequences of size declines impedes prediction, prevention, and mitigation. We highlight widespread declines in Pacific salmon size based on 60 years of measurements from 12.5 million fish across Alaska, the last largely pristine North American salmon-producing region. Declines in salmon size, primarily resulting from shifting age structure, are associated with climate and competition at sea. Compared to salmon maturing before 1990, the reduced size of adult salmon after 2010 has potentially resulted in substantial losses to ecosystems and people; for Chinook salmon we estimated average per-fish reductions in egg production (−16%), nutrient transport (−28%), fisheries value (−21%), and meals for rural people (−26%). Downsizing of organisms is a global concern, and current trends may pose substantial risks for nature and people.

Rising anthropogenic CO 2 in the atmosphere is accompanied by an increase in oceanic CO 2 and a concomitant decline in seawater pH (ref. 1). This phenomenon, known as ocean acidification (OA), has been experimentally shown to impact the biology and ecology of numerous animals and plants 2 , most notably those that precipitate calcium carbonate skeletons, such as reef-building corals 3 . Volcanically acidified water at Maug, Commonwealth of the Northern Mariana Islands (CNMI) is equivalent to near-future predictions for what coral reef ecosystems will experience worldwide due to OA. We provide the first chemical and ecological assessment of this unique site and show that acidification-related stress significantly influences the abundance and diversity of coral reef taxa, leading to the often-predicted shift from a coral to an algae-dominated state 4,5 . This study provides field evidence that acidification can lead to macroalgae dominance on reefs.Coral reefs contain the highest concentration of biodiversity in the marine realm, with abundant flora and fauna that form the backbone of complex and dynamic ecosystems 6 . From an anthropocentric standpoint, coral reefs provide valuable goods and services, supporting fisheries and tourism, and protect shorelines from storms 7 . Recently, widespread coral mortality has led to the flattening of reef frameworks and the loss of essential habitat 4 . This trend will be accelerated by ocean acidification (OA), as calcification is impaired, and dissolution is accelerated 8,9 . Furthermore, experimental evidence suggests that OA could enhance the growth 10 and competitive ability of fleshy macroalgae 11 . This OA-induced shift in the competitive balance between corals and algae could exacerbate direct effects of OA on calcifying reef species 12 and lead to ecosystem shifts favouring non-reef-forming algae over coral 4,5 . Understanding the individual responses of taxa to OA, as well as alteration of multi-species assemblages, is therefore critical to predicting ecosystem persistence and managing reef health in an era of global change.At present, much of what is known concerning the impacts of OA on coral reef biota has been laboratory-based experimental work focused on the responses of select taxa 2 . This has been expanded to mesocosm-based studies, allowing manipulation of groups of organisms and investigation of community responses 13 .Although these multi-species experimental studies are vital, they cannot recreate the variability (physical, chemical, biological) of real-world reef systems 14 . In an effort to overcome the limitations of laboratory studies, real-world low-saturation-state (Ω) sites have been investigated. In the eastern Pacific, nutrient and CO 2 -enriched upwelled waters impact coral calcification and the precipitation of carbonate cements, influencing the distribution of reefs 15 . In Mexico, freshwater springs depress Ω, influencing coral calcification and species distributions 16 . In Palau, restricted circulation and biological activity contribute to ...

Much research emphasizes heuristic use of stereotypes, though stereotypes have long been considered as capable of influencing more thoughtful processing of social information. Direct comparisons between thoughtful and non-thoughtful stereotyping are lacking in the literature. Recent research in attitude change emphasizes the different consequences of judgments arising from relatively thoughtful versus non-thoughtful processes. Therefore, increased thought could not only fail to decrease stereotyping but might also create stereotypic perceptions that are more likely to have lasting impact. The current studies demonstrate thoughtful and non-thoughtful stereotyping within the same setting. More thoughtful stereotyping is more resistant to future attempts at change and to warnings of possible bias. Implications are discussed for the typical research questions asked after observing stereotypic judgements.