Auditory perception is our main gateway to communication with others via speech and music, and it also plays an important role in alerting and orienting us to new events. This review provides an overview of selected topics pertaining to the perception and neural coding of sound, starting with the first stage of filtering in the cochlea and its profound impact on perception. The next topic, pitch, has been debated for millennia, but recent technical and theoretical developments continue to provide us with new insights. Cochlear filtering and pitch both play key roles in our ability to parse the auditory scene, enabling us to attend to one auditory object or stream while ignoring others. An improved understanding of the basic mechanisms of auditory perception will aid us in the quest to tackle the increasingly important problem of hearing loss in our aging population.

We review the phenomenon of hedonic decline, whereby repeated exposure to a stimulus typically reduces the hedonic response (e.g., enjoyment). We first discuss the typical trajectory of hedonic decline and the common research paradigms used to study it. We next discuss the most popular theories regarding general mechanisms widely believed to underlie hedonic decline. We then propose a taxonomy to organize these various general theories and to incorporate more recent work on top-down, self-reflective theories. This taxonomy identifies three general classes of antecedents to hedonic decline: physiological feedback, perceptual changes, and self-reflection. For each class, we review the supporting evidence for specifically identified antecedents and recent developments on how each antecedent influences hedonic decline. Our review focuses especially on more recent work in the growing area of self-reflection.

Humans acquire much of their knowledge from the testimony of other people. An understanding of the way that information can be conveyed via gesture and vocalization is present in infancy. Thus, infants seek information from well-informed interlocutors, supply information to the ignorant, and make sense of communicative acts that they observe from a third-party perspective. This basic understanding is refined in the course of development. As they age, children's reasoning about testimony increasingly reflects an ability not just to detect imperfect or inaccurate claims but also to assess what inferences may or may not be drawn about informants given their particular situation. Children also attend to the broader characteristics of particular informants—their group membership, personality characteristics, and agreement or disagreement with other potential informants. When presented with unexpected or counterintuitive testimony, children are prone to set aside their own prior convictions, but they may sometimes defer to informants for inherently social reasons.

Abstract Involvement of GTP-binding proteins in angiotensin II-induced mobilization of calcium has been examined in adrenal glomerulosa cells by using pertussis toxin. Pretreatment of glomerulosa cells with pertussis toxin abolishes angiotensin II-induced calcium influx without blocking inositol trisphosphate production. These results suggest a role of the pertussis toxin-sensitive GTP-binding protein in transducing angiotensin II-receptor occupancy into opening of calcium channel.