The purpose of this work is to describe how the visual system groups surfaces of unequal lightness under complex patterns of illumination. We propose that the Gestalt principle of Grouping by Regularity explains this process better than the more often cited principle of Grouping by Similarity. In our first experiment we demonstrate that in a perceptual organization task, pitting proximity again...

What motivates individuals to regulate their emotions? One answer, which has been highlighted in emotion-regulation research, is that individuals are motivated by short-term hedonic goals (e.g., the motivation to feel pleasure). Another answer, however, is that individuals are motivated by instrumental goals (e.g., the motivation to perform certain behaviors). We suggest that both answers have ...

In a series of four experiments we investigated whether dogs use information about a human's visual perspective when responding to pointing gestures. While there is evidence that dogs may know what humans can and cannot see, and that they flexibly use human communicative gestures, it is unknown if they can integrate these two skills. In Experiment 1 we first determined that dogs were capable of...

Humans and other social animals interact regularly with conspecifics as part of affiliative groups. Many of these interactions are cooperative, but many others involve competition for resources. Competitive exchanges are often resolved on the basis of dominance relationships, with higher-ranking individuals receiving priority access to desired goods. Although no single cue can establish permane...

Clinical manifestations of hereditary spherocytosis (HS), the most common red blood cell (RBC) membrane disorder, can be abrogated or markedly reduced by splenectomy. However, concerns regarding risks from overwhelming infections after splenectomy have restricted its use, especially in children. This study was designed to determine if partial splenectomy can decrease the hemolytic rate while ma...

The driving force behind the transition from a foraging to a farming lifestyle in prehistoric Europe (Neolithization) has been debated for more than a century [1-3]. Of particular interest is whether population replacement or cultural exchange was responsible [3-5]. Scandinavia holds a unique place in this debate, for it maintained one of the last major hunter-gatherer complexes in Neolithic Eu...

The postcanine dentition of Diademodon was well adapted, in both morphology and pattern of replacement, to exercising and maintaining precise occlusion. These teeth may be grouped into three morphological classes, consisting of conical, gomphodont and sectorial teeth. The anterior conicals may have acted as gripping teeth, and the posterior sectorials may have been utilized as food "tenderizers...

Histological specimens of 30 distinct adenomas and 30 distinct carcinomas were studied by image analysis to quantify nuclear size and shape. These data were used to derive a discriminant equation, which permitted the lesions to be classified into two groups based on nuclear atypia. Next, 50 superficial type tumors of the colon (34 IIa lesions, 9 IIc + IIa lesions, and 7 IIc lesions) <10 mm in l...