A molecular phylogeny of the vataireoid legumes underscores floral evolvability that is general to many early-branching papilionoid lineages.

Premise Of Study: Flowering traits can sometimes be overemphasized in taxonomic classifications. The fused and completely differentiated papilionate floral organs in the neotropical legume trees Vatairea and Vataireopsis were traditionally used in part to ascribe these genera to the tribe Dalbergieae. In contrast, the free and mostly undifferentiated floral parts of Luetzelburgia and Sweetia fit the circumscription of the "primitive" Sophoreae.

The Müller-Lyer illusion as a tool for schizophrenia screening.

The perceptual deficit hypothesis for schizophrenia is based on more general models of normal human visual perception, which have traditionally postulated that objects must compete for attention and processing space in the visual system. Recent evidence suggests that susceptibility of schizophrenics to the Müller-Lyer (ML) illusion may be a marker of vulnerability, detectable in prodromic patients, but disappearing with the progression of the illness. This illusion consists of overestimating the length of a straight line with converging arrowheads at the ends, while underestimating those with diverging arrowheads.

Perception of the Müller-Lyer illusion in capuchin monkeys (Cebus apella).

Visual illusions are formed by differences between the perception of one figure and its real physical characteristics. The Müller-Lyer illusion is the best known and most studied geometric illusion, consisting in the subject's judgment between two parallel lines that have the same size, one flanked with outward-pointing arrowheads, and the other with inward-pointing arrowheads. These arrowheads act as inductors that make the lines to be perceived as having different sizes, inward-pointing stimuli being estimated as longer.

Influence of stimuli size on color discrimination in capuchin monkeys.

Large-field trichromacy is a general feature of protanope and deuteranope humans, provided that the stimuli size extends to an 8 degrees visual angle. In this study we compared the performance of five male and three female tufted capuchin monkeys (Cebus apella) in discriminating pairs of Munsell color papers. Human subjects were also studied in two-choice discrimination tests, using the same stimuli and apparatus employed for the monkeys.