Primates are apparently unique amongst the mammals in possessing trichromatic colour vision. However, not all primates are trichromatic. Amongst the haplorhine (higher) primates, the catarrhines possess uniformly trichromatic colour vision, whereas ...

Many otherwise puzzling aspects of the way we see brightness, colour, orientation and motion can be understood in wholly empirical terms. The evidence reviewed here leads to the conclusion that visual percepts are based on patterns of reflex neural ...

This paper is concerned with a striking visual experience: that of seeing geometric visual hallucinations. Hallucinatory images were classified by Klüver into four groups called form constants comprising (i) gratings, lattices, fretworks, filigrees, ...

Metabolic organization of individual organisms follows simple quantitative rules that can be understood from basic physical chemical principles. Dynamic energy budget (DEB) theory identifies these rules, which quantify how individuals acquire and use ...

Patterns of origination, extinction and standing diversity through time have been inferred from tallies of taxa preserved in the fossil record. This approach assumes that sampling of the fossil record is effectively uniform over time. Although recent ...

Specific language impairment (SLI) is the term used to refer to unexplained difficulties in language acquisition in children. Over the past decade, there has been rapid growth of evidence indicating that genes play an important part in the aetiology ...

The plant Cannabis sativa has been used by humans for thousands of years because of its psychoactivity. The major psychoactive ingredient of cannabis is δ⁹–tetrahydrocannabinol, which exerts effects in the brain by binding to a G–protein–coupled ...