Token values

laws and have a correct physical description, " writes H. Pattee, at the State University of New York. But despite such statements there is no doubt the field has a lot of ground to cover to avoid inventing new and sometimes unnecessary words or using the same words to mean different things, and redescribing the familiar for no obvious reason. The Introduction to Biosemiotics is not an easy read so there is a long way to go before most mainstream biologists can even begin to assess Barbieri's claim that the " basic unit of life is the sign, not the molecule ". The Holyhead telegraph is altogether a more comprehensible system. While some biologists are exploring whether semiotics can be a useful tool for looking at interactions amongst biological entities as far down as the cellular and molecular level, there has been a long-standing curiosity about the extent to which our closest relatives, the apes and monkeys, are able to grasp the concept of the symbol — an object that represents something else with no physical connection. Language is perhaps the human triumph, not only can we recognise the symbolic meaning of words, spoken or written, but we also have a grammar to manipulate those symbols into statements of almost unlimited complexity. The human ability to learn the meaning of symbols outside language is hugely impressive too. But the history of experiments to assess our relatives' abilities have often been controversial: it's hard to devise a watertight experimental system, especially if only one or a few animals are involved (as has often has been the case). And there is no doubt individuals can vary substantially, as in humans, in their cognitive skills. But the cumulative evidence suggests that the recognition of symbols is not a human exclusive and a recent paper adds to the belief that at least some monkeys within a group tested can use symbols to their advantage. Elsa Addessi and colleagues at the Institute of Cognitive Researchers are engaged on the tough task of determining how apes and monkeys can use symbols. Nigel Williams reports. Sciences in Rome have been looking at whether capuchin monkeys are able to use plastic tokens as symbols of differing food rewards. The experiment involved choices between combinations of tokens A and B, worth one and three rewards respectively. The researchers, reporting in the Proceedings B of the Royal Society series B …