Can animals comprehend the power of symbols?
Humans interpret symbols every day, from traffic lights to warning labels on tins. We also use symbols on a more complex level such as currency. When we use money, be it a paper note or a coin, we inherently understand the corresponding intrinsic value that that note or coin has. Our whole economic system runs on the basis that we all understand the value currency has. The question is, do animals also have this understanding? The project SEDSU, funded by the EU with around €37,500 in financing, is saying yes, animals may very well understand the power of symbols and of currency. Conducted by the CNR, Institute of Cognitive Sciences and Technologies, Unit of Cognitive Primatology and Primate Center, Rome, Italy, the SEDSU ('Stages in the evolution and development of sign use') study was funded by the NEST ('New and emerging science and technology') programme of the EU's Sixth Framework Programme (FP6) and examined the fundamental question of 'Can non-human animals comprehend and employ symbols?' Traditionally speaking, it has been humans who have been defined as the 'symbolic species'. Perhaps the most complex implementation of symbols humans have devised is in the languages and scripts they have created. According to this study: 'This mental representation of symbols - objects that arbitrarily represent other objects - ultimately affords the development of language, and almost certainly played a decisive role in the evolution of our hominid ancestors.' Over the years it appears as though humans have been unique in the evolution of the use of symbols. While some evidence does exist however that apes can use symbols in various contexts and indeed, have even been trained to use language, data is lacking when it comes to species of monkeys which are further removed from the human family tree. This is why the study focused on the tufted capuchin monkeys, a South American species that diverged from humans about 35 million years ago. In this experiment five capuchins were engaged in 'economic choice' behaviour. Each monkey was given the chance to choose between three different foods offered in variable amounts. The monkeys chose between 'tokens' that represent actual foods. After choosing one of the two token options, monkeys could exchange their token with the corresponding food. What they saw was that the capuchin monkeys assigned a value for each token and food item. Capuchins were indifferent between one Cheerio and two pieces of parmesan cheese, indicating that the value of one Cheerio is equal to two times the value of one piece of parmesan cheese. When choosing between tokens that represented the same foods, the relative value increased - for example, capuchins were indifferent between one Cheerio-token and four parmesan-tokens. These results indicate that capuchin monkeys can indeed apply reason to symbols. However, as they do so, capuchins also experience the cognitive burden of figuring out what each symbol represents. In this respect they appear to behave similarly to young children. The study concludes that while capuchin monkeys may not achieve the same standard of adult humans with regard to symbolic competence, the study is able to demonstrate that animal species relatively distant from humans have undertaken the path of symbolic use and understanding.