Animals can also understand and use symbols

From paintings and photos to coins or credit cards, symbolic artifacts surround us. The mental symbolism of the symbol - the object that represents another object - provides the fundamental development of language that plays a decisive role in the evolution of our ancestors.Can other animals understand and use symbols?

Some evidence suggests that our closest monkey, relative, can use the symbol in many cases. However, the ability to use symbols of more distant species in phylogenetic systems is still unknown.

A new study provides evidence of the possibility of using capuchin monkeys - a South American monkey species separated from humans 35 million years ago. In the experiment, five capuchin monkeys participated in 'economic choices'. Each monkey chooses between 3 types of food (called A, B and C) with different weight. Selection is made in 2 different contexts. In the 'real' context , monkeys choose between real food. In the 'symbolic' context , they have to choose 'tokens' (which are actually worthless items like poker cards) that represent true food. After selecting one of the two card exchange options, they can exchange their exchange cards for the corresponding food. Researchers examine whether the capuchin selection for both the real and symbolic context responds to bridging or not - the basic character of rational decision making, for example, if the child monkeys like A more than B, prefer B than C, then it must prefer A over C.

Cap monkey (Cebus paella).(Photo: Elisabetta Visalberghi)

Capuchin monkey selection meets the requirement both in the real context and in the symbolic context. According to the capuchin system, it prefers A to B, B to be more than C, and A to C and both tokens and real foods. Therefore, their choice is the same in terms of quality in both cases. However, in terms of the number of choices in the iconic context has increased the value gap between the corresponding foods.

For example, when choosing between real food, capuchin monkeys are not biased between Cheerio and two pieces of Parmesan cheese, indicating the value of a Cheerio is twice that of a piece of Parmesan cheese. When choosing between tokens, relative value increases - for example, capuchins do not favor a Cheerio card and 4 Parmesan cards.

This result shows that capuchin monkeys have a symbolic reasoning. However, when doing so, they experience the perceived burden of symbols. In this respect, they behave like a child. In summary, although capuchins cannot achieve symbolic recognition as an adult, research has proven that species that are quite far away are also capable of using and understanding symbols.

Refer:

Addessi et al. Mô tả Transitivity and Symbolic Representation in Capuchin Monkeys (Cebus apella). PLoS One, 2008; 3 (6): e2414 DOI: 10.1371 / journal.pone.0002414