London, June 11 : Italian researchers have demonstrated that monkeys too possess the ability to learn how to exchange money for their favourite food items, and whether to trade for one piece of tasty food or many pieces of a less appetizing snack.

Elsa Addessi at the CNR, the Italian National Research Council in Rome, says that the findings of her experiments on capuchin monkeys suggest that they can understand the symbolic value of an object just like humans.

The researcher points out that the capuchins could grasp the ‘money’ concept despite the fact that they had diverged from humans about 35 million years ago.

“It’s quite surprising to find such an ability in a monkey species that is so [evolutionarily] distant from humans,” Nature magazine quoted Addessi as saying.

During the study, the capuchins were trained to associate valueless tokens of different shapes and sizes with specific foods.

Addessi has revealed that a poker chip could have been used to represent dried apricot, and brass hooks could have represented parmesan cheese.

The researchers then gave the monkeys a choice of two trays, each containing a piece or pieces of one of three different foods labelled A, B, and C.

The selection of the foods was made keeping in mind the established tastes of the individual monkeys, so that A was nicer than B, which was nicer than C.

It was observed that the monkeys chose one piece of A over two pieces of B, and would choose one piece of B over two pieces of C.

According to the researchers, the effect continued so that the monkeys might choose one piece of A, which was their favourite food, over four pieces of less tempting C.

The researchers later incorporated trays carrying tokens representing the different foods in a similar experiment, and found the monkeys responging in the same way—choosing one A token over two B tokens.

While presenting the results in the journal PLoS ONE 1, Addessi said that the finding shows that the same reasoning is used for both tasks.

The research team, however, found the monkeys behaving differently with real food and tokens, which became apparent when the animals had to decide whether a large amount of a less-tasty food would be better than a single piece of their favourite food.

They observed that in both tests, there came a point when the monkeys would prefer lots of B pieces or tokens to a single A piece or token.

In the case of the real food, the threshold was around three pieces of B.

However, when it came to the token test, much more of the less-favoured food was required to make the monkeys leave their favourite food.

Addessi admits that the research team is not clear why this should be the case.

“They are able to reason with tokens as with real food, but they find it more difficult to reason with tokens,” she says, adding that this behaviour is similar to that of a small child. (ANI)