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Orangutans make complex economic decisions

"Our study shows that orangutans can simultaneously consider multi-dimensional task components in order to maximize their gains," researcher Josep Call said.

By
Brooks Hays
Orangutans make economic decisions related to tool usage. Photo by Alice Auersperg
Orangutans make economic decisions related to tool usage. Photo by Alice Auersperg

Feb. 14 (UPI) -- According to a new study, orangutans make complex economic decisions related to tool usage.

Biologists have long considered tool usage a sign of advanced cognition, but increasingly, scientists are realizing tools can be used in primitive, less-sophisticated ways, as well as more flexible, innovative and intelligent ways.

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The new research -- published in the journal PLOS ONE -- showed orangutans use tools more intelligently than most animals.

To test the ape's tool-using smarts, scientists presented the orangutans with a choice involving two different treats: a lesser but immediately available treat, apple pieces, or a better treat, banana-pellets, requiring a bit of effort. To earn their favorite banana snack, the apes had to solve multidimensional tasks using tools made available to them by the researchers.

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Scientists varied the difficulty of the task and the usefulness of the tools for the specific task. One test required the apes to retrieve the treat using a stick, while another required the apes to drop a ball into an apparatus to release the treat.

When deciding between the treats, the orangutans had to quickly size up the problem and his or her ability to solve it given the available technology.

When offered their favorite banana treat or the chance to solve the problem, the apes choose the immediate reward every time.

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"However, when the orangutans could choose between the apple-piece and a tool they chose the tool but only if it worked for the available apparatus," Isabelle Laumer, researcher at the University of Vienna in Austria, said in a news release. "For example, when the stick and the likable food was available but the apes faced the ball-apparatus baited with the favorite banana-pellet, they chose the apple-piece over the non-functional tool."

"However when the stick-apparatus with the banana-pellet inside was available they chose the stick-tool over the immediate apple-piece," Laumer said. "In a final task, that required the orangutans to simultaneously focus on the two apparatuses, one baited with the banana-pellet and the other with the apple and the orangutans had to choose between the two tools they were still able to make profitable decisions by choosing the tool that enabled them to operate the apparatus with the favorite food."

The findings suggest orangutans are capable to suppressing short-term impulses for long-term gains. Researchers think the tests reflect the strategies the apes use to strategically target different types of foods in the forest.

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"Optimality models suggest that orangutans should flexibly adapt their foraging decisions depending on the availability of high nutritional food sources, such as fruits," said Josep Call, researcher at the University of St. Andrews. "Our study shows that orangutans can simultaneously consider multi-dimensional task components in order to maximize their gains and it is very likely that we haven't even reached the full extent of their information processing capabilities."

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