June 20, 2008 -- What goes on in an ape's mind might be more similar to our own way of thinking than previously realized, suggests a new study that found chimpanzees and orangutans plan for their futures.
Since this skill also entails forethought involving self-control and mental time travel, the findings point to a complex "inner mental world" possessed by apes, including gorillas, which were studied in trials before the official research began.
"When humans shut their eyes, a new vivid world takes hold," co-author Mathias Osvath told Discovery News.
"This mental world with its first-person perspective has been suggested to be unique to humans," added Osvath of Lunds University Cognitive Science in Sweden. "It is arguably impossible to plan like the apes do without having an inner world of some sort. (Our results) strongly imply a consciousness that many think is restricted to the human domain."
For the study, published in Animal Cognition, he and colleague Helena Osvath first showed two female chimps, Linda and Maria Magdalena, along with a male orangutan named Naong, how to sip a yummy fruit soup using a straw-like hose.
The researchers next presented their furry test subjects with a favorite fruit -- a grape -- and the hose, which the animals could save and use to sip soup later. The apes exercised self-control by foregoing the immediate grape reward. They instead chose the hose and patiently waited for the bigger food payoff.
To control for associative learning, a process whereby someone just blindly links one thing to another, the researchers again offered fruit to the apes, as well as one functional tool and three non-functional ones.
The scientists also conducted a similar test, where they again presented the sippy hose, but tried to distract the animals with a blue plastic car, a small teddy bear, a colorful screwdriver handle, a brown bootlace, a yellow plastic toy spade, a picture of a banana, and other items potentially coveted by apes.
The chimps and the orangutan aced the tests, choosing the hose 11 out of 12 trials. In fact, one of the few glitches during the entire study occurred when Linda's playing infant grabbed the hose and hid it.
"In our study, we show that the value of the hose is not intrinsic, meaning it is not worth anything in itself, as it would have if it were associatively learned," said Osvath.
The research determined that, at least for this particular food exercise, apes show an ability to plan that is comparable to that of a four- to five-year-old child. Osvath, however, said such comparisons with humans are inherently flawed.
"A four- or five-year-old human would die quickly in the forest, but a chimp or an orangutan can live for 60 years and base its survival on cognition," he explained, adding that the ape skill for planning might be much more advanced than currently realized, but future studies must address the possibilities.
Apes obviously aren't sucking juice out of a straw in the wild, but the planning skills come in handy during hunting and chimp warfare, when a party sets out to organize themselves into patrols before meeting the enemy. Chimps are also known to save stones good for future nut cracking.
Additionally, there is the "I scratch your back now because I want this or that far into the future," Osvath says.
Although this latest study takes animal planning to human levels, prior work has demonstrated that birds, such as the Western scrub jay and chickens, also plan ahead. Since planning involves mental time travel, it could also mean that chickens raised for meat dread their final moments, if they learn to associate certain objects or happenings with death.
"An animal that can anticipate an event might benefit from cues to aid prediction, but may also be capable of expectations rendering it vulnerable to thwarting, frustration and pre-emptive anxiety," Siobhan Abeyesinghe, a member of the Biophysics Group at the Silsoe Research Institute, told Discovery News.
In future, such research could therefore lead to more humane treatment of captive birds and animals.
Related Links:
Jennifer Viegas' blog: Born Animal
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