June 30,2006 — People generally define intelligence in terms that place our own species at the apex, but recent studies on other animals suggest skills such as abstract thinking, problem solving, reasoning, and language — once thought unique to us — may not be so uncommon after all.
"The closer we examine animals, the more they surprise us with their intelligence and awareness," said Jonathan Balcombe, a research scientist at Physicians Committee for Responsible Medicine in Washington, DC.
"Chickens practice deception, pigeons can categorize images in photographs as quickly as we can, a gorilla plays a joke on a human teacher, and a tiny fish leaps from one tide pool to another using a mental map formed during high tide."
Balcombe did admit that in the evolutionary lottery, humans got lucky. Factors such as climate, the need for socialization, and challenges associated with foraging for intermittently available food may have contributed to our unique skill set.
Taken individually or in other combinations, though, these skills are being increasingly noticed in other creatures.
Beyond Instinct
A prevailing view, which at least dates back to French philosopher Rene Descartes and was reiterated by noted behaviorist B.F. Skinner, holds that all examples of non-human intelligence are simply conditioned behaviors.
Recent studies are putting that view to rest.
For example, Ohio State University entomologists implanted electrodes into the brains of sphinx moths.
The researchers monitored the moths' nervous systems while presenting them with different odors — including sugar water, a favorite moth treat.
"We saw a dramatic restructuring of the neural networks that convert scent into a code that the rest of the brain can understand," said lead author Kevin Daly, who concluded that, like humans, moths learn as well as act on instinct.
Key to human intelligence is our ability to think in abstract terms, and the ability to apply previously acquired concepts in problem solving.
While it is well known that some animals use tools and learn from past mistakes, the question of how much they understand about such tools and their environment has long been contentious.
A recent study on rooks suggests the crow-like birds can apply learned rules when solving problems.
Biologists at the University of Cambridge set up a "trap-tube task" consisting of a horizontal tube with a trap along its length.
To solve the puzzle, the birds had to use a tool to push a piece of food out of the tube and away from the trap. Two rules allowed the birds to obtain the food: learning how the position of the food related to the trap, and understanding how the overall task worked.
The birds aced the tests, even when trap appearance and the level of difficulty changed. The study suggests this species, and possibly all birds, possess rule abstraction. Other research has determined that baboons and chimpanzees think abstractly.
